Document:

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                                                                   EXHIBIT 10.49

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                    REAL PROPERTY PURCHASE AND SALE AGREEMENT

                                   dated as of

                                  July 26, 2002

                                 by and between

                     WILLIAMS HEADQUARTERS BUILDING COMPANY,
                                   as Seller,

                        WILLIAMS TECHNOLOGY CENTER, LLC,
                                  as Purchaser,

                          WILLIAMS COMMUNICATIONS, LLC

                                       and

                      WILLIAMS COMMUNICATIONS GROUP, INC.,
                                 as Guarantors,

                                       and

                         WILLIAMS AIRCRAFT LEASING, LLC
                   (for the limited purposes set forth herein)

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                    REAL PROPERTY PURCHASE AND SALE AGREEMENT

                  This REAL PROPERTY PURCHASE AND SALE AGREEMENT, dated as of
July 26, 2002, by and between WILLIAMS HEADQUARTERS BUILDING COMPANY, a Delaware
corporation ("Seller"), WILLIAMS TECHNOLOGY CENTER, LLC, a Delaware limited
liability company ("Purchaser"), WILLIAMS COMMUNICATIONS, LLC, a Delaware
limited liability company ("WCL"), WILLIAMS COMMUNICATIONS GROUP, INC., a
Delaware corporation ("Communications," Communications and WCL being jointly and
severally liable with Purchaser for all obligations of Purchaser set forth
herein, collectively, "Guarantors") and WILLIAMS AIRCRAFT LEASING, LLC (formerly
known as Williams Communications Aircraft, LLC), a Delaware limited liability
company (for the limited purposes set forth herein).

                                   WITNESSETH:

                  WHEREAS, Seller owns the Acquired Assets (as defined below)
relating to the office building and related facilities in Tulsa, Oklahoma,
commonly known as the Williams Technology Center;

                  WHEREAS, Communications and its subsidiary, CG Austria, Inc.,
a Delaware corporation, which is not a party to this Agreement (collectively,
the "Debtors") are debtors, having filed voluntary petitions on April 22, 2002,
for relief pursuant to chapter 11 of title 11 of the United States Code, 11
U.S.C. Sections 101-1330 (as amended, the "Bankruptcy Code"), whose cases are
pending in the United States Bankruptcy Court for the Southern District of New
York (the "Bankruptcy Court") and procedurally consolidated under Case No.
02-11957 (the "Bankruptcy Case");

                  WHEREAS, Seller desires to sell to Purchaser, and Purchaser
desires to purchase from Seller, the Acquired Assets, in the manner and subject
to the terms and conditions set forth herein;

                  WHEREAS, each of Purchaser and WCL is a wholly owned
subsidiary of Communications; and

                  WHEREAS, Guarantors will obtain benefits from the Purchaser's
acquisition of the Acquired Assets and, in order to induce Seller to enter into
this Agreement, Guarantors have agreed to jointly and severally guaranty
Purchaser's obligations hereunder.

                  NOW, THEREFORE, in consideration of the foregoing premises and
the representations, warranties, covenants and agreements contained herein, and
for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, and intending to be legally bound hereby, the parties
hereto hereby agree as follows:

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                                   ARTICLE I

                         DEFINITIONS AND INTERPRETATION

         Section 1.01. Definitions. For all purposes of this Agreement, except
as otherwise expressly provided or unless the context clearly requires
otherwise, the following capitalized terms shall have the following meanings:

                  "Acquired Assets" shall mean, subject to Section 7.24,
collectively, the fee simple title to the Real Property and the Improvements;
all contract rights, subsurface rights, air rights, easements, privileges,
servitudes, appurtenances and other rights belonging to or inuring to the
benefit of Seller and appurtenant to the Real Property and Improvements
(including, without limitations, the Skywalk); all documents, specifications and
plans related to the Real Property and Improvements; all Licenses and Permits;
and all other rights, easements, titles, interests, privileges and appurtenances
of Seller related to and used in connection with the construction, ownership,
use, operation or management of the Real Property and Improvements, as expressly
set forth in this Agreement; and all Personal Property.

                  "Affiliate" shall mean, with respect to any Person, any other
Person which, directly or indirectly, through one or more intermediaries,
controls, or is controlled by, or is under common control with, such Person;
provided that, for the purposes of this definition, "control" (including with
correlative meanings, the terms "controlled by" and "under common control
with"), as used with respect to any Person, shall mean the possession, directly
or indirectly, of the power to direct or cause the direction of the management
and policies of such Person, whether through the ownership of voting securities
or partnership interests, by contract or otherwise.

                  "Agreed Allocation" has the meaning set forth in Section 2.06.

                  "Agreement" shall mean this Real Property Purchase and Sale
Agreement, together with the Schedules and Exhibits hereto, as amended,
supplemented or otherwise modified from time to time.

                  "Aircraft" shall mean the aircraft leased pursuant to the
Aircraft Dry Leases.

                  "Aircraft Dry Leases" shall mean (a) the Aircraft Dry Lease
(N358WC) dated as of September 13, 2001 by and between Williams Aircraft
Leasing, LLC (formerly known as Williams Communications Aircraft, LLC), as
"Lessor", and WCL, as "Lessee", and/or (b) the Aircraft Dry Lease (N359WC) dated
as of September 13, 2001 by and between Williams Aircraft Leasing, LLC (formerly
known as Williams Communications Aircraft, LLC), as "Lessor", and WCL, as
"Lessee".

                  "Allocated Lease Principal" shall have the meaning set forth
in Section 7.21.

                  "Applicable Law" shall mean any applicable law, regulation,
rule, order, judgment or decree.

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                  "April Agreement" shall mean the agreement dated as of April
19, 2002 by and among Debtors, WCL, certain subsidiaries of Communications,
certain bondholders, and certain Lenders under the WCG Bank Facility.

                  "Bank Agent" shall mean Bank of America, N.A., as agent under
the WCG Bank Facility.

                  "Bankruptcy Case" has the meaning set forth in the recitals
hereof.

                  "Bankruptcy Code" has the meaning set forth in the recitals
hereof.

                  "Bankruptcy Rules" shall mean the Federal Rules of Bankruptcy
Procedure, as the same are applicable to the Bankruptcy Case.

                  "Bill of Sale" shall mean the Special Warranty Bill of Sale
and Assignment covering all of the Personal Property, to be executed by Seller
in favor of Purchaser in substantially the form attached hereto as EXHIBIT A.

                  "Business Day" shall mean any day other than a Saturday,
Sunday or a day on which banks in New York City are authorized or obligated by
law or executive order to close or are otherwise generally closed.

                  "Cash Portion of the Purchase Price" has the meaning set forth
in Section 2.02(a).

                  "Center" shall mean the multi-story office building located on
the Center Parcel commonly known as One Technology Center or the Williams
Technology Center.

                  "Center Parcel" shall mean that portion of the Real Property
more particularly described in SCHEDULE 1, which shall include the air rights
associated with the Skywalk; provided, however, the description on said Schedule
shall be deemed to be amended for purposes of this Agreement to reflect the
description for such property on the Initialed Title Commitment and the Survey.

                  "Central Plant" shall mean the equipment, fixtures, piping,
wiring, machinery, and all other items of personal property comprising the plant
for chilled and hot water production and circulation, and electricity generation
and transmission located in the basement of the Center in the Central Plant
Space and on the Cooling Tower Parcel.

                  "Central Plant Lease" shall mean that certain Lease Agreement
originally entered into between Purchaser, as "Landlord," and Seller, as
"Tenant," effective as of April 23, 2001, as amended from time to time,
pertaining to the Central Plant; it being understood between Purchaser and
Seller that Purchaser shall be the landlord and that Seller shall be the tenant
upon completion of Closing.

                  "Central Plant Space" shall mean that portion of the basement
of the Center located in the Improvements which is described in the Central
Plant Lease.

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                  "Claims Purchase" shall mean the sale pursuant to the Claims
Purchase Agreement by TWC (a) on its own behalf, of certain claims against
Communications and (b) as agent for United States Trust Company of New York, a
New York banking corporation, in its capacity as indenture trustee and
securities intermediary under the Indenture dated as of March 28, 2001, among
WCG Note Trust, a special purpose statutory business trust created under laws of
Delaware, WCG Note Corp., Inc., a special purpose corporation organized under
the laws of the state of Delaware, as co-issuers of certain Senior Secured Notes
due 2004, and the Indenture Trustee, of that certain Senior Reset Note due 2008
issued by Communications to the WCG Note Trust.

                  "Claims Purchase Agreement" shall mean that certain Purchase
and Sale Agreement dated as of the date hereof between TWC, as "Seller," and
Leucadia National Corporation, as "Purchaser."

                  "Closing" has the meaning set forth in Section 2.03.

                  "Closing Date" has the meaning set forth in Section 2.03.

                  "Closing Documents" shall mean all documents and other
instruments contemplated to be delivered pursuant to this Agreement or the
Transactions at Closing.

                  "Code" shall mean the Internal Revenue Code of 1986, as
amended.

                  "Committee" shall mean the Official Committee of Unsecured
Creditors appointed in the Bankruptcy Case.

                  "Communications" has the meaning set forth in the preamble
hereof.

                  "Contracts" shall have the meaning set forth in Section 7.19.

                  "Construction Agreement" shall mean that certain Agreement of
Purchase and Sale and Construction Completion effective as of February 26, 2001
between Seller, as "Seller," and WCL, as "Purchaser."

                  "Construction Documents" shall have the meaning set forth in
Section 7.24.

                  "Construction Warranties" shall have the meaning set forth in
Section 7.24.

                  "Cooling Tower Parcel" shall mean the real property upon which
the cooling towers relating to the Central Plant are located, as described in
SCHEDULE 3.

                  "Corridor" shall have the meaning set forth in Section 7.19.

                  "Debtors" has the meaning set forth in the recitals hereof.

                  "Deed" shall mean the Special Warranty Deed covering the Real
Property, those portions of the Acquired Assets that constitute real property,
the Improvements and all of

<PAGE>

Seller's right, title and interest in and to the Skywalk, excluding, however,
Seller's interest in and to the Central Plant, in substantially the form
attached hereto as EXHIBIT B.

                  "Disposition" shall have the meaning set forth in Section
7.21.

                  "Easement for Backup Generation" shall mean an easement
agreement in a form reasonably acceptable to both Purchaser and Seller, in which
Seller and its co-tenant shall grant to Purchaser certain easement rights to
install and maintain Purchaser's backup electrical generation equipment.

                  "Existing Construction Claims" shall have the meaning set
forth in Section 7.24.

                  "Fee" shall have the meaning set forth in Section 7.21.

                  "Financing Statements" shall mean proper UCC-1 or the
appropriate equivalent, for filing under the Uniform Commercial Code of each
jurisdiction as may be necessary or, in the opinion of Seller, desirable to
perfect the security interests lien created by the Purchase Money Mortgage.

                  "Governmental Entity" shall mean a court, arbitral tribunal,
administrative agency or commission or other governmental or quasi-governmental
body or agency or other regulatory authority or agency.

                  "Guarantors" shall have the meaning set forth in the preamble
hereof.

                  "Improvements" shall mean, collectively, all buildings,
structures, fixtures, facilities, parking structures and areas, and other
improvements partially or completely constructed and located on or connected
with the Real Property or the Skywalk, except those expressly excepted in the
definition of Acquired Assets.

                  "Initialed Title Commitment" shall mean the Title Commitment,
marked and redated to the Closing Date and initialed by a representative of the
Title Company, insuring Purchaser's fee simple title to the Real Property, the
Improvements and those portions of the Acquired Assets which constitute real
property interests (including all recorded appurtenant easements, insured as
separate legal parcels), with gap coverage from Seller through the date of
recording, subject only to the Permitted Exceptions and containing such
endorsements and affirmative coverages as may be reasonably required by
Purchaser, including without limitation, a Non-Imputation Endorsement.

                  "Insured Property" has the meaning set forth in Section 4.04.

                  "Legal Opinion" shall mean an opinion from Oklahoma counsel
reasonably satisfactory to Seller addressed to Seller and its successors and
assigns dated as of the Closing Date opining as to the enforceability of the
Purchase Money Note, the enforceability of, and the perfection of the security
interests granted pursuant to the Purchase Money Mortgage and Financing
Statements, and such other matters incident to the Transactions contemplated
herein, which shall be in form and substance reasonably satisfactory to Seller.

<PAGE>

                  "Lenders" shall mean the lenders under the WCG Bank Facility.

                  "Licenses and Permits" shall mean collectively all of the
direct or indirect right, title and interest of Seller in and to all licenses,
permits, building permits, certificates of occupancy, approvals, government
orders, resolutions, dedications, subdivision maps and entitlements issued,
approved or granted by any Governmental Entity in connection with the Real
Property and Improvements, together with all renewals and modifications thereof.

                  "Management Agreement" shall mean the Management Services
Agreement, dated April 23, 2001, between Seller, as "Manager," and Purchaser, as
"Owner," under which Seller manages the Acquired Assets (exclusive of the
Parking Garage and Parking Garage Parcel), as amended from time to time.

                  "Master Lease" shall mean the Master Lease dated as of
September 13, 2001, by and between Seller, as "landlord," and Purchaser, as
"tenant," covering the Real Property and Improvements.

                  "Members" shall mean the members of the Committee.

                  "Monthly Debt Service" shall have the meaning set forth in
Section 7.21.

                  "Mortgage Title Policy" shall mean a title commitment, marked
and redated to the Closing Date and initialed by a representative of the Title
Company, to issue a 1992 ALTA title insurance policy dated and effective as of
the Closing Date, issued by the Title Company in an amount not less than the
face amount of the Purchase Money Note insuring the first priority lien of the
Purchase Money Mortgage, subject only to Permitted Exceptions and containing
such endorsements and affirmative coverages as Seller shall reasonably require,
including without limitation, a Non-Imputation Endorsement, if and to the extent
available.

                  "New Communications" has the meaning set forth in Section
4.11.

                  "Non-Foreign Entity Certification" has the meaning set forth
in Section 2.04(d).

                  "Parking Garage" shall mean those Improvements which are
located on the Parking Garage Parcel.

                  "Parking Garage Parcel" shall mean that portion of the Real
Property more particularly described in SCHEDULE 5; provided, however, the
description on said Schedule shall be deemed to be amended for purposes of this
Agreement to reflect the description for such property on the Initialed Title
Commitment and the Survey.

                  "Permitted Exceptions" shall mean those exceptions set forth
on EXHIBIT D.

                  "Person" shall mean a natural person, partnership,
corporation, limited liability company, business trust, joint stock company,
trust, unincorporated association, joint venture, Governmental Entity or other
entity or organization.

<PAGE>

                  "Personal Property" shall mean, collectively, all of the
tangible and intangible (other than goodwill and any other intangible property
that is severable from Seller's "interest in real property" within the meaning
of Section 856(d) of the Code, or any similar or successor provision thereto)
personal property constituting a portion of the Acquired Assets including,
without limitation, the Category 1 FF&E and Category 2 FF&E, each as defined in
the Master Lease, and any personal property hereafter acquired pursuant to the
Construction Agreement.

                  "Plan" shall mean any chapter 11 plan of reorganization with
respect to the Debtors as it may be altered, amended, modified or supplemented
from time to time in accordance with its terms, the Bankruptcy Code and the
Bankruptcy Rules.

                  "Prior Purchase and Sale Agreement" shall mean that certain
Agreement of Purchase and Sale, as amended, among Purchaser, as "Seller,"
Seller, as "Purchaser," and WCL, as "Guarantor," effective as of September 13,
2001.

                  "Purchase Money Mortgage" shall mean the Mortgage With Power
of Sale, Security Agreement, Assignments of Leases, Rents and Profits, Financing
Statement and Fixture Filing to be granted at Closing in favor of Seller by
Purchaser in a form reasonably acceptable to both Seller and Purchaser.

                  "Purchase Money Note" shall mean the note to be issued at
Closing by Purchaser and Communications, as co-issuers, and guaranteed by WCL,
in favor of Seller in a form reasonably acceptable to both Seller and Purchaser,
which note shall be in the principal amount of One Hundred Million Dollars
($100,000,000) and secured by the Purchase Money Mortgage.

                  "Purchase Price" has the meaning set forth in Section 2.02.

                  "Purchaser" has the meaning set forth in the preamble hereof.

                  "Real Property" shall mean the Center Parcel and the Parking
Garage Parcel.

                  "Sales Tax Certificate" has the meaning set forth in Section
2.04(g).

                  "Seller" has the meaning set forth in the preamble hereof.

                  "Settlement Agreement" shall mean the agreement dated as of
July 26, 2002 between TWC, Debtors, the Committee, and Leucadia National
Corporation, providing for, inter alia, this Agreement and the Transactions.

                  "Skywalk" shall mean an elevated pedestrian bridge and support
structure, connecting the Parking Garage to the Center Parcel over a portion of
South Cincinnati Avenue and a portion of East First Street, Tulsa, Oklahoma,
that is approximately twenty-seven feet (27') above the driving lanes of such
streets, together with the air rights for the three (3) dimensional space within
which it is suspended.

                  "Survey" has the meaning set forth in Section 4.06.

<PAGE>

                  "Tax" or "Taxes" shall mean all taxes, duties, levies,
interest, penalties or other assessments imposed by any Taxing Authority,
including gross receipts, excise, personal and real property (including
leaseholds and interests in leaseholds), sales, gain, use, license, custom duty,
Transfer Taxes, unemployment, capital stock, franchise, payroll, withholding,
social security, minimum estimated, profit, gift, severance, value added,
disability, premium, recapture, credit, occupation, service, leasing,
employment, stamp and other taxes, and shall include interest, penalties or
additions attributable thereto or attributable to any failure to comply with any
requirement regarding Tax Returns.

                  "Tax Determination" shall have the meaning set forth in
Section 6.01(c).

                  "Tax Return" shall mean any return (including estimated
returns), report, information return, statement, declaration or other document
(including any related or supporting information), and any amendment thereof,
filed or required to be filed with any Taxing Authority.

                  "Taxing Authority" shall mean any federal, state, local or
foreign governmental authority responsible for the determination, assessment or
collection of any Tax.

                  "Termination Date" shall have the meaning set forth in Section
7.21.

                  "Title Commitment" shall mean a Commitment for Title Insurance
to be issued by the Title Company on behalf of Lawyers Title Insurance
Corporation.

                  "Title Company" shall mean Guaranty Abstract Company of Tulsa,
Oklahoma, or another title company reasonably satisfactory to Purchaser.

                  "Title Policy" shall mean the 1992 ALTA owner's title
insurance policy or policies dated and effective as of the Closing Date, to be
issued by the Title Company based upon the Initialed Title Commitment in an
amount not less than the Purchase Price (and reinsured in a manner acceptable to
Purchaser).

                  "Title/Survey Cap" has the meaning set forth in Section 4.05.

                  "Transactions" shall mean all the transactions provided for or
contemplated by this Agreement.

                  "Transfer Tax" shall mean any federal, state, county, local,
foreign and other sales, use, transfer, conveyance, documentary transfer,
recording or other similar tax, fee or charge imposed upon the sale, transfer or
assignment of property or any interest therein or the recording thereof, and any
penalty, addition to tax or interest with respect thereto.

                  "TWC" shall mean The Williams Companies, Inc., a Delaware
corporation.

                  "Utility Services Agreement" shall mean the Utility Services
Agreement, dated as of April 23, 2001, between Purchaser, as "Customer," and
Seller, as "Owner," as amended from time to time.

<PAGE>

                  "WCG Bank Facility" shall mean the Amended and Restated Credit
Agreement dated as of September 8, 1999, as amended, among WCL, as borrower,
Communications, as guarantor, the Bank Agent, the Lenders, The Chase Manhattan
Bank, as syndication agent, Salomon Smith Barney Inc. and Lehman Brothers, Inc.,
as joint lead arrangers and joint bookrunners with respect to the Incremental
Facility referred to therein, and Salomon Smith Barney Inc., Lehman Brothers,
Inc. and Merrill Lynch & Co., Inc., as co-documentation agents.

                  "WCL" shall have the meaning set forth in the preamble hereof.

                                   ARTICLE II

                             SALE OF ACQUIRED ASSETS

         Section 2.01. Sale of Acquired Assets. On the terms, and subject to the
conditions, set forth in this Agreement, Seller agrees to sell, assign,
transfer, convey and deliver to Purchaser on the Closing Date, and Purchaser
agrees to purchase from Seller on the Closing Date, all of Seller's right, title
and interest in and to the Acquired Assets (but as to any Licenses and Permits
comprising part of the Acquired Assets, only to the extent assignable), subject
to all existing leases (provided however, that the Master Lease under which
Purchaser is the lessee will be merged into the feehold and extinguished at
Closing) and agreements listed on SCHEDULE 2.01 or otherwise entered into in
accordance with the Management Agreement (including, without limitation, the
Central Plant Lease, the Construction Agreement, the Prior Purchase Agreement,
the Management Agreement and the Utility Services Agreement, as the same may be
modified pursuant to the Settlement Agreement) and Permitted Exceptions.

         Section 2.02. Closing Payment. In consideration for the purchase by
Purchaser of the Acquired Assets, on the Closing Date Purchaser shall pay to
Seller (or such other party or parties as Seller shall direct) One Hundred Fifty
Million Dollars ($150,000,000) in the aggregate (the "Purchase Price") as
follows:

                  (a) Fifty Million Dollars ($50,000,000) (the "Cash Portion of
         the Purchase Price") in immediately available funds, which shall be
         reduced by the amount of $5,200,000, reflecting net credits in favor of
         Purchaser pursuant to the Construction Agreement.

                  (b) One Hundred Million Dollars ($100,000,000) in the form of
         the Purchase Money Note (which amount may be reduced in accordance with
         Section 7.21 hereof).

         Section 2.03. Closing. The sale referred to in Section 2.01 (the
"Closing") shall take place at 10:00 A.M., New York time, at the offices of
White & Case LLP, 1155 Avenue of the Americas, New York, New York 10036,
simultaneously with the satisfaction or waiver of all of the conditions set
forth in Article V hereof, or at such other time and date as Seller and
Purchaser shall agree ("Closing Date").

         Section 2.04. Deliveries by Seller. At the Closing, Seller shall
deliver or cause to be delivered to Purchaser (unless previously delivered), the
following:

                  (a) a duly executed and acknowledged Deed in favor of
         Purchaser;

<PAGE>

                  (b) a duly executed Bill of Sale in favor of Purchaser;

                  (c) evidence reasonably satisfactory to Purchaser and the
         Title Company that the Persons executing the Closing Documents on
         behalf of Seller have full right, power and authority to execute same
         and that Seller has the full right, power and authority to perform its
         obligations thereunder;

                  (d) a duly executed and acknowledged certificate (the
         "Non-Foreign Entity Certification") certifying that Seller is not a
         "foreign person" as defined in Section 1445 of the Code in
         substantially the form attached hereto as EXHIBIT C;

                  (e) possession of the Acquired Assets, subject to the
         Permitted Exceptions;

                  (f) the Initialed Title Commitment;

                  (g) an Oklahoma Sales Tax report to cover any sales tax
         assessed on the tangible Personal Property, or the written
         certification of Seller (which shall also be executed by Purchaser),
         stating that no tangible Personal Property sales tax is payable;

                  (h) an assignment agreement, executed by Seller, assigning to
         Purchaser all of Seller's right, title and interest in any general
         guarantees and warranties (including the Construction Warranties) now
         or hereafter given in connection with the operation, construction,
         improvement, alteration or repair of the Real Property and the
         Improvements;

                  (i) the consents listed on Schedule 3.01(e);

                  (j) an ALTA Statement, Gap Indemnity and such other affidavits
         and indemnities as may be reasonably required by the Title Company in
         forms reasonably acceptable to the Title Company;

                  (k) the Easement for Backup Generation, duly executed and
         acknowledged by Seller and its co-tenant; and

                  (l) all other previously undelivered documents required by
         this Agreement to be delivered by Seller to Purchaser at or prior to
         the Closing in connection with the Transactions.

         Section 2.05. Deliveries by Purchaser. At the Closing, Purchaser shall
deliver or cause to be delivered to Seller (unless previously delivered), the
following:

                  (a) the Cash Portion of the Purchase Price (less the amount of
         the credit specified in Section 2.02(a) hereof) by wire transfer of
         immediately available funds to the account or accounts identified by
         Seller;

                  (b) the Financing Statements and the duly executed (and
         acknowledged as required) Purchase Money Note and Purchase Money
         Mortgage, together with all other documents and instruments
         contemplated by the foregoing;

<PAGE>

                  (c) evidence reasonably satisfactory to Seller and the Title
         Company that the Persons executing the Closing Documents on behalf of
         Purchaser, Communications and WCL have full right, power and authority
         to execute same and that each of Purchaser, Communications and WCL has
         the full right, power and authority to perform its obligations
         thereunder;

                  (d) the Mortgage Title Policy;

                  (e) the duly executed Legal Opinion; and

                  (f) all other previously undelivered documents required by
         this Agreement to be delivered by Purchaser to Seller at or prior to
         the Closing in connection with the Transactions.

         Section 2.06. Agreed Allocation. Purchaser and Seller agree that the
fair market value allocation of the Purchase Price among the Acquired Assets
(the "Agreed Allocation") is set forth on SCHEDULE 2.06. The provisions of this
Section 2.06 shall survive the Closing without limitation.

                                   ARTICLE III

                         REPRESENTATIONS AND WARRANTIES

         Section 3.01. Representations of Seller. Seller represents and warrants
to Purchaser as follows:

                  (a) Seller is (i) a corporation duly organized, validly
         existing and in good standing under the laws of the state of Delaware
         and (ii) authorized under the laws of the State of Oklahoma to conduct
         business in Oklahoma;

                  (b) Seller has the requisite power and authority to execute
         and deliver this Agreement and any other agreements or instruments
         contemplated by this Agreement to be executed by it and to perform its
         obligations hereunder and thereunder;

                  (c) This Agreement has been duly executed and delivered by
         Seller and constitutes the valid and binding obligation of Seller,
         enforceable against Seller in accordance with its terms;

                  (d) When executed and delivered as provided in this Agreement,
         each other agreement and instrument contemplated hereby to be executed
         by Seller will be a valid and binding obligation of Seller, enforceable
         against Seller in accordance with its terms;

                  (e) Except as set forth in SCHEDULE 3.01(e), none of the
         execution and delivery of this Agreement or the other agreements and
         instruments contemplated by this Agreement to be executed by Seller,
         the consummation by Seller of the Transactions or compliance by Seller
         with any of the provisions hereof or thereof will (i) conflict with or
         constitute a breach of or default under any of Seller's charter or
         bylaws, (ii) result in a violation or breach of, or constitute (with or
         without notice or lapse of time or both) a

<PAGE>
         default (or give rise to any third-party right of termination,
         cancellation, material modification or acceleration) under, any note,
         loan agreement, bond, mortgage, indenture, license, contract,
         commitment, arrangement, understanding, agreement or other instrument
         or obligation of any kind to which Seller is a party or by which Seller
         or any of its properties or assets may be bound, (iii) violate any
         order, writ, injunction, decree, judgment, statute, rule or regulation
         applicable to Seller or any of its properties or assets or (iv) require
         any order, consent, approval or authorization of, notice to, or
         declaration, filing, application, qualification or registration with,
         any Person or Governmental Entity;

                  (f) No broker, finder or other Person acting under Seller's
         authority is entitled to any broker's commission or other fee in
         connection with the Transactions for which Purchaser could be
         responsible;

                  (g) Seller has not received notice of, nor does Seller have
         knowledge of, any presently pending or threatened condemnation, eminent
         domain or other actions, litigation, proceedings, or any special
         assessments of any nature with respect to the Acquired Asset, except as
         may be set forth in the Permitted Exceptions;

                  (h) Except as contemplated by this Agreement and the
         Transactions or as set forth on SCHEDULE 3.01(h), Seller has not
         entered into any contracts or agreements which materially and adversely
         affect the Acquired Assets and which will survive the Closing and be
         binding on the Purchaser, other than as may be set forth in the
         Permitted Exceptions or entered into pursuant to and in accordance with
         the Management Agreement;

                  (i) The Real Property, Improvements and Personal Property are
         free and clear from all liens, claims and encumbrances, other than the
         Permitted Exceptions and any liens, claims and encumbrances resulting
         from any act or omission of Purchaser, its Affiliates, agents,
         employees, licensees, invitees or any other Person acting by or on
         behalf of Purchaser;

                  (j) Seller has not received notice from any Governmental
         Entity which has not been complied with asserting that the Acquired
         Assets are in violation of any laws, ordinances and regulations
         (including, but not limited to, any environmental and hazardous
         substance laws, ordinances and regulations); and

                  (k) Seller has obtained all Licenses and Permits required in
         connection with the Acquired Assets by any Governmental Entity, and
         Seller is not aware of any violations thereunder.

                  (l) Except for the representations and warranties contained in
         this Section 3.01, neither Seller nor any other Person makes any other
         express or implied representation or warranty to Purchaser or upon
         which Purchaser may rely in connection with this Agreement or the
         Transactions.

         Section 3.02. Representations of Purchaser. Purchaser hereby represents
and warrants to Seller as follows:

<PAGE>
                  (a) Purchaser is a limited liability company duly organized,
         validly existing and in good standing under the laws of the state of
         Delaware;

                  (b) Purchaser has the requisite power and authority to execute
         and deliver this Agreement and any other agreements or instruments
         contemplated by this Agreement to be executed by Purchaser (including
         without limitation the Purchase Money Mortgage and the Purchase Money
         Note) and to perform its obligations hereunder and thereunder;

                  (c) This Agreement has been duly executed and delivered by
         Purchaser and this Agreement constitutes the valid and binding
         obligation of Purchaser, enforceable against Purchaser in accordance
         with its terms;

                  (d) When executed and delivered as provided in this Agreement,
         each other agreement and instrument contemplated hereby to be executed
         by Purchaser will be a valid and binding obligation of Purchaser,
         enforceable against Purchaser in accordance with its terms;

                  (e) Except as set forth in SCHEDULE 3.02(e), none of the
         execution and delivery of this Agreement and any other agreements or
         instruments contemplated by this Agreement to be executed by Purchaser
         (including without limitation the Purchase Money Mortgage and the
         Purchase Money Note), nor the consummation by Purchaser of the
         Transactions or compliance by Purchaser with any of the provisions
         hereof or thereof will (i) conflict with or constitute a breach of or
         default under any of Purchaser's charter or operating agreement, (ii)
         result in a violation or breach of, or constitute (with or without
         notice or lapse of time or both) a default (or give rise to any third
         party right of termination, cancellation, material modification or
         acceleration) under, any note, loan agreement, bond, mortgage,
         indenture, license, contract, commitment, arrangement, understanding,
         agreement or other instrument or obligation of any kind to which
         Purchaser is a party or by which Purchaser or any of its properties or
         assets may be bound, (iii) violate any order, writ, injunction, decree,
         judgment, statute, rule or regulation application to Purchaser or any
         of its properties or assets or (iv) require any order, consent,
         approval or authorization of, notice to, or declaration, filing,
         application, qualification or registration with, any Person or
         Governmental Entity;

                  (f) As lessee under the Master Lease, Purchaser is currently
         in possession of the Real Property and Improvements and is familiar
         with the other Acquired Assets and (i) is a sophisticated Person with
         respect to the purchase of the Acquired Assets, (ii) is able to bear
         the economic risk associated with the purchase of the Acquired Assets,
         (iii) has adequate information concerning the business and financial
         condition of the Debtors and the status of the Bankruptcy Case and the
         Acquired Assets to make an informed decision regarding the purchase of
         the Acquired Assets, (iv) has such knowledge and experience, and has
         made investments of a similar nature, so as to be aware of the risks
         and uncertainties inherent in the purchase of rights and assumption of
         liabilities of the type contemplated in this Agreement and (v) has
         independently and without reliance upon Seller, and based on such
         information as it has deemed appropriate, made its own analysis and
         decision to enter into this Agreement, except that Purchaser has relied
         upon Seller's express representations and warranties in this Agreement.
         Purchaser

<PAGE>
         acknowledges that Seller has not given Purchaser any investment advice,
         credit information or opinion on whether the purchase of the Acquired
         Assets is prudent; and

                  (g) No broker, finder or other Person acting under the
         authority of Purchaser is entitled to any broker's commission or other
         fee in connection with the Transactions for which Seller could be
         responsible.

         Section 3.03. Representations of Communications. Communications hereby
represents and warrants to Seller as follows:

                  (a) Communications is a corporation duly organized, validly
         existing and in good standing under the laws of the state of Delaware;

                  (b) Communications has the requisite power and authority to
         execute and deliver this Agreement and any other agreements or
         instruments contemplated by this Agreement to be executed by
         Communications (including without limitation the Purchase Money Note)
         and to perform its obligations hereunder and thereunder;

                  (c) This Agreement has been duly executed and delivered by
         Communications and this Agreement constitutes the valid and binding
         obligation of Communications, enforceable against Communications in
         accordance with its terms;

                  (d) When executed and delivered as provided in this Agreement,
         each other agreement and instrument contemplated hereby to be executed
         by Communications will be a valid and binding obligation of
         Communications, enforceable against Communications in accordance with
         its terms; and

                  (e) Except as set forth in SCHEDULE 3.02(e), none of the
         execution and delivery of this Agreement and any other agreements or
         instruments contemplated by this Agreement to be executed by
         Communications (including without limitation the Purchase Money Note),
         nor the consummation by Communications of the Transactions or
         compliance by Communications with any of the provisions hereof or
         thereof will (i) conflict with or constitute a breach of or default
         under any of Communications' charter or by-laws, (ii) result in a
         violation or breach of, or constitute (with or without notice or lapse
         of time or both) a default (or give rise to any third party right of
         termination, cancellation, material modification or acceleration)
         under, any note, loan agreement, bond, mortgage, indenture, license,
         contract, commitment, arrangement, understanding, agreement or other
         instrument or obligation of any kind to which Communications is a party
         or by which Communications or any of its properties or assets may be
         bound, (iii) violate any order, writ, injunction, decree, judgment,
         statute, rule or regulation application to Communications or any of its
         properties or assets or (iv) require any order, consent, approval or
         authorization of, notice to, or declaration, filing, application,
         qualification or registration with, any Person or Governmental Entity.

