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                            TRUST AGREEMENT [____]

                         Dated as of [______________]


                                   Between


                         [_________________________]


                                     and


                        FIRST SECURITY BANK, NATIONAL
                                 ASSOCIATION

                    _____________________________________


                   One Boeing Model [_____________]Aircraft
               Bearing Manufacturer's Serial No. [___________]








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<PAGE>

                                TABLE OF CONTENTS

                                                                          PAGE

SECTION 1.    DEFINITIONS..................................................1

SECTION 2.    DECLARATION OF TRUST.........................................1

SECTION 3.    AUTHORIZATION; CONDITIONS PRECEDENT..........................1

        3.1   Authorization................................................1
        3.2   Conditions Precedent.........................................2

SECTION 4.    RECEIPT, DISTRIBUTION AND APPLICATION OF INCOME
              FROM THE TRUST ESTATE........................................3

        4.1   Payments from Trust Estate Only..............................3
        4.2   Distribution of Payments.....................................3
        4.3   Method of Payments...........................................4

SECTION 5.    DUTIES OF OWNER TRUSTEE......................................5

        5.1   Notice of Event of Default...................................5
        5.2   Action upon Instructions.....................................5
        5.3   Limitations on Duties........................................6
        5.4   No Duties except as Specified; No Action except as
              Specified....................................................6
        5.5   Satisfaction of Conditions Precedent.........................6
        5.6   Fixed Investment Trust.......................................7

SECTION 6.    OWNER TRUSTEE................................................7

        6.1   Acceptance of Trusts and Duties..............................7
        6.2   Absence of Certain Duties....................................7
        6.3   No Representations or Warranties as to Certain
              Matters......................................................8
        6.4   No Segregation of Monies; Interest...........................9
        6.5   Reliance upon Certificates, Counsel and Agents...............9
        6.6   Not Acting in Individual Capacity............................10
        6.7   Fees; Compensation...........................................10
        6.8   Tax Returns..................................................10

SECTION 7.    INDEMNIFICATION OF FIRST SECURITY BY OWNER
              PARTICIPANT..................................................10


SECTION 8.    TRANSFER OF OWNER PARTICIPANT'S INTEREST.....................12

        8.1   Transfer of Interest.........................................12


<PAGE>

                                TABLE OF CONTENTS
                                     CONT'D
                                                                          PAGE


SECTION 9.    SUCCESSOR OWNER TRUSTEES; CO-TRUSTEES........................12

        9.1   Resignation of Owner Trustee; Appointment of
              Successor....................................................12
        9.2   Co-Trustees and Separate Trustees............................13

SECTION 10.   SUPPLEMENTS AND AMENDMENTS TO TRUST AGREEMENT AND
              OTHER DOCUMENTS..............................................15

        10.1  Supplements and Amendments and Delivery Thereof..............15
        10.2  Discretion as to Execution of Documents......................16
        10.3  Absence of Requirements as to Form...........................16
        10.4  Distribution of Documents....................................16
        10.5  No Request Needed as to Lease Supplement and Trust
              Indenture Supplement.........................................16

SECTION 11.   MISCELLANEOUS................................................16

        11.1  Termination of Trust Agreement...............................16
        11.2  Termination at Option of the Owner Participant...............17
        11.3  Owner Participant Has No Legal Title in Trust Estate.........17
        11.4  Assignment, Sale, etc. of Aircraft...........................17
        11.5  Trust Agreement for Benefit of Certain Parties Only..........17
        11.6  [Reserved]...................................................18
        11.7  Notices......................................................18
        11.8  Severability.................................................18
        11.9  Waivers, Etc.................................................18
        11.10 Counterparts.................................................18
        11.11 Binding Effect, Etc..........................................19
        11.12 Headings; References.........................................19
        11.13 Governing Law................................................19

<PAGE>

                            TRUST AGREEMENT [_______]

      This TRUST AGREEMENT [______], dated as of [________________], between
[_________], a corporation organized under the laws of the OP Jurisdiction
("Owner Participant"), and First Security Bank, National Association, a national
banking association (in its individual capacity, "First Security" and otherwise
not in its individual capacity but solely as trustee hereunder, "Owner
Trustee").