         Section 3.04. Representations of WCL. WCL hereby represents and
warrants to Seller as follows:

<PAGE>
                  (a) WCL is a limited liability company duly organized, validly
         existing and in good standing under the laws of the state of Delaware;

                  (b) WCL has the requisite power and authority to execute and
         deliver this Agreement and any other agreements or instruments
         contemplated by this Agreement to be executed by WCL (including without
         limitation the Purchase Money Note) and to perform its obligations
         hereunder and thereunder;

                  (c) This Agreement has been duly executed and delivered by WCL
         and this Agreement constitutes the valid and binding obligation of WCL,
         enforceable against WCL in accordance with its terms;

                  (d) When executed and delivered as provided in this Agreement,
         each other agreement and instrument contemplated hereby to be executed
         by WCL will be a valid and binding obligation of WCL, enforceable
         against WCL in accordance with its terms; and

                  (e) Except as set forth in SCHEDULE 3.02(e), none of the
         execution and delivery of this Agreement and any other agreements or
         instruments contemplated by this Agreement to be executed by WCL
         (including without limitation the Purchase Money Note), nor the
         consummation by WCL of the Transactions or compliance by WCL with any
         of the provisions hereof or thereof will (i) conflict with or
         constitute a breach of or default under any of WCL's charter or
         by-laws, (ii) result in a violation or breach of, or constitute (with
         or without notice or lapse of time or both) a default (or give rise to
         any third party right of termination, cancellation, material
         modification or acceleration) under, any note, loan agreement, bond,
         mortgage, indenture, license, contract, commitment, arrangement,
         understanding, agreement or other instrument or obligation of any kind
         to which WCL is a party or by which WCL or any of its properties or
         assets may be bound, (iii) violate any order, writ, injunction, decree,
         judgment, statute, rule or regulation application to WCL or any of its
         properties or assets or (iv) require any order, consent, approval or
         authorization of, notice to, or declaration, filing, application,
         qualification or registration with, any Person or Governmental Entity.

         Section 3.05. Survival. All the representations and warranties set
forth in this Article III shall survive the Closing.

                                   ARTICLE IV

                            COVENANTS AND AGREEMENTS

         Section 4.01. Pre-Closing Covenants. Seller covenants and agrees that
from and after the date of this Agreement Seller shall:

                  (a) not amend any lease concerning the Acquired Assets nor
         execute any new lease, license, or other agreement affecting the
         ownership or operation of the Acquired Assets, without Purchaser's
         prior written approval, except in accordance with the terms of the
         Management Agreement;

<PAGE>
                  (b) not enter into any contract with respect to the ownership
         and operation of the Acquired Assets that will survive the Closing,
         without Purchaser's prior written consent, except in accordance with
         the terms of the Management Agreement;

                  (c) not take any action that would reasonably be expected to
         adversely affect the use, occupancy or value of the Acquired Assets
         except as permitted in respect of Seller's rights set forth in the
         paragraph defining "Acquired Assets" in Section 1.01;

                  (d) promptly deliver to Purchaser any notice received by
         Seller (i) asserting a violation of Applicable Law or (ii) in respect
         of a condemnation of the Real Property, the Improvements or any portion
         of the Acquired Assets that constitute real property interests; and

                  (e) operate and manage the Acquired Assets in accordance with
         the terms of the Management Agreement.

         Section 4.02. Taxes; Closing Costs. Purchaser and Seller each agree to
pay their respective attorneys' fees and one-half of any and all Taxes assessed
or levied as a result of the execution and delivery of this Agreement or the
Closing Documents (including all recording and filing fees and other charges in
respect thereof) and all fees, expenses and charges incurred in connection with
the Closing and/or the Transactions; provided, however, all fees, expenses,
premiums and charges incurred by or on behalf of, or payable to, the Title
Company in connection with the issuance of the Title Policy and Mortgage Title
Policy shall be borne and paid solely by Purchaser.

         Section 4.03. Reserved.

         Section 4.04. Closing Prorations (a) Purchaser acknowledges and agrees
that Purchaser is now and after Closing shall continue to be solely responsible
for all real property and personal property ad valorem taxes and any annual
special assessments relating to the Acquired Assets, and therefore, such Taxes
will not be pro rated in connection with the transfer of the Acquired Assets.

                  (b) All rents and other charges under the Master Lease shall
be pro rated between Seller and Purchaser on a per diem basis as of 11:59 P.M.
on the day immediately preceding the Closing Date. For purposes of such pro
rations, Purchaser shall be deemed the owner of the Acquired Assets for the
entire Closing Date.

         Section 4.05. Title Insurance. Seller will use its best efforts to
assist Purchaser in obtaining the Title Commitment and Title Policy, within the
time periods set forth herein, including removing from title any liens or
encumbrances which are not Permitted Exceptions; provided, however, that Seller
shall not be obligated to cure or eliminate any encumbrances (other than
existing mortgage and mechanic liens) to the extent that the cost to cure or
eliminate same would exceed $100,000 (the "Title/Survey Cap"), but if Seller
elects not to so cure or eliminate same, then Purchaser's sole remedy shall be
that Purchaser shall be entitled to elect to terminate this Agreement or accept
title and survey subject to such items after taking a $100,000 credit against
the Cash Portion of the Purchase Price. Purchaser and Seller agree that the

<PAGE>

Title/Survey Cap shall serve as a limitation of Seller's expenditures in
compliance with its obligation hereunder to cure encumbrances and encroachments
related to both title and survey.

         Section 4.06. Surveys. Seller shall deliver to Purchaser prior to
Closing a survey of the Real Property, dated no earlier than the date of this
Agreement, prepared by a surveyor licensed in Oklahoma and satisfactory to the
Purchaser, and conforming to 1999 ALTA/ACSM Minimum Detail Requirements for Land
Title Surveys, including Table A Items Nos. 1, 2, 3, 4, 6, 7(a), 7(b)(1), 7(c),
8, 9, 10, 11(b)(2), 13, 14, 15 and 16, and such other standards as the Title
Company and Purchaser reasonably require as a condition to the removal of any
survey exceptions from the Title Commitment, and certified to Purchaser, Seller
and the Title Company, in a form and with a certification satisfactory to each
of such parties (the "Survey"). The Survey shall not disclose any encroachment
from or onto any of the Real Property or any portion thereof or any other survey
defect which has not been cured or insured over to Purchaser's reasonable
satisfaction prior to the Closing; provided, however, Seller shall not be
obligated to cure or eliminate any such encroachments to the extent that the
cost to cure or eliminate the same exceeds the Title/Survey Cap when combined
with the costs to cure liens or encumbrances against title. Seller shall pay or
commit to pay all fees, costs and expenses with respect to the Survey.

         Section 4.07. No Recording. The parties hereto agree that neither this
Agreement nor any memorandum or affidavit concerning it shall be recorded in the
land records of Tulsa County; provided, however, that upon Closing, the Deed,
the Purchase Money Mortgage, the Financing Statements and any other Closing
Documents or instruments necessary or desirable in Seller's opinion to
consummate or evidence the Transactions shall be so recorded and filed, as
applicable and appropriate.

         Section 4.08. Condition of Assets. SUBJECT ONLY TO ANY OBLIGATIONS OF
SELLER WHICH MAY EXIST PURSUANT TO THE TERMS OF THE CONSTRUCTION AGREEMENT OR
PRIOR PURCHASE AND SALE AGREEMENT TO THE EXTENT NOT PERFORMED PRIOR TO THE
CLOSING, EACH OF PURCHASER AND THE GUARANTORS AGREES THAT AS PART OF THE
CONSIDERATION FOR SELLER ENTERING INTO THIS AGREEMENT, THE ACQUIRED ASSETS BEING
SOLD HEREUNDER ARE BEING SOLD AND CONVEYED (AND ARE BEING ACCEPTED BY PURCHASER)
ON AN "AS IS, WHERE IS" BASIS WITHOUT ANY REPRESENTATION AND WARRANTY
(INCLUDING, WITHOUT LIMITATION, ANY ENVIRONMENTAL REPRESENTATION OR WARRANTY)
OTHER THAN THE TITLE REPRESENTATION AND WARRANTY EXPRESSLY CONTAINED HEREIN
WHICH IS IN LIEU OF ALL OTHER WARRANTIES WHETHER EXPRESS OR IMPLIED, AND EACH OF
PURCHASER AND THE GUARANTORS HEREBY WAIVES, RELEASES AND RENOUNCES ALL OTHER
EXPRESS OR IMPLIED WARRANTIES, CONDITIONS OR REPRESENTATIONS WITH REGARD TO THE
CONDITION OF THE ACQUIRED ASSETS AND ALL OBLIGATIONS AND LIABILITIES OF SELLER
FOR OR WITH RESPECT TO DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES THEREFROM, AND
ALL RIGHTS, CLAIMS AND REMEDIES OF EACH OF PURCHASER AND THE GUARANTORS, EXPRESS
OR IMPLIED, ARISING OUT OF LAW OR OTHERWISE WITH RESPECT THERETO, THE OWNERSHIP,
USE OR OPERATION OF THE ACQUIRED ASSETS AND ANYTHING GIVEN OR SOUGHT TO BE
IMPLIED FROM ANYTHING

<PAGE>

SAID OR WRITTEN IN THE NEGOTIATIONS BETWEEN THE PARTIES HERETO OR THEIR
REPRESENTATIVES PRIOR TO ENTERING INTO THIS AGREEMENT WITH RESPECT THERETO. ANY
STATUTORY OR OTHER WARRANTY, CONDITION, DESCRIPTION OR REPRESENTATION, EXPRESS
OR IMPLIED, AS TO THE STATE, QUALITY OR FITNESS OF THE ACQUIRED ASSETS
(ENVIRONMENTAL OR OTHERWISE) IS EXPRESSLY EXCLUDED, INCLUDING BUT NOT LIMITED
TO, AS APPLICABLE: (i) ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS; (ii)
ANY IMPLIED WARRANTY ARISING FROM COURSE OF PERFORMANCE, COURSE OF DEALING OR
USAGE OF TRADE; (iii) ANY OBLIGATION OR LIABILITY WITH RESPECT TO ANY ACTUAL OR
ALLEGED INFRINGEMENT OF PATENTS, LICENSES OR THE LIKE, OR ANY OTHER INTELLECTUAL
PROPERTY; (iv) ANY OBLIGATION, LIABILITY, RIGHT, CLAIM OR REMEDY IN TORT,
WHETHER OR NOT ARISING FROM EACH PARTY'S OR ITS ASSIGNS' NEGLIGENCE, ACTUAL OR
IMPUTED; AND (v) ANY OBLIGATION, LIABILITY, RIGHT, CLAIM OR REMEDY FOR LOSS OF
OR DAMAGE TO THE ACQUIRED ASSETS, FOR LOSS OF USE, REVENUE OR PROFIT WITH
RESPECT TO PURCHASER OR FOR ANY OTHER DIRECT, INCIDENTAL OR CONSEQUENTIAL
DAMAGES OF WHATEVER DESCRIPTION. PURCHASER'S OBLIGATION TO PROCEED TO AND
CONCLUDE CLOSING HEREUNDER IS CONDITIONED SOLEY ON THE SELLER'S COMPLIANCE WITH
SECTION 5.01 AND EACH OF PURCHASER AND THE GUARANTORS AGREES THAT ANY
NON-COMPLIANCE EXISTING ON THE DATE HEREOF OR AT CLOSING BY ANY PARTY (OTHER
THAN SELLER) TO ANY PROPERTY DOCUMENT OR OTHER DOCUMENTS OR AGREEMENT RELATING
TO THE ACQUIRED ASSETS, SHALL NOT CONSTITUTE A DEFAULT BY SELLER HEREUNDER OR
OTHERWISE PERMIT PURCHASER OR EITHER OF THE GUARANTORS TO TERMINATE THIS
AGREEMENT OR TO OBJECT TO OR FAIL TO CONSUMMATE THE CLOSING ON THE CLOSING DATE.

                  Section 4.09. Make-Whole Provision. (a) As more explicitly set
forth in the Purchase Money Note and Purchase Money Mortgage, if within one year
of the date on which the Settlement Agreement is executed and filed with the
Bankruptcy Court, Purchaser or any of its Affiliates directly or indirectly
exchanges or disposes of (or enters into an agreement or agreements with respect
thereto) any or all of the Acquired Assets (to any transferee other than an
entity which has the same ultimate beneficial ownership as the transferor has
immediately prior to such transfer) for an aggregate sales price in cash,
obligations or other consideration in an amount greater than One Hundred Fifty
Million Dollars ($150,000,000), Purchaser shall, on the date on which the
consummation of such a transaction occurs, (i) prepay the Purchase Money Note in
full and (ii) pay to Seller in immediately available funds (except as provided
in Section 4.09(b)) to an account designated by Seller in writing, an amount
equal to the product of (x) Fifty Percent (50%) multiplied by (y) the excess of
the aggregate sales price over (A) One Hundred Fifty Million Dollars
($150,000,000) less (B) the amount equal to (i) the aggregate consideration
received by Seller or any of its Affiliates in connection with the disposition
of the Aircraft Dry Leases or (ii) the amount of proceeds received by Seller or
any of its Affiliates in connection with the refinancing of the Aircraft
pursuant to Section 7.21, which obligations shall be secured by the Purchase
Money Mortgage. Purchaser agrees that it will notify Seller in writing within
three (3) Business Days of entering into a transaction or agreement of the type
specified in this Section 4.09.

<PAGE>

         (b) In the event the consideration received or to be received by
Purchaser in a transaction of the type set forth in Section 4.09(a) is to be
paid in whole or in part other than in Dollars, for purposes of Section 4.09(a),
the value of such consideration shall be mutually agreed between Purchaser and
Seller. Notwithstanding anything in this Agreement to the contrary, in the event
Purchaser receives non-Dollar consideration in a transaction of the type set
forth in Section 4.09(a), unless otherwise agreed between Purchaser and Seller,
any payment by Purchaser to Seller under Section 4.09(a) shall be made pro rata
(based on the amount of non-Dollar consideration relative to the amount of
Dollar consideration received by Purchaser in such transaction(s)) in such
non-Dollar consideration.

         (c) The provisions of this Section 4.09 are set forth in more detail in
the Purchase Money Note and Purchase Money Mortgage. In the event of any
inconsistency between the provisions of this Section 4.09 and the provisions of
the Purchase Money Note and Purchase Money Mortgage, the Purchase Money Note and
Purchase Money Mortgage shall supersede and control.

         Section 4.10. Covenant to Satisfy Conditions. Each party hereto agrees
to use all commercially reasonable best efforts to insure that the conditions
set forth in Article V hereof are satisfied, insofar as such matters are within
the control of such party.

         Section 4.11. Substitution of New Communications. In the event that
Communications is reorganized under the Plan and/or a new entity succeeds to the
equity and assets of Communications under the Plan (such reorganized or
successor entity, "New Communications") prior to the Closing Date, the
representations and warranties of Communications set forth herein shall apply to
the New Communications as of the Closing Date and New Communications shall, with
such changes as are necessary or desirable in the opinion of Seller or its
counsel, (a) execute and deliver, as a co-issuer, the Purchase Money Note, (b)
execute and deliver or cause the execution and delivery of such other documents
and instruments required to be delivered on the Closing Date, and shall execute
and deliver or cause the execution and delivery of such other documents and
instruments and take such further actions, as may be necessary in order to
consummate the Transactions and (c) shall otherwise assume all of
Communications' rights and obligations under this Agreement and the Closing
Documents, and otherwise in respect of the Transactions.

         Section 4.12. Further Assurances. Each party shall execute and deliver
or cause the execution and delivery of such other documents and instruments and
take such further actions, as may be necessary in order to ensure that the other
party receives the full benefit of this Agreement. The obligations set forth in
this Section 4.12 shall survive the Closing.

                                    ARTICLE V

                              CONDITIONS PRECEDENT

         Section 5.01. Conditions to Purchaser's Obligation to Effect the
Closing. The obligation of Purchaser to consummate the Closing shall be subject
to the satisfaction on or prior to the Closing Date of each of the following
conditions, unless validly waived in writing by Purchaser:

<PAGE>
                  (a) Representations and Warranties. All of the representations
         and warranties of Seller set forth in this Agreement that are qualified
         as to materiality shall be true and correct and any such
         representations and warranties that are not so qualified shall be true
         and correct in all material respects, in each case as of the date
         hereof and as of the Closing Date, other than representations and
         warranties that speak as of a specific date or time (which need only be
         so true and correct as of such date or time).

                  (b) Seller's Performance of Covenants. Seller shall not have
         failed to perform in any material respect any obligation or to comply
         in any material respect with any agreement or covenant of Seller to be
         performed or complied with by it under this Agreement.

                  (c) Injunctions. On the Closing Date, there shall not be any
         injunction, writ, preliminary restraining order or other order in
         effect of any nature issued by a Governmental Entity of competent
         jurisdiction that restrains, prohibits or limits, in whole or in part,
         the consummation of the Transactions.

                  (d) Consents. All consents identified in SCHEDULES 3.01(e) and
         3.02(e) which are necessary to effect the Closing shall have been
         obtained.

                  (e) Closing Deliveries. Seller shall have made or cause to
         have been made all closing deliveries to Purchaser as set forth in
         Section 2.04.

The foregoing conditions are for the sole benefit of Purchaser and may be waived
by Purchaser, in whole or in part, at any time and from time to time in its sole
discretion.

         Section 5.02. Conditions to Seller's Obligation to Effect the Closing.
The obligation of Seller to consummate the Closing shall be subject to the
satisfaction on or prior to the Closing Date of each of the following
conditions, unless waived in writing by Seller:

                  (a) Representations and Warranties. All of the representations
         and warranties of each of Purchaser and Guarantors set forth in this
         Agreement that are qualified as to materiality shall be true and
         correct and any such representations and warranties that are not so
         qualified shall be true and correct in all material respects, in each
         case as of the date hereof and as of the Closing Date, other than
         representations and warranties that speak as of a specific date or time
         (which need only be so true and correct as of such date or time).

                  (b) Purchaser's Performance of Covenants. Neither Purchaser
         nor either Guarantor shall have failed to perform in any material
         respect any obligation or to comply in any material respect with any
         agreement or covenant to be performed or complied with by it under this
         Agreement.

                  (c) Injunctions. On the Closing Date, there shall not be any
         injunction, writ, preliminary restraining order or other order in
         effect of any nature issued by a Governmental Entity of competent
         jurisdiction that restrains, prohibits or limits, in whole or in part,
         the consummation of the Transactions.

<PAGE>
                  (d) Consents. All consents identified in SCHEDULE 3.02(e) and
         necessary to effect the Closing shall have been obtained.

                  (e) Closing Deliveries. Purchaser shall have made or cause to
         have been made all closing deliveries to Seller as set forth in Section
         2.05.

                  (f) Claims Purchase. The Claims Purchase shall have been
         consummated or shall be consummated concurrently with the Closing.

The foregoing conditions are for the sole benefit of Seller and may be waived by
Seller, in whole or in part, at any time and from time to time in its sole
discretion.

                                   ARTICLE VI

                                   TERMINATION

         Section 6.01. Termination. This Agreement may be terminated or
abandoned at any time prior to the Closing Date:

                  (a) By the mutual written consent of Purchaser and Seller;

                  (b) By Purchaser or Seller by giving notice to the other of
         such termination if any Governmental Entity shall have issued an order,
         decree or ruling or taken any other action restraining, enjoining or
         otherwise prohibiting the consummation of the Transactions and such
         order, decree, ruling or other action shall have become final and
         non-appealable;

                  (c) By Purchaser or Seller by giving notice to the other of
         such termination if the Bankruptcy Court denies approval of the
         Settlement Agreement;

                  (d) By Purchaser by giving notice to Seller if an order of the
         Bankruptcy Court approving the Settlement Agreement (including a
         determination (the "Tax Determination") by the Bankruptcy Court that no
         sales, use, excise tax or similar tax imposed pursuant to 68 O.S.
         Section 1354 by the State of Oklahoma or by the City or County of Tulsa
         or any other applicable local government authority shall be imposed on
         the Transactions) is not entered by October 15, 2002; provided,
         however, in the event the Tax Determination is not so obtained,
         Purchaser and Seller agree, subject to their respective rights to
         terminate this Agreement pursuant any provision hereof other than this
         Section 6.01(d), that Seller shall transfer its interest in the
         Acquired Assets to a limited liability company and shall cause the
         membership interests in such company to be sold to Purchaser, and
         Purchaser shall purchase same, on the terms and conditions provided
         herein, to the extent applicable to such transaction, and otherwise on
         customary terms and conditions consistent with this Agreement.
         Purchaser shall pay all fees, costs, expenses, Taxes (including the
         Taxes which are the subject of the Tax Determination) and charges,
         other than Seller's attorneys' fees, in connection with the
         transactions contemplated by this Agreement, including, without
         limitation, such fees, costs, expenses or Taxes resulting from, the
         restructuring of this Agreement pursuant to the foregoing; and/or

<PAGE>

                  (e) By Purchaser or Seller by giving notice to the other of
         such termination if the Closing has not occurred on or before February
         28, 2003; unless the failure of such consummation shall be due to the
         failure of such party to comply in all material respects with the
         representations, warranties, agreements and covenants contained herein
         or to be performed by such party on or prior to February 28, 2003.

         Section 6.02. Effect of Termination. In the event of the termination or
abandonment of this Agreement by any party hereto pursuant to the terms of this
Agreement, (i) written notice thereof shall forthwith be given to the other
party specifying the provision hereof pursuant to which such termination or
abandonment of this Agreement is made, (ii) the Master Lease shall continue in
full force and effect without regard to this Agreement and (iii) there shall be
no liability or obligation thereafter on the part of Purchaser or Seller except
(A) as set forth in Section 7.07, (B) for fraud, and (C) for breach of this
Agreement prior to such termination or abandonment of the Transactions.

                                   ARTICLE VII

                                  MISCELLANEOUS

         Section 7.01. Expenses. All costs and expenses incurred in connection
with this Agreement and the consummation of the Transactions shall be paid by
the party incurring such expenses, except as specifically provided to the
contrary in this Agreement or the Closing Documents.

         Section 7.02. Extension; Waiver. At any time prior to the Closing, each
of the parties hereto may (i) extend the time for the performance of any of the
obligations or acts of any other party hereto, (ii) waive any inaccuracies in
the representations and warranties of any other party contained herein or in any
document delivered pursuant hereto, (iii) waive compliance with any of the
agreements of the other party contained herein, or (iv) waive any condition to
its obligations hereunder. Any agreement on the part of a party hereto to any
such extension or waiver shall be valid only if set forth in a written
instrument signed on behalf of such party.

         Section 7.03. Reserved.

         Section 7.04. Notices. All notices and other communications hereunder
shall be in writing and shall be deemed given when mailed, delivered personally,
telecopied (which is confirmed) or sent by an overnight courier service, such as
Federal Express, to the parties at the following addresses (or at such other
address for a party as shall be specified by such party by like notice):

<PAGE>

                  if to Purchaser to:

                  Williams Technology Center, LLC
                  One Technology Center
                  Tulsa, OK  74103
                  Mail Drop 15
                  Attention: P. David Newsome, General Counsel
                  Facsimile: (918) 547-2360

                  if to Seller to:

                  Williams Headquarters Building Company
                  One Williams Center
                  Tulsa, OK  74172
                  Mail Drop 41-3
                  Attention: Tami Carson, Esq.
                  Facsimile: (918) 573-5942

                  with a copy (which shall not constitute notice) to:

                  White & Case LLP
                  1155 Avenue of the Americas
                  New York, NY  10036
                  Attention: John Reiss, Esq.
                  Facsimile: (212) 354-8113

                  and

                  White & Case LLP
                  First Union Financial Center
                  200 South Biscayne Boulevard
                  Miami, FL  33131-2352
                  Attention: Thomas E. Lauria, Esq.
                  Facsimile: (305) 358-5744

                  or to such other address, telecopier number or person's
attention as a party may from time to time designate in writing in accordance
with this Section. Each notice or other communication given to any party hereto
in accordance with the provisions of this Agreement shall be deemed to have been
received (a) on the Business Day it is sent, if sent by personal delivery or
telecopied, or (b) on the first Business Day after sending, if sent by overnight
delivery, properly addressed and prepaid or (c) upon receipt, if sent by mail
(regular, certified or registered); provided, however, that notice of change of
address shall be effective only upon receipt. The parties agree that delivery of
process or other papers in connection with any action or proceeding in
connection with this Agreement in the manner provided in this Section 7.04, or
in such other manner as may be permitted by Applicable Law, shall be valid and
sufficient service thereof.

<PAGE>
         Section 7.05. Entire Agreement; Amendment. This Agreement and the
Transactions constitute the entire agreement and understandings, both written
and oral, among the parties with respect to the subject matter hereof and
thereof and, except as expressly provided herein (including, without limitation,
as provided Sections 7.17 and 7.18) or therein, supersede and cancel all prior
agreements, negotiations, correspondence, undertakings, understandings and
communications of the parties, oral and written, with respect to the subject
matter hereof, including without limitation, the Master Lease, which shall be
merged into the feehold and extinguished at Closing. This Agreement may only be
modified or amended by a written instrument executed by the parties hereto.

         Section 7.06. Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of Oklahoma (without giving
effect to the provisions thereof relating to conflicts of law).

         Section 7.07. Remedies. (a) The parties hereto acknowledge and agree
that any breach of the terms of this Agreement which is not cured within the
applicable cure period set forth in Section 7.07(b), would give rise to
irreparable harm for which money damages alone would not be an adequate remedy
and accordingly the parties hereto expressly agree that the non-defaulting party
shall be entitled to exercise any and all rights and remedies for such breach
that it may have under applicable law including, without limitation, specific
performance and injunctive or other equitable relief without the necessity of
proving the inadequacy of money damages as a remedy or posting a bond or other
security in connection with such remedy; provided however, in no event shall the
Guarantors be entitled to declare any default or pursue any rights or remedies
against either Seller or Purchaser based upon any alleged default by either of
such parties under this Agreement. If any litigation is commenced to enforce
this Agreement or for any other remedy arising from a breach hereof, the
prevailing party shall be entitled to an award for its reasonable fees and
expenses in connection with such litigation.

                  (b) In the event there is a default by either Purchaser or
Seller under the terms of this Agreement, the non-defaulting party shall give
written notice of such default (with sufficient specificity to allow the
defaulting party to determine the nature and extent of such default and to the
extent possible, the manner in which such default can be remedied), and a period
of thirty (30) days thereafter in which the defaulting party may cure such
default, provided however, with respect to any such cure which by its nature,
can not be accomplished during such period, such period shall be extended so
long as the defaulting party has commenced such cure during such thirty (30) day
period, and thereafter continuously and diligently prosecutes such cure
thereafter. In the event a cure by the defaulting party is accomplished within
such period, the parties shall be restored to their relative positions prior to
the occurrence of such default as if no such default had taken place. The
provisions of this Section 7.07 shall survive the Closing without limitation.

         Section 7.08. Jurisdiction. Purchaser and Seller each hereby
irrevocably and unconditionally submit to the nonexclusive jurisdiction of any
Oklahoma State court or Federal court of the United States of America sitting in
Tulsa County, and any appellate court from any thereof, but solely in any action
or proceedings to enforce this Agreement. Each of the parties hereto agrees that
a final judgment in any such action or proceeding will be conclusive and may

<PAGE>

be enforced in other jurisdictions by suit on the judgment or in any other
manner provided by law.

         Section 7.09. Counterparts. This Agreement may be executed in any
number of counterparts and by different parties hereto in separate counterparts
and by facsimile, with the same effect as if all parties had signed the same
document. All such counterparts are to be deemed an original, construed together
and constitute one and the same instrument.

         Section 7.10. Severability. Any term or provision of this Agreement
that is invalid or unenforceable in any jurisdiction, will, as to that
jurisdiction, be ineffective to the extent of such invalidity or
unenforceability without rendering invalid or unenforceable the remaining terms
and provisions of this Agreement or affecting the validity or enforceability of
any of the terms or provisions of this Agreement in any other jurisdiction. If
any provision of this Agreement is so broad as to be unenforceable, the
provision will be interpreted to be only so broad as is enforceable.

         Section 7.11. Headings. The headings of the paragraphs of this
Agreement are inserted for convenience only and not to affect the interpretation
hereof.

         Section 7.12. Assignment. Neither this Agreement nor the rights or the
obligations of any party hereto are assignable in whole or in part (whether by
operation of law or otherwise), without the written consent of the other party
and any attempt to do so in contravention of this Section 7.12 will be void.

         Section 7.13. Successors and Assigns. This Agreement, including the
representations, warranties and covenants contained in this Agreement, shall
inure to the benefit of, be binding upon and be enforceable by and against the
parties and their respective successors and permitted assigns.

         Section 7.14. No Third-Party Beneficiaries. This Agreement is solely
for the benefit of the parties hereto, their respective successors and permitted
assigns, and the Persons identified as beneficiaries herein.

         Section 7.15. Publicity. The parties agree that until the filing of the
Plan, or the date the Transactions are terminated or abandoned pursuant to
Article VI, neither Seller nor Purchaser nor any of their respective Affiliates,
shall issue or cause the publication of any press release or other public
announcement with respect to this Agreement or the Transactions without prior
consultation with the other(s), except as may be (a) required by Applicable Law,
which shall include such filings and/or statements as any party shall determine
to be necessary or advisable in its reasonable judgment in order to comply with
its obligations under the Securities Exchange Act of 1934, as amended, or (b)
appropriate to the Debtors' administration of the Bankruptcy Case.

         Section 7.16. Interpretation. When a reference is made in this
Agreement to a section, article, paragraph, exhibit or schedule, such reference
shall be to a section, article, paragraph, exhibit or schedule of this Agreement
unless clearly indicated to the contrary.

<PAGE>

                  (a) Whenever the words "include", "includes" or "including"
         are used in this Agreement they shall be deemed to be followed by the
         words "without limitation."

                  (b) The words "hereof", "herein" and "herewith" and words of
         similar import shall, unless otherwise stated, be construed to refer to
         this Agreement as a whole and not to any particular provision of this
         Agreement.

                  (c) The meaning assigned to each term defined herein shall be
         equally applicable to both the singular and the plural forms of such
         term, and words denoting any gender shall include all genders. Where a
         word or phrase is defined herein, each of its other grammatical forms
         shall have a corresponding meaning.

                  (d) A reference to any party to this Agreement or any other
         agreement or document shall include such party's predecessors,
         successors and permitted assigns.

                  (e) A reference to any legislation or to any provision of any
         legislation shall include any amendment to, and any modification or
         re-enactment thereof, any legislative provision substituted therefor
         and all regulations and statutory instruments issued thereunder or
         pursuant thereto.

                  (f) References to Dollars or $ are to United States Dollars.

         Section 7.17. Survival of Construction Obligations. Nothing contained
in this Agreement, nor the closing of the Transactions contemplated hereby,
shall in any way affect, modify, restrict or diminish any rights and obligations
of Seller and Purchaser which may exist pursuant to the terms, covenants or
conditions of the Construction Agreement or the Prior Purchase and Sale
Agreement, including, without limitation, any insurance and indemnity
obligations, as the same may be modified by the Settlement Agreement.

         Section 7.18. Survival of Central Plant Lease. Nothing contained in
this Agreement, nor the closing of the Transactions contemplated hereby, shall
in any way modify, restrict or diminish any of the rights, obligations or
interests of the Seller or Purchaser under the Central Plant Lease, which shall
remain in full force and effect for all purposes according to its terms without
regard to (and without merger into or with) this Agreement and the Transactions
contemplated hereby, as the same may be modified by the Settlement Agreement.

Section 7.19. AFE's. The parties hereby agree to the following regarding
Seller's obligation to fund the Construction Contracts, the Interior Furniture
and Fixtures Contracts, and the Future Interior Furniture and Fixtures Contracts
(all as defined in the Construction Agreement, but collectively referred to for
purposes of this Section 7.19 as the "Contracts"):

         (a) Seller shall continue to reimburse Purchaser for invoices paid by
         Purchaser pursuant to the terms of the Construction Agreement and the
         Contracts; the parties agree to continue their current course of
         dealing with regard to such reimbursement processes;

         (b) Seller's obligation for reimbursement under subparagraph (a) above
         shall be limited to a total reimbursement of $11,087,612.00 as of July
         1, 2002 (the "Total Reimbursement"); provided, however, upon completion
         of the Contracts and payment by

<PAGE>

         Purchaser of all outstanding invoices thereunder, Seller will pay to
         Purchaser the difference, if any, between the Total Reimbursement and
         the total amount reimbursed by Seller to such date. Seller shall pay
         any difference remaining to Purchaser within thirty (30) days of
         receipt of a detailed accounting of the amount due; if there are any
         disputes as to such amount due, Seller and Purchaser agree to work
         together in good faith to promptly resolve the dispute, and Seller
         shall pay any undisputed amount prior to expiration of the thirty-day
         period referred to above; and

         (c) Purchaser and Seller agree on the good faith estimate of $465,000
         for the completion of the corridor connection between the Center and
         the adjoining Bank of Oklahoma Tower. Completion thereof shall be the
         sole responsibility of Seller, pursuant to Purchaser's sign-off and
         acceptance of construction drawings. No "true-up" shall be made between
         Purchaser and Seller upon completion of the corridor between the Center
         and the adjoining Bank of Oklahoma Tower (the "Corridor"). Purchaser
         agrees that upon expenditure by Seller of the Total Reimbursement and
         the completion of the Corridor, Seller shall have fulfilled its
         obligation in connection with the AFE's under the Contracts and the
         Construction Agreement, and in no event shall additional sums of money
         be due Purchaser in connection therewith; provided, however, the
         foregoing shall not be construed to limit Seller's obligations to
         expend money to fulfill Seller's other surviving obligations under the
         Construction Agreement.

         Section 7.20. Continuing Cooperation. Seller and Purchaser acknowledge
and agree that the nature of the transactions contemplated by this Agreement
necessitate that both before and after the Closing Date, both Seller and
Purchaser, together with their respective Affiliates, will need to work together
and cooperate on a continuing basis to (i) insure the satisfaction of the
Seller's surviving obligations under this Agreement, the Construction Agreement
and the Prior Purchase and Sale Agreement. Seller and Purchaser agree to
cooperate in good faith and to cause each of their respective officers,
employees, representatives, affiliates, agents and contractors to cooperate in
good faith with the other party and all of its respective officers, employees,
representatives, affiliates, agents and contractors, to accomplish such goals,
Seller and Purchaser hereby acknowledging that such cooperation shall work for
the mutual benefit of both parties.

         Section 7.21. Disposition of Aircraft Dry Leases. Seller, WCL and
Purchaser agree that (A) TWC and Seller shall have the exclusive right to
dispose of or refinance the Aircraft Dry Leases on commercially reasonable terms
and at market rates prior to the Closing Date and (B) if TWC and Seller shall
not have so disposed of or refinanced the Aircraft Dry Leases by the Closing
Date, then on the Closing Date, TWC shall terminate the Aircraft Dry Leases and
cause to be transferred to WCL or its designee, at the option of WCL, (i) title
to the Aircraft (in which case the Purchaser shall be responsible for paying all
applicable sales/excise taxes) or (ii) the entire ownership interest in the
entity holding title to the Aircraft. Any such transfer shall be effectuated
pursuant to documentation reasonably acceptable to the parties, containing such
representations and warranties as are appropriate for such a transaction. Upon
such transfer, WCL shall thereafter have the exclusive right to dispose of or
refinance the Aircraft on commercially reasonable terms and at market rates. The
Purchaser shall cause the net proceeds of any such disposition or refinancing
(collectively, a "Disposition") to be paid at the closing of

<PAGE>

such Disposition to Seller or its designee. If such Disposition does not occur
on or before the day which is 180 days after the Closing Date (the "Termination
Date"), then WCL shall pay to TWC within three (3) Business Days after the
Termination Date, an amount (the "Fee") equal to 3 times the difference between
(a) the amount of the last (monthly) installment of Rent (as such term is
defined in each Aircraft Dry Lease) under each of the Aircraft Dry Leases which
would have been payable prior to the Termination Date if the Aircraft Dry Leases
were then still in effect and (b) that portion of the Monthly Debt Service (as
defined below) payment which is attributable to $20,000,000 of principal under
the Purchase Money Note. The Fee shall not be applied against the principal of
the Purchase Money Note. On the Termination Date, all accrued and unpaid
interest on the Purchase Money Note, together with interest which would accrue
thereunder through the last day of the month in which such Termination Date
occurs, shall be paid. Thereafter, commencing on the first day of the second
month which commences after the Termination Date, the monthly installments of
principal and interest under the Purchase Money Note (the "Monthly Debt
Service") shall be changed to equal the sum of (A) the monthly payment amount
which would be necessary to amortize a principal amount of $80,000,000 with
interest on the unpaid principal thereof at a rate of 7% per annum in equal
monthly installments over 360 months (but there shall be no corresponding
reduction of the principal amount of the Purchase Money Note or extension of the
maturity date thereof); and (B) the monthly Rent which would have been payable
under each of the Aircraft Dry Leases (if they were then still in effect). A
portion of each monthly Rent payment referred to in clause (B) above equal to
the sum of the portions of the corresponding payments for the corresponding
month under the Aircraft Dry Leases which would have been applied to principal
thereunder (the "Allocated Lease Principal") shall be applied against the
principal of the Purchase Money Note. Thereafter, upon the Disposition of the
Aircraft, and application of the proceeds thereof against the principal of the
Purchase Money Note (i) the sums specified in clause (B) above shall no longer
be payable by WCL; and (ii) the fixed monthly payment amount referred to in
clause (A) above shall, for the period commencing on the date of such
Disposition and continuing thereafter for the remainder of the period to the
scheduled maturity date of the Purchase Money Note, be changed to equal the
product of (x) the original Monthly Debt Service under the Purchase Money Note
and (y) a fraction, the numerator of which is $100,000,000 minus without
duplication the Allocated Lease Principal, minus all other principal payments
made under the Purchase Money Note and minus net proceeds of the Disposition of
the Aircraft which were applied to reduce the outstanding principal of the
Purchase Money Note, and the denominator of which is $100,000,000. Any net
proceeds from the sale of the Aircraft Dry Leases or the Disposition of the
Aircraft received by Seller or any of its Affiliates (i) prior to the Closing
Date will be applied to reduce the portion of the Purchase Price to be financed
under the Purchase Money Note by the amount of such proceeds; and (ii) following
Closing will be applied to reduce the principal balance of the Purchase Money
Note in accordance with the terms hereof which shall be set forth in the
Purchase Money Note.

         Section 7.22. Casualty/Condemnation. In the event all or any portion of
the Real Property, Improvements, Acquired Assets which constitute real property
interests, or Personal Property are damaged or destroyed or taken by eminent
domain or condemnation prior to the Closing Date, each party shall notify the
other of such fact promptly after obtaining knowledge thereof and this Agreement
shall remain in full force and effect without abatement, counterclaim or set-off
of any kind and, with respect to restoration and replacement thereof, and Seller
and Purchaser shall comply with the applicable terms and conditions of the
Master Lease and the

<PAGE>

Construction Agreement to effect restoration; provided, however, on the Closing
Date Seller shall assign, transfer, convey and release to Purchaser all of its
rights, title and interest in and to any insurance proceeds or other amounts
payable to Seller by reason of such casualty, condemnation or other taking.

         Section 7.23. License for Parking Structure. Seller agrees to obtain
within a reasonable time after Closing the consent of the City of Tulsa to
Seller's assignment to Purchaser of the License Agreement dated December 3,
1999, between Seller and the City of Tulsa and recorded in Book 6316 at Page
1299, in the Clerk's Office of Tulsa County, Oklahoma.

         Section 7.24. Construction Warranties

                  (a) Notwithstanding anything to the contrary contained herein,
the term "Acquired Assets" shall not include, the (i) Central Plant, (ii)
Manhattan Expansion Tower Contract, (iii) Manhattan Interior Design Contract,
(iv) HOK Expansion Project Contract and (v) HOK Interior Design Contract (with
regard to clauses (ii)-(v), each as defined in the Construction Agreement and
collectively referred to herein as the "Construction Documents"), but shall
include all of Seller's right, title and interest in and to all construction and
equipment warranties relating to the Real Property and Improvements
(collectively, the "Construction Warranties") and all causes of action in
connection with the Construction Warranties arising under or pursuant to the
Construction Documents; provided, however, with respect to the Manhattan
Expansion Tower Contract and Manhattan Interior Design Contract, the term
"Acquired Assets" shall include only those Construction Warranties and causes of
action which remain after Seller has completed its settlement of any existing
claims and causes of action arising under or pursuant thereto (collectively
"Existing Construction Claims"). Notwithstanding the foregoing, with respect to
Manhattan Expansion Tower Contract and the Manhattan Interior Design Contract,
the Seller shall not (A) waive any rights thereunder with respect to future
causes of action with regard to the Center which are based on facts not known to
Seller on the date hereof or (B) release the contractor thereunder from
completion of the punchlist items created after consultation with Purchaser.

                  (b) Seller shall within thirty (30) days after substantial
completion of its obligations under the Construction Agreement (or earlier upon
written request of Purchaser to the extent necessary for Purchaser to commence a
cause of action under the Construction Documents, but with respect to the
Manhattan Expansion Tower Contract and the Manhattan Interior Design Contract,
not before Seller shall have completed settlement of its Existing Construction
Claims), assign to Purchaser all of Seller's beneficial interest in, to and
under (but Purchaser shall not be obligated to assume any of Seller's
obligations thereunder) the Construction Documents, subject to Seller's right to
prosecute or defend its own claims arising under or relating to such contracts.

                  (c) The obligations set forth in this Section 7.24 shall
survive the Closing.

         Section 7.25. Guaranty. Communications and WCL, by their execution of
this Agreement, unconditionally and irrevocably jointly and severally guaranty
the obligations of the Purchaser under this Agreement.

<PAGE>

                            [SIGNATURE PAGE FOLLOWS]

<PAGE>

                  IN WITNESS WHEREOF, the parties below have executed this Real
Property Purchase and Sale Agreement by their duly authorized officers as of the
date first set forth above.

                                    WILLIAMS HEADQUARTERS BUILDING COMPANY

                                    By: /s/ Jack D. McCarthy
                                       -----------------------------------------
                                       Title: Vice President

                                    WILLIAMS TECHNOLOGY CENTER, LLC

                                    By: /s/ Howard E. Janzen
                                       -----------------------------------------
                                       Title:  President and CEO

                                    WILLIAMS COMMUNICATIONS, LLC

                                    By: /s/ Howard E. Janzen
                                       -----------------------------------------
                                       Title:  President and CEO

                                    WILLIAMS COMMUNICATIONS GROUP, INC.

                                    By: /s/ Howard E. Janzen
                                       -----------------------------------------
                                       Title:  President and CEO

                  Solely for the purposes set forth in Section 7.21:

                                    WILLIAMS AIRCRAFT LEASING, LLC

                                    By:  WILLIAMS AIRCRAFT, INC.,
                                           member

                                    By: /s/ Jack D. McCarthy
                                       -----------------------------------------
                                       Title: Vice President

<PAGE>

                                                                  CONFORMED COPY

                                 SHORT TERM NOTE

$74,360,295.30
                                                                October 15, 2002

                  FOR VALUE RECEIVED, the undersigned, WILLIAMS TECHNOLOGY
CENTER, LLC, a Delaware limited liability company having an address at One
Technology Center, Tulsa, OK 74103 ("Borrower"), and, for the sole purpose and
to the effect specified in Paragraph 22 hereof, WILTEL COMMUNICATIONS GROUP,
INC., a Nevada corporation (formerly known as Williams Communications Group,
Inc., a Delaware corporation, prior to its reorganization pursuant to the Plan)
having an address at One Technology Center, Tulsa, OK 74103 ("WCG"), and
WILLIAMS COMMUNICATIONS, LLC, a Delaware limited liability company having an
address at One Technology Center, Tulsa, OK 74103 ("WCL"), (Borrower, WCG and
WCL being sometimes individually referred to herein as a "Maker" and
collectively as the "Makers") jointly and severally, irrevocably, absolutely and
unconditionally promise to pay WILLIAMS HEADQUARTERS BUILDING COMPANY, a
Delaware corporation which, together with its successors and assigns of its
interest in this note (this "Note"), is referred to in this Note as "Lender", at
The Williams Companies, Inc., Attn: Corporate Treasury, Mail Drop 50-4, One
Williams Center, Tulsa, Oklahoma 74172, or such other place as Lender may from
time to time designate, the sum of SEVENTY FOUR MILLION THREE HUNDRED SIXTY
THOUSAND TWO HUNDRED NINETY FIVE AND 30/100 DOLLARS ($74,360,295.30) (the
"Loan") as described in and subject to the provisions of Paragraph 1(a) hereof,
on the Maturity Date (as hereinafter defined), which sum includes principal and
interest on principal from the date hereof to the Maturity Date at the
applicable rates hereafter provided, payable in the manner specified below in
lawful money of the United States. All capitalized terms used herein but not
defined herein shall have the meanings ascribed to such terms in the Mortgage
(as defined in Paragraph 2 hereof).

                  WHEREAS, Borrower is a wholly owned subsidiary of WCL and WCL
is a wholly owned subsidiary of WCG;

                  WHEREAS, each Maker will obtain benefits from Lender's making
the Loan and, in order to induce Lender to make the Loan, WCL and WCG have
agreed to perform their obligations set forth herein; and

                  WHEREAS, it is a condition precedent to Lender's making the
Loan to Borrower that Borrower and the other Makers shall have executed and
delivered this Note;

                  NOW, THEREFORE, to satisfy the condition in the preceding
paragraph and to induce Lender to make the Loan, in consideration thereof, and
in consideration of the benefits to accrue to the Makers therefrom, the receipt
and sufficiency of which are hereby acknowledged by the Makers, the Makers
jointly and severally agree and covenant to comply with the terms and provisions
hereof.

<PAGE>

         1. Principal and Interest

                  The parties hereto acknowledge and agree that (i) the first
page of this Note shall specify a stated face amount of $74,360,295.30 (the
"Stated Face Amount"); (ii) the Stated Face Amount represents the sum of the
original principal amount of $44,800,000 plus all accrued and capitalized
interest payable thereon from the date hereof until the Maturity Date
(hereinafter defined) pursuant to the terms of this Note and as set forth on
Schedule A attached hereto; and (iii) the Stated Face Amount is based on the
assumption that all of such original principal amount and all such accrued and
capitalized interest shall be paid to Lender on the Maturity Date.

                  Principal shall be payable as follows and interest shall
                  accrue and be payable as follows:

                  (a) On the date hereof the principal amount of the Loan is
$44,800,000. Commencing on the date hereof and continuing thereafter through
December 29, 2006 (the "Maturity Date"), interest on the outstanding principal
of the Loan shall accrue at the following rates during the following periods and
shall be capitalized to and become principal of the Loan at the end of each of
such respective periods:

                  (i) Ten percent (10%) per annum from the date hereof through
         December 31, 2003 (all such interest that has accrued and remains
         unpaid during such period shall be capitalized to and become principal
         of the Loan on December 31, 2003);

                  (ii) Twelve percent (12%) per annum from January 1, 2004
         through December 31, 2004 (all such interest that has accrued and
         remains unpaid during such period shall be capitalized to and become
         principal of the Loan on December 31, 2004);

                  (iii) Fourteen percent (14%) per annum from January 1, 2005
         through December 31, 2005 (all such interest that has accrued and
         remains unpaid during such period shall be capitalized to and become
         principal of the Loan on December 31, 2005); and

                  (iv) Sixteen percent (16%) per annum from January 1, 2006
         until the Maturity Date and if not paid by the Maturity Date, then at
         the Default Rate (as hereafter defined) until paid.

                  (b) If not sooner paid, the entire unpaid principal balance of
this Note and all accrued but unpaid interest under this Note and all other sums
payable under this Note shall be due and payable in full on the Maturity Date or
such earlier date as same may become due and payable pursuant to the terms
hereof.

                  (c) All payments by Borrower, including any fees and charges,
payable hereunder or under any other Loan Document shall be made to Lender
unconditionally and without deduction, setoff or counterclaim of any kind. If
any payment hereunder becomes due and payable on a day which is not a Business
Day (as hereinafter defined), the maturity thereof shall be extended to the next
succeeding Business Day. As used herein, "Business Day" shall

<PAGE>

mean a day other than a Saturday, Sunday or day on which banks are authorized to
be closed in Tulsa, Oklahoma.

                  (d) Payments in federal funds immediately available in the
place designated for payment received by Lender prior to 2:00 p.m. local time at
the place of payment on a day in which Lender is open for business shall be
credited prior to the close of business. Any payment received after 2:00 p.m.
local time at said place of payment on a day on which Lender is open for
business shall be deemed to be received on the next succeeding Business Day.

                  (e) All payments received under this Note shall be applied to
the payment of any outstanding fees, charges, advances, interest and principal
in such order and amounts as Lender shall determine in its sole discretion. The
Borrower may, in accordance with Paragraph 13 hereof, from time to time make
prepayments without any premium or penalty of all or any part of the principal
amount of the Loan by simultaneously paying accrued interest on the outstanding
amount of principal then being prepaid hereunder at the applicable above-stated
rates as of the prepayment date.

                  (f) In the event that at any time any payment received by
Lender hereunder shall be deemed by a court of competent jurisdiction to have
been a voidable preference or fraudulent conveyance under any bankruptcy,
insolvency or other debtor relief law, then the obligation to make such payment
shall survive any cancellation or satisfaction of this Note or return thereof to
the Makers and shall not be discharged or satisfied with any prior payment
thereof or cancellation of this Note, but shall remain a valid and binding
obligation enforceable in accordance with the terms and provisions hereof, and
such payment shall be due and payable upon demand.

                  (g) Interest payable on the unpaid principal balance shall be
calculated on the basis of a three hundred sixty (360) day year consisting of
twelve (12) months of thirty (30) days each.

         2. Security

                  This Note is secured by that certain Mortgage with Power of
Sale, Security Agreement, Assignment of Leases, Rents and Profits, Financing
Statement and Fixture Filing, of even date herewith, made by Borrower to Lender
(the "Mortgage") to be recorded in the County Clerk's Office of Tulsa County,
Oklahoma and that certain Pledge Agreement, of even date herewith, made by CG
Austria, Inc., a Delaware Corporation to Lender (the "Pledge") (this Note, the
Long-Term Note, the Mortgage, the Pledge and any other documents or instruments
now or hereinafter entered into from time to time further evidencing or securing
the indebtedness evidenced hereby, as the same may be amended, restated,
replaced, supplemented or otherwise modified from time to time, being
collectively referred to herein as the "Loan Documents").

         3. Default; Acceleration

                  Upon the occurrence and during the continuance of any "Event
of Default" (as defined in the Mortgage) (an "Event of Default"), the entire
principal sum and all other sums payable hereunder and under the Loan Documents,
together with all accrued interest thereon, shall at the option of Lender,
immediately become due and payable, without notice or demand.

<PAGE>

Failure to exercise this option shall not constitute a waiver of the right to
exercise same in the event of any subsequent Event of Default.

         4. Late Payment Charge; Default Interest

                  In addition to the payment of all principal, interest and
other fees or expenses payable under this Note, if any payment under this Note
(whether of principal, interest or other fees or expenses and including the
payment due on the Maturity Date) (i) is not paid within fifteen (15) days after
the due date thereof, the Borrower shall pay to Lender without any requirement
of notice or demand by Lender, a late payment charge equal to two percent (2%)
of the amount of the delinquent payment, and (ii) is not paid by the due date
thereof, then such unpaid amounts hereunder, together with all accrued but
unpaid interest thereon, shall, on and from the original due date without any
requirement of notice or demand by Lender, bear interest at the rate of two
percent (2)% per annum greater than the interest rate otherwise then in effect
pursuant to Paragraph 1(a) hereof (the "Default Rate"). THE MAKERS ACKNOWLEDGE
AND AGREE THAT (x) LENDER'S ACTUAL DAMAGES RESULTING FROM ANY SUCH DEFAULT OR
DELINQUENCY AND RELATING TO LOST USE OF FUNDS AND COSTS OF INTERNAL
ADMINISTRATION OF DELINQUENT PAYMENTS HEREUNDER OR RELATING TO SUCH DEFAULT
WOULD BE EXTREMELY DIFFICULT TO ASCERTAIN, AND (y) UNDER THE CIRCUMSTANCES IN
EXISTENCE AS OF THE DATE HEREOF, INTEREST HEREUNDER ACCRUED AT THE DEFAULT RATE
AND SUCH LATE CHARGE CONSTITUTE A REASONABLE LIQUIDATION OF SUCH DAMAGES AND DO
NOT CONSTITUTE A PENALTY. No provision of this Note (including without
limitation the provisions for a late payment charge, accrual of interest at the
Default Rate, or for the continued accrual of interest on any amounts remaining
unpaid after the Maturity Date) shall be construed as in any way excusing
Borrower from its obligations to make each payment as and when due under this
Note. Acceptance by Lender of any late charge and/or interest at the Default
Rate shall not be deemed a waiver of any of Lender's rights and remedies
hereunder or under the other Loan Documents.

         5. Costs of Collection

                  The Makers jointly and severally promise to pay (a) all costs
and expenses reasonably incurred, including, without limitation, attorneys' fees
and disbursements, if this Note or any portion of this Note is placed in the
hands of any attorney for collection and such collection is effected without
suit; (b) out-of-pocket attorneys' fees and disbursements reasonably incurred
and all other costs, expenses and fees reasonably incurred by Lender in
enforcing its rights under this Note or the other Loan Documents, including,
without limitation, the institution of a judicial or foreclosure sale or other
power of sale or a suit to collect all or any portion of amounts owing hereunder
or thereunder or any appeals therefrom, until payment of the full amount due to
Lender is made; and (c) all out-of-pocket costs and expenses reasonably incurred
by Lender (including, without limitation, actual attorneys' fees and
disbursements) in connection with any bankruptcy, insolvency or reorganization
proceeding or receivership involving any of the Makers, including, without
limitation, attorneys' fees and disbursements reasonably incurred in making any
appearances in any such proceeding or in seeking relief from any stay or
injunction issued in or arising out of any such proceeding or any appeals
therefrom.

<PAGE>

         6. Certain Waivers

                  Except as otherwise expressly specified in this Note, the
Mortgage or any of the other Loan Documents, each of the Makers jointly and
severally waive diligence, grace, demand, presentment for payment, exhibition of
this Note, protest and notice of protest and notice of nonpayment. Any payment
by any of the Makers or other circumstance which by operation of law tolls any
statute of limitations as to any of the Makers shall operate to toll the statute
of limitations as to all of them. From time to time, without affecting the
obligation of the Makers to pay the outstanding principal balance of this Note
and observe the covenants contained herein, without giving notice to or
obtaining the consent of the Makers, and without liability on the part of
Lender, Lender may, at the option of Lender, extend the time for payment of said
outstanding principal balance, or any part thereof, reduce the payments thereon,
release anyone liable for any of said outstanding principal balance, accept a
renewal of this Note, join in any extension or subordination agreement, release
any security given in respect hereof, take or release other or additional
security, and agree in writing with the Makers to modify the rate of interest
and/or the Maturity Date or otherwise change the date(s) and/or amounts of
payment(s) thereof.

                  No single or partial exercise of any power, right or privilege
of Lender hereunder or under the other Loan Documents and no course of dealing
between the Lender on the one hand and any one or more of the Makers on the
other hand, shall operate as a waiver of or preclude other and further exercise
thereof or the exercise of any other power, right or privilege of Lender. Lender
shall at all times have the right to proceed against any portion of the
Mortgaged Property pursuant to and in accordance with the Mortgage and/or
against any one or more of the Makers in such order and in such manner as Lender
may deem fit, without waiving any rights with respect to any of the other Makers
or other portion of the Mortgaged Property. No delay, action or omission on the
part of Lender in exercising any right or remedy hereunder shall operate or be
construed as a waiver or release of (i) such right or remedy or of any other
right or remedy of Lender, (ii) any liability or obligation of the Makers
hereunder or under the other Loan Documents or (iii) an Event of Default. The
rights and remedies of Lender herein provided are cumulative and not exclusive
of any other rights or remedies which the Lender would have hereunder, under the
other Loan Documents or at law or in equity.

         7. Loss, Theft, Destruction or Mutilation of Note

                  In the event of the loss, theft or destruction of this Note,
upon Borrower's receipt of a reasonably satisfactory indemnification agreement
executed in favor of the Makers by the party who held this Note immediately
prior to its loss, theft or destruction, or in the event of the mutilation of
this Note, upon Lender's surrender to Borrower of the mutilated Note, the Makers
shall execute and deliver to such party or Lender, as the case may be, a new
promissory note in form and content identical to this Note in replacement of the
lost, stolen, destroyed or mutilated Note.

         8. Notices

                  Any notice and other communication required or desired to be
given or delivered under this Note shall be made in accordance with the notice
provisions of the Mortgage directed to the intended party at its respective
address set forth on the first page hereof.

<PAGE>

         9. Time of Essence

                  Time is of the essence in the performance of each and every
provision of this Note.

         10. Severability

                  If any provision of this Note or the other Loan Documents
shall for any reason be held unenforceable or void by a court of competent
jurisdiction in any respect, then such provision shall be deemed separable from
the remaining provisions hereof and shall in no way affect any other provision
or the validity of this Note.

         11. Amendment or Waiver; etc.

                  This Note may not be changed, extended, modified, or amended
except by an instrument in writing signed by Lender and the Makers and none of
the rights or benefits of Lender hereunder can be waived except in a written
instrument signed by Lender.

         12. Governing Law

                  This Note shall be governed by and construed and interpreted
in accordance with the laws of the State of Oklahoma, without regard to
conflicts of laws principles. To the fullest extent permitted by applicable law,
each of Lender on the one hand and the Makers jointly and severally on the other
hand, hereby unconditionally and irrevocably waive any claim to assert that the
laws of any other jurisdiction govern this Note and acknowledge and agree that
this Note represents its knowing, voluntary and conscious decision made with
full advice of counsel, and that the State of Oklahoma has a substantial
relationship to the parties hereto and the transactions contemplated hereby.

         13. Prepayment

                  (a) Borrower shall have the right without any premium or
         penalty to prepay in whole or in part, at any time from time to time,
         the principal amount outstanding under this Note (initially
         $44,800,000, as specified in Paragraph 1(a)), provided that, in the
         case of prepayment in whole, Lender shall simultaneously receive in
         immediately available funds, in addition to the entire principal amount
         then outstanding under this Note as of the date of prepayment, (i) all
         unpaid interest accrued under this Note pursuant to Paragraph 1(a) as
         of the date of prepayment, and (ii) all other sums owing under this
         Note.

                  In the case of a partial prepayment by Borrower of principal
owing under this Note, such payment shall be made in immediately available funds
and applied by Lender in the following order: (i) first, to all unpaid interest
accrued under this Note pursuant to Paragraph 1(a) as of the date of prepayment
on the principal amount being prepaid, (ii) second, to all other sums then due
and owing under this Note (other than principal), and (iii) third, to the
outstanding principal balance under this Note.

                  (b) [Reserved].

<PAGE>
                  (c) (i) If within one year after the date hereof, Borrower or
         any of its Affiliates directly or indirectly exchanges or disposes of
         (or enters into an agreement or agreements with respect thereto) any or
         all of the Acquired Assets (to any transferee other than an entity
         which has the same ultimate beneficial ownership as the transferor had
         immediately prior to such transfer) for an aggregate sales price in
         cash, obligations or other consideration in an amount greater than One
         Hundred Fifty Million Dollars ($150,000,000), Borrower shall, on the
         date on which the consummation of such a transaction occurs, (i) prepay
         the entire outstanding principal of this Note and all accrued and
         unpaid interest thereon and all other sums payable under this Note and
         the other Loan Documents in full and (ii) pay to Lender in immediately
         available funds (except as provided in Paragraph 13(c)(ii) below) to an
         account designated by Lender in writing, an amount equal to the product
         of (x) Fifty Percent (50%) multiplied by (y) the excess of the
         aggregate sales price over (A) One Hundred Fifty Million Dollars
         ($150,000,000) less (B) the amount equal to the (i) aggregate
         consideration received by Lender, or any of its Affiliates, in
         connection with the disposition of the Aircraft Dry Leases or (ii) the
         amount of proceeds received by Lender or any of its Affiliates in
         connection with the refinancing of the Aircraft pursuant to Paragraph
         13(b) of the Long-Term Note, which obligations are secured by the
         Mortgage. Borrower agrees that it will notify Lender in writing no
         later than three (3) Business Days prior to entering into a transaction
         or agreement of the type specified in this Paragraph 13(c).

                  (ii) In the event the consideration received or to be received
by Borrower in a transaction of the type set forth in Paragraph 13(c)(i) is to
be paid in whole or in part other than in Dollars, for purposes of Paragraph
13(c)(i), the value of such consideration shall be mutually agreed between
Borrower and Lender. Notwithstanding anything in this Paragraph 13 to the
contrary, in the event Borrower receives non-Dollar consideration in a
transaction of the type set forth in Paragraph 13(c)(i), unless otherwise agreed
between Borrower and Lender, any payment by Borrower to Lender under Paragraph
13(c)(i) shall be made pro rata (based on the amount of non-Dollar consideration
relative to the amount of Dollar consideration received by Lender in such
transaction(s)) in such non-Dollar consideration.

                  (d) No principal amount repaid may be reborrowed.

         14. Usury Laws

                  This Note and the other Loan Documents are subject to the
express condition that at no time shall any Maker be obligated or required to
pay interest on the Obligations at a rate which could subject the holder of this
Note either to civil or criminal liability as a result of being in excess of the
maximum interest rate which is permitted by applicable law. If, by the terms of
this Note and the other Loan Documents, any Maker is at any time required or
obligated to pay interest on the Obligations at a rate in excess of such maximum
rate, the rate of interest under the same shall be deemed to be immediately
reduced to such maximum rate and the interest payable shall be computed at such
maximum rate and all prior interest payments in excess of such maximum rate, to
the extent permitted by law, shall be applied, at the option of Lender, against
any sums outstanding in such order as Lender may determine. The right to
accelerate this Note pursuant to Paragraph 3 hereof does not include a right to
require payment of any interest which has not otherwise accrued by the date of
such acceleration, and Lender does not intend to collect

<PAGE>

any unearned interest in the event of acceleration; provided, however, that
Lender shall, to the extent specified herein, be entitled to receive interest at
the applicable rate herein specified on any amounts payable pursuant to this
Note through the date collected.

         15. Consent to Jurisdiction; Waiver of Jury Trial

              (a) ANY LEGAL ACTION OR PROCEEDING WITH RESPECT TO THIS NOTE OR
THE OTHER LOAN DOCUMENTS MAY BE BROUGHT IN THE STATE AND FEDERAL COURTS LOCATED
IN THE COUNTY OF TULSA, OKLAHOMA AND BY EXECUTION AND DELIVERY OF THIS NOTE,
EACH MAKER HEREBY IRREVOCABLY ACCEPTS FOR ITSELF AND IN RESPECT OF ITS PROPERTY
(INCLUDING THE MORTGAGED PROPERTY), GENERALLY AND UNCONDITIONALLY, THE
JURISDICTION OF THE AFORESAID COURTS WITH RESPECT TO ANY SUCH ACTION OR
PRECEDING. EACH MAKER HEREBY FURTHER IRREVOCABLY WAIVES ANY CLAIM THAT ANY SUCH
COURTS LACK PERSONAL JURISDICTION OVER IT, AND AGREES NOT TO PLEAD OR CLAIM, IN
ANY LEGAL ACTION OR PROCEEDING WITH RESPECT TO THIS NOTE OR THE OTHER LOAN
DOCUMENTS BROUGHT IN ANY OF THE AFOREMENTIONED COURTS, THAT SUCH COURTS LACK
PERSONAL JURISDICTION OVER THE MAKERS. EACH MAKER FURTHER IRREVOCABLY CONSENTS
TO THE SERVICE OF PROCESS OUT OF ANY OF THE AFOREMENTIONED COURTS IN ANY SUCH
ACTION OR PROCEEDING BY, IN ADDITION TO SUCH OTHER METHODS AS ARE PERMITTED
UNDER APPLICABLE LAW, THE MAILING OF COPIES THEREOF BY REGISTERED OR CERTIFIED
MAIL, POSTAGE PREPAID, TO IT AT ITS ADDRESS FOR NOTICES PURSUANT TO PARAGRAPH 8
HEREOF, SUCH SERVICE TO BECOME EFFECTIVE THIRTY (30) DAYS AFTER SUCH MAILING.
EACH MAKER HEREBY IRREVOCABLY WAIVES ANY OBJECTION TO SUCH SERVICE OF PROCESS
AND FURTHER IRREVOCABLY WAIVES AND AGREES NOT TO PLEAD OR CLAIM IN ANY ACTION OR
PROCEEDING COMMENCED HEREUNDER THAT SERVICE OF PROCESS WAS IN ANY WAY INVALID OR
INEFFECTIVE. NOTHING HEREIN SHALL AFFECT THE RIGHT OF LENDER TO SERVE PROCESS IN
ANY OTHER MANNER PERMITTED BY LAW OR TO COMMENCE LEGAL PROCEEDINGS OR OTHERWISE
PROCEED AGAINST ANY OF THE MAKERS IN ANY OTHER JURISDICTION.

         (b) EACH MAKER HEREBY WAIVES ANY OBJECTION WHICH IT MAY NOW OR
HEREAFTER HAVE TO THE LAYING OF VENUE OF ANY OF THE AFORESAID ACTIONS OR
PROCEEDINGS ARISING OUT OF OR IN CONNECTION WITH THIS NOTE OR THE OTHER LOAN
DOCUMENTS BROUGHT IN THE COURTS REFERRED TO IN CLAUSE (A) ABOVE AND HEREBY
FURTHER WAIVES AND AGREES NOT TO PLEAD OR CLAIM IN ANY SUCH COURT THAT ANY SUCH
ACTION OR PROCEEDING BROUGHT IN ANY SUCH COURT HAS BEEN BROUGHT IN AN
INCONVENIENT FORUM.

         (c) EACH MAKER AND LENDER HEREBY IRREVOCABLY WAIVES ALL RIGHT TO A
TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING OUT OF OR
RELATING TO THIS NOTE OR ANY OTHER LOAN DOCUMENT AND THE TRANSACTIONS
CONTEMPLATED HEREBY AND THEREBY.

<PAGE>

         16. Recourse

                  The Makers shall be jointly and severally subject to full
personal liability, including, without limitation, full recourse to the property
(including the Mortgaged Property) and the assets of the Makers, for the
repayment of any indebtedness evidenced by this Note or the other Loan Documents
to which Borrower is a party and the payment and performance of the other
Obligations, provided that such recourse shall not extend to (i) any officer,
director, employee, agent or representative of any Maker or (ii) any shareholder
of WCG.

         17. Recovery of Judgments

                  The recovery of any judgment by Lender and/or the levy of
execution under any judgment upon the Mortgaged Property, shall not affect in
any manner or to any extent the lien of any of the Loan Documents securing this
Note upon, or any security interest in, the Mortgaged Property, or any rights,
remedies or powers of Lender under any of the Loan Documents, but such liens and
such security interests, and such rights, remedies and powers of Lender, shall
continue unimpaired as before. The exercise by Lender of its rights and
remedies, and the entry of any judgment by Lender shall not adversely affect in
any way the rate of interest payable hereunder on any amounts due to Lender, but
interest shall continue to accrue on such amounts at the Default Rate specified
herein.

         18. No Joint Venture

                  The relationship created under this Note and the other Loan
Documents is solely that of debtor and creditor. Nothing herein or in the other
Loan Documents is intended to create nor shall it create an equity investment on
the part of Lender or a joint venture, partnership, tenancy in common or joint
tenancy relationship between the Makers (individually or collectively) and
Lender or render Lender in any way responsible for any of the debts, losses and
liabilities of the Makers. Lender does not owe any fiduciary obligation under
the Loan Documents or by operation of law to any Maker, or any of their
officers, directors, partners, agents or representatives. The Makers and Lender
agree that each shall report this transaction for income tax purposes, and file
all related tax returns, in a manner consistent with the form of this
transaction as a loan.

         19. Sales and Pledges

                  Lender shall have the right to enter into and consummate any
sale(s) and/or pledge(s) and/or transfers of its interests in the Loan, this
Note and/or the other Loan Documents and the Makers, upon the reasonable request
of Lender and at the expense of the Makers, shall promptly execute, acknowledge,
deliver and record or file such instruments and do such further acts as may be
reasonably necessary, desirable or proper to carry out such right.

         20. Jointly Drawn

                  This Note and the other Loan Documents are the result of a
full and complete negotiation at arms length between the respective parties
hereto and thereto. Accordingly, no prior drafts of the Note or any of the Loan
Documents, or any memoranda prepared by Lender, or any of the Makers shall be
used to construe or interpret any provision of this Note or any other

<PAGE>

Loan Document. Lender and the Makers expressly acknowledge that this Note and
the other Loan Documents were jointly drawn between the Lender and the Makers
and no inference shall therefore be drawn against any of them based upon the
identity of the preparer of this Note and/or the other Loan Documents.

         21. Successors and Assigns

                  This Note inures to the benefit of and binds Lender and the
Makers and their respective permitted successors and assigns, and reference to
such parties whenever occurring herein, shall be deemed to include such party's
respective permitted successors and assigns. However, none of the Makers shall
voluntarily, or by operation of law, assign or transfer any interest which it
may have under the Note or the other Loan Documents without the prior written
approval of Lender, which approval may be withheld in its sole and absolute
discretion.

         22. Nature of WCL's and WCG's Obligations

                  WCL and WCG, by their execution of this Note, unconditionally
and irrevocably agree to be liable for the full and prompt payment and
performance when due of the Obligations if not paid or performed as and when
from time to time due by Borrower, including, without limitation, the payment of
the Loan and all interest, fees and other charges payable hereunder and under
the other Loan Documents. Notwithstanding any characterization of WCL or WCG
herein (or in any other document) as a "maker", "co-maker", "obligor", or
"co-obligor" (or any other word of similar meaning) of this Note, WCL and WCG
shall be jointly and severally liable for and shall be obligated to and they
shall, jointly and severally, pay and perform the Obligations, to the effect
that they jointly and severally hereby guaranty payment and performance of the
Obligations. In the event of the Borrower's failure to do so, each of WCL and
WCG shall, upon Lender's demand, pay and perform the same as though each of them
was, jointly and severally with Borrower, a co-maker with primary (as distinct
from contingent) liability hereunder.

                            [Signature Page Follows]

<PAGE>

                  IN WITNESS WHEREOF, this Note has been executed as of the date
first above written.