                                 WITNESSETH:

SECTION 1. DEFINITIONS

      Capitalized terms used but not defined herein shall have the respective
meanings set forth or incorporated by reference, and shall be construed and
interpreted in the manner described, in Annex A to the Lease.

SECTION 2. DECLARATION OF TRUST

      First Security hereby declares that it will hold the Trust Estate as Owner
Trustee upon the trusts hereinafter set forth for the use and benefit of Owner
Participant, subject, however, to the provisions of and the Lien created by the
Trust Indenture and to the provisions of the Lease and the Participation
Agreement.

SECTION 3. AUTHORIZATION; CONDITIONS PRECEDENT

      3.1 AUTHORIZATION

      In respect of the Aircraft, Owner Participant hereby authorizes and
directs Owner Trustee to, and Owner Trustee agrees for the benefit of Owner
Participant that it will, on and after the Delivery Date, subject (except with
respect to Section 3.1(a)) to due compliance with the terms of Section 3.2:

      (a) execute and deliver the Participation Agreement, the Trust Indenture,
the Lease and the other Owner Trustee Agreements (in the respective forms in
which they are delivered from time to time by Owner Participant to Owner
Trustee);

      (b) subject to the terms of this Trust Agreement, exercise (i) its rights
and perform its duties under the Participation Agreement, (ii) the rights and
perform the duties of Lessor under the Lease and (iii) its rights and perform
its duties under the Trust Indenture and the other Owner Trustee Agreements;

      (c) execute, issue and deliver to Mortgagee for authentication and further
delivery to the Subordination Agent the Equipment Notes in the amount and as
provided in Section 2 of the Participation Agreement;

      (d) purchase the Aircraft pursuant to the Purchase Agreement as assigned
to Owner Trustee pursuant to the Purchase Agreement Assignment;


<PAGE>

      (e) accept from Airframe Manufacturer the delivery of the Aircraft Bill of
Sale, the FAA Bill of Sale and the invoice with respect to such Aircraft and
from Lessee the delivery of the BFE Bill of Sale and the invoice with respect to
such BFE;

      (f) effect the registration of the Aircraft with the FAA in the name of
Owner Trustee by filing or causing to be filed with the FAA: (i) the FAA Bill of
Sale; (ii) an Aircraft Registration Application in the name of Owner Trustee
(including, without limitation, an affidavit from Owner Trustee in compliance
with the provisions of Section 47.7(c)(2) of the FAA Regulations); and (iii)
this Trust Agreement;

      (g) execute and deliver the Financing Statements referred to in Section
5.1.2 (xxii) of the Participation Agreement, together with all other agreements,
documents and instruments referred to in Section 5 of the Participation
Agreement to which Owner Trustee is to be a party;

      (h) make payment of Lessor's Cost for the Aircraft from the aggregate
amount of the Commitments for the Aircraft of Owner Participant and Loan
Participants, to the extent received by Owner Trustee, in the manner provided in
the Participation Agreement;

      (i) execute and deliver Lease Supplement No. 1 covering the Aircraft;

      (j) execute and deliver a Trust Indenture Supplement covering the
Aircraft; and

      (k) execute and deliver all such other instruments, documents or
certificates and take all such other actions in accordance with the direction of
Owner Participant, as Owner Participant may deem necessary or advisable in
connection with the transactions contemplated by this Trust Agreement and the
other Operative Agreements.

      3.2 CONDITIONS PRECEDENT

      The rights and obligations of Owner Trustee to take the actions required
by Section 3.1 shall be subject to the following conditions precedent:

      (a) Owner Trustee shall have received the notice described in Section
5.1.1 of the Participation Agreement, when and as required thereby, or shall
have been deemed to have waived such notice in accordance with Section 5.1.1 of
the Participation Agreement;

      (b) Each Participant shall have made the full amount of its Commitment
specified in Section 2.1 of the Participation Agreement available to Owner
Trustee, in immediately available funds, in accordance with Sections 2 and 4 of
the Participation Agreement; and

      (c) Owner Participant shall have notified Owner Trustee that the terms and
conditions of Section 5 of the Participation Agreement, insofar as they relate
to conditions precedent to performance by Owner Participant of its obligations
thereunder, have been either fulfilled to the satisfaction of, or waived by,
Owner Participant. Owner Participant shall, by instructing Owner Trustee to
release the full amount of its Commitment then held by Owner Trustee as provided
in Section 2 of the Participation Agreement, be deemed to have found
satisfactory to it, or waived, all such conditions precedent.