                                    BORROWER:

                                    WILLIAMS TECHNOLOGY CENTER, LLC,
                                    a Delaware limited liability company

                                    By: Williams Communications, LLC, a Delaware
                                        limited liability company, its sole
                                        member and manager

                                    By: /s/ Howard S. Kalika
                                        ------------------------
                                        Title: Vice President and Group
                                               Executive, Corporate Development
                                               and Finance and and Assistant
                                               Secretary

                                    GUARANTORS:

                                    WILTEL COMMUNICATIONS GROUP, INC.,
                                    a Nevada corporation

                                    By: /s/ Howard S. Kalika
                                        ------------------------
                                        Title: Vice President and Group
                                               Executive, Corporate Development
                                               and Finance and and Assistant
                                               Secretary

                                    WILLIAMS COMMUNICATIONS, LLC,
                                    a Delaware limited liability company

                                    By: /s/ Howard S. Kalika
                                        ------------------------
                                        Title: Vice President and Group
                                               Executive, Corporate Development
                                               and Finance and and Assistant
                                               Secretary

<PAGE>
--------------------------------------------------------------------------------
SHORT TERM NOTE PAYMENT IN KIND (PIK) AMORTIZATION SCHEDULE

Original Principal Balance of $44,800,000.00

Interest Rate Periods Per the Grid in Section 1(a) of the Short Term Note

Based upon the Closing Date: 10/15/02

Accrued Interest Paid In Kind in Arrears and Capitalized Annually at the
   beginning of the next Interest Rate Period

Full Payment of Principal and Accrued Interest of $74,360,295.30 Due on Maturity
   Date of December 29, 2006

<Table>
<Caption>
   Period         Date         Interest Rate    Principal Balance         Payment In Kind       Accrued Interest
   ------         ----         -------------    -----------------         ---------------       ----------------
<S>             <C>            <C>              <C>                       <C>                   <C>
     0          10/15/02                        $   44,800,000.00

     1          11/01/02          10.00%                                                            $199,111.11

     2          12/01/02          10.00%                                                            $373,333.33

     3          01/01/03          10.00%                                                            $373,333.33

     4          02/01/03          10.00%                                                            $373,333.33

     5          03/01/03          10.00%                                                            $373,333.33

     6          04/01/03          10.00%                                                            $373,333.33

     7          05/01/03          10.00%                                                            $373,333.33

     8          06/01/03          10.00%                                                            $373,333.33

     9          07/01/03          10.00%                                                            $373,333.33

     10         08/01/03          10.00%                                                            $373,333.33

     11         09/01/03          10.00%                                                            $373,333.33

     12         10/01/03          10.00%                                                            $373,333.33

     13         11/01/03          10.00%                                                            $373,333.33

     14         12/01/03          10.00%                                                            $373,333.33

     15         01/01/04          10.00%        $   50,225,777.78             $5,425,777.78         $373,333.33

     16         02/01/04          12.00%                                                            $502,257.78

     17         03/01/04          12.00%                                                            $502,257.78

     18         04/01/04          12.00%                                                            $502,257.78

     19         05/01/04          12.00%                                                            $502,257.78

     20         06/01/04          12.00%                                                            $502,257.78

     21         07/01/04          12.00%                                                            $502,257.78

     22         08/01/04          12.00%                                                            $502,257.78

     23         09/01/04          12.00%                                                            $502,257.78

     24         10/01/04          12.00%                                                            $502,257.78

     25         11/01/04          12.00%                                                            $502,257.78

     26         12/01/04          12.00%                                                            $502,257.78

     27         01/01/05          12.00%        $    56,252,871.11            $6,027,093.33         $502,257.78

     28         02/01/05          14.00%                                                            $656,283.50

     29         03/01/05          14.00%                                                            $656,283.50
</Table>

<PAGE>

<Table>
<Caption>
   Period         Date         Interest Rate    Principal Balance         Payment In Kind       Accrued Interest
   ------         ----         -------------    -----------------         ---------------       ----------------
<S>             <C>            <C>              <C>                       <C>                   <C>
     30         04/01/05          14.00%                                                            $656,283.50

     31         05/01/05          14.00%                                                            $656,283.50

     32         06/01/05          14.00%                                                            $656,283.50

     33         07/01/05          14.00%                                                            $656,283.50

     34         08/01/05          14.00%                                                            $656,283.50

     35         09/01/05          14.00%                                                            $656,283.50

     36         10/01/05          14.00%                                                            $656,283.50

     37         11/01/05          14.00%                                                            $656,283.50

     38         12/01/05          14.00%                                                            $656,283.50

     39         01/01/06          14.00%        $    64,128,273.07            $7,875,401.96         $656,283.50

     40         02/01/06          16.00%                                                            $855,043.64

     41         03/01/06          16.00%                                                            $855,043.64

     42         04/01/06          16.00%                                                            $855,043.64

     43         05/01/06          16.00%                                                            $855,043.64

     44         06/01/06          16.00%                                                            $855,043.64

     45         07/01/06          16.00%                                                            $855,043.64

     46         08/01/06          16.00%                                                            $855,043.64

     47         09/01/06          16.00%                                                            $855,043.64

     48         10/01/06          16.00%                                                            $855,043.64

     49         11/01/06          16.00%                                                            $855,043.64

     50         12/01/06          16.00%                                                            $855,043.64

     51         12/29/06          16.00%        $    74,360,295.30           $10,232,022.24         $826,542.19
</Table>

<PAGE>

                                                                  CONFORMED COPY

                                 LONG TERM NOTE

$100,000,000
                                                                October 15, 2002

                  FOR VALUE RECEIVED, the undersigned, WILLIAMS TECHNOLOGY
CENTER, LLC, a Delaware limited liability company having an address at One
Technology Center, Tulsa, OK 74103 ("Borrower"), and, for the sole purpose and
to the effect specified in Paragraph 22 hereof, WILTEL COMMUNICATIONS GROUP,
INC., a Nevada corporation (formerly known as Williams Communications Group,
Inc., a Delaware corporation, prior to its reorganization pursuant to the Plan)
having an address at One Technology Center, Tulsa, OK 74103 ("WCG"), and
WILLIAMS COMMUNICATIONS, LLC, a Delaware limited liability company having an
address at One Technology Center, Tulsa, OK 74103 ("WCL"), (Borrower, WCG and
WCL being sometimes individually referred to herein as a "Maker" and
collectively as the "Makers") jointly and severally, irrevocably, absolutely and
unconditionally promise to pay WILLIAMS HEADQUARTERS BUILDING COMPANY, a
Delaware corporation which, together with its successors and assigns of its
interest in this note (this "Note"), is referred to in this Note as "Lender", at
The Williams Companies, Inc., Attn: Corporate Treasury, Mail Drop 50-4, One
Williams Center, Tulsa, Oklahoma 74172, or such other place as Lender may from
time to time designate, the principal sum of ONE HUNDRED MILLION DOLLARS
($100,000,000) (the "Loan"), together with interest on unpaid principal from the
date hereof to the date paid at the rate of seven percent (7%) per annum with
principal and interest payable in the manner specified below in lawful money of
the United States. All capitalized terms used herein but not defined herein
shall have the meanings ascribed to such terms in the Mortgage (as defined in
Paragraph 2 hereof).

                  WHEREAS, Borrower is a wholly owned subsidiary of WCL and WCL
is a wholly owned subsidiary of WCG;

                  WHEREAS, each Maker will obtain benefits from Lender's making
the Loan and, in order to induce Lender to make the Loan, WCL and WCG have
agreed to perform their obligations set forth herein; and

                  WHEREAS, it is a condition precedent to Lender's making the
Loan to Borrower that Borrower and the other Makers shall have executed and
delivered this Note;

                  NOW, THEREFORE, to satisfy the condition in the preceding
paragraph and to induce Lender to make the Loan, in consideration thereof, and
in consideration of the benefits to accrue to the Makers therefrom, the receipt
and sufficiency of which are hereby acknowledged by the Makers, the Makers
jointly and severally agree and covenant to comply with the terms and provisions
hereof.

         1. Payment of Principal and Interest

                  Principal and interest shall be payable as follows:

<PAGE>

                  1.1.     Installments of Principal and Interest

                  (a) On the first day of the first calendar month after the
         date hereof (the "Initial Date"), Borrower shall pay to Lender an
         installment of interest equal to the amount of interest that has
         accrued on and from the date hereof up to and including the final day
         of the month prior to the Initial Date.

                  (b) Commencing on the Initial Date and continuing thereafter
         on the first day of each of the following months for a total of ninety
         (90) calendar months, Borrower shall pay to Lender installments of
         principal and interest each in the amounts and on the dates specified
         in Schedule A attached hereto, subject to adjustment pursuant to
         Paragraph 13(b). The amount of each such constant monthly installment
         specified in Schedule A is based on amortization of the initial
         principal amount of the Loan specified above and accrued interest on
         unpaid principal at the rate of seven percent (7%) per annum in 360
         monthly installments and based on payment in advance (i.e., not in
         arrears).

                  (c) The entire unpaid principal balance of this Note and all
         accrued but unpaid interest under this Note and all other sums payable
         under this Note and the Loan Documents (as defined in Paragraph 2
         hereof) shall be due and payable in full on April 1, 2010 or such
         earlier date as same may become due and payable pursuant to the terms
         hereof (the "Maturity Date").

                  (d) All payments by Borrower on account of principal and
         interest and any fees and charges payable hereunder or under any other
         Loan Document shall be made to Lender unconditionally and without
         deduction, setoff or counterclaim of any kind. If any payment hereunder
         becomes due and payable on a day which is not a Business Day (as
         hereinafter defined), the maturity thereof shall be extended to the
         next succeeding Business Day. As used herein, "Business Day" shall mean
         a day other than a Saturday, Sunday or day on which banks are
         authorized to be closed in Tulsa, Oklahoma.

                  (e) Payments in federal funds immediately available in the
         place designated for payment received by Lender prior to 2:00 p.m.
         local time at the place of payment on a day in which Lender is open for
         business shall be credited prior to the close of business. Any payment
         received after 2:00 p.m. local time at said place of payment on a day
         on which Lender is open for business shall be deemed to be received on
         the next succeeding Business Day.

                  (f) Except as provided in Paragraph 13 hereof, each monthly
         installment paid pursuant to Paragraph 1.1(b) hereof shall be applied
         first to the payment of accrued interest and then to reduction of
         principal. All other payments received under this Note shall be applied
         to any outstanding fees, charges, advances, interest and principal in
         such order and amounts as Lender shall determine in its sole
         discretion.

                  (g) In the event that at any time any payment received by
         Lender hereunder shall be deemed by a court of competent jurisdiction
         to have been a voidable preference or fraudulent conveyance under any
         bankruptcy, insolvency or other debtor relief law, then the obligation
         to make such payment shall survive any cancellation or satisfaction of

<PAGE>

         this Note or return thereof to the Makers and shall not be discharged
         or satisfied with any prior payment thereof or cancellation of this
         Note, but shall remain a valid and binding obligation enforceable in
         accordance with the terms and provisions hereof, and such payment shall
         be due and payable upon demand.

                  1.2 Calculation of Interest

                  Interest payable on the unpaid principal balance shall be
calculated on the basis of a three hundred sixty (360) day year consisting of
twelve (12) months of thirty (30) days each.

         2. Security

                  This Note is secured by that certain Mortgage with Power of
Sale, Security Agreement, Assignment of Leases, Rents and Profits, Financing
Statement and Fixture Filing, of even date herewith, made by Borrower to Lender
(the "Mortgage") to be recorded in the County Clerk's Office of Tulsa County,
Oklahoma and that certain Pledge Agreement, of even date herewith, made by CG
Austria, Inc., a Delaware corporation to Lender (the "Pledge") (this Note, the
Short-Term Note, the Mortgage, the Pledge and any other documents or instruments
now or hereinafter entered into from time to time further evidencing or securing
the indebtedness evidenced hereby, as the same may be amended, restated,
replaced, supplemented or otherwise modified from time to time, being
collectively referred to herein as the "Loan Documents").

         3. Default; Acceleration

                  Upon the occurrence and during the continuance of any "Event
of Default" (as defined in the Mortgage) (an "Event of Default"), the entire
principal sum and all other sums payable hereunder and under the Loan Documents,
together with all accrued interest thereon, shall at the option of Lender,
immediately become due and payable, without notice or demand. Failure to
exercise this option shall not constitute a waiver of the right to exercise same
in the event of any subsequent Event of Default.

         4. Late Payment Charge; Default Interest

                  In addition to the payment of all principal, interest and
other fees or expenses payable under this Note, if any payment under this Note
(whether of principal, interest or other fees or expenses and including the
payment due on the Maturity Date) (i) is, more than two (2) times in any twelve
(12) month period, not paid by the due date thereof, the Borrower shall pay to
Lender without any requirement of notice or demand by Lender, a late payment
charge equal to two percent (2%) of the amount of the delinquent payment, and
(ii) is not paid by the date which is five (5) days after the due date thereof,
then such unpaid amounts hereunder, together with all accrued but unpaid
interest thereon, shall, on and from the original due date without any
requirement of notice or demand by Lender, bear interest at the rate of nine
percent (9)% per annum (the "Default Rate"), instead of at the rate of seven
percent (7%) per annum. THE MAKERS ACKNOWLEDGE AND AGREE THAT (x) LENDER'S
ACTUAL DAMAGES RESULTING FROM ANY SUCH DEFAULT OR DELINQUENCY AND RELATING TO
LOST USE OF FUNDS AND COSTS OF INTERNAL ADMINISTRATION OF DELINQUENT PAYMENTS
HEREUNDER OR RELATING TO SUCH DEFAULT WOULD BE EXTREMELY DIFFICULT TO ASCERTAIN,
AND (y) UNDER THE CIRCUMSTANCES

<PAGE>

IN EXISTENCE AS OF THE DATE HEREOF, INTEREST HEREUNDER ACCRUED AT THE DEFAULT
RATE AND SUCH LATE CHARGE CONSTITUTE A REASONABLE LIQUIDATION OF SUCH DAMAGES
AND DO NOT CONSTITUTE A PENALTY. No provision of this Note (including without
limitation the provisions for a late payment charge, accrual of interest at the
Default Rate, or for the continued accrual of interest on any amounts remaining
unpaid after the Maturity Date) shall be construed as in any way excusing
Borrower from its obligations to make each payment as and when due under this
Note. Acceptance by Lender of any late charge and/or interest at the Default
Rate shall not be deemed a waiver of any of Lender's rights and remedies
hereunder or under the other Loan Documents.

         5. Costs of Collection

                  The Makers jointly and severally promise to pay (a) all costs
and expenses reasonably incurred, including, without limitation, attorneys' fees
and disbursements, if this Note or any portion of this Note is placed in the
hands of any attorney for collection and such collection is effected without
suit; (b) out-of-pocket attorneys' fees and disbursements reasonably incurred
and all other costs, expenses and fees reasonably incurred by Lender in
enforcing its rights under this Note or the other Loan Documents, including,
without limitation, the institution of a judicial or foreclosure sale or other
power of sale or a suit to collect all or any portion of amounts owing hereunder
or thereunder or any appeals therefrom, until payment of the full amount due to
Lender is made; and (c) all out-of-pocket costs and expenses reasonably incurred
by Lender (including, without limitation, actual attorneys' fees and
disbursements) in connection with any bankruptcy, insolvency or reorganization
proceeding or receivership involving any of the Makers, including, without
limitation, attorneys' fees and disbursements reasonably incurred in making any
appearances in any such proceeding or in seeking relief from any stay or
injunction issued in or arising out of any such proceeding or any appeals
therefrom.

         6. Certain Waivers

                  Except as otherwise expressly specified in this Note, the
Mortgage or any of the other Loan Documents, each of the Makers jointly and
severally waive diligence, grace, demand, presentment for payment, exhibition of
this Note, protest and notice of protest and notice of nonpayment. Any payment
by any of the Makers or other circumstance which by operation of law tolls any
statute of limitations as to any of the Makers shall operate to toll the statute
of limitations as to all of them. From time to time, without affecting the
obligation of the Makers to pay the outstanding principal balance of this Note
and observe the covenants contained herein, without giving notice to or
obtaining the consent of the Makers, and without liability on the part of
Lender, Lender may, at the option of Lender, extend the time for payment of said
outstanding principal balance, or any part thereof, reduce the payments thereon,
release anyone liable for any of said outstanding principal balance, accept a
renewal of this Note, join in any extension or subordination agreement, release
any security given in respect hereof, take or release other or additional
security, and agree in writing with the Makers to modify the rate of interest or
period of amortization of this Note or change the amount of the monthly
installments payable hereunder.

                  No single or partial exercise of any power, right or privilege
of Lender hereunder or under the other Loan Documents and no course of dealing
between the Lender on the one

<PAGE>

hand and any one or more of the Makers on the other hand, shall operate as a
waiver of or preclude other and further exercise thereof or the exercise of any
other power, right or privilege of Lender. Lender shall at all times have the
right to proceed against any portion of the Mortgaged Property pursuant to and
in accordance with the Mortgage and/or against any one or more of the Makers in
such order and in such manner as Lender may deem fit, without waiving any rights
with respect to any of the other Makers or other portion of the Mortgaged
Property. No delay, action or omission on the part of Lender in exercising any
right or remedy hereunder shall operate or be construed as a waiver or release
of (i) such right or remedy or of any other right or remedy of Lender, (ii) any
liability or obligation of the Makers hereunder or under the other Loan
Documents or (iii) an Event of Default. The rights and remedies of Lender herein
provided are cumulative and not exclusive of any other rights or remedies which
the Lender would have hereunder, under the other Loan Documents or at law or in
equity.

         7. Loss, Theft, Destruction or Mutilation of Note

                  In the event of the loss, theft or destruction of this Note,
upon Borrower's receipt of a reasonably satisfactory indemnification agreement
executed in favor of the Makers by the party who held this Note immediately
prior to its loss, theft or destruction, or in the event of the mutilation of
this Note, upon Lender's surrender to Borrower of the mutilated Note, the Makers
shall execute and deliver to such party or Lender, as the case may be, a new
promissory note in form and content identical to this Note in replacement of the
lost, stolen, destroyed or mutilated Note.

         8. Notices

                  Any notice and other communication required or desired to be
given or delivered under this Note shall be made in accordance with the notice
provisions of the Mortgage directed to the intended party at its respective
address set forth on the first page hereof.

         9. Time of Essence

                  Time is of the essence in the performance of each and every
provision of this Note.

         10. Severability

                  If any provision of this Note or the other Loan Documents
shall for any reason be held unenforceable or void by a court of competent
jurisdiction in any respect, then such provision shall be deemed separable from
the remaining provisions hereof and shall in no way affect any other provision
or the validity of this Note.

         11. Amendment or Waiver; etc.

                  This Note may not be changed, extended, modified, or amended
except by an instrument in writing signed by Lender and the Makers and none of
the rights or benefits of Lender hereunder can be waived except in a written
instrument signed by Lender.

<PAGE>

         12. Governing Law

                  This Note shall be governed by and construed and interpreted
in accordance with the laws of the State of Oklahoma, without regard to
conflicts of laws principles. To the fullest extent permitted by applicable law,
each of Lender on the one hand and the Makers jointly and severally on the other
hand, hereby unconditionally and irrevocably waive any claim to assert that the
laws of any other jurisdiction govern this Note and acknowledge and agree that
this Note represents its knowing, voluntary and conscious decision made with
full advice of counsel, and that the State of Oklahoma has a substantial
relationship to the parties hereto and the transactions contemplated hereby.

         13. Prepayment

                  (a) Borrower shall have the right without any premium or
penalty to prepay in whole or in part, at any time from time to time, the
principal amount outstanding under this Note, provided that, in the case of
prepayment in whole, Lender shall simultaneously receive in immediately
available funds, in addition to the entire principal amount outstanding under
this Note as of the date of prepayment, (i) all interest accrued and unpaid as
of the date of prepayment and (ii) all other sums owing under this Note and
under the other Loan Documents.

                  In the case of a partial prepayment by Borrower, such payment
shall be made in immediately available funds and applied by Lender in the
following order: (i) first, to all interest accrued under the Loan Documents and
unpaid as of the date of prepayment on the principal amount being prepaid, (ii)
second, to all other sums then due and owing under this Note (other than
principal) and under the other Loan Documents, and (iii) third, to the
outstanding principal balance under this Note, without reduction in the amount
of the monthly installments payable pursuant to the terms hereof.

                  (b) If TWC has transferred to WCL the entire ownership
interest in the entity holding title to the Aircraft, WCL, having the exclusive
right to do so, shall dispose of the Aircraft on commercially reasonable terms
and at market rates, and shall cause the net proceeds of any such disposition
(collectively, a "Disposition") to be paid at the closing of such Disposition to
Lender. If such Disposition does not occur on or before April 13, 2003, which is
180 days after the date hereof (the "Termination Date"), then WCL shall pay to
Lender within three (3) Business Days after the Termination Date, an amount (the
"Fee") equal to 3 times the difference between (a) the amount of the last
(monthly) installment of Rent (as such term is defined in each Aircraft Dry
Lease) under each of the Aircraft Dry Leases which would have been payable prior
to the Termination Date if the Aircraft Dry Leases were then still in effect and
(b) that portion of the Monthly Debt Service (as defined below) payment which is
attributable to $20,000,000 of principal under this Note. The Fee shall not be
applied against the principal of this Note. On the Termination Date, all accrued
and unpaid interest on this Note, together with interest which would accrue
thereunder through the last day of the month in which such Termination Date
occurs, shall be paid commencing with the installment of Rent which is due on
the first day of the second month which commences after the Termination Date.
Thereafter, the monthly installments of principal and interest payable by
Borrower under this Note (hereinafter, in this Paragraph 13(b), the "Monthly
Debt Service") shall be changed to equal the sum of (A) the monthly payment
amount which would be necessary to amortize a principal amount of

<PAGE>
$80,000,000 with interest on the unpaid principal thereof at a rate of 7% per
annum in equal monthly installments over 360 months (but there shall be no
corresponding reduction of the principal amount of this Note or extension of the
maturity date thereof); and (B) the monthly Rent which would have been payable
under each of the Aircraft Dry Leases (if they were then still in effect). A
portion of each monthly Rent payment referred to in clause (B) above equal to
the sum of the portions of the corresponding payments for the corresponding
month under the Aircraft Dry Leases which would have been applied to principal
thereunder (the "Allocated Lease Principal") shall be applied against the
principal of this Note. Thereafter, upon the Disposition of the Aircraft, and
application of the proceeds thereof against the principal of this Note (i) the
sums specified in clause (B) above shall no longer be payable; and (ii) the
fixed monthly payment amount referred to in clause (A) above shall, for the
period commencing on the date of such Disposition and continuing thereafter for
the remainder of the period to the scheduled maturity date of this Note, be
changed to equal the product of (x) the original Monthly Debt Service under this
Note and (y) a fraction, the numerator of which is $100,000,000 minus (without
duplication) the Allocated Lease Principal, minus all other principal payments
made under this Note and minus net proceeds of the Disposition of the Aircraft
which were applied to reduce the outstanding principal of this Note, and the
denominator of which is $100,000,000. Any net proceeds from the sale of the
Aircraft Dry Leases or the Disposition of the Aircraft received by Lender or any
of its Affiliates after the date hereof shall be applied to reduce the principal
balance of this Note in accordance with the terms hereof.

                  (c) (i) If within one year after the date hereof, Borrower or
any of its Affiliates directly or indirectly exchanges or disposes of (or enters
into an agreement or agreements with respect thereto) any or all of the Acquired
Assets (to any transferee other than an entity which has the same ultimate
beneficial ownership as the transferor had immediately prior to such transfer)
for an aggregate sales price in cash, obligations or other consideration in an
amount greater than One Hundred Fifty Million Dollars ($150,000,000), Borrower
shall, on the date on which the consummation of such a transaction occurs, (i)
prepay the entire principal of this Note and all accrued and unpaid interest
thereon and all other sums payable under this Note and the other Loan Documents
in full and (ii) pay to Lender in immediately available funds (except as
provided in Paragraph 13(c)(ii) below) to an account designated by Lender in
writing, an amount equal to the product of (x) Fifty Percent (50%) multiplied by
(y) the excess of the aggregate sales price over (A) One Hundred Fifty Million
Dollars ($150,000,000) less (B) the amount equal to the (i) aggregate
consideration received by Lender, or any of its Affiliates, in connection with
the disposition of the Aircraft Dry Leases or (ii) the amount of proceeds
received by Lender or any of its Affiliates in connection with the refinancing
of the Aircraft pursuant to Paragraph 13(b), which obligations are secured by
the Mortgage. Borrower agrees that it will notify Lender in writing no later
than three (3) Business Days prior to entering into a transaction or agreement
of the type specified in this Paragraph 13(c).

                  (ii) In the event the consideration received or to be received
by Borrower in a transaction of the type set forth in Paragraph 13(c)(i) is to
be paid in whole or in part other than in Dollars, for purposes of Paragraph
13(c)(i), the value of such consideration shall be mutually agreed between
Borrower and Lender. Notwithstanding anything in this Paragraph 13 to the
contrary, in the event Borrower receives non-Dollar consideration in a
transaction of the type set forth in Paragraph 13(c)(i), unless otherwise agreed
between Borrower and Lender, any payment by Borrower to Lender under Paragraph
13(c)(i) shall be made pro rata (based on the amount of

<PAGE>

non-Dollar consideration relative to the amount of Dollar consideration received
by Lender in such transaction(s)) in such non-Dollar consideration.

                  (d) No principal amount repaid may be reborrowed.

         14. Usury Laws

                  This Note and the other Loan Documents are subject to the
express condition that at no time shall any Maker be obligated or required to
pay interest on the Obligations at a rate which could subject the holder of this
Note either to civil or criminal liability as a result of being in excess of the
maximum interest rate which is permitted by applicable law. If, by the terms of
this Note and the other Loan Documents, any Maker is at any time required or
obligated to pay interest on the Obligations at a rate in excess of such maximum
rate, the rate of interest under the same shall be deemed to be immediately
reduced to such maximum rate and the interest payable shall be computed at such
maximum rate and all prior interest payments in excess of such maximum rate, to
the extent permitted by law, shall be applied, at the option of Lender, against
any sums outstanding in such order as Lender may determine. The right to
accelerate this Note pursuant to Paragraph 3 hereof does not include a right to
require payment of any interest which has not otherwise accrued by the date of
such acceleration, and Lender does not intend to collect any unearned interest
in the event of acceleration; provided, however, that Lender shall, to the
extent specified herein, be entitled to receive interest at the applicable rate
herein specified on any amounts payable pursuant to this Note through the date
collected.

         15. Consent to Jurisdiction; Waiver of Jury Trial

                  (a) ANY LEGAL ACTION OR PROCEEDING WITH RESPECT TO THIS NOTE
OR THE OTHER LOAN DOCUMENTS MAY BE BROUGHT IN THE STATE AND FEDERAL COURTS
LOCATED IN THE COUNTY OF TULSA, OKLAHOMA AND BY EXECUTION AND DELIVERY OF THIS
NOTE, EACH MAKER HEREBY IRREVOCABLY ACCEPTS FOR ITSELF AND IN RESPECT OF ITS
PROPERTY (INCLUDING THE MORTGAGED PROPERTY), GENERALLY AND UNCONDITIONALLY, THE
JURISDICTION OF THE AFORESAID COURTS WITH RESPECT TO ANY SUCH ACTION OR
PRECEDING. EACH MAKER HEREBY FURTHER IRREVOCABLY WAIVES ANY CLAIM THAT ANY SUCH
COURTS LACK PERSONAL JURISDICTION OVER IT, AND AGREES NOT TO PLEAD OR CLAIM, IN
ANY LEGAL ACTION OR PROCEEDING WITH RESPECT TO THIS NOTE OR THE OTHER LOAN
DOCUMENTS BROUGHT IN ANY OF THE AFOREMENTIONED COURTS, THAT SUCH COURTS LACK
PERSONAL JURISDICTION OVER THE MAKERS. EACH MAKER FURTHER IRREVOCABLY CONSENTS
TO THE SERVICE OF PROCESS OUT OF ANY OF THE AFOREMENTIONED COURTS IN ANY SUCH
ACTION OR PROCEEDING BY, IN ADDITION TO SUCH OTHER METHODS AS ARE PERMITTED
UNDER APPLICABLE LAW, THE MAILING OF COPIES THEREOF BY REGISTERED OR CERTIFIED
MAIL, POSTAGE PREPAID, TO IT AT ITS ADDRESS FOR NOTICES PURSUANT TO PARAGRAPH 8
HEREOF, SUCH SERVICE TO BECOME EFFECTIVE THIRTY (30) DAYS AFTER SUCH MAILING.
EACH MAKER HEREBY IRREVOCABLY WAIVES ANY OBJECTION TO SUCH SERVICE OF PROCESS
AND FURTHER IRREVOCABLY WAIVES AND AGREES NOT TO PLEAD OR CLAIM IN ANY ACTION OR
PROCEEDING COMMENCED HEREUNDER THAT

<PAGE>

SERVICE OF PROCESS WAS IN ANY WAY INVALID OR INEFFECTIVE. NOTHING HEREIN SHALL
AFFECT THE RIGHT OF LENDER TO SERVE PROCESS IN ANY OTHER MANNER PERMITTED BY LAW
OR TO COMMENCE LEGAL PROCEEDINGS OR OTHERWISE PROCEED AGAINST ANY OF THE MAKERS
IN ANY OTHER JURISDICTION.

                  (b) EACH MAKER HEREBY WAIVES ANY OBJECTION WHICH IT MAY NOW OR
HEREAFTER HAVE TO THE LAYING OF VENUE OF ANY OF THE AFORESAID ACTIONS OR
PROCEEDINGS ARISING OUT OF OR IN CONNECTION WITH THIS NOTE OR THE OTHER LOAN
DOCUMENTS BROUGHT IN THE COURTS REFERRED TO IN CLAUSE (A) ABOVE AND HEREBY
FURTHER WAIVES AND AGREES NOT TO PLEAD OR CLAIM IN ANY SUCH COURT THAT ANY SUCH
ACTION OR PROCEEDING BROUGHT IN ANY SUCH COURT HAS BEEN BROUGHT IN AN
INCONVENIENT FORUM.

                  (c) EACH MAKER AND LENDER HEREBY IRREVOCABLY WAIVES ALL RIGHT
TO A TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING OUT OF OR
RELATING TO THIS NOTE OR ANY OTHER LOAN DOCUMENT AND THE TRANSACTIONS
CONTEMPLATED HEREBY AND THEREBY.

         16. Recourse

                  The Makers shall be jointly and severally subject to full
personal liability, including, without limitation, full recourse to the property
(including the Mortgaged Property) and the assets of the Makers, for the
repayment of any indebtedness evidenced by this Note or the other Loan Documents
to which Borrower is a party and the payment and performance of the other
Obligations, provided that such recourse shall not extend to (i) any officer,
director, employee, agent or representative of any Maker or (ii) any shareholder
of WCG.

         17. Recovery of Judgments

                  The recovery of any judgment by Lender and/or the levy of
execution under any judgment upon the Mortgaged Property, shall not affect in
any manner or to any extent the lien of any of the Loan Documents securing this
Note upon, or any security interest in, the Mortgaged Property, or any rights,
remedies or powers of Lender under any of the Loan Documents, but such liens and
such security interests, and such rights, remedies and powers of Lender, shall
continue unimpaired as before. The exercise by Lender of its rights and
remedies, and the entry of any judgment by Lender shall not adversely affect in
any way the rate of interest payable hereunder on any amounts due to Lender, but
interest shall continue to accrue on such amounts at the Default Rate specified
herein.

         18. No Joint Venture

                  The relationship created under this Note and the other Loan
Documents is solely that of debtor and creditor. Nothing herein or in the other
Loan Documents is intended to create nor shall it create an equity investment on
the part of Lender or a joint venture, partnership, tenancy in common or joint
tenancy relationship between the Makers (individually or

<PAGE>

collectively) and Lender or render Lender in any way responsible for any of the
debts, losses and liabilities of the Makers. Lender does not owe any fiduciary
obligation under the Loan Documents or by operation of law to any Maker, or any
of their officers, directors, partners, agents or representatives. The Makers
and Lender agree that each shall report this transaction for income tax
purposes, and file all related tax returns, in a manner consistent with the form
of this transaction as a loan.

         19. Sales and Pledges

                  Lender shall have the right to enter into and consummate any
sale(s) and/or pledge(s) and/or transfers of its interests in the Loan, this
Note and/or the other Loan Documents and the Makers, upon the reasonable request
of Lender and at the expense of the Makers, shall promptly execute, acknowledge,
deliver and record or file such instruments and do such further acts as may be
reasonably necessary, desirable or proper to carry out such right.

         20. Jointly Drawn

                  This Note and the other Loan Documents are the result of a
full and complete negotiation at arms length between the respective parties
hereto and thereto. Accordingly, no prior drafts of the Note or any of the Loan
Documents, or any memoranda prepared by Lender, or any of the Makers shall be
used to construe or interpret any provision of this Note or any other Loan
Document. Lender and the Makers expressly acknowledge that this Note and the
other Loan Documents were jointly drawn between the Lender and the Makers and no
inference shall therefore be drawn against any of them based upon the identity
of the preparer of this Note and/or the other Loan Documents.

         21. Successors and Assigns

                  This Note inures to the benefit of and binds Lender and the
Makers and their respective permitted successors and assigns, and reference to
such parties whenever occurring herein, shall be deemed to include such party's
respective permitted successors and assigns. However, none of the Makers shall
voluntarily, or by operation of law, assign or transfer any interest which it
may have under the Note or the other Loan Documents without the prior written
approval of Lender, which approval may be withheld in its sole and absolute
discretion.

         22. Nature of WCL's and WCG's Obligations

                  WCL and WCG, by their execution of this Note, unconditionally
and irrevocably agree to be liable for the full and prompt payment and
performance when due of the Obligations if not paid or performed as and when
from time to time due by Borrower, including, without limitation, the payment of
the Loan and all interest, fees and other charges payable hereunder and under
the other Loan Documents. Notwithstanding any characterization of WCL or WCG
herein (or in any other document) as a "maker", "co-maker", "obligor", or
"co-obligor" (or any other word of similar meaning) of this Note, WCL and WCG
shall be jointly and severally liable for and shall be obligated to and they
shall, jointly and severally, pay and perform the Obligations, to the effect
that they jointly and severally hereby guaranty payment and performance of the
Obligations. In the event of the Borrower's failure to do so, each of WCL and
WCG shall, upon Lender's demand, pay and perform the same as though each of them
was,

<PAGE>

jointly and severally with Borrower, a co-maker with primary (as distinct from
contingent) liability hereunder.

                            [Signature Page Follows]

<PAGE>

                  IN WITNESS WHEREOF, this Note has been executed as of the date
first above written.

                                 BORROWER:

                                 WILLIAMS TECHNOLOGY CENTER, LLC,
                                 a Delaware limited liability company

                                 By:  Williams Communications, LLC, a Delaware
                                      limited liability company, its sole member
                                      and manager

                                 By: /s/ Howard S. Kalika
                                     ------------------------
                                     Title: Vice President and Group Executive,
                                            Corporate Development and Finance
                                            and and Assistant Secretary

                                 GUARANTORS:

                                 WILTEL COMMUNICATIONS GROUP, INC.,
                                 a Nevada corporation

                                 By: /s/ Howard S. Kalika
                                     ------------------------
                                     Title: Vice President and Group Executive,
                                            Corporate Development and Finance
                                            and and Assistant Secretary

                                 WILLIAMS COMMUNICATIONS, LLC,
                                 a Delaware limited liability company

                                 By: /s/ Howard S. Kalika
                                     ------------------------
                                     Title: Vice President and Group Executive,
                                            Corporate Development and Finance
                                            and and Assistant Secretary

<PAGE>

                                                                  CONFORMED COPY

                                                       This document is intended
                                                               to be recorded in
                                                          Tulsa County, Oklahoma

This Mortgage was prepared by
and when recorded should be returned to:

Roger W. Noble
White & Case LLP
1155 Avenue of the Americas
New York, New York  10036
(212)819-8970
1149477/0008

                MORTGAGE WITH POWER OF SALE, SECURITY AGREEMENT,

                    ASSIGNMENT OF LEASES, RENTS AND PROFITS,

                     FINANCING STATEMENT AND FIXTURE FILING

                                     made by

                         WILLIAMS TECHNOLOGY CENTER, LLC

                                as the Mortgagor,

                                       to

                     WILLIAMS HEADQUARTERS BUILDING COMPANY

                                as the Mortgagee

--------------------------------------------------------------------------------

A POWER OF SALE HAS BEEN GRANTED IN THIS MORTGAGE. A POWER OF SALE MAY ALLOW THE
MORTGAGEE TO TAKE THE MORTGAGED PROPERTY AND SELL IT WITHOUT GOING TO COURT IN A
FORECLOSURE ACTION UPON DEFAULT BY THE MORTGAGOR UNDER THIS MORTGAGE.

<PAGE>

                MORTGAGE WITH POWER OF SALE, SECURITY AGREEMENT,
                    ASSIGNMENT OF LEASES, RENTS AND PROFITS,
                     FINANCING STATEMENT AND FIXTURE FILING

                  THIS MORTGAGE WITH POWER OF SALE, SECURITY AGREEMENT,
ASSIGNMENT OF LEASES, RENTS AND PROFITS, FINANCING STATEMENT AND FIXTURE FILING,
dated as of October 15, 2002 (as amended, restated, modified or supplemented
from time to time, this "Mortgage"), made by WILLIAMS TECHNOLOGY CENTER, LLC, a
Delaware limited liability company (the "Mortgagor"), having an address at One
Technology Center, Mail Drop 15, Tulsa, Oklahoma 74103, as the mortgagor, to
WILLIAMS HEADQUARTERS BUILDING COMPANY, a Delaware corporation (together with
any successor mortgagee, the "Mortgagee"), having an address at One Williams
Center, Mail Drop 41-3, Tulsa, Oklahoma 74172, as the mortgagee.

                  All capitalized terms used but not otherwise defined herein
shall have the same meanings ascribed to such terms in the Note described below.

                                   WITNESSETH:

                  WHEREAS, the Mortgagee as seller, the Mortgagor as purchaser,
Wiltel Communications Group, Inc., a Nevada corporation, formerly known as
Williams Communications Group, Inc., a Delaware corporation, prior to its
reorganization pursuant to the Plan ("WCG"), Williams Communications, LLC, a
Delaware limited liability company ("WCL") and Williams Aircraft Leasing, LLC
are parties to that certain Real Property Purchase and Sale Agreement dated as
of July 26, 2002 (as amended, the "Purchase Agreement");

                  WHEREAS, in consideration of the benefits to the Mortgagor
derived from the Purchase Agreement, and the Mortgagee's performance of its
obligations thereunder (including, without limitation, the Mortgagee's
conveyance of the Land and Improvements (each as hereinafter defined) to the
Mortgagor pursuant thereto) the Mortgagor, WCG, and WCL executed and delivered
to the Mortgagee as payee, (a) a promissory note dated as of even date herewith
in the original principal amount of $100,000,000, with a maturity date of April
1, 2010 or such earlier date to which it may be accelerated pursuant to the
terms thereof (as hereafter amended, extended, replaced, restated, supplemented,
restructured, increased or refinanced from time to time, "Long-Term Note"); and
(b) a promissory note dated as of even date herewith in the aggregate (principal
and interest) amount of $74,360,295.30 with a maturity date of December 29, 2006
or such earlier date to which it may be accelerated pursuant to the terms
thereof (as hereafter amended, extended, replaced, restated, supplemented,
restructured, increased or refinanced from time to time, the "Short-Term Note");

                  WHEREAS, the Mortgagor is a wholly owned direct subsidiary of
WCL and WCL is a wholly owned direct subsidiary of WCG and each of WCL and WCG
will benefit from the extensions of credit under the Notes;

<PAGE>

                  WHEREAS, the Mortgagor is the owner of fee simple title to the
Land and the Improvements (each as hereinafter defined) subject to Permitted
Encumbrances (as hereinafter defined);

                  WHEREAS, it is a condition precedent to the extensions of
credit under the Notes that (a) the Mortgagor shall have executed and delivered
to the Mortgagee this Mortgage and (b) WCL and WCG (the "Guarantors") shall have
guaranteed the Obligations (as hereinafter defined); and

                  WHEREAS, the Mortgagor desires to enter into this Mortgage to
satisfy the condition in the preceding paragraph and to secure (and this
Mortgage shall secure) the following, whether now existing or hereafter arising:

                  (i) the full and prompt payment and performance when due
         (whether at the stated maturity, by acceleration or otherwise) of all
         obligations, liabilities and indebtedness of the Mortgagor and the
         Guarantors under this Mortgage, the Pledge (as hereinafter defined) and
         the Notes including, without limitation, payment of principal, premium
         and interest including, without limitation, all interest that accrues
         after the commencement of any case, proceeding or other action relating
         to the bankruptcy, insolvency, reorganization or similar proceeding of
         the Mortgagor, WCL and/or WCG at the applicable rates provided for in
         the Notes, whether or not a claim for post-petition interest is allowed
         in any such proceeding;

                  (ii) any and all sums advanced by the Mortgagee (in accordance
         with the terms of this Mortgage) in order to preserve the Mortgaged
         Property or preserve its security interest in the Mortgaged Property;

                  (iii) in the event of any proceeding for the collection or
         enforcement of any indebtedness, obligations, or liabilities of the
         Mortgagor, WCL and/or WCG under the Notes or this Mortgage, all out-of
         pocket expenses reasonably incurred of re-taking, holding, preparing
         for sale or lease, selling or otherwise disposing of or realizing on
         the Mortgaged Property, or of any exercise by the Mortgagee of its
         rights hereunder or under the Notes, including reasonable attorneys'
         fees and disbursements and court costs (including without limitation
         all such amounts referred to in Section 4.08 hereof);

                  (iv) all amounts paid by any Indemnitee as to which such
         Indemnitee has the right to reimbursement under Section 4.10 hereof;
         and

                  (v) any and all renewals, extensions and modifications of any
         of the obligations and liabilities referred to in clauses (i) through
         (iv) above, inclusive;

all obligations, liabilities, sums and expenses set forth in clauses (i) through
(v) above being herein collectively called the "Obligations".

                  NOW, THEREFORE, as security for the Obligations and in
consideration of the payment of ten dollars ($10.00) and the other benefits
accruing to the Mortgagor, the receipt and sufficiency of which are hereby
acknowledged, THE MORTGAGOR HEREBY MORTGAGES, GRANTS, BARGAINS, SELLS, CONVEYS
AND CONFIRMS TO THE MORTGAGEE AND

<PAGE>

ITS SUCCESSORS AND ASSIGNS AND HEREBY GRANTS TO THE MORTGAGEE AND ITS SUCCESSORS
AND ASSIGNS A SECURITY INTEREST IN, WITH POWER OF SALE (subject to applicable
law), all of the following property, rights, interests and estates owned or
hereafter acquired by Mortgagor:

                  A. The land described in EXHIBIT A hereto, together with all
rights, privileges, franchises and powers related thereto which are appurtenant
to said land or its ownership, including all minerals, oil and gas and other
hydrocarbon substances thereon or therein; waters, water courses, water stock,
water rights (whether riparian, appropriative, or otherwise, and whether or not
appurtenant), sewer rights, shrubs, crops, trees, timber and other emblements
now or hereafter on, under or above the same or any part or parcel thereof
(collectively, the "Land");

                  B. All buildings, structures, tenant improvements (including,
but not limited to, Fixtures (as defined below) which are incorporated into the
Building) and other improvements of every kind and description now or hereafter
located in or on the Land, including, but not limited to, all structures,
improvements, rail spurs, dams, reservoirs, water, sanitary and storm sewers,
drainage, electricity, steam, gas, telephone and other utility facilities,
parking areas, roads, driveways, walks and other site improvements of every kind
and description now or hereafter erected or placed on the Land, together with
all additions thereto and all renewals, alterations, substitutions and
replacements thereof (collectively, the "Improvements");

                  C. All equipment, machinery, and fixtures (as defined in
Article 9 of the Uniform Commercial Code), and other items of real and/or
personal property, including all components thereof, now and/or hereafter
located in, on or used in connection with, or incorporated into Improvements,
including, without limitation, the Central Plant (as hereinafter defined) if and
to the extent Mortgagor now or hereafter has any interest therein and all
furnaces, boilers, heaters, electrical equipment, heating, plumbing, lighting,
ventilating, refrigerating, incineration, air and water pollution control, waste
disposal, air-cooling and air-conditioning systems and apparatus (other than
individual units), sprinkler systems and fire and theft protection equipment,
towers and other devices for the transmission of radio, television and other
signals, together with all replacements, substitutions, renewals, modifications,
alterations and additions thereto (excluding the Excluded Property,
collectively, the "Fixtures");

                  D. All surface rights, appurtenant rights and easements,
rights of way, and other rights appurtenant to the use and enjoyment of or used
in connection with the Land and/or the Improvements;

                  E. All streets, roads and public places (whether open or
proposed) now or hereafter adjoining or otherwise providing access to the Land,
the land lying in the bed of such streets, roads and public places, and all
other sidewalks, alleys, ways, passages, vaults, water courses, strips and gores
of land now or hereafter adjoining or used or intended to be used in connection
with all or any part of the Land and/or the Improvements;

                  F. Any leases, lease guaranties or any other agreements
(whether verbal or written) relating to the use and occupancy of the Land and/or
the Improvements or any portion

<PAGE>

thereof, including, but not limited to, any use or occupancy arrangements
created pursuant to Section 365(h) of Title 11 of the United States Code (the
"Bankruptcy Code") or otherwise in connection with the commencement or
continuance of any bankruptcy, reorganization, arrangement, insolvency,
dissolution, receivership or similar proceedings, or any assignment for the
benefit of creditors, in respect of any tenant or occupant of any portion of the
Land and/or the Improvements (collectively, the "Leases");

                  G. All rents, issues and profits arising from any of the
Leases (collectively, the "Rents");

                  H. To the extent assignable, all permits, licenses and rights
relating to the use, occupation and operation of the Land and/or the
Improvements;

                  I. Any zoning lot agreements, air rights and development
rights which may be vested in the Mortgagor together with any additional air
rights or development rights which have been or may hereafter be conveyed to or
become vested in the Mortgagor; and

                  J. All proceeds (including insurance and Condemnation [as
hereinafter defined] proceeds) and products of the conversion, voluntary or
involuntary, including, but not limited to, those from sale, exchange, transfer,
collection, loss, damage, disposition, substitution or replacement, of any of
the foregoing, whether into cash, liquidated claims or otherwise.

                  All of the forgoing estates, rights, properties and interests
hereby mortgaged to the Mortgagee are sometimes referred to collectively herein
as the "Mortgaged Property." Notwithstanding anything to the contrary contained
in this Mortgage, the Mortgagee shall not have a Lien on, and the term
"Mortgaged Property" shall not include, any Excluded Property (as hereinafter
defined).

                  TO HAVE AND TO HOLD the above granted and described Mortgaged
Property unto the Mortgagee and to its successors and assigns for the uses and
purposes set forth herein until the Obligations are paid and performed in full.

                  PROVIDED, HOWEVER, that if the Obligations shall have been
paid and performed in full, then, in such case the Mortgagee shall, at the
request and expense of the Mortgagor, promptly satisfy this Mortgage (without
recourse and without representations or warranties) and the estate, right, title
and interest of the Mortgagee in the Mortgaged Property shall cease, and upon
payment to the Mortgagee of all out-of-pocket costs and expenses reasonably
incurred for the preparation of the release hereinafter referenced and all
recording costs if allowed by law, the Mortgagee shall promptly release the Lien
of this Mortgage by proper instrument.

                                    ARTICLE I

                     REPRESENTATIONS, WARRANTIES, COVENANTS
                         AND AGREEMENTS OF THE MORTGAGOR

         1.01 Title to the Mortgaged Property. The Mortgagor represents and
warrants: (a) it has fee simple title to the Land and Improvements and good
title to the remainder of the

<PAGE>

Mortgaged Property, free and clear of any Liens, other than the Liens specified
on EXHIBIT B attached hereto (the "Permitted Encumbrances"); Mortgagor shall
warrant, defend and preserve such title and the validity and priority of the
lien of this Mortgage against the claims of all Persons; (b) upon being recorded
in the real property records of Tulsa County, this Mortgage will be a valid
first priority Lien upon the Mortgaged Property (subject only to the Permitted
Encumbrances existing on the date hereof); (c) it has the power and authority to
encumber the Mortgaged Property in the manner set forth herein; and (d) there
are no defenses or offsets to this Mortgage or to the Obligations which it
secures. The Mortgagor shall take no action nor shall it fail to take any action
which would result in an impairment of the Lien of this Mortgage or which would
form the basis for any Person(s) to properly claim an interest in the Mortgaged
Property (including, without limitation, any claim for adverse use or possession
or any implied dedication or easement by prescription) other than Permitted
Encumbrances. If any Lien (other than a Permitted Encumbrance) attaches to the
Mortgaged Property, the Mortgagor shall promptly, at its expense: (a) provide
the Mortgagee with written notice of such Lien, including information relating
to the amount of such Lien; and (b) pay the Lien in full or take such other
action as shall be required to cause the Lien to be released; provided, that,
after written notice to Mortgagee, Mortgagor, at its own expense, may contest
such Lien by appropriate legal proceedings, promptly initiated and conducted in
good faith and with due diligence, provided that (i) no Event of Default has
occurred and is continuing, (ii) Mortgagor is permitted to do so under any other
mortgage or deed of trust affecting the Mortgaged Property, (iii) the proceeding
is permitted under and is conducted in accordance with the provisions, if any,
of the Credit Agreement and shall not constitute a default thereunder, (iv)
neither the Mortgaged Property, or any part thereof, nor the Mortgagor shall be
affected in any material adverse way as a result of such proceeding, and (v) the
Lien has been discharged of record (by payment, bonding or in a manner otherwise
reasonably acceptable to Mortgagee). If an Event of Default shall have occurred
and be continuing, the Mortgagee may, but shall not be obligated, to pay any
such asserted Lien if not timely paid by the Mortgagor.

         1.02 Compliance with Law. The Mortgagor represents and warrants that it
possesses all material environmental and other licenses, authorizations,
registrations, permits and/or approvals required by Governmental Authorities (as
hereinafter defined) for the ownership or operation of the Land, Improvements
and Fixtures (each being defined as a "License"), all of which, the Mortgagor
hereby represents and warrants, are in full force and effect, and are not the
subject of any revocation proceeding, release, suspension or forfeiture. The
Mortgagor represents and warrants that the present and contemplated use and
occupancy of the Land, Improvements and Fixtures does not violate any License.
The Mortgagor shall take no action nor shall it fail to take any action with
respect to any License or the zoning classification of the Mortgaged Property if
such action or failure to act would have a material adverse effect on the value,
use and/or operation of the Mortgaged Property or would cause or result in the
revocation, suspension or forfeiture of any License.

         1.03 Payment and Performance of Obligations. The Mortgagor shall pay
and perform all of the Obligations when due and payable without offset or
counterclaim. The Mortgagor shall observe and comply in all respects with all of
the terms, provisions, conditions, covenants and agreements to be observed and
performed by it under the Loan Documents.

<PAGE>

         1.04 Maintenance, Repair, Alterations, Etc. The Mortgagor shall: (i)
keep and maintain the Improvements and Fixtures in good condition and repair
(normal wear and tear, casualty and condemnation excepted, subject to subsection
(iii) below and Section 1.07); (ii) make or cause to be made, as and when
necessary, all repairs, renewals and replacements, structural and nonstructural,
exterior and interior which are necessary to so maintain the Improvements and
Fixtures in good condition; (iii) restore, repair or replace any Improvement or
Fixture which may be damaged or destroyed so that the same shall be at least
substantially equal to its value and condition immediately prior to the damage
or destruction; (iv) not commit or permit any waste or deterioration (normal
wear and tear excepted) of the Improvements and Fixtures; (v) not permit the
Improvements or Fixtures to be demolished or altered in any manner that
substantially decreases the value thereof; (vi) promptly pay when due all claims
for labor performed and materials furnished therefor, provided, that, after
notice to Mortgagee, Mortgagor, at its own expense, may contest such claims and
any Liens related thereto by appropriate legal proceedings, promptly initiated
and conducted in good faith and with due diligence, provided that (A) no Event
of Default has occurred and is continuing, (B) Mortgagor is permitted to do so
under any other mortgage or deed of trust affecting the Mortgaged Property, (C)
the proceeding is permitted under and is conducted in accordance with the
provisions, if any, of the Credit Agreement and shall not constitute a default
thereunder, (D) neither the Mortgaged Property, or any part thereof, nor
Mortgagor shall be affected in any material adverse way as a result of such
proceeding, and (E) the Lien has been discharged of record (by payment, bonding
or in a manner otherwise reasonably acceptable to Mortgagee) and (vii) comply
with all applicable statutes, regulations and orders of all Governmental
Authorities, as well as comply with the provisions of any lease, easement or
other agreement affecting all or any part of the Mortgaged Property, except to
the extent that any failure to so comply would not have a material adverse
effect on the value, use and/or operation of the Mortgaged Property.

         1.05 Required Insurance; Use of Proceeds. The Mortgagor shall keep the
Improvements and Fixtures insured against loss or damage by fire, hazards
customarily included within "extended coverage" policies, and any other
casualties, liabilities, contingencies, risks or hazards, including flood and
earthquake, which are customarily insured against by owners and/or lenders with
respect to similar properties located in the geographical region of the
Improvements, in an amount not less than the full replacement cost of the
Improvements and Fixtures with a company or companies and in such form and with
such endorsements as shall be required by and be reasonably satisfactory to the
Mortgagee. The Mortgagor shall also carry public liability insurance in such
form and amounts and with such companies as are reasonably satisfactory to the
Mortgagee. The Mortgagee agrees that the types of insurance currently purchased
by the Mortgagor with respect to the Mortgaged Property, as disclosed in writing
to the Mortgagee, are presently satisfactory for purposes of this Mortgage. The
Mortgagee shall be named an additional insured under the public liability
insurance policy, a loss payee under any rental interruption insurance policy
(whether or not required hereunder) and an additional insured and as loss payee
under the hazard insurance policy. All of the above-mentioned insurance policies
shall be endorsed with a standard noncontributory mortgagee clause in favor of
and in form reasonably acceptable to the Mortgagee, and may expire, be cancelled
or be modified only upon at least thirty (30) days prior written notice to the
Mortgagee. Certificates of such insurance reasonably satisfactory to the
Mortgagee, together with, upon demand from time to time by the Mortgagee,
receipts evidencing the payment of premiums thereon, shall be delivered to and
be held by the Mortgagee. At least thirty (30) days prior to the expiration date
of any such policy,

<PAGE>

the Mortgagor shall deliver to the Mortgagee evidence of the renewal or
replacement of such policy in a form reasonably satisfactory to the Mortgagee,
which evidence may be in the form of certificates of insurance demonstrating
compliance with the terms hereof. In the event that any such certificate of
insurance and evidence of payment of the premium therefor are not so delivered
to the Mortgagee, the Mortgagor hereby specifically authorizes the Mortgagee to
obtain such insurance upon ten (10) days prior notice to Mortgagor. Without
releasing the Mortgagor from any obligation hereunder, the Mortgagee may (but is
not obligated to) obtain such insurance as hereinabove set forth through or from
any reasonably acceptable insurance agency or company. The Mortgagee shall not
be chargeable with or responsible for the procurement or maintenance of any such
insurance or the collection of any proceeds from such insurance. The Mortgagee
shall not by the fact of approving, disapproving, accepting, preventing,
obtaining or failing to obtain any insurance, incur any liability for or with
respect to the amount of insurance carried, form or legal sufficiency of
insurance contracts, solvency of insurance companies, or payment or defense of
lawsuits, and the Mortgagor hereby expressly assumes full responsibility
therefor and agrees to indemnify, defend and hold the Mortgagee harmless from
and against all loss, cost, expense and liability, if any, with respect thereto.
Except as otherwise provided by applicable law, the Mortgagee may from time to
time furnish to any insurance agency or company, or any other Person, any
information contained in or extracted from any certificate of insurance
delivered to the Mortgagee hereunder and any information concerning this
Mortgage. The Mortgagor hereby assigns to the Mortgagee all insurance proceeds
which the Mortgagor may be entitled to receive under any insurance policy issued
with respect to the Mortgaged Property, whether or not required hereunder. In
the event of the foreclosure or other transfer of the title to the Mortgaged
Property in extinguishment of the Obligations, in whole or in part, secured
hereby, all right, title and interest of the Mortgagor in and to any payments in
satisfaction of claims under any casualty insurance policy issued with respect
to the Mortgaged Property shall pass to the purchaser, transferee or grantee of
the Mortgaged Property. The Mortgagor shall give prompt written notice to the
Mortgagee of the occurrence of any damage to or destruction of the Improvements
(which term as used in this Section 1.05 and in Section 1.07 shall include
Fixtures) in excess of $2,000,000, generally describing the extent of the damage
or destruction to the Improvements. In the event of any damage to or destruction
of the Improvements or any part thereof which would reduce the value of the
Improvements by less than 35%, Mortgagor shall have the right to adjust and
collect all proceeds of insurance with respect to such damage or destruction and
Mortgagor shall promptly repair such damage in a manner that will result in the
Improvements being of the same or better condition and quality as immediately
prior to such damage or destruction, with all repairs to be performed and
completed in compliance with all federal, state and local laws, rules,
regulations, and ordinances; provided however, that the Mortgagee shall have the
right to participate in and monitor any restoration work and participate in and
approve the settlement of any claim in respect of any damage or destruction
which would reduce the value of the Improvements by greater than $10,000,000. If
a casualty occurs which would reduce the value of the Improvements by more than
35%, the Mortgagee may upon notice to Mortgagor declare the Obligations
immediately due and payable, collect all insurance proceeds payable with respect
to such casualty, and apply such proceeds against the Obligations in such order
and amounts as the Mortgagee may determine in its sole discretion.

         1.06 Preservation of Property. The Mortgagor agrees to pay for any and
all reasonable fees, costs and expenses incurred in connection with the
creation, preservation or protection of

<PAGE>

the Mortgagee's Liens on the Mortgaged Property, including, without limitation,
all fees and taxes in connection with the recording or filing of instruments and
documents in public offices (including stamp and mortgage recording taxes or
other taxes imposed on the Mortgagee by virtue of its ownership of this
Mortgage), which are imposed upon the recording of this Mortgage or thereafter,
all reasonable attorneys' fees, payment or discharge of any taxes or Liens upon
or in respect of the Mortgaged Property, premiums for insurance with respect to
the Mortgaged Property and all other fees, costs and expenses reasonably
incurred in connection with protecting, maintaining or preserving the Mortgaged
Property and the Mortgagee's interest therein, whether through judicial
proceedings or otherwise, or in defending or prosecuting any actions, suits or
proceedings arising out of or relating to the Mortgaged Property.

         1.07 Condemnation. Should the Mortgagor receive any notice that the
Land or Improvements or any part thereof or interest therein may be taken or
damaged by reason of any public improvements or condemnation proceeding or in
any other similar manner (a "Condemnation"), the Mortgagor shall give prompt
written notice thereof to the Mortgagee. In the event of any Condemnation, the
Mortgagee shall have the right to participate in any settlement of any claim
made by Mortgagor in respect of such Condemnation if the value of the property
taken exceeds $10,000,000 or if such claim is otherwise in an amount which
exceeds $10,000,000. In the event of a Condemnation or successive Condemnations
which would reduce the value of the Land and the Improvements by 35% or less,
Mortgagor shall have the right to adjust and collect all compensation, awards,
damages and proceeds payable on account of such Condemnation or Condemnations
and shall promptly restore the (remainder of the Land and Improvements (after
giving effect to such Condemnation) to a fully functional operating unit, with
all restoration work being performed and completed in compliance with all
federal, state and local laws, rules, regulations, and ordinances, and shall,
promptly upon receipt, apply any remaining proceeds of its Condemnation award to
payment of the Obligations as a prepayment. In the event of a Condemnation or
successive Condemnations which would reduce the value of the Land and
Improvements by more than 35%, the Mortgagee may upon notice to Mortgagor
declare the Obligations immediately due and payable, collect all compensation,
awards, damages and proceeds payable on account of such Condemnation or
Condemnations, and apply such compensation, awards, damages, and proceeds
against the Obligations in such order and amounts as the Mortgagee may determine
in its sole discretion.

         1.08 Inspections. The Mortgagor hereby authorizes the Mortgagee, its
agents, employees and representatives, upon reasonable prior written notice to
the Mortgagor (except in an emergency or following the occurrence and during the
continuance of any Event of Default, in which case notice shall not be required)
to visit and inspect the Mortgaged Property or any portion(s) thereof, all at
such reasonable times and as often as the Mortgagee may reasonably request.

         1.09 Transfers.

         (a) Neither the Mortgagor nor WCG shall Transfer (as hereinafter
defined), or agree to Transfer, in any manner either voluntarily or
involuntarily (other than a Condemnation), by operation of law or otherwise, all
or any portion of the Mortgaged Property, or any interest therein (including any
air or development rights) without, in any such case, the prior written consent
of the Mortgagee which may be granted or denied in the Mortgagee's sole
discretion.

<PAGE>

Notwithstanding the foregoing to the contrary, any Permitted Transfer (as
hereinafter defined) may be made without the consent of the Mortgagee provided
that, with respect to any Permitted Transfer which would adversely affect the
value, use and/or operation of the Mortgaged Property or the Mortgagor's and/or
any Guarantor's ability to pay or perform the Obligations, at least ten (10)
Business Days prior to the effective date of such Permitted Transfer the
Mortgagor gives notice to the Mortgagee describing such Permitted Transfer in
detail reasonably sufficient to establish that it is a Permitted Transfer. All
Transfers shall be subject and subordinate (except with respect to Liens
described in clause (e) of Exhibit B) to the Lien and the terms, covenants and
conditions of this Mortgage and all other Loan Documents. Notwithstanding
anything herein to the contrary, if any Transfer will result in the conveyance
of fee simple title to all or any portion of the Mortgaged Property, it shall be
a condition precedent to such Transfer and the Mortgagee's consent thereto that
the transferee of such Mortgaged Property assume all of the Obligations;
provided that, in no event shall such assumption be deemed to be a release of
the Mortgagor's or any Guarantor's obligations under the Loan Documents. Consent
to one such Transfer shall not be deemed to be a waiver of the right to refuse
consent to future or successive Transfers.

         (b) As used herein "Transfer" shall mean:

                  (i) any transfer, sale, assignment, conveyance or other
         disposition, whether voluntarily or involuntarily, directly or
         indirectly, of the Mortgaged Property, by operation of law or
         otherwise; and

                  (ii) any sale, transfer, merger or other disposition of a
         controlling or majority of the equity interests in the Mortgagor;

         (c) As used herein, "Permitted Transfer" shall mean:

                  (i) Permitted Encumbrances (as such term is defined in Section
         1.01(a) hereof);

                  (ii) the granting of the Second Mortgage, Assignment of Leases
         and Rents, Security Agreement, Financing Statement and Fixture Filing
         dated as of October 15, 2002 made by Mortgagor, as mortgagor, to the
         Administrative Agent, as mortgagee (the "Second Mortgage") and intended
         to be recorded in the real estate records of Tulsa County, Oklahoma
         immediately subsequent to the recording of this Mortgage; provided that
         that Lien of the Second Mortgage is subordinate and junior to the Lien
         and the provisions, terms, and conditions of this Mortgage;

                  (iii) any transfer of all or part of the equity interests in
         Mortgagor to any entity of which WCG owns directly or indirectly a
         majority of the equity interests;

                  (iv) the granting to the Administrative Agent of a security
         interest in all of the equity interests in the Mortgagor and the
         Guarantors pursuant to the Credit Agreement; and

<PAGE>

                  (v) provided that no Event of Default has occurred and is
         continuing, any Lease of the Mortgaged Property or any part thereof
         entered into in accordance with the provision of Section 1.14 hereof.

                  (d) Notwithstanding anything is this Section 1.09 to the
         contrary, any Transfer (including, without limitation, Permitted
         Transfers), whether or not consent is required hereunder, shall not be
         deemed to release the Mortgagor or any Guarantor from its obligations
         under the Loan Documents.

         1.10 Hazardous Substances.

         (a) The following terms shall have the following meanings: (i) the term
"Hazardous Material" shall mean any material or substance that is now or
hereafter defined as a hazardous waste, hazardous substance, pollutant or
contaminant under any Environmental Law, or which is toxic, explosive,
corrosive, flammable, infectious, radioactive, carcinogenic, mutagenic or
otherwise hazardous (including, without limitation, asbestos or PCB's in any
form or condition) or which is or contains petroleum, gasoline, diesel fuel or
another petroleum hydrocarbon product and which, in each instance specified
above, is now or hereafter regulated under any Environmental Law; and (ii) the
term "Environmental Laws" shall collectively mean all present and future laws,
statutes, ordinances, rules, regulations, orders, codes, licenses, permits,
decrees, judgments, or directives of any Governmental Authority and relating to
Hazardous Materials or addressing the protection of the environment or human
health.

         (b) The Mortgagor hereby represents and warrants to the Mortgagee that:
(i) no Hazardous Material is currently located at, on, in, or under the Land,
Fixtures or the Improvements in violation of any Environmental Laws, except in
quantities not prohibited by Environmental Laws; (ii) no releasing, emitting,
discharging, leaching, dumping or disposing of any Hazardous Material from the
Land, Fixtures or the Improvements onto or into any other property or from any
other property onto or into the Land, Fixtures or Improvements has occurred or
is occurring in violation of any Environmental Laws; (iii) no notice of
violation, Lien, complaint, suit, order or other notice with respect to the
Land, Improvements or Fixtures is presently outstanding under any Environmental
Laws; and (iv) the Land, Improvements and Fixtures and the operation thereof are
in full compliance with all Environmental Laws, except to the extent
non-compliance would not result in the imposition of any fine, penalty and/or
other liability or damages to the Mortgagee or the Mortgagor in excess of
$100,000 per occurrence and provided that any such non-compliance is not caused
by the willful misconduct of the Mortgagor or its agents, employees, invitees or
Affiliates. The Mortgagor shall comply (subject to subclause (iv) of the
preceding sentence), and shall exercise reasonable efforts to cause all tenants
or other occupants of the Land and the Improvements to comply, in all respects
with all Environmental Laws, and will not generate, store, handle, process,
dispose of or otherwise use, and will not permit any tenant or other occupant of
the Land and the Improvements to generate, store, handle, process, dispose of or
otherwise use, Hazardous Materials at, in, on or under the Land, Fixtures or the
Improvements in a manner that could reasonably be expected to lead to the
imposition on the Mortgagor, the Mortgagee or the Land, Fixtures, Improvements
or Fixtures of any liability or Lien of any nature whatsoever under any
Environmental Laws. The Mortgagor shall notify the Mortgagee promptly in the
event of any spill or other release of any Hazardous Material at, in, on, or
under the Land, Improvements or Fixtures which is required to be reported

<PAGE>

to a Governmental Authority under any Environmental Laws, will promptly forward
to the Mortgagee copies of any notices received by the Mortgagor relating to
alleged violations of any Environmental Laws and will promptly pay when due any
fine or assessment against the Mortgagor, the Mortgagee or the Land,
Improvements or Fixtures relating to any Environmental Laws; provided that,
after written notice to Mortgagee, Mortgagor, at its own expense, may contest
any such fine or assessment or any resulting environmental Lien by appropriate
legal proceedings, promptly initiated and conducted in good faith and with due
diligence, provided, that, (i) no Event of Default has occurred and is
continuing, (ii) the Mortgagor is permitted to do so under any other mortgage or
deed of trust affecting the Mortgaged Property, (iii) the proceeding is
permitted under and is conducted in accordance with the provisions, if any, of
Credit Agreement and shall not constitute a default thereunder, (iv) neither the
Mortgaged Property, or any part thereof nor the Mortgagor shall be affected in
any material adverse way as a result of such proceeding, and (v) the Lien has
been discharged of record (by payment, bonding or in a manner otherwise
reasonably acceptable to the Mortgagee) or if no such Lien has been recorded,
Mortgagor shall have furnished such security as may be required in the
proceeding, or as may be reasonably requested by Mortgagee, to insure that no
environmental lien is recorded and that the payment of any contested sums,
together with all interest and penalties thereon as may be necessary to protect
the Mortgagor and the Mortgagee from any exposure to liability by reason of such
noncompliance pending resolutions of such contest.

         (c) If at any time it is determined that the operation or use of any
portion of the Mortgaged Property violates any applicable Environmental Laws or
that there are Hazardous Materials located at, in, on, or under the Mortgaged
Property which, under any Environmental Laws, require special handling in
collection, storage, treatment or disposal, or any other form of cleanup or
corrective action, the Mortgagor shall, within thirty (30) days after receipt of
notice thereof from any Governmental Authority, take, at its sole cost and
expense, such actions as may be necessary to fully comply in all respects with
all Environmental Laws, provided, however, that if such compliance cannot
reasonably be completed within such thirty (30) day period, the Mortgagor shall
commence such necessary action within such thirty (30) day period and shall
thereafter diligently and expeditiously proceed to fully comply in all respects
and in a timely fashion with all Environmental Laws. If the Mortgagor fails to
timely take any such action, the Mortgagee may, in its sole and absolute
discretion, after five (5) days prior written notice to the Mortgagor make
advances or payments towards the performance or satisfaction of the same, but
shall in no event be under any obligation to do so.