<PAGE>

SECTION 4. RECEIPT, DISTRIBUTION AND APPLICATION OF INCOME FROM THE TRUST ESTATE

      4.1 PAYMENTS FROM TRUST ESTATE ONLY

      Except as provided in Section 6.1, all payments to be made by Owner
Trustee under this Trust Agreement shall be made only from (a) in the case of
funds made available in accordance with Section 4 of the Participation
Agreement, the Commitments (except as otherwise provided in Section 14 of the
Participation Agreement) and (b) in the case of all other payments, the income
from and proceeds of the Trust Estate to the extent that Owner Trustee shall
have received sufficient income or proceeds from the Trust Estate to make such
payments. Owner Participant agrees that it will look solely (y) in the case of
funds made available in accordance with Section 4 of the Participation
Agreement, to the Commitments and any income therefrom (except as otherwise
provided in Section 14 of the Participation Agreement) and (z) in the case of
all other payments, to the income from and proceeds of the Trust Estate to the
extent available for distribution to Owner Participant as provided in this Trust
Agreement. Except as provided in Section 6.1, Owner Participant agrees that
First Security is neither personally liable to Owner Participant for any amounts
payable nor subject to any other liability under this Trust Agreement.

      4.2 DISTRIBUTION OF PAYMENTS

            4.2.1 PAYMENTS TO MORTGAGEE

      Until the Trust Indenture shall have been discharged pursuant to Section
10.01 thereof, all Rent, insurance proceeds and requisition or other payments of
any kind included in the Trust Estate (other than Excluded Payments) payable to
Owner Trustee shall be payable directly to Mortgagee (and, if any of the same
are received by Owner Trustee, shall upon receipt be paid over to Mortgagee
without deduction, set-off or adjustment of any kind) for distribution in
accordance with the provisions of Article III of the Trust Indenture; PROVIDED,
that any payments received by Owner Trustee from (a) Lessee with respect to
Owner Trustee's fees and disbursements or (b) Owner Participant pursuant to
Section 7 shall not be paid over to Mortgagee but shall be retained by Owner
Trustee and applied toward the purpose for which such payments were made.

            4.2.2 PAYMENTS TO OWNER TRUSTEE, OTHER PARTIES

      After the Trust Indenture shall have been discharged pursuant to
Section 10.01 thereof, any payment of the type referred to in Section 4.2.1
(other than Excluded Payments) received by Owner Trustee, any payment
received from Mortgagee (other than Excluded Payments) and any other amount
received as part of the Trust Estate and for the application or distribution
of which no provision is made in this Trust Agreement shall be distributed
forthwith upon receipt by Owner Trustee in the following order of priority:
FIRST, so much of such payment as shall be required to reimburse Owner
Trustee for any expenses not otherwise reimbursed as to which Owner Trustee
is entitled to be so reimbursed pursuant to the provisions hereof shall be
retained by Owner Trustee; SECOND, so much of the remainder for which
provision as to the application thereof is contained in the Lease or any of

<PAGE>

the other Operative Agreements shall be applied and distributed in accordance
with the terms of the Lease or such other Operative Agreement; and THIRD, the
balance, if any, shall be paid to Owner Participant.

            4.2.3 CERTAIN DISTRIBUTIONS TO OWNER PARTICIPANT

      All amounts from time to time distributable by Mortgagee to Owner
Participant pursuant to the Trust Indenture shall, if paid to Owner Trustee,
be distributed by Owner Trustee to Owner Participant in accordance with the
provisions of Article III of the Trust Indenture; PROVIDED, that any payments
received by Owner Trustee from (a) Lessee with respect to Owner Trustee's
fees and disbursements or (b) Owner Participant pursuant to Section 7 shall
not be paid over to Owner Participant but shall be retained by Owner Trustee
and applied toward the purpose for which such payments were made.

            4.2.4 EXCLUDED PAYMENTS

      Any Excluded Payments received by Owner Trustee shall be paid by Owner
Trustee to the Person to whom such Excluded Payments are payable under the
provisions of the Participation Agreement, the Tax Indemnity Agreement or the
Lease.