         (d) All sums so advanced or paid by the Mortgagee (including, without
limitation, counsel and consultant fees and expenses reasonably incurred,
investigation and laboratory fees and expenses, and fines or other penalty
payments) and all sums advanced or paid in connection with any judicial or
administrative investigation or proceeding relating thereto, will immediately,
upon demand, become due and payable from the Mortgagor and shall bear interest
at the Default Rate from the date any such sums are so advanced or paid by the
Mortgagee until the date any such sums are paid by the Mortgagor to the
Mortgagee. The Mortgagor will execute and deliver, promptly upon request, such
instruments as may be necessary to cause the Mortgaged Property to secure all
sums so advanced or paid by the Mortgagee. If a Lien is filed against the
Mortgaged Property by any Governmental Authority in connection with any
violation of Environmental Laws and the Mortgagor is not contesting same in
accordance with the provisions of Section 1.10 (b), then the Mortgagor will,
within thirty (30) days from the date that the

<PAGE>

Mortgagor is first aware that such Lien has been placed against the Mortgaged
Property (or within such shorter period of time as may be specified by the
Mortgagee if such Governmental Authority has commenced steps to cause the
Mortgaged Property to be sold pursuant to such Lien) either (i) pay the claim
and remove the Lien, or (ii) furnish a cash deposit, bond or such other security
with respect thereto as is reasonably satisfactory in all respects to the
Mortgagee and is sufficient to effect a complete discharge of such Lien of
record.

         (e) The Mortgagee may, at its option, at intervals of not less than two
years, or more frequently if the Mortgagee reasonably believes that a Hazardous
Material or other environmental condition violates or threatens to violate any
Environmental Law, cause an environmental audit of the Mortgaged Property or
portions thereof to be conducted at the Mortgagor's expense to confirm the
Mortgagor's compliance with the provisions of this Section 1.10, and the
Mortgagor shall cooperate in all reasonable ways with the Mortgagee in
connection with any such audit.

         (f) If this Mortgage is foreclosed, or if the Mortgaged Property is
sold pursuant to the provisions of this Mortgage, or if the Mortgagor tenders a
deed or assignment in lieu of foreclosure or sale, the Mortgagor shall deliver
the Mortgaged Property to the purchaser at foreclosure or sale or to the
Mortgagee, its nominees, or wholly owned subsidiary, as the case may be, in a
condition that complies in all respects with all Environmental Laws. The
Mortgagor will defend, protect, indemnify, and hold harmless the Mortgagee and
its employees, agents, officers, and directors, from and against any and all
claims, demands, penalties, causes of action, fines, liabilities, settlements,
damages, costs, or expenses of whatever kind or nature, known or unknown,
foreseen or unforeseen, contingent or otherwise (including, without limitation,
counsel and consultant fees and expenses reasonably incurred, investigation and
laboratory fees and expenses, court costs, and litigation expenses) arising out
of, or in any way related to: (i) any breach by the Mortgagor of any of the
provisions of this Section 1.10, (ii) the presence, disposal, spillage,
discharge, emission, leakage, release, or threatened release of any Hazardous
Material which is at, in, on, under, about, from or affecting the Mortgaged
Property prior to the date on which title to the Mortgaged Property is
transferred to the Mortgagee or its successors and assigns pursuant to
foreclosure or deed-in-lieu of foreclosure, including without limitation any
damage or injury resulting from any such Hazardous Material to or affecting the
Mortgaged Property or the soil, water, air, vegetation, buildings, personal
property, persons or animals located on the Mortgaged Property or on any other
property or otherwise; (iii) any personal injury (including wrongful death) or
property damage (real or personal) arising out of or related to any such
Hazardous Material; (iv) any lawsuit brought or threatened, settlement reached,
or order or directive of or by any Governmental Authority relating to such
Hazardous Material; or (v) any violation of any Environmental Laws
(collectively, "Indemnified Environmental Liabilities"), but excluding any
Indemnified Environmental Liabilities to the extent arising on or after the date
hereof from the gross negligence or willful misconduct of the Mortgagee or any
of its Affiliates. The obligations and liabilities of the Mortgagor under this
paragraph shall survive and continue in full force and effect and shall not be
terminated, discharged or released, in whole or in part, irrespective of whether
the Obligations have been paid in full and irrespective of any foreclosure of
this Mortgage, sale of the Mortgaged Property pursuant to the provisions of this
Mortgage or acceptance by the Mortgagee, its nominee or wholly owned subsidiary
of a deed or assignment in lieu of foreclosure or sale.

<PAGE>

         1.11 After Acquired Property Interests. All right, title and interest
of the Mortgagor in and to the Mortgaged Property, hereafter acquired by the
Mortgagor (the "After Acquired Property Interests"), immediately upon such
acquisition, and in each such case, without any further mortgage, conveyance,
assignment or other act by the Mortgagor, shall become subject to the Lien of
this Mortgage. The Mortgagor shall execute and deliver to the Mortgagee all such
other mortgages and other agreements as the Mortgagee may reasonably require for
the purpose of expressly and specifically subjecting such After Acquired
Property Interests to the Lien of this Mortgage.

         1.12 Authority of the Mortgagor; Validity. The Mortgagor represents and
warrants that its execution and delivery of, and performance under this Mortgage
and the other Loan Documents to which it is a party: (i) are within its power;
(ii) do not require any government approval (other than the Confirmation Order);
(iii) do not materially violate any provisions of law or any order of any court
or agency of government, (iv) do not violate the charter documents to which it
is a party or any indenture, agreement or any other instrument to which it is a
party or by which it is bound on the Effective Date or conflict with, result in
a breach of or constitute (with due notice or lapse of time or both) a default
under any such indenture, agreement or other instrument; and (v) constitutes its
legal, valid, binding and enforceable obligation, except to the extent that the
enforceability of this Mortgage may be limited by bankruptcy, insolvency and
other laws affecting creditors' rights generally and general principles of
equity.

         1.13 Additional Debt. The Mortgagor shall not create or suffer to exist
any indebtedness which is not permitted under the Credit Agreement or any
indebtedness for borrowed money, secured or unsecured, direct or indirect,
absolute or contingent (including issuance of any guarantee of such
indebtedness).

         1.14 Leasing. In respect of each Lease which may be entered into on or
after the date hereof, the following shall apply: the Lien and estate, as well
as the provisions, terms, and conditions of each Lease shall in all respects be
subordinate and junior to the Lien and the provisions terms and conditions of
this Mortgage and shall (i) contain an express statement so providing, (ii) be
on terms consistent with this Mortgage; (iii) require the tenant thereunder to
execute, upon request by the Mortgagee, from time to time, a tenant estoppel
certificate and/or subordination agreement, reasonably satisfactory to
Mortgagor, and (iv) be for a use and occupancy permitted by applicable law,
including Environmental Laws, zoning regulations and building codes. Mortgagor
shall be responsible for an act and omission of lessees under the Leases; to the
effect that any such acts or omissions by such lessees shall constitute a breach
by the Mortgagor hereunder if and to the extent same would be a breach if
committed by the Mortgagor itself.

                                   ARTICLE II

                               SECURITY AGREEMENT

         2.01 Grant of Security; Incorporation by Reference.

In addition to constituting a mortgage Lien on those portions of the Mortgaged
Property classified as real property (including Fixtures to the extent they are
real property), this Mortgage

<PAGE>

shall constitute a security agreement within the meaning of the Uniform
Commercial Code with respect to those parts of the Mortgaged Property classified
as personal property, including Fixtures to the extent they are personal
property.

         2.02 Fixture Filing and Financing Statements.

This Mortgage constitutes a security agreement, fixture filing and financing
statement as those terms are used in the Uniform Commercial Code. For purposes
of this Section 2.02, this Mortgage is to be filed and recorded in, among other
places, the real estate records of Tulsa County, Oklahoma, in which the Land is
located and the following information is included: (1) the Mortgagor shall be
deemed the "Debtor" with the address set forth for the Mortgagor on the first
page of this Mortgage which the Mortgagor certifies is accurate; (2) the
Mortgagee shall be deemed to be the "Secured Party" with the address set forth
for the Mortgagee on the first page of this Mortgage and shall have all of the
rights of a secured party under the Uniform Commercial Code; (3) this Mortgage
covers goods which are or are to become Fixtures and the portions of the
Mortgaged Property which are or may become Fixtures are described by item or
type in the granting clauses hereof; (4) the name of the record owner of the
Land is the Debtor; (5) the organizational identification number of the Debtor
is 73-1619292; (6) the Debtor is a limited liability company, organized under
the laws of the State of Delaware; and (7) the legal name of the Debtor is
Williams Technology Center, LLC. The Debtor hereby authorizes the Mortgagee to
file any financing statements covering the Mortgaged Property and terminations
thereof or amendments or modifications thereto without the signature of the
Debtor where permitted by applicable law.

                                   ARTICLE III

                     ASSIGNMENT OF LEASES, RENTS AND PROFITS

         3.01 Assignment. The Mortgagor hereby absolutely, irrevocably and
unconditionally sells, assigns, transfers and conveys to the Mortgagee all of
the Mortgagor's right, title and interest in and to all current and future
Leases and Rents, including those Rents now due, past due, or to become due by
virtue of any Lease. The Mortgagor intends that this assignment constitute a
present and absolute assignment and not an assignment for additional security
only. Such assignment to the Mortgagee shall not be construed to bind the
Mortgagee to the performance of any of the covenants, conditions or provisions
contained in any Lease or otherwise impose any obligation upon the Mortgagee. If
an Event of Default shall have occurred and be continuing, the Mortgagor
covenants that it will not thereafter collect or accept payment of any Rents
more than one month prior to the due dates of such Rents and that no Rents will
be waived, released, reduced, discounted or otherwise discharged or compromised
by the Mortgagor, except with respect to Leases of less than 10,000 square feet
or as may be previously approved in writing by the Mortgagee. The Mortgagor
agrees that it will not assign any of the Leases or Rents to any other Person,
except for Permitted Transfers. The Mortgagee shall have no liability for any
loss which may arise from a failure or inability to collect any Rents. The
Mortgagor shall maintain all security deposits in accordance with applicable
law.

         3.02 Revocable License; Agent. Notwithstanding the foregoing, but
subject to the terms of this Article III, the Mortgagee hereby grants to the
Mortgagor a revocable license to

<PAGE>

enter into, modify, administer and otherwise deal with all Leases and to collect
the Rents and hereby directs each tenant under a Lease to pay such Rents to, or
at the direction, of the Mortgagor, until such time as the Mortgagee provides
notice to the contrary to such tenants. Any Rents received by Mortgagor in good
funds, shall be held by the Mortgagor in trust for the benefit of Mortgagee for
application to the then currently due and next accruing portion of the
Obligations, up to but not in excess of the then currently due or next accruing
portion of the Obligations, provided however, so long as an Event of Default has
not occurred and is continuing, the Mortgagor may transfer any Rents received to
a third party and shall not be required to keep any such trust funds in a
segregated account and Mortgagor may commingle such trust funds with other
general funds of Mortgagor.

         3.03 Rents.

         (a) If an Event of Default shall have occurred and be continuing, the
Mortgagee may by notice to the Mortgagor, terminate the license granted in
Section 3.02 hereof and the Mortgagee shall immediately and automatically be
entitled to possession of all Rents, regardless whether the Mortgagee enters
upon or takes control of the Mortgaged Property. Upon the revocation of such
license, the Mortgagor grants to the Mortgagee the right, at its option, to
exercise all the rights granted in Section 4.02(a) hereof. Nothing herein
contained shall be construed as constituting the Mortgagee a mortgagee or
trustee in possession in the absence of the taking of actual possession of the
Mortgaged Property by the Mortgagee pursuant to such Section 4.02(a).

         (b) From and after the termination of such license, the Mortgagor
shall, if the Mortgagee so directs in writing, be the agent for the Mortgagee
for collection of the Rents and all of the Rents so collected by the Mortgagor
shall be held in trust by the Mortgagor for the sole and exclusive benefit of
the Mortgagee and the Mortgagor shall, within two (2) Business Days after
receipt of any Rents, pay the same to the Mortgagee to be applied by the
Mortgagee as provided herein. All Rents collected shall be applied against all
expenses of collection (including, but not limited to, attorneys' fees), costs
of operation and management of the Mortgaged Property reasonably incurred and
the Obligations, in whatever order or priority as to any of such items as the
Mortgagee directs in its sole and absolute discretion and without regard to the
adequacy of its security. Neither demand for nor collection of Rents by the
Mortgagee shall constitute any assumption by the Mortgagee of any obligations
under any Lease or agreement relating thereto.

         (c) Any funds reasonably expended by the Mortgagee during the existence
of an Event of Default to take control of and manage the Mortgaged Property and
collect the Rents shall become part of the Obligations secured hereby. Such
amounts shall be payable upon demand given by the Mortgagor to the Mortgagee and
shall bear interest from the date of expenditure at the Default Rate set forth
in the Note.

         3.4 Sale of Mortgaged Property.

         (a) Upon any permitted sale of the Mortgaged Property by or for the
benefit of the Mortgagee pursuant to this Mortgage, the Rents shall be included
in such sale and shall pass to the purchaser free and clear of any rights
granted herein to the Mortgagor.

<PAGE>

         (b) The Mortgagor acknowledges and agrees that, upon recordation of
this Mortgage, the Mortgagee's interest in the Rents shall be deemed to be fully
perfected, "choate" and enforceable against the Mortgagor and all third parties,
including, without limitation, any debtor in possession or trustee in any case
under the Bankruptcy Code, without the necessity of (i) commencing a foreclosure
action with respect to this Mortgage, (ii) furnishing notice to the Mortgagor or
tenants under the Leases, (iii) making formal demand for the Rents, (iv) taking
possession of the Mortgaged Property as a lender-in-possession, (v) obtaining
the appointment of a receiver of the Rents, (vi) sequestering or impounding the
Rents or (vii) taking any other affirmative action.

         3.05 Bankruptcy Provisions. Without limiting the provisions of this
Article III or the absolute nature of the assignment of the Rents hereunder, the
Mortgagor and the Mortgagee agree that, to the extent that the assignment of the
Rents hereunder is deemed to be other than an absolute assignment, (a) this
Mortgage shall constitute a "security agreement" for purposes of Section 552(b)
of the Bankruptcy Code, (b) the security interest created by this Mortgage
extends to the property intended to be covered by this Mortgage which is
acquired before the commencement of a bankruptcy case and to all amounts paid as
Rents and (c) such security interest shall extend to all Rents acquired by the
estate after the commencement of any bankruptcy case. Without limiting the
absolute nature of the assignment of the Rents hereunder, to the extent the
Mortgagor (or the Mortgagor's bankruptcy estate) shall be deemed to hold any
interest in the Rents after the commencement of a voluntary or involuntary
bankruptcy case, the Mortgagor hereby acknowledges and agrees that such Rents
are and shall be deemed to be "cash collateral" under Section 363 of the
Bankruptcy Code.

                                   ARTICLE IV

                         EVENTS OF DEFAULT AND REMEDIES

         4.01 Events of Default. The occurrence of any of the following events,
shall constitute an event of default (each an "Event of Default") hereunder:

         (a) any failure to make any payment in respect of the Obligations when
and as same shall become due (subject to any applicable grace periods),
including without limitation, any payment to be made by the Mortgagor pursuant
to Paragraph 13 of the Notes, whether at the due date thereof or a date fixed
for prepayment thereof or otherwise and such failure shall continue for a period
of five (5) days;

         (b) a default shall occur under any one or more of Sections 1.05, 1.09,
1.10 or 1.13 and such default is not cured prior to the expiration of any
applicable grace periods;

         (c) a default by the Mortgagor and/or any Guarantor in the due
observance or performance of any other covenant or agreement in the Notes, this
Mortgage or in any of the other Loan Documents (other than those defaults
specified in subsections (a) and (b) of this Section) and such default shall
continue for a period of thirty (30) days after notice thereof shall have been
given to the Mortgagor by the Mortgagee; provided, however, that if such default
shall not be curable within said thirty (30) day period, then so long as the
Mortgagor is diligently and continuously proceeding to cure such default, then
such default shall not constitute an Event of

<PAGE>

Default unless it shall continue uncured for one hundred twenty (120) days after
the giving by the Mortgagee of such notice to the Mortgagor;

         (d) by order of a court of competent jurisdiction, a trustee, receiver
or liquidator shall be appointed with respect to the Mortgaged Property, the
Mortgagor, any Guarantor and such order shall not be discharged or dismissed
within sixty (60) days after such appointment;

         (e) the Mortgagor and/or any Guarantor shall file a petition in
bankruptcy or for an arrangement or for reorganization pursuant to the United
States Federal Bankruptcy Code, or the Mortgagor or any Guarantor shall be
adjudicated a bankrupt by a court of competent jurisdiction, or the Mortgagor
and/or any Guarantor shall make an assignment for the benefit of creditors, or
the Mortgagor shall consent to the appointment of a receiver or receivers of all
or any part of the Mortgaged Property;

         (f) any of the creditors of the Mortgagor and/or any Guarantor shall
file a petition in bankruptcy against the Mortgagor and/or for reorganization
pursuant to the United States Federal Bankruptcy Code and such petition shall
not be discharged or dismissed within sixty (60) days after the date on which
such petition was filed;

         (g) the rendering of a final judgment or judgment for the payment of
money, not subject to appeal or covered by insurance under a policy under which
the insurer shall, in writing, have accepted defense and liability, against the
Mortgagor in an aggregate amount in excess of $2,000,000 and same is not
discharged or otherwise satisfied within sixty (60) days from the entry date
thereof; and

         (h) any representation or warranty made by the Mortgagor and/or any
Guarantor in any of the Loan Documents shall have been false or misleading in
any material respect as of the date such representation or warranty was made.

         4.02 Remedies Upon Default. If an Event of Default shall have occurred
and be continuing, the Mortgagee may, in the Mortgagee's sole discretion, either
itself or by or through one or more trustees, agents, nominees, assignees or
otherwise, to the fullest extent permitted by law, exercise any or all of the
following rights and remedies individually, collectively or cumulatively:

         (a) either in person or by its agent, with or without bringing any
action or proceeding, or by a receiver appointed by a court and without regard
to the adequacy of its security, (i) enter upon and take possession of the
Mortgaged Property or any part thereof and of all books, records and accounts
directly relating thereto, and without in any event being constituted a
mortgagee-in-possession in its own name or in the name of the Mortgagor, and do
or cause to be done any acts which it deems necessary or desirable to preserve
the value of the Mortgaged Property or any part thereof or interest therein,
increase the income therefrom or protect the security hereof; (ii) with or
without taking possession of the Mortgaged Property make such repairs,
alterations, additions and improvements as the Mortgagee deems necessary or
desirable and do any and all acts and perform any and all work which the
Mortgagee deems necessary or desirable to complete any unfinished construction
on the Mortgaged Property; (iii) make, cancel or modify Leases and sue for or
otherwise collect the Rents thereof, including those past due and unpaid;

<PAGE>

(iv) make any payment or perform any act which the Mortgagor has failed to make
or perform hereunder; (v) appear in and defend any action or proceeding
purporting to affect the security hereof or the rights or powers of the
Mortgagee; (vi) pay, purchase, contest or compromise any encumbrance, charge or
Lien on the Mortgaged Property; and (vii) take such other actions as the
Mortgagee deems necessary or reasonably desirable in accordance with applicable
law;

         (b) commence and maintain one or more actions at law or in equity or by
any other appropriate remedy (i) to protect and enforce the Mortgagee's rights
hereunder, including for the specific performance of any covenant or agreement
herein contained (which covenants and agreements the Mortgagor agrees shall be
specifically enforceable by injunctive or other appropriate equitable remedy),
(ii) to collect any sum then due hereunder, (iii) to aid in the execution of any
power herein granted, or (iv) to foreclose this Mortgage in accordance with
Section 4.03 hereof;

         (c) exercise any or all of the remedies available to a secured party
under the Uniform Commercial Code;

         (d) without notice or demand, presentment, notice of intention to
accelerate or of acceleration, protest or notice of protest, all of which are
hereby waived by the Mortgagor, declare all of the Obligations immediately due
and payable, and upon such declaration all of such Obligations shall become and
be immediately due and payable, anything in this Mortgage or the other Loan
Documents to the contrary notwithstanding; and

         (e) exercise any other right or remedy available to the Mortgagee under
the Loan Documents.

         4.03 Right of Foreclosure.

         (a) If an Event of Default shall have occurred and be continuing, the
Mortgagee shall have the right, in its sole discretion, to proceed at law or in
equity to foreclose this Mortgage with respect to all or any portion of the
Mortgaged Property, either by judicial action or by power of sale. The Mortgagor
hereby grants to and confers upon the Mortgagee the power to sell the Mortgaged
Property or any portion thereof in the manner and pursuant to the procedures set
forth in the Oklahoma Power of Sale Mortgage Foreclosure Act, 46 O.S. Sections
40-49, as amended and in effect from time to time (the "Act") or pursuant to
other applicable statutory or judicial authority. If no cure is effected within
the time limits set forth in the Act, the Mortgagee may accelerate the
Obligations without further notice and may then proceed in the manner and
subject to the conditions of the Act to send to the Mortgagor and other
necessary parties a notice of sale and may sell and convey the Mortgaged
Property in accordance with the Act. The Mortgagee may foreclose this Mortgage
by exercising said power of sale or, at the Mortgagee's sole option, by judicial
foreclosure proceedings as provided by law. No action of the Mortgagee based
upon the provisions contained herein or in the Act, including, without
limitation, the giving of the notice of intent to foreclose by power of sale or
the notice of sale, shall constitute an election of remedies which would
preclude the Mortgagee from accelerating the Obligations and pursuing judicial
foreclosure before or at any time after commencement of the power of sale
foreclosure procedure. If the Mortgaged Property consists of several lots,

<PAGE>

parcels or items of Mortgaged Property, the Mortgagee may, in its sole
discretion: (i) designate the order in which such lots, parcels or items shall
be offered for sale or sold, or (ii) elect to sell such lots, parcels or items
through a single sale, or through two or more successive sales, or in any other
manner the Mortgagee may elect. Should the Mortgagee desire that more than one
sale or other disposition of the Mortgaged Property be conducted, the Mortgagee
may, at its option, cause the same to be conducted simultaneously, or
successively, on the same day, or at such different days or times and in such
order as the Mortgagee may elect, and no such sale shall terminate or otherwise
affect the lien of this Mortgage on any part of the Mortgaged Property not sold
until all Obligations have been fully paid in cash and performed. The Mortgagee
may elect to sell the Mortgaged Property for cash or credit. The Mortgagee may,
to the extent permitted by law, adjourn from time to time any sale by it to be
made under or by virtue of this Mortgage by announcement at the time and place
appointed for such sale or for such adjourned sale or sales; and, to the extent
permitted by law, the Mortgagee may make such sale at the time and place to
which the same shall be so adjourned. Following the occurrence and during the
continuance of an Event of Default, with respect to all components of the
Mortgaged Property, the Mortgagee is hereby appointed the true and lawful
attorney-in-fact of the Mortgagor (which appointment is irrevocable and coupled
with an interest), in its name and stead, to make all necessary conveyances,
assignments, transfers and deliveries of the Mortgaged Property, and for that
purpose the Mortgagee may execute all necessary instruments of conveyance,
assignment, transfer and delivery, and may substitute one or more persons with
such power, the Mortgagor hereby ratifying and confirming all that its said
attorney-in-fact or such substitute or substitutes shall lawfully do by virtue
hereof. Notwithstanding the foregoing, the Mortgagor, if so requested by the
Mortgagee, shall ratify and confirm any such sale or sales by executing and
delivering to the Mortgagee or to such purchaser or purchasers all such
instruments as may be advisable, in the judgment of the Mortgagee, for such
purpose, and as may be designated in such request. To the extent permitted by
law, any such sale or sales made under or by virtue of this Article IV shall
operate to divest all the estate, right, title, interest, claim and demand
whatsoever, whether at law or in equity, of the Mortgagor in and to the
properties and rights so sold, and shall be a perpetual bar both at law and in
equity against the Mortgagor and against any and all persons claiming or who may
claim the same, or any part thereof, from, through or under the Mortgagor. Upon
any sale made under or by virtue of this Article IV, the Mortgagee may, to the
extent permitted by law, bid for and acquire the Mortgaged Property or any part
thereof and in lieu of paying cash therefor may make settlement for the purchase
price by crediting upon the Obligations secured hereby the net sale price after
deducting therefrom the expenses of the sale and the cost of the action and any
other sums which the Mortgagee is authorized to deduct by law or under this
Mortgage.

         (b) Any foreclosure of this Mortgage and any other transfer of all or
any part of the Mortgaged Property in extinguishment of all or any part of the
Obligations may, at the Mortgagee's option, be subject to any or all Leases of
all or any part of the Mortgaged Property and the rights of tenants under such
Leases. No failure to make any such tenant a defendant in any foreclosure
proceedings or to foreclose or otherwise terminate any such Lease and the rights
of any such tenant in connection with any such foreclosure or transfer shall be,
or be asserted to be, a defense or hindrance to any such foreclosure or transfer
or to any proceedings seeking collection of all or any part of the Obligations
(including, without limitation, any deficiency remaining unpaid after completion
of any such foreclosure or transfer).

<PAGE>

         (c) If the Mortgagor retains possession of the Mortgaged Property or
any part thereof subsequent to a sale, the Mortgagor will be considered a tenant
at sufferance of the purchaser, and will, if the Mortgagor remains in possession
after demand to remove, be guilty of forcible detainer and will be subject to
eviction and removal, forcible or otherwise, with or without process of law, and
all damages to the Mortgagor by reason thereof are hereby expressly waived by
the Mortgagor.

         4.04 Application of Proceeds. The proceeds of any sale of, and the
Rents and other amounts generated by the holding, leasing, management, operation
or other use of, the Mortgaged Property pursuant to this Mortgage shall be
applied by the Mortgagee (or the receiver, if one is appointed) to the
Obligations in such order and amounts as the Mortgagee determines in its sole
discretion.

         4.05 Appointment of Receiver. Upon the occurrence and during the
continuance of an Event of Default, the Mortgagee as a matter of strict right
and without notice to the Mortgagor or anyone claiming under the Mortgagor, and
without regard to the adequacy or the then value of the Mortgaged Property or
the interest of the Mortgagor therein or the solvency of any party bound for
payment of the Obligations, the Mortgagee shall have the right to apply to any
court of competent jurisdiction to appoint a receiver or receivers of the
Mortgaged Property, and the Mortgagor hereby irrevocably consents to such
appointment and waives notice of any application therefor. Any such receiver or
receivers shall have all the usual rights, powers and duties of receivers in
like or similar cases and all the rights, powers and duties of the Mortgagee in
case of entry as provided in Section 4.02 hereof, including, but not limited to,
the full power to rent, maintain and otherwise operate the Mortgaged Property
upon such terms as are approved by such court and shall continue as such and
exercise all such powers until the date of confirmation of sale of the Mortgaged
Property unless such receivership is sooner terminated.

         4.06 Exercise of Rights and Remedies. The entering upon and taking
possession of the Mortgaged Property, the collection of any Rents and the
exercise of any of the other rights contained in this Article IV, shall not,
alone, cure or waive any Event of Default or notice of default hereunder or
invalidate any act done in response to such Event of Default or pursuant to such
notice of default and, notwithstanding the continuance in possession of the
Mortgaged Property or the collection, receipt and application of Rents, the
Mortgagee shall be entitled to exercise every right provided for herein or in
the other Loan Documents, or at law or in equity upon the occurrence of any
Event of Default.

         4.07 Remedies Not Exclusive. The Mortgagee shall be entitled to enforce
payment and performance of the Obligations and to exercise all rights and powers
under this Mortgage or any of the other Loan Documents or any laws now or
hereafter in force, notwithstanding that some or all of the Obligations may now
or hereafter be otherwise secured, whether by mortgage, deed of trust, security
deed, pledge, lien, assignment or otherwise. Neither the acceptance of this
Mortgage or its enforcement, whether by court action or pursuant to the powers
herein contained, shall prejudice or in any manner affect the Mortgagee's right
to realize upon or enforce any other security now or hereafter held by the
Mortgagee, it being agreed that the Mortgagee shall be entitled to enforce this
Mortgage and any other security now or hereafter held by the Mortgagee in such
order and manner as it may in its absolute and sole discretion and election
determine. No remedy herein conferred upon or reserved to the Mortgagee is
intended to be exclusive of any

<PAGE>

other remedy herein or in any of the other Loan Documents or by law provided or
permitted, but each shall be cumulative and shall be in addition to every other
remedy given hereunder or now or hereafter existing at law or in equity or by
statute. Every power or remedy to which the Mortgagee is entitled may be
exercised, concurrently or independently, from time to time and as often as may
be deemed expedient by the Mortgagee, and the Mortgagee may pursue inconsistent
remedies. No delay or omission of the Mortgagee to exercise any right or power
accruing upon any Event of Default shall impair any right or power or shall be
construed as a waiver of any Event of Default or any acquiescence therein. If
the Mortgagee shall have proceeded to invoke any right or remedy hereunder or
under the other Loan Documents and shall thereafter elect to discontinue or
abandon it for any reason, the Mortgagee shall have the unqualified right to do
so and, in such an event, the rights and remedies of the Mortgagee shall
continue as if such right or remedy had never been invoked and no such
discontinuance or abandonment shall waive any Event of Default which may then
exist or the right of the Mortgagee thereafter to exercise any right or remedy
under the Loan Documents for such Event of Default.

         4.08 WAIVER OF REDEMPTION, NOTICE, MARSHALLING, ETC. NOTWITHSTANDING
ANYTHING HEREIN CONTAINED TO THE CONTRARY, TO THE EXTENT PERMITTED BY LAW, THE
MORTGAGOR: (A) ACKNOWLEDGING THAT IT IS AWARE OF AND HAS HAD THE ADVICE OF
COUNSEL OF ITS CHOICE WITH RESPECT TO ITS RIGHTS HEREUNDER, WILL NOT (I) AT ANY
TIME INSIST UPON, OR PLEAD, OR IN ANY MANNER WHATSOEVER, CLAIM OR TAKE ANY
BENEFIT OR ADVANTAGE OF ANY STAY OR EXTENSION OR MORATORIUM LAW, ANY LAW
RELATING TO THE ADMINISTRATION OF ESTATES OF DECEDENTS, REDEMPTION, STATUTORY
RIGHT OF REDEMPTION, OR THE MATURING OR DECLARING DUE OF THE WHOLE OR ANY PART
OF THE OBLIGATIONS, NOTICE OF INTENTION OF SUCH MATURING OR DECLARING DUE, OTHER
NOTICE (WHETHER OF DEFAULTS, ADVANCES, THE CREATION, EXISTENCE, EXTENSION OR
RENEWAL OF ANY OF THE OBLIGATIONS OR OTHERWISE, EXCEPT FOR RIGHTS TO NOTICES
EXPRESSLY GRANTED HEREIN OR IN THE LOAN DOCUMENTS), SUBROGATION, ANY SET-OFF
RIGHTS, HOMESTEAD OR ANY OTHER EXEMPTIONS FROM EXECUTION OR SALE OF THE
MORTGAGED PROPERTY OR ANY PART THEREOF, WHEREVER ENACTED, NOW OR AT ANY TIME
HEREAFTER IN FORCE, WHICH MAY AFFECT THE COVENANTS AND TERMS OF PERFORMANCE OF
THIS MORTGAGE, OR (II) AFTER ANY SUCH SALE OR SALES, CLAIM OR EXERCISE ANY RIGHT
UNDER ANY STATUTE HERETOFORE OR HEREAFTER ENACTED TO REDEEM THE MORTGAGED
PROPERTY SO SOLD OR ANY PART THEREOF; AND (B) COVENANTS NOT TO HINDER, DELAY OR
IMPEDE THE EXECUTION OF ANY POWER HEREIN GRANTED OR DELEGATED TO THE MORTGAGEE,
BUT TO SUFFER AND PERMIT THE EXECUTION OF EVERY POWER AS THOUGH NO SUCH LAW OR
LAWS HAD BEEN MADE OR ENACTED. THE MORTGAGOR, FOR ITSELF AND ALL WHO MAY CLAIM
UNDER IT, WAIVES, TO THE EXTENT THAT IT LAWFULLY MAY, ALL RIGHT TO HAVE THE
MORTGAGED PROPERTY MARSHALLED UPON ANY FORECLOSURE HEREOF. APPRAISEMENT OF THE
MORTGAGED PROPERTY IS HEREBY WAIVED OR NOT WAIVED AT THE OPTION OF THE
MORTGAGEE, SUCH OPTION TO BE EXERCISED AT OR PRIOR TO THE ENTRY OF JUDGMENT IN
ANY FORECLOSURE ACTION.

<PAGE>

         4.09 Expenses of Enforcement. In connection with any action to enforce
any remedy of the Mortgagee under this Mortgage, the Mortgagor agrees to pay all
out-of-pocket costs and expenses which may be reasonably paid or incurred by or
on behalf of the Mortgagee, including, without limitation, reasonable attorneys'
fees, receiver's fees, appraiser's fees, outlays for documentary and expert
evidence, stenographer's charges, publication costs, and costs (which may be
estimated as to items to be expended after entry of the decree) of procuring all
such abstracts of title, title searches and examinations, title insurance
policies and similar data and assurances with respect to title and value as the
Mortgagee may deem necessary or desirable, and neither the Mortgagee nor any
other Person shall be required to accept tender of any portion of the
Obligations unless the same be accompanied by a tender of all such expenses,
costs and commissions. All of the costs and expenses described in this Section
4.09 and such expenses and fees as may be reasonably incurred by the Mortgagee
in any litigation or proceeding (including appellate proceedings) arising from
the enforcement of this Mortgage or the Mortgaged Property (including, without
limitation, the occupancy thereof or any construction work performed thereon),
including bankruptcy proceedings, or in preparation for the commencement or
defense of any such proceeding or such threatened suit or proceeding whether or
not an action is actually commenced, shall be immediately due and payable by the
Mortgagor, with interest thereon at the Default Rate and shall be part of the
Obligations secured by this Mortgage.

         4.10 Indemnity.

         (a) The Mortgagor agrees to indemnify, reimburse and hold the Mortgagee
and its successors, permitted assigns, employees, affiliates and agents
(hereinafter in this Section 4.10 referred to individually as "Indemnitee," and
collectively as "Indemnitees") harmless from any and all liabilities,
obligations, damages, penalties, claims, demands, actions, suits, judgments and
any and all costs, expenses or disbursements (including attorneys' fees and
expenses reasonably incurred) (for the purposes of this Section 4.10 the
foregoing are collectively called "expenses") (collectively the "Indemnified
Liabilities") of whatsoever kind and nature imposed on, asserted against or
reasonably incurred by any of the Indemnitees relating to or arising out of this
Mortgage or in connection with the administration of the transactions
contemplated hereby or the enforcement of any of the terms of, or the
preservation of any rights under this Mortgage, or in any way relating to or
arising out of the manufacture, ownership, ordering, purchase, delivery,
control, acceptance, lease, financing, possession, operation, condition, sale,
return or other disposition, or use of the Mortgaged Property (including,
without limitation, latent or other defects, whether or not discoverable), the
violation of the laws of any country, state or other governmental body or unit,
any tort (including, without limitation, claims arising or imposed under the
doctrine of strict liability, or for or on account of injury to or the death of
any person (including any Indemnitee), or property damage), or contract claim;
provided that no Indemnitee shall be indemnified pursuant to this Section 4.10
for Indemnified Liabilities to the extent caused by the gross negligence or
willful misconduct of such Indemnitee (as determined by a court of competent
jurisdiction in a final and non-appealable decision) on or after the date
hereof. The Mortgagor agrees that upon notice by any Indemnitee of the assertion
of an Indemnified Liability, the Mortgagor shall assume full responsibility for
the defense thereof. Each Indemnitee agrees to use its best efforts to promptly
notify the Mortgagor of any such assertion of which such Indemnitee has
knowledge.

<PAGE>

         (b) If and to the extent that the obligations of the Mortgagor under
this Section 4.10 are unenforceable pursuant to applicable law, the Mortgagor
hereby agrees to the extent permitted by applicable law to make the maximum
contribution to the payment and satisfaction of such obligations which is
permissible under applicable law.

         4.11 Indemnity Obligations Secured by Mortgaged Property; Survival. Any
amounts paid by any Indemnitee as to which such Indemnitee has the right to
reimbursement from Mortgagor pursuant to this Mortgage or any other Loan
Document shall constitute Obligations secured by the Mortgaged Property. The
indemnity obligations of the Mortgagor contained in this Article IV shall
continue in full force and effect notwithstanding the full payment of all of the
other Obligations and notwithstanding the full payment of all principal and
interest payable under the Note and the discharge of the lien of this Mortgage.

                                    ARTICLE V

                               ADDITIONAL REMEDIES

         5.01 Additional Remedies.

         (a) The Mortgagor acknowledges and agrees that the Obligations are
secured by the Mortgaged Property. The Mortgagor specifically acknowledges and
agrees that the Mortgaged Property, in and of itself, if foreclosed or realized
upon might not be sufficient to satisfy the outstanding amount of the
Obligations. Accordingly, the Mortgagor acknowledges that any other assets of
the Mortgagor may be pursued by the Mortgagee in separate proceedings in the
various States, counties and other countries where such assets may be located
and additionally that the Mortgagor and the Guarantors will remain liable for
any deficiency judgments in addition to any amounts the Mortgagee may realize on
sales of such other property or any other assets of such parties. Specifically,
and without limitation of the foregoing, it is agreed that it is the intent of
the Mortgagor and the Mortgagee that in the event of a foreclosure of this
Mortgage, the Obligations shall not be deemed merged into any judgment of
foreclosure, but rather shall remain outstanding. It is the further intent and
understanding of the Mortgagor and the Mortgagee that if an Event of Default
shall have occurred and be continuing, the Mortgagee may pursue all Mortgaged
Property with the Obligations remaining outstanding and in full force and effect
notwithstanding any judgment of foreclosure or any other judgment which the
Mortgagee may obtain.

         (b) The Mortgagor waives and relinquishes any and all rights it may
have, whether at law or equity, to require the Mortgagee to proceed to enforce
or exercise any rights, powers and remedies it may have under the Loan Documents
in any particular manner or in any particular order. Furthermore, the Mortgagor
acknowledges and agrees that the Mortgagee shall be allowed to enforce payment
and performance of the Obligations and to exercise all rights and powers
provided under this Mortgage, or the other Loan Documents or under any provision
of law, by one or more proceedings, (whether contemporaneous, consecutive or
both). Neither the acceptance of this Mortgage or any other Loan Document nor
the enforcement in one proceeding, whether by court action, power of sale, or
otherwise, shall prejudice or in any way limit or preclude enforcement of such
documents through one or more additional proceedings.

<PAGE>

         (c) The Mortgagor further agrees that any particular remedy or
proceeding, including, without limitation, foreclosure through court action (in
a state or federal court) or power of sale, may be brought and prosecuted as to
all or any part of the Mortgaged Property, wherever located, without regard to
the fact that any one or more prior or contemporaneous proceedings have been
situated elsewhere with respect to the same or any other part of the Mortgaged
Property.

         (d) The Mortgagee may resort to any other security of the Mortgaged
Property held by the Mortgagee for the payment of the Obligations in such order
and manner as the Mortgagee may elect.

         (e) Notwithstanding anything contained herein to the contrary, the
Mortgagee shall be under no duty to the Mortgagor or others, including, without
limitation, the holder of any junior, senior or subordinate mortgage on the
Mortgaged Property or any part thereof or on any other security held by the
Mortgagee, to exercise or exhaust all or any of the rights, powers and remedies
available to the Mortgagee.

         (f) Notwithstanding anything contained herein to the contrary, if an
Event of Default occurs (i) the Mortgagee shall endeavor to give the
Administrative Agent a courtesy copy of any notice of such default
simultaneously with its giving of any such notice to the Mortgagor to the extent
that the Mortgagor is required to receive notice thereof under the Loan
Documents, provided that, in no event shall the Mortgagee's failure to give such
notice to the Administrative Agent preclude or in any way limit the Mortgagee's
rights or remedies pursuant to this Mortgage or the other Loan Documents; and
(ii) to the extent the Mortgagor can cure such default under the Loan Documents,
the Mortgagee shall accept such cure directly from the Administrative Agent if
so tendered.

                                   ARTICLE VI

                                  MISCELLANEOUS

         6.01 Governing Law. The provisions of this Mortgage shall be governed
by and construed under the laws of the State of Oklahoma.

         6.02 Limitation on Interest. It is the intent of the Mortgagor and the
Mortgagee in the execution of this Mortgage and all other Loan Documents to
contract in strict compliance with applicable usury laws. In furtherance
thereof, the Mortgagee and the Mortgagor stipulate and agree that none of the
terms and provisions contained in this Mortgage shall ever be construed to
create a contract for the use, forbearance or retention of money requiring
payment of interest at a rate in excess of the maximum interest rate permitted
to be charged under applicable law. If this Mortgage or any other Loan Documents
violate any such applicable usury law, then the interest rate payable in respect
of the Notes shall be the highest rate permissible under applicable law. The
right to accelerate the Notes pursuant to Section 4.02 hereof does not include a
right to require payment of any interest which has not otherwise accrued by the
date of such acceleration, and Lender does not intend to collect any unearned
interest in the event of acceleration; provided, however, that Lender shall, to
the extent specified herein, be entitled to receive interest at the applicable
rate herein specified on any amounts payable pursuant to this Mortgage through
the date collected.

<PAGE>

         6.03 Notices. Except as otherwise expressly provided herein, all
notices, requests, demands or other communications provided for hereunder shall
be in writing and mailed, transmitted via facsimile, or delivered via courier
service: if to the Mortgagor, at its address set forth in the first paragraph
hereof, Attention: General Counsel, facsimile (918) 547-2360; if to the
Mortgagee, at its address set forth in the first paragraph hereof, with copy to
White & Case LLP at 1155 Avenue of the Americas, New York, NY 10036, Attention:
John Reiss, Esq. and Roger Noble, Esq., facsimile (212) 354-8113; if to the
Administrative Agent for the purposes set forth in Section 5.01(f), at Bank of
America, N.A. 901 Main Street, 66th Floor, Dallas, Texas 75202-3714, Attention:
John W. Woodiel III, facsimile, (214) 209-3533, with a copy to Clifford Chance
US LLP, 200 Park Avenue, New York, NY 10166, Attention: Dawn Goldberg, Esq.,
facsimile (212) 878-8375; or at such other address as shall be designated by
such party in a written notice to the other parties hereto. All notices required
or permitted hereunder shall be given either by (a) personal delivery, (b)
professional expedited delivery service (postage prepaid), (c) facsimile
(provided that a confirmation copy immediately follows by any of the other
methods of delivery permitted herein), or (d) certified mail return receipt
requested (postage prepaid), and if so given, shall be deemed to have been given
either at the time of personal delivery, or, in the case of expedited delivery
service, as of the date of delivery or the date of attempted or refused delivery
at the address or in the manner provided herein, or, in the case of facsimile
with confirmation as required above, upon receipt or, in the case of certified
mail, five (5) Business Days after posting with the U.S. Postal Service.

         6.04 Captions. The captions or headings at the beginning of each
Article and Section hereof are for the convenience of the parties hereto and are
not a part of this Mortgage.

         6.05 Amendment. None of the terms and conditions of this Mortgage may
be changed, waived, modified or varied in any manner whatsoever except with the
prior written consent of the Mortgagee and the Mortgagor.

         6.06 Obligations Absolute. Except to the extent, if any, otherwise
expressly hereafter agreed by the Mortgagee and the Mortgagor by an amendment
pursuant to Section 6.05, the obligations of the Mortgagor hereunder shall
remain in full force and effect without regard to, and shall not be impaired by,
(a) any bankruptcy, insolvency, reorganization, arrangement, readjustment,
composition, liquidation or the like of the Mortgagor; (b) any exercise or
non-exercise, or any waiver of, any right, remedy, power or privilege under or
in respect of this Mortgage or any other Loan Document; or (c) any amendment to
or modification of any Loan Document; whether or not the Mortgagor shall have
notice or knowledge of any of the foregoing.

         6.07 Further Assurances. The Mortgagor shall, upon the reasonable
request of the Mortgagee and at the expense of the Mortgagor: (a) promptly
correct any defect, error or omission which may be discovered in this Mortgage
or any UCC financing statements filed in connection herewith; (b) promptly
execute, acknowledge, deliver and record or file, as applicable, such further
agreements, instruments and documents (including, without limitation, further
mortgages, deeds of trust, security deeds, security agreements, financing
statements, continuation statements and assignments of rents or leases) and
promptly do such further acts as may be necessary or reasonably desirable to
carry out the terms and purposes of this Mortgage and to subject to the Liens
and security interests hereof, any of the Mortgaged Property; and (c) promptly
execute, acknowledge, deliver, procure and record or file any document or

<PAGE>

instrument (including specifically any financing statement) reasonably required
by the Mortgagee to protect, continue or perfect the liens or the security
interests hereunder against the rights or interests of third persons.

         6.08 Partial Invalidity. If any of the provisions of this Mortgage or
the application thereof to any person, party or circumstances shall to any
extent be invalid or unenforceable, the remainder of this Mortgage, or the
application of such provision or provisions to persons, parties or circumstances
other than those as to whom or which it is held invalid or unenforceable, shall
not be affected thereby, and every provision of this Mortgage shall be valid and
enforceable to the fullest extent permitted by law.

         6.09 Partial Releases. No release from the lien of this Mortgage of any
part of the Mortgaged Property by the Mortgagee shall in any way alter, vary or
diminish the force or effect of this Mortgage on the balance of the Mortgaged
Property or the priority of the lien of this Mortgage on the balance of the
Mortgaged Property.

         6.10 RESERVED.

         6.11 Covenants Running with the Land. All Obligations are intended by
the Mortgagor and the Mortgagee to be, and shall be construed as, covenants
running with the Mortgaged Property. As used herein, "Mortgagor" shall refer to
the party named in the first paragraph of this Mortgage and to any subsequent
owner of any interest in all or any portion of the Mortgaged Property. All
persons who may have or acquire an interest in the Mortgaged Property shall be
deemed to have notice of, and be bound by, the terms of the Notes and the other
Loan Documents; provided, however, that no such party shall be entitled to any
rights thereunder without prior written consent of the Mortgagee.

         6.12 Successors and Assigns. This Mortgage shall be binding upon and
inure to the benefit of the Mortgagee and the Mortgagor and their respective
successors and assigns. Except as otherwise permitted by the Notes, the
Mortgagor shall not assign any rights, duties, or obligations hereunder.

         6.13 Purpose of Notes. The Mortgagor hereby represents and agrees that
the Notes secured by this Mortgage are being obtained for business or commercial
purposes, and the proceeds thereof will not be used for personal, family,
residential, household or agricultural purposes.

         6.14 No Joint Venture or Partnership. The relationship created
hereunder and under the other Loan Documents is that of creditor/debtor. The
Mortgagee does not owe any fiduciary obligation to the Mortgagor and/or any of
the Mortgagor's officers, partners, agents, or representatives pursuant to the
Loan Documents. Nothing herein or in any other Loan Document is intended to
create a joint venture, partnership, tenancy-in-common or joint tenancy
relationship between the Mortgagor and the Mortgagee.

         6.15 RESERVED.

         6.16 Full Recourse. This Mortgage is made with full recourse to the
Mortgagor and to all assets of the Mortgagor, including the Mortgaged Property
and pursuant to and upon all the

<PAGE>

warranties, representations, covenants and agreements on the part of the
Mortgagor contained herein and in the other Loan Documents, provided that such
recourse shall not extend to (i) any officer, director, employee, agent or
representative of (x) the Mortgagor or (y) any Guarantor or (ii) any shareholder
of WCG (except to the extent that the Mortgagor or any Guarantor is a
shareholder of WCG).

         6.17 RESERVED.

         6.18 Acknowledgment of Receipt. The Mortgagor hereby acknowledges
receipt of a true copy of this Mortgage.

         6.19 Release Upon Full Payment. Following the Termination Date (as
hereinafter defined), this Mortgage shall be released of record, and the
Mortgagee, at the request and expense of the Mortgagor, will promptly execute
and deliver to the Mortgagor (without recourse and without representation or
warranty) a proper instrument or instruments acknowledging the satisfaction and
termination of this Mortgage and release of the Liens of this Mortgage;
provided, however, that all indemnities set forth herein (including, without
limitation Section 4.10 hereof) shall survive such termination. As used herein,
the "Termination Date" shall mean the date upon which all Obligations of the
Mortgagor under the Notes and the other Loan Documents shall have been paid and
performed in full.

         6.20 Time of the Essence. Time is of the essence with respect to the
obligations of the Mortgagor under this Mortgage.

         6.21 The Mortgagee's Powers. Without affecting the liability of any
other Person liable for the payment and performance of the Obligations and
without affecting the Lien of this Mortgage in any way, the Mortgagee may, from
time to time, regardless of consideration and without notice to or consent by
the holder of any subordinate Lien, right, title or interest in or to the
Mortgaged Property, (a) release any Persons liable for the Obligations, (b)
extend the maturity of, increase or otherwise alter any of the terms of the
Obligations, (c) modify the interest rate payable on the principal balance of
the Obligations, (d) release or reconvey, or cause to be released or reconveyed
all or any portion of the Mortgaged Property, or (e) take or release any other
or additional security for the Obligations.

         6.22 Rules of Usage; Certain Defined Terms. The following rules of
usage shall apply to this Mortgage unless otherwise required by the context:

         (a) Singular words shall connote the plural as well as the singular,
and vice versa, as may be appropriate.

         (b) The words "herein", "hereof" and "hereunder" and words of similar
import appearing in this Mortgage shall be construed to refer to such document
as a whole and not to any particular section, paragraph or other subpart thereof
unless expressly so stated.

         (c) References to any Person shall include such Person and its
successors and permitted assigns.

<PAGE>

         (d) Each of the parties hereto and their counsel have reviewed and
revised, or requested revisions to, this Mortgage, and the usual rule of
construction that any ambiguities are to be resolved against the drafting party
shall be inapplicable in the construction and interpretation of such documents
and any amendments or exhibits thereto.

         (e) Unless an express provision requires otherwise, each reference to
"the Mortgaged Property" shall be deemed a reference to "the Mortgaged Property
or any part thereof".

         (f) As used in this Mortgage, the following terms shall have the
meanings set forth in this paragraph (f):

         "Acquired Assets" shall have the meaning provided in the Purchase
Agreement.

         "Administrative Agent" means Bank of America, N.A., as administrative
         agent for the Lenders under the Credit Agreement and any successor or
         other administrative agent under the Credit Agreement.

         "Affiliate" shall mean with respect to any Person, any other Person
         which, directly or indirectly, through one or more intermediaries,
         controls, or is controlled by, or is under common control with, such
         Person.

         "Aircraft Dry Leases" shall mean (a) the Aircraft Dry Lease (N358WC)
         dated as of September 13, 2001 by and between Williams Aircraft
         Leasing, LLC, as "Lessor", and WCL, as "Lessee", and/or (b) the
         Aircraft Dry Lease (N359WC) dated as of September 13, 2001 by and
         between Williams Aircraft Leasing, LLC, as "Lessor", and WCL, as
         "Lessee".

         "Bankruptcy Court" means the United States Bankruptcy Court for the
         Southern District of New York.

         "Business Day" shall mean a day other than a Saturday, Sunday or day on
         which banks are authorized to be closed in Tulsa, Oklahoma.

         "Central Plant" shall mean the equipment, fixtures, piping, wiring,
         machinery, and all other items of personal property comprising the
         plant for chilled and hot water production and circulation, and
         electricity generation and transmission located in the basement of the
         building comprising a portion of the Improvements, which building is
         commonly known as One Technology Center or the Williams Technology
         Center, as described in the Central Plant Lease.

         "Central Plant Lease" shall mean that certain Lease Agreement
         originally entered into between the Mortgagor, as "Landlord," and the
         Mortgagee, as "Tenant," effective as of April 23, 2001, as the same may
         be amended, supplemented or otherwise modified from time to time,

         "control" (including with correlative meanings, the terms "controlled
         by" and "under common control with"), as used with respect to any
         Person, shall mean the possession, directly or indirectly, of the power
         to direct or cause the direction of the management and policies of such
         Person, whether through the ownership of voting securities or
         partnership interests, by contract or otherwise.

         "CGI" means CG Austria, Inc., a Delaware corporation and wholly owned
         subsidiary of WCL.

<PAGE>

         "Chapter 11 Cases" means the cases commenced by the Debtors under
         chapter 11, title 11, United States Code, 11 U.S.C. sec. 101 et seq.,
         in the Bankruptcy Court.

         "Confirmation Order" has the meaning specified in the Plan.

         "Credit Agreement" means that certain Second Amended and Restated
         Credit and Guaranty Agreement dated as of September 8, 1999, as amended
         and restated as of April 25, 2001, and as further amended and restated
         as of October 15, 2002, among WCL, as borrower, the guarantors party
         thereto, the Lenders, the Administrative Agent, JP Morgan Chase Bank as
         Syndication Agent, and Salomon Smith Barney Inc. and Merrill Lynch &
         Co., as Co-Documentation Agents, as the same may be further amended,
         restated, modified, supplemented, extended, renewed, consolidated,
         restructured, rearranged, refinanced, refunded or replaced from time to
         time.

         "Debtors" means WCG and CGI.

         "Default Rate" has the meaning specified in the Long-Term Note.

         "Effective Date" has the meaning specified in the Plan.

         "Equitable Mortgage" shall mean that certain Equitable Mortgage dated
         as of October 15, 2002 made by CGI to the Mortgagee, as the same may be
         amended, supplemented or otherwise modified from time to time.

         "Excluded Property" means the following: (a) all equipment, machinery
         and other items of personal property (including the components
         thereof), together with all replacements, substitutions, renewals,
         modifications, alterations and additions thereto and the proceeds
         thereof, now or hereafter located in, on or affixed to the Improvements
         that are necessary or used predominantly for the operation of the
         telecommunications network owned or operated by Mortgagor and/or the
         Guarantors, including without limitation the items described on Exhibit
         C attached hereto; provided, however, notwithstanding anything to the
         contrary contained in this Mortgage (including the inclusion of any
         item described on Exhibit C), the Second Mortgage or the Loan Documents
         (as defined in the Second Mortgage), "Excluded Property" shall not
         include any real property or fixtures (as such term is defined in the
         Uniform Commercial Code) located in, on or affixed to the
         Improvements); and (b) any equipment or machinery (other than any
         equipment or machinery existing on the date hereof or any replacement
         thereof) securing purchase money indebtedness or operating leases of
         the Mortgagor incurred to finance the acquisition of such equipment or
         machinery if the written terms and conditions governing such purchase
         money indebtedness or operating leases prohibit other Liens on or
         security interests in the equipment or machinery financed thereunder.

         "Governmental Authority" shall mean the Federal government, or any
         state or other political subdivision thereof, or any agency, court or
         body of the Federal government, any state or other political
         subdivision thereof, exercising executive, legislative, judicial,
         regulatory or administrative functions and which shall have
         jurisdiction on the matter in question.

         "Lenders" shall mean each of the Lenders from time to time party to the
         Credit Agreement.

         "Lien" shall mean any mortgage, security interest, pledge,
         hypothecation, assignment, encumbrance, lien (statutory or other), or
         other security agreement of any kind or nature whatsoever (including,
         without limitation, any conditional sale or other title retention

<PAGE>

         agreement, any financing or similar statement or notice filed under the
         Uniform Commercial Code or any other similar recording or notice
         statute, and any lease having substantially the same effect as any of
         the foregoing).

         "Loan Documents" means the Notes, this Mortgage, the Equitable
         Mortgage, the Pledge, UCC-1 financing statements and any other
         documents or instruments further evidencing or securing the
         Obligations.

         "Notes" means the collective reference to the Long-Term Note and the
         Short-Term Note.

         "Person" shall mean any individual, partnership, joint venture, limited
         liability company, firm, corporation, association, trust or other
         enterprise or any government or political subdivision or any agency,
         department or instrumentality thereof.

         "Plan" means the Second Amended Joint Chapter 11 Plan of Reorganization
         of the Debtors filed with the Bankruptcy Court on August 12, 2002, and
         the Plan Schedules and Plan Documents (as each such term is defined
         therein), and all supplements, appendices, and schedules to any of the
         foregoing, either in their present form or as any of them may be
         amended, restated, or modified from time to time.

         "Pledge" means that certain Pledge Agreement of even date herewith made
         by CGI for the benefit of the Mortgagee.

         "Uniform Commercial Code" means the Uniform Commercial Code as from
         time to time in effect in the State of Oklahoma.

         6.23 No Off-Set. All sums payable by the Mortgagor shall be paid
without counterclaim, other compulsory counterclaims, set-off, or deduction and
without abatement, suspension, deferment, diminution or reduction, and the
Obligations shall in no way be released, discharged or otherwise affected
(except as provided in Section 1.05 and Section 1.07 or as otherwise expressly
provided herein) by reason of: (i) any damage or any condemnation of the
Mortgaged Property or any part thereof; (ii) any title defect or encumbrance or
any eviction from the Mortgaged Property or any part thereof by title paramount
or otherwise; or (iii) any bankruptcy, insolvency, reorganization, composition,
adjustment, dissolution, liquidation or other like proceeding relating to the
Mortgagee or the Mortgagor, or any action taken with respect to this Mortgage by
any agent or receiver of the Mortgagee. Except as may otherwise be expressly
provided in the Notes, the Mortgagor waives, to the extent permitted by
applicable law, all rights now or hereafter conferred by law or otherwise to any
abatement, suspension, deferment, diminution or reduction of any of the
Obligations.

         6.24 Consent to Jurisdiction and Service of Process; Waiver of Jury
Trial.

         (a) ANY LEGAL ACTION OR PROCEEDING WITH RESPECT TO THIS MORTGAGE OR ANY
OTHER LOAN DOCUMENT MAY BE BROUGHT IN THE STATE AND FEDERAL COURTS OF OKLAHOMA,
WHICH IN EACH CASE IS LOCATED IN THE COUNTY OF TULSA, AND, BY EXECUTION AND
DELIVERY OF THIS MORTGAGE, THE MORTGAGOR HEREBY IRREVOCABLY ACCEPTS FOR ITSELF
AND IN RESPECT OF ITS PROPERTY, GENERALLY AND UNCONDITIONALLY, THE NON-EXCLUSIVE
JURISDICTION OF THE AFORESAID COURTS WITH RESPECT TO ANY SUCH LEGAL ACTION OR
PROCEEDING. THE MORTGAGOR HEREBY

<PAGE>

FURTHER IRREVOCABLY WAIVES ANY CLAIM THAT ANY SUCH COURTS LACK JURISDICTION OVER
THE MORTGAGOR, AND AGREES NOT TO PLEAD OR CLAIM, IN ANY LEGAL ACTION OR
PROCEEDING WITH RESPECT TO THIS MORTGAGE OR ANY OTHER LOAN DOCUMENT BROUGHT IN
ANY OF THE AFORESAID COURTS THAT ANY SUCH COURT LACKS JURISDICTION OVER THE
MORTGAGOR. THE MORTGAGOR FURTHER IRREVOCABLY CONSENTS TO THE SERVICE OF PROCESS
OUT OF ANY OF THE AFOREMENTIONED COURTS IN ANY SUCH ACTION OR PROCEEDING BY THE
MAILING OF COPIES THEREOF BY REGISTERED OR CERTIFIED MAIL, POSTAGE PREPAID, TO
THE MORTGAGOR AT ITS ADDRESS FOR NOTICES PURSUANT TO SECTION 6.03 HEREOF, SUCH
SERVICE TO BECOME EFFECTIVE 30 DAYS AFTER SUCH MAILING. THE MORTGAGOR HEREBY
IRREVOCABLY WAIVES ANY OBJECTION TO SUCH SERVICE OF PROCESS AND FURTHER
IRREVOCABLY WAIVES AND AGREES NOT TO PLEAD OR CLAIM IN ANY ACTION OR PROCEEDING
COMMENCED HEREUNDER OR ANY OTHER LOAN DOCUMENT THAT SUCH SERVICE OF PROCESS WAS
IN ANY WAY INVALID OR INEFFECTIVE. NOTHING HEREIN SHALL AFFECT THE RIGHT OF THE
MORTGAGEE, TO SERVE PROCESS IN ANY OTHER MANNER PERMITTED BY LAW OR TO COMMENCE
LEGAL PROCEEDINGS OR OTHERWISE PROCEED AGAINST THE MORTGAGOR IN ANY OTHER
JURISDICTION (INCLUDING THE JURISDICTION IN WHICH THE MORTGAGED PROPERTY IS
LOCATED).

         (b) THE MORTGAGOR HEREBY IRREVOCABLY WAIVES ANY OBJECTION WHICH IT MAY
NOW OR HEREAFTER HAVE TO THE LAYING OF VENUE OF ANY OF THE AFORESAID ACTIONS OR
PROCEEDINGS ARISING OUT OF OR IN CONNECTION WITH THIS MORTGAGE OR ANY OTHER
DOCUMENT BROUGHT IN THE COURTS REFERRED TO IN CLAUSE (a) ABOVE AND HEREBY
FURTHER IRREVOCABLY, TO THE EXTENT PERMITTED BY APPLICABLE LAW, WAIVES AND
AGREES NOT TO PLEAD OR CLAIM IN ANY SUCH COURT THAT ANY SUCH ACTION OR
PROCEEDING BROUGHT IN ANY SUCH COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM.

         (c) EACH OF THE MORTGAGOR AND THE MORTGAGEE HEREBY IRREVOCABLY WAIVES
ALL RIGHT TO A TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING
OUT OF OR RELATING TO THIS MORTGAGE, THE OTHER LOAN DOCUMENTS OR THE
TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY.

         6.25 Future Advances. This Mortgage secures all Obligations under the
Loan Documents, now or hereafter incurred, whether interest or otherwise, and
whether the same shall be deferred, accrued or capitalized, including future
advances and re-advances, if any, pursuant to the Notes or the other Loan
Documents, whether such advances are obligatory or to be made at the option of
the Mortgagee, or otherwise, to the same extent as if such future advances were
made on the date of the execution of this Mortgage. The Lien of this Mortgage
shall be valid as to all indebtedness secured hereby, including future advances,
from the time of its filing for record in the recorder's office of the county in
which the Mortgaged Property is located.

<PAGE>
         6.26 Mortgagor's Address. The address of the Mortgagee set forth in the
first paragraph of this Mortgage is the mailing address of the Mortgagee for
purposes of 19 O.S. Section 298 and 68 O.S. Section 3127.

                            [Signature Page follows]

<PAGE>

                  IN WITNESS WHEREOF, the Mortgagor has caused this Mortgage to
be duly executed and delivered as of the day and year first above written.

                                 WILLIAMS TECHNOLOGY CENTER, LLC,
                                      a Delaware limited liability company

                                 By: Williams Communications, LLC,
                                          a Delaware limited liability company,
                                          as sole member and manager

                                 By:  /s/ Howard S. Kalika
                                      ------------------------------------------
                                      Title: Vice President

<PAGE>

STATE OF NEW YORK   )
                    )    ss:
COUNTY OF NEW YORK  )

                  This instrument was acknowledged before me this 15th day of
October, 2002, by Howard S. Kalika as Vice President of Williams Communications,
LLC, a Delaware limited liability company, as Sole Member and Manager of
Williams Technology Center, LLC, a Delaware limited liability company.

                  IN WITNESS WHEREOF, I have hereunto set my hand and official
seal.

                                  /s/ Yahayra Reyes
                                  -----------------------

                                  Notary Public

                                  Print or Type Name:  Yahayra Reyes
                                                     ---------------------------
                                  My Commission Expires:
                                                        ------------------------

[SEAL]<PAGE>

                                                                   EXHIBIT 10.50

          FIRST AMENDMENT TO REAL PROPERTY PURCHASE AND SALE AGREEMENT

         THIS FIRST AMENDMENT dated as of October 15, 2002 (this "Amendment") to
Real Property Purchase and Sale Agreement dated as of July 26, 2002 (the
"Agreement"), is entered into by and among Williams Headquarters Building
Company, a Delaware corporation ("Seller"), Williams Technology Center, LLC, a
Delaware limited liability company ("Purchaser"), Williams Communications, LLC,
a Delaware limited liability company ("WCL"), Williams Communications Group,
Inc., a Delaware corporation ("Communications"), Williams Aircraft Leasing, LLC,
a Delaware limited liability company ("WAL"), WilTel Communications Group, Inc.,
a Nevada corporation ("New WCG"), Williams Aircraft, Inc., a Delaware
corporation ("WAI") and CG Austria, Inc., a Delaware corporation ("CG Austria").
All capitalized terms not otherwise defined herein shall have the meanings given
to such terms in the Agreement (as amended by the Amendment).

         WHEREAS, the parties have agreed to modify the provisions relating to
the payment of the Purchase Price and certain other provisions of the Agreement
pursuant to the terms of this Amendment;

         WHEREAS, Communications and its subsidiary, CG Austria, Inc., a
Delaware corporation, filed voluntary petitions on April 22, 2002 for relief
pursuant to chapter 11 of title 11 of the United States Code, 11 U.S.C. Sections
101-1330 (as amended, the "Bankruptcy Code"), which cases are pending in the
United States Bankruptcy Court for the Southern District of New York (the
"Bankruptcy Court") and procedurally consolidated under Case No. 02-11957; and

         WHEREAS, pursuant to and in connection with the Second Amended Joint
Chapter 11 Plan of Reorganization of Communications and CG Austria, Inc., a
Delaware corporation ("CG Austria") dated August 12, 2002, filed with the U.S.
Bankruptcy Court for the Southern District of the State of New York (the "Plan")
and the Escrow Agreement (hereinafter defined), the parties hereto have
determined to amend the Agreement to consummate the Plan and the transactions
contemplated thereby and in connection therewith allow New WCG, the successor
entity to Communications created pursuant to and in accordance with the Plan,
and WAI to become parties to the Agreement.

         NOW, THEREFORE, in consideration of the foregoing premises and the
mutual promises and obligations contained herein, the receipt and sufficiency of
which are hereby acknowledged, the Parties hereto hereby agree as follows:

         1. Section 1.01 of the Agreement is hereby amended by deleting the
defined term "Purchase Money Note" set forth therein and substituting in lieu
thereof the defined term "Purchase Money Notes" as follows:

                                      -1-
<PAGE>

                  "Purchase Money Notes" shall mean the collective reference to
                  the Long Term Note and the Short Term Note, each of which
                  shall be secured by the Purchase Money Mortgage and the Pledge
                  Agreement.

         2. Section 1.01 of the Agreement is hereby amended by adding the
following defined terms thereto:

                  "Administrative Services Agreement" shall mean the Amended and
                  Restated Administrative Services Agreement dated as of April
                  23, 2001, between TWC and Communications, as amended,
                  restated, supplemented or otherwise modified from time to
                  time.

                  "Agreement for Resolution of Continuing Contract Disputes"
                  shall mean the Agreement for the Resolution of Continuing
                  Contract Disputes dated as of July 26, 2002, among TWC,
                  Communications and WCL, as amended, restated, supplemented or
                  otherwise modified from time to time.

                  "Aircraft Refinancing Net Cash Proceeds" shall have the
                  meaning specified in Section 2.08(b).

                  "Australian Legal Opinion" shall mean an opinion of
                  Atanaskovic Hartnell addressed to Seller and its successors
                  and assigns dated as of the Closing Date, opining as to the
                  enforceability of the Equitable Mortgage, the perfection of
                  the security interest granted thereby and such other matters
                  incident to the Transactions contemplated by the Equitable
                  Mortgage and the Pledge Agreement, which shall be in form and
                  substance reasonably satisfactory to Seller.

                  "Building Purchase Escrowee" means Lawyers Title Insurance
                  Corporation, acting in the capacity of title insurance company
                  pursuant to the Title Instruction Letter.

                  "Building Purchase Closing Documents" means the collective
                  reference to the Company Building Purchase Closing Documents
                  and the TWC Building Purchase Closing Documents.

                  "CG Austria" shall mean CG Austria, Inc., a Delaware
                  corporation.

                  "Company Building Purchase Closing Documents" shall have the
                  meaning specified in the Escrow Agreement.

                  "Equitable Mortgage" means that certain Second Equitable
                  Mortgage of Shares dated as of October 15, 2002, executed by
                  CG Austria in favor of Seller, as amended, restated,
                  supplemented or otherwise modified from time to time.

                  "Escrow Agent" shall mean The Bank of New York, a New York
                  banking corporation.

                                      -2-
<PAGE>

                  "Escrow Agreement" shall mean the Escrow Agreement dated as of
                  October 15, 2002, among New WCG, TWC, Leucadia and the Escrow
                  Agent, as amended, restated, supplemented or otherwise
                  modified from time to time.

                  "Escrow Period" shall mean the period between (a) October 15,
                  2002 and (b) the earlier of (i) the Escrow Period Termination
                  Date or (ii) the Escrow Period Breakage Date.

                  "Escrow Period Breakage Date" shall mean any date on which the
                  Escrow Period terminates other than as a result of the
                  occurrence of an Escrow Period Termination Date.

                  "Escrow Period Purchase Agreement Default" shall mean the
                  occurrence and continuance of one or more of the following
                  during the Escrow Period (in each case taking into account any
                  grace period or grace periods specified in Section 7.07 (b) of
                  this Agreement (which shall be applicable in all respects
                  during the Escrow Period): (a) the breach or violation of any
                  representation or warranty under Article III of this
                  Agreement; (b) the breach of or violation of any covenant
                  under Article IV of this Agreement; or (c) the breach of any
                  term or provision specified in Section 5.03 of this Agreement.

                  "Escrow Period Differential" shall have the meaning specified
                  in Section 2.08 of this Agreement.

                  "Escrow Period Termination Date" shall mean the date on which
                  the Building Purchase Closing Documents are released by the
                  Escrow Agent pursuant to and in accordance with Section 4 of
                  the Escrow Agreement.

                  "Intercreditor Agreement (Mortgage)" shall mean that certain
                  Intercreditor and Subordination Agreement (Mortgaged Property)
                  dated as of October 15, 2002, by and between Seller and the
                  Bank Agent, as amended, restated, supplemented or otherwise
                  modified from time to time, relating to the Purchase Money
                  Mortgage.

                  "Intercreditor Agreement (Pledge Agreement)" shall mean that
                  certain Intercreditor and Subordination Agreement (PowerTel
                  Collateral) dated as of October 15, 2002, by and between
                  Seller and the Bank Agent, as amended, restated, supplemented
                  or otherwise modified from time to time, relating to the
                  Pledge Agreement, in the form attached hereto as Exhibit 8.

                  "Intercreditor Agreements" shall mean the collective reference
                  to the Intercreditor Agreement (Pledge Agreement) and the
                  Intercreditor Agreement (Mortgage).

                  "Jones Day Legal Opinion" shall mean an opinion of Jones, Day,
                  Reavis & Pogue reasonably satisfactory to Seller addressed to
                  Seller dated as of the Closing Date, opining as to the
                  organization and good standing of Purchaser, WCL and CG
                  Austria in the State of Delaware, authorization of the
                  execution, delivery and performance by Purchaser and WCL of
                  the Purchase Money Notes, authorization of the execution and
                  delivery by Purchaser of the Purchase Money Mortgage and
                  authorization

                                      -3-
<PAGE>

                  of the execution and delivery by CG Austria of the Pledge
                  Agreement, and the execution and delivery of the Pledge
                  Agreement by, and the enforceability of the Pledge Agreement
                  against, CG Austria and such other matters incident to the
                  Transactions contemplated herein, which shall be in form and
                  substance reasonably satisfactory to Seller.

                  "Leucadia" shall mean Leucadia National Corporation, a New
                  York corporation.

                  "Loan Documents" shall have the meaning specified in the WCG
                  Bank Facility.

                  "Long Term Note" shall have the meaning provided in Section
                  2.02(b) of this Agreement.

                  "New WCG" shall mean WilTel Communications Group, Inc., a
                  Nevada corporation, the successor entity to Communications
                  created pursuant to the Plan.

                  "New WCG Legal Opinion" shall mean an opinion of Jones Vargas
                  addressed to Seller dated as of the Closing Date, opining as
                  to the incorporation, existence and good standing of New WCG
                  under the laws of the State of Nevada, authorization of the
                  execution and delivery by New WCG of the Purchase Money Notes,
                  and such other matters incident to the Transactions
                  contemplated herein, which shall be in form and substance
                  reasonably satisfactory to Seller.

                  "Plan" shall mean the Second Amended Joint Chapter 11 Plan of
                  Reorganization of Communications and CG Austria dated August
                  12, 2002, filed with the U.S. Bankruptcy Court for the
                  Southern District of the State of New York, as may be amended,
                  supplemented or otherwise modified from time to time.

                  "Pledge Agreement" shall mean that certain Pledge Agreement
                  dated as of October 15, 2002, made by CG Austria in favor of
                  Seller at Closing (as amended, restated, supplemented or
                  otherwise modified from time to time), including the
                  Acknowledgment, Consent and Agreement attached thereto, in
                  form attached hereto as Exhibit 9 pursuant to which (a) CG
                  Austria shall pledge and grant a security interest in all of
                  its right, title and interest in and to the Pledged Shares and
                  certain related collateral to Seller, in form and substance
                  mutually satisfactory to Purchaser and Seller, provided that
                  any such liens and security interest shall be expressly junior
                  and subordinate to the liens and security interests granted by
                  CG Austria to the Bank Agent pursuant to the terms thereof and
                  shall be subject to the Intercreditor Agreement (Pledge
                  Agreement); and (b) CG Austria shall agree to cause WCP to
                  amend its organizational documents or to enter into other
                  agreements and documents to make WCP a "special purpose
                  entity", the purpose and activities of which shall be limited
                  to owning the stock of PowerTel and to conduct activities
                  necessary or appropriate in connection with such ownership.

                  "Pledged Shares" shall mean 66% of the beneficial interests of
                  WCP.

                                      -4-
<PAGE>

                  "PowerTel" shall mean PowerTel Limited (f/k/a Spectrum Network
                  Systems Limited) (ACN 001 760 103), a corporation organized
                  and existing under the laws of Australia.

                  "Purchase Agreement" shall mean the Agreement of Purchase and
                  Sale dated as of September 13, 2001 among Williams Technology
                  Center, LLC, a Delaware limited liability company, as
                  "Seller", Williams Headquarters Building Company, a Delaware
                  corporation, as "Purchaser", and Williams Communications, LLC,
                  a Delaware limited liability company, as "Guarantor", as
                  amended, restated, supplemented or otherwise modified from
                  time to time.

                  "Sale Leaseback Default" shall mean the occurrence and
                  continuance of any "Event of Default" specified in the defined
                  term "Event of Default" (as such term is defined in the Master
                  Lease or in any Sale Leaseback Transaction Document or any
                  default or event of default under, or any breach or violation
                  of any term or provision of, any Sale Leaseback Transaction
                  Document (in each case after taking into account any
                  applicable grace period or grace periods).

                  "Sale Leaseback Transaction Documents" shall mean the Master
                  Lease and the Aircraft Dry Leases, as any of the foregoing may
                  have been amended, restated, supplemented or otherwise
                  modified through and including the Closing Date and as any of
                  the foregoing may be amended, restated, supplemented or
                  otherwise modified from time to time following the Closing
                  Date.

                  "Second Mortgage" shall mean that certain Second Mortgage,
                  Assignment of Leases and Rents, Security Agreement, Financing
                  Statement and Fixture Filing dated as of October 15, 2002,
                  made by Purchaser in favor of the Bank Agent for the benefit
                  of the Lenders, as amended, restated, supplemented or
                  otherwise modified from time to time, pursuant to which
                  Purchaser shall grant mortgage liens and security interests in
                  all of its right, title and interest in certain of the
                  Acquired Assets and related collateral to the Bank Agent for
                  the benefit of the Lenders, provided that any such liens and
                  security interest shall be expressly junior and subordinate to
                  the liens and security interests granted by Purchaser to the
                  Seller in the Mortgaged Property (as such term is defined in
                  the Purchase Money Mortgage) and related collateral pursuant
                  to the terms thereof and shall be subject to the Intercreditor
                  Agreement (Mortgage).

                  "Side Letter" means that certain Letter Agreement dated as of
                  October 15, 2002, among Seller, Purchaser, WCL and New WCG,
                  with respect to the Purchase Money Mortgage, in the form
                  attached hereto as Exhibit E.

                  "Termination Statements" shall mean UCC financing statement
                  amendments prepared for filing under the Uniform Commercial
                  Code of each jurisdiction as may be necessary to terminate the
                  security interests and liens in favor of Seller created
                  pursuant to and in accordance with the Master Lease.

                                      -5-
<PAGE>

                  "Title Instruction Letter" shall mean that Title Instruction
                  Letter dated as of October 15, 2002, issued to the Building
                  Purchase Escrowee, among Purchaser, Seller, Building Purchase
                  Escrowee and the Bank Agent, as amended, supplemented or
                  otherwise modified from time to time.

                  "Title Policies" shall have the meaning specified in the Title
                  Instruction Letter.

                  "TWC Building Purchase Closing Documents" shall have the
                  meaning specified in the Escrow Agreement.

                  "TWC Party" shall mean TWC, Seller, WAL, WAI and any of their
                  respective subsidiaries and Affiliates.

                  "WCG Party" shall mean New WCG, Communications, WCL, Purchaser
                  and any of their respective subsidiaries and Affiliates.

                  "Williams Aircraft Leasing Transfer Agreement" shall mean the
                  Membership Interest Purchase Agreement, between WAI, as
                  "Seller", and WCL, as "Purchaser", in the form attached hereto
                  as Exhibit F.

                  "Williams Aircraft Leasing Transfer Documents" shall mean the
                  Williams Aircraft Leasing Transfer Agreement and all other
                  agreements, instruments, documents, and certificates required
                  or reasonably requested by Purchaser or WCL in connection
                  therewith.

                  "WAI" shall mean Williams Aircraft, Inc., a Delaware
                  corporation, and the sole member of Williams Aircraft Leasing,
                  LLC, a Delaware limited liability company.

                  "WAL" shall mean Williams Aircraft Leasing, LLC, a Delaware
                  limited liability company.

                  "WCP" shall mean WilTel Communications Pty Limited (ACN 081
                  547 042), a corporation organized and existing under the laws
                  of Australia.

         3. Section 1.01 of the Agreement is hereby amended by deleting the
defined term "Cash Portion of the Purchase Price" therein in its entirety.

         4. Section 1.01 of the Agreement is hereby amended by amending and
restating the defined term "Financing Statements" in full to read as follows:

                  "Financing Statements" shall mean UCC-1 financing statements
                  for filing under the Uniform Commercial Code of each
                  jurisdiction as may be necessary or, in the reasonable opinion
                  of Seller, desirable to perfect the security interest created
                  by the Purchase Money Mortgage and the Pledge Agreement.

                                      -6-
<PAGE>
         5. Section 1.01 of the Agreement is hereby amended by amending and
restating the defined term "Purchase Money Mortgage" in full to read as follows:

                  "Purchase Money Mortgage" shall mean the Mortgage With Power
                  of Sale, Security Agreement, Assignment of Leases, Rents and
                  Profits, Financing Statement and Fixture Filing, to be granted
                  at Closing by Purchaser in favor of Seller in a form
                  reasonably acceptable to each of Purchaser and Seller.

         6. Section 1.01 of the Agreement is hereby amended by amending and
restating the defined term "WCG Bank Facility" in full to read as follows:

                  "WCG Bank Facility" shall mean the Second Amended and Restated
                  Credit and Guaranty Agreement dated as of September 8, 1999,
                  as amended and restated as of April 25, 2001, and as further
                  amended and restated as of October 15, 2002, among WCL, as
                  "Borrower", New WCG and the other Guarantors referred to
                  therein, the Lenders referred to therein, the Bank Agent, JP
                  Morgan Chase Bank as Syndication Agent, and Salomon Smith
                  Barney Inc. and Merrill Lynch & Co., as Co-Documentation
                  Agents (as further amended, restated, replaced, renewed,
                  extended, consolidated, modified, supplemented, refinanced or
                  refunded (in whole or in part), from time to time.

         7. Section 1.01 of the Agreement is hereby amended by amending the
defined term "Settlement Agreement" by adding thereto the phrase ", as amended,
restated, supplemented or otherwise modified from time to time" immediately
after the phrase "and the Transactions" set forth on the last line thereof.

         8. Section 1.01 of the Agreement is hereby amended by amending the
defined term "Master Lease" by adding thereto the phrase ", as amended,
restated, supplemented or otherwise modified from time to time" immediately
after the phrase "Real Property and Improvements" set forth on the last line
thereof.

         9. Section 2.02(a) and Section 2.02(b) of the Agreement are each hereby
amended and restated in full to read as follows:

                 "(a) Forty Four Million Eight Hundred Thousand Dollars
                      ($44,800,000) (which sum reflects the original $50,000,000
                      portion of the Purchase Price reduced by $5,200,000
                      relating to the net credits agreed to by the Parties
                      pursuant to the Construction Agreement), in the form of a
                      promissory note made by Purchaser and WCL, as co-issuers,
                      and guaranteed by New WCG (the "Short Term Note"). The
                      original principal amount of the Short-Term Note shall be
                      $44,800,000 (the "Loan"). The Short Term Note shall have
                      the stated face amount of $74,360,295.30 (the "Stated
                      Amount"), and reference to such amount shall include the
                      original principal amount of $44,800,000 and all accrued
                      but unpaid interest thereon. The calculation of the Stated
                      Amount shall assume that all interest payable under the
                      Short-Term Note shall accrue and be capitalized pursuant
                      to the terms set forth below and that the original

                                      -7-

<PAGE>

                      principal amount and all such accrued and capitalized
                      interest will be paid to Seller on December 29, 2006 (the
                      "Maturity Date"). All interest on the outstanding
                      principal balance of the Short Term Note shall accrue at
                      the following rates of interest during the following
                      periods and shall be capitalized to the outstanding
                      principal amount of the Loan at the end of such periods:
                      (i) first, at the initial rate of ten percent (10%) per
                      annum, commencing on the Closing Date and continuing
                      thereafter until December 31, 2003, and all such interest
                      that accrues and remains unpaid during such period shall
                      be capitalized as principal of the Short-Term Note on
                      December 31, 2003; (ii) second, at the rate of twelve
                      percent (12%) per annum, commencing on January 1, 2004 and
                      continuing thereafter until December 31, 2004, and all
                      such interest that accrues and remains unpaid during such
                      period shall be capitalized as principal of the Short-Term
                      Note on December 31, 2004; (iii) third, at the rate of
                      fourteen percent (14%) per annum, commencing on January 1,
                      2005 and continuing thereafter until December 31, 2005,
                      and all such interest that accrues and remains unpaid
                      during such period shall be capitalized as principal of
                      the Short-Term Note on December 31, 2005; and (iv) sixteen
                      percent (16%) per annum, commencing on January 1, 2006 and
                      continuing thereafter until the Maturity Date, and all
                      such interest that accrues and remains unpaid during such
                      period shall be payable on the Maturity Date.

                 (b)  One Hundred Million Dollars ($100,000,000) in the form of
                      a promissory note made by Purchaser and WCL, as
                      co-issuers, and guaranteed by New WCG (the "Long Term
                      Note") which amount may be reduced in accordance with
                      Section 2.08 and Section 7.21 hereof. The Long Term Note
                      shall bear interest at the rate of seven percent (7%) per
                      annum, amortized over 30 years, with the entire
                      outstanding principal balance and accrued but unpaid
                      interest thereon due and payable in full on the date which
                      is seven and one half (7 1/2) years from the Closing
                      Date."

         10. Section 2.03 of the Agreement is hereby amended by deleting the
phrase "simultaneously with the satisfaction or waiver of all of the conditions
set forth in Article V hereof, or at such other time and date as Seller and
Purchaser shall agree" set forth therein and substituting in lieu thereof the
phrase "on and as of October 15, 2002, provided that all conditions set forth in
Article V hereof are satisfied or waived".

         11. Section 2.04(f) of the Agreement is hereby amended by adding
thereto the phrase "and the Termination Statements" immediately after the phrase
"Initialed Title Commitment" set forth therein.

         12. Section 2.04(h) of the Agreement is hereby deleted in its entirety.

         13. Section 2.04(k) of the Agreement is hereby amended by deleting the
word "and" at the end of the second line thereof.

                                      -8-
<PAGE>

         14. Section 2.04(l) of the Agreement is hereby amended and restated in
full to read as follows:

                  "(l) the Side Letter, duly executed by Seller; and"

         15. Section 2.04 of the Agreement is hereby amended by adding thereto a
new subsection (m) to read as follows:

                  "(m) all other previously undelivered documents required by
                  this Agreement to be delivered by Seller to Purchaser at or
                  prior to the Closing in connection with the Transactions."

         16. Section 2.05(a) of the Agreement is hereby deleted in its entirety.

         17. Section 2.05(b) of the Agreement is hereby amended by adding
thereto the phrase "Pledge Agreement," immediately before the phrase "Purchase
Money Notes".

         18. Section 2.05(e) of the Agreement is hereby amended by (a) adding
thereto the phrase ", the Jones Day Legal Opinion and the New WCG Legal Opinion"
immediately after the phrase "Legal Opinion" and by deleting (b) the word "and"
set forth therein.

         19. Section 2.05(f) of the Agreement is hereby amended and restated in
full to read as follows:

                  "(f) the Side Letter, duly executed by Purchaser, WCL and New
                  WCG; and"

         20. Section 2.05 of the Agreement is hereby amended by adding thereto a
new subsection (g) to read as follows:

                  "(g) all other previously undelivered documents required by
                  this Agreement to be delivered by Purchaser to Seller at or
                  prior to the Closing in connection with the Transactions."

         21. Article II of the Agreement is hereby amended by adding thereto a
new Section 2.07 to read as follows:

                  "2.07 Delivery of Closing Documents. The parties hereto hereby
                  agree that all of the Building Purchase Closing Documents and
                  the Title Instruction Letter shall be executed (as applicable)
                  and, together with the Title Instruction Letter, shall be
                  delivered into escrow pursuant to the terms of the Escrow
                  Agreement; provided, however, that the Pledge Agreement,
                  Equitable Mortgage, the Australian Legal Opinion, the
                  Intercreditor Agreement (Pledge Agreement) and the related
                  UCC-1 shall be executed and delivered into Escrow on or before
                  October 23, 2002, in accordance with the terms and provisions
                  of the Escrow Agreement. The Escrow Agreement shall direct the
                  Escrow Agent to deliver certain of the Closing Documents and
                  the Title Instruction Letter to the Building Purchase Escrowee
                  to consummate the transactions contemplated by the Closing
                  Documents if the

                                      -9-
<PAGE>

                  conditions specified in the Escrow Agreement are met or waived
                  in accordance with the terms thereof."

         22. Article II of the Agreement is hereby amended by adding thereto a
new Section 2.08 to read as follows:

                  "2.08 True-Up.

                           (a) The parties hereto hereby agree that all
                  regularly scheduled payments due and owing by Purchaser to
                  Seller under the Master Lease and the Aircraft Dry Leases
                  during the Escrow Period shall be paid by Purchaser to Seller
                  in accordance with the terms of the Master Lease and the
                  Aircraft Dry Leases, respectively, during the Escrow Period
                  until the Escrow Period Termination Date. Upon the occurrence
                  of the Escrow Period Termination Date, Purchaser and Seller
                  shall calculate the difference and associated timing (if any)
                  of (a) the aggregate amount paid by Purchaser to Seller
                  pursuant to and in accordance with the Master Lease and the
                  Aircraft Dry Leases during the Escrow Period and (b) the
                  aggregate amount that would have been paid by the Co-Makers to
                  Seller under the Purchase Money Notes during the Escrow Period
                  (the "Escrow Period Differential") in the same manner set
                  forth on Schedule 2.08(a) attached hereto, and TWC, Seller,
                  WAI or any of their respective Affiliates receiving such
                  Escrow Period Differential shall thereafter immediately apply
                  or cause to be applied the Escrow Period Differential first to
                  accrued but unpaid interest of and then to outstanding
                  principal of the Long-Term Note as specifically set forth in
                  Schedule 2.08(a).

                           (b) If the Aircraft Dry Leases are refinanced at any
                  time during the Escrow Period (the "Aircraft Refinancing"),
                  (i) TWC and Seller shall on the date of any such Aircraft
                  Refinancing cause WAI to execute and deliver, and WCL shall
                  execute and deliver, the Williams Aircraft Leasing Purchase
                  Agreement and the other Williams Aircraft Leasing Transfer
                  Documents, (ii) Purchaser and Seller shall calculate in good
                  faith the net cash proceeds of such Aircraft Refinancing (the
                  "Aircraft Refinancing Net Cash Proceeds"), and (iii) TWC,
                  Seller, WAI or any of their respective Affiliates receiving
                  such Aircraft Refinancing Net Cash Proceeds shall immediately
                  thereafter apply or cause to be applied such Aircraft
                  Refinancing Net Cash Proceeds pro rata to the then outstanding
                  principal balances under the Master Lease specified on each of
                  the three amortization schedules attached hereto as Schedule
                  2.08(b)-1, Schedule 2.08(b)-2 and Schedule 2.08(b)-3,
                  respectively.

                           (c) If the Aircraft Refinancing occurs during the
                  Escrow Period and an Escrow Period Termination Date occurs
                  thereafter, TWC and Seller shall calculate in good faith the
                  Aircraft Refinancing Net Cash Proceeds and TWC, Seller, WAI or
                  any of their respective Affiliates receiving such Aircraft
                  Refinancing Net Cash Proceeds shall immediately thereafter
                  apply or cause to be

                                      -10-
<PAGE>

                  applied such Aircraft Refinancing Net Cash Proceeds first to
                  accrued but unpaid interest (if any) of and then to
                  outstanding principal of the Long-Term Note.

                           (d) If the Aircraft Refinancing does not occur during
                  the Escrow Period and an Escrow Period Breakage Date occurs,
                  the Master Lease, the Aircraft Dry Leases and the other
                  existing Sale Leaseback Transaction Documents shall continue
                  in full force and effect."

         23. Section 3.01 of the Agreement is hereby amended by (a) deleting the
word "and" set forth at the end of the last line of subsection (j) thereof; and
(b) deleting the period in the last line of subsection (k) thereof and
substituting in lieu thereof a semi-colon.

         24. Section 3.02 of the Agreement is hereby amended by (a) deleting the
word "and" set forth in the last line of subsection (f) thereof; and (b)
deleting the period in the last line of subsection (g) thereof and substituting
in lieu thereof a semi-colon.

         25. Article III of the Agreement is hereby amended by amending and
restating Section 3.05 set forth therein in full to read as follows:

                  "3.05 Survival and Continuation of Representations and
                  Warranties During Escrow Period. The parties hereto hereby
                  agree that all representations and warranties set forth in
                  this Article III shall survive the Closing Date and shall in
                  any event be true and correct on and as of the Escrow Period
                  Termination Date."

         26. Article IV of the Agreement is hereby amended by adding a new
Section 4.13 thereto to read as follows:

                  "4.13 Survival and Continuation of Covenants During Escrow
                  Period. The parties hereto hereby agree that the covenants
                  specified in Section 4.01, Section 4.02, Section 4.09, Section
                  4.10, Section 4.11 and Section 4.12 shall survive the Closing
                  Date and shall continue in full force and effect during the
                  Escrow Period until the occurrence of the Escrow Period
                  Termination Date."

         27. The caption immediately below the caption "ARTICLE V" of the
Agreement is hereby amended in full to read "CONDITIONS PRECEDENT; ESCROW PERIOD
DEFAULTS".

         28. Article V of the Agreement is hereby amended by adding thereto a
new Section 5.03 to read as follows:

                  "5.03 Escrow Period Purchase Agreement Defaults. The parties
                  hereto hereby agree that upon the occurrence and during the
                  continuance of an Escrow Period Purchase Agreement Default (a)
                  the defaulting party or parties shall upon obtaining notice of
                  such Escrow Period Purchase Agreement Default promptly
                  thereafter provide written notice of such Escrow Period
                  Default to each other non-defaulting party hereto, and
                  describe in reasonable detail therein the nature of such
                  Escrow Period Purchase Agreement Default and the actions
                  proposed to be

                                      -11-
<PAGE>

                  undertaken by such defaulting party or parties for the prompt
                  resolution and cure thereof; and (b) the non-defaulting party
                  or parties' remedy or remedies for any such Escrow Period
                  Purchase Agreement Default shall be limited solely to seeking
                  recovery of the actual damages incurred by such non-defaulting
                  party or parties arising in respect of such Escrow Period
                  Purchase Agreement Default (i) first, by seeking such recovery
                  under and pursuant to the Title Policies (if applicable) and
                  (ii) second, by seeking such recovery thereof from the
                  defaulting party or parties."

         29. Article V of the Agreement is hereby amended by adding thereto a
new Section 5.04 to read as follows:

                  "5.04 Escrow Period Sale Leaseback Defaults. The parties
                  hereto hereby agree that upon the occurrence and during the
                  continuance of a Sale Leaseback Default (a) the defaulting
                  party or parties shall upon the occurrence and during the
                  continuance of such Sale Leaseback Default promptly thereafter
                  provide written notice of such Sale Leaseback Default to each
                  other non-defaulting party hereto, and describe in reasonable
                  detail therein the nature of such Sale Leaseback Default and
                  the actions proposed to be undertaken by such defaulting party
                  or parties for the prompt resolution and cure thereof within
                  the applicable grace period provided under the Sale Leaseback
                  Transaction Documents, if any; and (b) the non-defaulting
                  party or parties shall, only for such Sale Leaseback Defaults
                  as are non-material and/or non-monetary, forbear from
                  exercising any rights or remedies available to it or them
                  under any Sale Leaseback Transaction Document until the
                  occurrence of the earlier of the Escrow Period Termination
                  Date or the Escrow Period Breakage Date, provided that there
                  shall be no termination or acceleration of the Master Lease
                  except for a payment default or cancellation of the insurance
                  required thereunder that in each case continues beyond one
                  Business Day after taking into account any applicable grace
                  period.

         30. Section 7.21 of the Agreement is hereby amended by deleting the
first, second, third and fourth sentences therefrom and substituting in lieu
thereof the following:

                  "The parties hereto hereby agree that (A) TWC, Seller, WAI and
                  WAL shall have the exclusive right to dispose of or refinance
                  the Aircraft Dry Leases on commercially reasonable terms and
                  at market rates prior to the Closing Date and (B) if TWC,
                  Seller, WAI and WAL shall not have disposed of or refinanced
                  the Aircraft Dry Leases by the Closing Date, then TWC, Seller,
                  WAI, WAL, WCL and WTC, shall each continue to be bound by the
                  terms and provisions of each Aircraft Dry Lease (as
                  applicable), provided that upon the occurrence of the Aircraft
                  Refinancing, TWC and Seller shall on the date of any such
                  Aircraft Refinancing cause WAI to execute and deliver, and WCL
                  shall execute and deliver, the Williams Aircraft Leasing
                  Purchase Agreement and the other Williams Aircraft Leasing
                  Transfer Documents, and TWC and Seller shall apply the
                  Aircraft Refinancing Net Cash Proceeds to accrued but unpaid
                  interest on and

                                      -12-
<PAGE>

                  outstanding principal of the Long-Term Note, all pursuant to
                  and in accordance with Section 2.08 hereof."

         31. Section 7.21 of the Agreement is further amended by (a) deleting
the term "Disposition" as set forth in the second sentence thereof (after giving
effect to the amendments to Section 7.21 of the Agreement as specified in
Section 28 of this Amendment) and substituting in lieu thereof the phrase
"Aircraft Refinancing or other disposition of the Aircraft"; and (b) deleting
therefrom the last sentence thereof.

         32. Article VII of the Agreement is hereby amended by adding a new
Section 7.26 thereto to read as follows:

                  "7.26. Side Letter. The parties hereto hereby agree to execute
                  and deliver the Side Letter on the Closing Date."

         33. The Agreement is hereby amended by adding thereto (a) a new
Schedule 2.08(a) in the form of Schedule 1 attached hereto; (b) a new Schedule
2.08(b)-1 in the form of Schedule 2 attached hereto; (c) a new Schedule
2.08(b)-2 in the form of Schedule 3 attached hereto; and (d) a new Schedule
2.08(b)-3 in the form of Schedule 4 attached hereto.

         34. Exhibit D (Permitted Exceptions) to the Agreement is hereby amended
and restated in its entirety in the form of Exhibit 1 attached hereto.

         35. The Agreement is hereby amended by adding thereto (a) a new Exhibit
E (Side Letter) in substantially the form of Exhibit 2 attached hereto; and (b)
a new Exhibit F (Williams Aircraft Leasing Transfer Agreement) in substantially
the form of Exhibit 3 attached hereto.

         36. The Agreement is hereby amended by (a) except as provided in
subsection (b) of this Paragraph 34, deleting the phrase "Purchase Money Note"
in each instance where it appears therein and substituting in lieu thereof in
each such instance the phrase "Purchase Money Notes" and (b) deleting the phrase
"Purchase Money Note" in each instance referenced in Section 7.21 of the
Agreement and substituting in lieu thereof in each such instance the phrase
"Long Term Note."

         37. The Agreement is hereby amended by deleting the phrase "Cash
Portion of the Purchase Price" in each instance where it appears therein.

         38. Purchaser, WCL, Communications and New WCG shall each use their
best efforts to ensure that any lien or security interest in the Acquired Assets
granted by any of them to the Bank Agent for the benefit of the Lenders under
Loan Documents shall be subject and fully subordinate to the first priority
mortgage liens and security interests granted by Purchaser to Seller in certain
of the Acquired Assets (except for the Excluded Property (as such term is
defined in the Purchase Money Mortgage)) pursuant to the Purchase Money Mortgage
(as the same may be amended, restated, supplemented or otherwise modified from
time to time) and the other rights and remedies of Seller pursuant thereto. Each
of New WCG, Purchaser, WCL, Communications and Seller hereby acknowledge and
agree that Purchaser may execute and deliver the Second Mortgage.

                                      -13-
<PAGE>

         39. The parties hereto agree to execute and deliver (or to cause the
execution and delivery of), on or prior to the Closing Date, each of (a) the POP
Easement Agreement dated as of October 15, 2002 between Seller and Williams
Field Services Company, a Delaware corporation, as "Grantors" and Purchaser, as
"Grantee", in the form of Exhibit 4 attached hereto; (b) the Satellite Easement
Agreement dated as of October 15, 2002 between Seller and Williams Field
Services Company, as "Grantors" and Purchaser, as "Grantee", in the form of
Exhibit 5 attached hereto; and (c) the First Amendment to Agreement for the
Resolution of Continuing Contract Disputes dated as of October 15, 2002, among
TWC, Communications and WCL, in the form of Exhibit 6 attached hereto.

         40. The parties hereto hereby agree that Exhibit 7 attached hereto
shall constitute, and shall be submitted by the parties hereto on or prior to
the Closing Date as, the Company Building Purchase Closing Documents and the TWC
Building Purchase Closing Documents set forth on Exhibit B to the Escrow
Agreement.

         41. Seller has requested that the other parties hereto agree to waive,
and the parties hereto hereby agree to waive, the requirement specified in
Section 2.04(i) of the Agreement that Seller deliver the consents specified in
Schedule 3.01(e) to the Agreement (each a "Consent" and collectively the
"Consents") at Closing (such waiver being hereinafter referred to as the
"Waiver"), provided that Seller shall promptly endeavor to obtain and deliver
each Consent to Purchaser. The Waiver shall be specifically limited as set forth
herein and shall not otherwise affect Seller's obligation to obtain and deliver
each Consent to Purchaser under this Agreement. As consideration for granting
the Waiver, Seller hereby agrees to indemnify, reimburse and hold harmless each
of Purchaser, WCL, New WCG and Communications and each of their respective
successors and assigns (hereinafter, an "Indemnitee" and collectively the
"Indemnitees"), to the fullest extent permitted by applicable law, from any and
all liabilities, obligations, damages, penalties, claims, demands, actions,
suits, judgments and any and all costs, expenses or disbursements (including
attorneys' fees and expenses reasonably incurred) (collectively, the
"Indemnified Liabilities") of whatsoever kind and nature imposed on or
reasonably incurred by any of the Indemnitees as a result of, relating to or
arising out of any actual or prospective claim, litigation or other proceeding
relating to or arising out of the Waiver or Seller's failure to obtain and
deliver any Consent to Purchaser, provided that no Indemnitee shall be
indemnified pursuant to this Section 41 for Indemnified Liabilities to the
extent caused by the gross negligence or willful misconduct of any Indemnitee
(as determined by a court of competent jurisdiction in a final non-appealable
decision) on or after the date hereof. The obligations of Seller under this
Section 41 shall survive and remain in full force and effect until Seller has
delivered each Consent specified on Schedule 3.01(e) to the Agreement to
Purchaser. Seller acknowledges and agrees that upon written notice by any
Indemnitee of the assertion of an Indemnified Liability, Seller shall assume
full responsibility for the defense thereof. Any amount due under this Section
41 shall be payable by Seller promptly upon and in any event within thirty (30)
days after receipt of written demand by any Indemnitee therefor. Each Indemnitee
agrees to use its best efforts to promptly notify Seller of any actual or
potential Indemnified Liability of which such Indemnitee has knowledge and to
specify in reasonable detail the nature and period of existence of any such
Indemnified Liability. Nothing contained in this Section 41 shall in any way
affect, modify, restrict or diminish any other rights or obligations of Seller,
Purchaser,

                                      -14-
<PAGE>

WCL, New WCG or Communications contained in the Agreement, the Purchase Money
Notes or the Purchase Money Mortgage.

         42. Each of WAI and New WCG (each a "New Transaction Party" and
collectively the "New Transaction Parties") by executing and delivering this
Amendment hereby expressly confirm that it has assumed, and agrees to perform
and observe, each and every one of the covenants, rights, promises, agreements,
terms, conditions, obligations, duties and liabilities applicable to it under
the Agreement (as amended by this Amendment) (each reference in this Section 42
to the "Agreement" shall mean the Agreement (as amended by this Amendment)).
Each New Transaction Party hereby represents and warrants that (a) such New
Transaction Party has the corporate power and authority to enter into the
Agreement by executing and delivering this Amendment; (b) the execution,
delivery and performance by such New Transaction Party of this Amendment and
such New Transaction Party's entering into the Agreement have been duly
authorized by its respective Board of Directors and no other corporate
proceedings on its part are necessary to authorize the execution, delivery and
performance of this Amendment and entering into the Agreement; and (c) this
Amendment has been duly executed and delivered by such New Transaction Party and
the Agreement constitutes such New Transaction Party's legal, valid and
enforceable obligation, enforceable against such New Transaction Party in
accordance with its terms, except as may be limited by applicable bankruptcy,
insolvency, reorganization or similar laws affecting creditors' rights generally
and by general principles of equity, whether such enforceability is considered
in a proceeding at law or in equity.

         43. This Amendment (and for each New Transaction Party, the Agreement
(as amended by the Amendment)) shall be binding upon each party hereto and shall
inure to the benefit of each party hereto and their respective successors and
permitted assigns.

         44. This Amendment may be executed in one or more counterparts, each of
which shall be deemed an original, but all of which shall constitute one and the
same instrument. The delivery of an executed counterpart to this Amendment by
facsimile shall be effective as delivery of a manually executed copy of this
Amendment.

         45. Except as specifically amended hereby, the Agreement is in all
respects confirmed, ratified and approved. All references in the Agreement to
"this Agreement" shall mean and refer to the Agreement as amended hereby.

                                      -15-
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement on
and as of the date and year first above written.

                                    WILLIAMS HEADQUARTERS BUILDING COMPANY

                                    By: /s/ Jack D. McCarthy
                                        ----------------------------------------
                                        Title: Vice President

                                    WILLIAMS TECHNOLOGY CENTER, LLC

                                    By: WILLIAMS COMMUNICATIONS, LLC,
                                        its sole Member

                                    By: /s/ Howard S. Kalika
                                        ----------------------------------------
                                        Title: Vice President and Group
                                               Executive, Corporate Development
                                               and Finance and Assistant
                                               Secretary

                                    WILLIAMS COMMUNICATIONS, LLC

                                    By: /s/ Howard S. Kalika
                                        ----------------------------------------
                                        Title: Vice President and Group
                                               Executive, Corporate Development
                                               and Finance and Assistant
                                               Secretary

                                    WILLIAMS COMMUNICATIONS GROUP, INC.

                                    By: /s/ Howard S. Kalika
                                        ----------------------------------------
                                        Title: Vice President and Group
                                               Executive, Corporate Development
                                               and Finance and Assistant
                                               Secretary

                                    WILTEL COMMUNICATIONS GROUP, INC.

                                    By: /s/ Howard S. Kalika
                                        ----------------------------------------
                                        Title: Vice President and Group
                                               Executive, Corporate Development
                                               and Finance and Assistant
                                               Secretary

                                      -16-
<PAGE>

                                    WILLIAMS AIRCRAFT LEASING, LLC

                                    By: WILLIAMS AIRCRAFT, INC., its sole member

                                        By: /s/ Jack D. McCarthy
                                            ------------------------------------
                                            Title: Vice President

                                    WILLIAMS AIRCRAFT, INC.

                                    By: /s/ Jack D. McCarthy
                                        ----------------------------------------
                                        Title: Vice President

                                      -17-

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