            4.2.5 MULTIPLE OWNER PARTICIPANTS

      If, as a result of a transfer by Owner Participant under Section 8.1,
there is more than one Owner Participant under this Trust Agreement, each
such Owner Participant shall hold in proportion to its respective beneficial
interest in the Trust Estate an undivided beneficial interest in the entire
Trust Estate and is entitled to receive ratably with any other Owner
Participant payments distributable by Owner Trustee under this Trust
Agreement.  No Owner Participant shall have legal title to the Aircraft or
any other portion of the Trust Estate.

      4.3 METHOD OF PAYMENTS

      Owner Trustee shall make distributions or cause distributions to be
made to Owner Participant pursuant to this Section 4 by transferring the
amount to be distributed by wire transfer in immediately available funds on
the day received (or on the next succeeding Business Day if the funds to be
so distributed shall not have been received by Owner Trustee by 12:00 noon,
New York City time, and which funds Owner Trustee shall not have been
reasonably able to distribute to Owner Participant on the day received) to
Owner Participant's account set forth in Schedule 1 to the Participation
Agreement or to such other account or accounts of Owner Participant as Owner
Participant may designate from time to time in writing to Owner Trustee;
PROVIDED, that Owner Trustee shall use reasonable efforts to invest
overnight, in investments that would be permitted under Section 4.4 of the
Lease, all funds received by it at or later than 12:00 noon, New York City
time, and which funds Owner Trustee shall not have been reasonably able to
distribute to Owner Participant on the day received).

<PAGE>

SECTION 5. DUTIES OF OWNER TRUSTEE

      5.1 NOTICE OF EVENT OF DEFAULT

      (a) If Owner Trustee shall have knowledge of a Lease Default or a Lease
Event of Default or an Indenture Default or an Indenture Event of Default, Owner
Trustee shall give to Owner Participant, Mortgagee and Lessee prompt telephonic
or telex notice thereof followed by prompt confirmation thereof by certified
mail, postage prepaid, PROVIDED, that (i) in the case of an event which with the
passage of time would constitute an Indenture Event of Default of the type
referred to in paragraph (c) or (e) of Section 4.02 of the Trust Indenture, such
notice shall in no event be furnished later than ten days after Owner Trustee
shall first have knowledge of such event and (ii) in the case of a
misrepresentation by Owner Trustee which with the passage of time would
constitute an Indenture Event of Default of the type referred to in paragraph
(d) of Section 4.02 of the Trust Indenture, such notice shall in no event be
furnished later than ten days after Owner Trustee shall first have knowledge of
such event.

      (b) Subject to the terms of Section 5.3, Owner Trustee shall take such
action or shall refrain from taking such action, not inconsistent with the
provisions of the Trust Indenture, with respect to such Lease Default, Lease
Event of Default, Indenture Default or Indenture Event of Default or other event
as Owner Trustee shall be directed in writing by Owner Participant. For all
purposes of this Trust Agreement, the Lease and the other Operative Agreements,
in the absence of Actual Knowledge of Owner Trustee, Owner Trustee shall not be
deemed to have knowledge of a Lease Default, Lease Event of Default, Indenture
Default or Indenture Event of Default unless notified in writing by Mortgagee,
Owner Participant or Lessee.

      5.2 ACTION UPON INSTRUCTIONS

      Subject to the terms of Sections 5.1 and 5.3, upon the written
instructions at any time and from time to time of Owner Participant, Owner
Trustee will take such of the following actions, not inconsistent with the
provisions of the Lease and the Trust Indenture, as may be specified in such
instructions: (a) give such notice or direction or exercise such right, remedy
or power under this Trust Agreement or any of the other Owner Trustee Agreements
or in respect of all or any part of the Trust Estate, or take such other action,
as shall be specified in such instructions (including entering into such
agreements and instruments as shall be necessary under Section 10); (b) take
such action to preserve or protect the Trust Estate (including the discharge of
Liens) as may be specified in such instructions; (c) approve as satisfactory to
it all matters required by the terms of the Lease or the other Operative
Agreements to be satisfactory to Owner Trustee, it being understood that without
written instructions of Owner Participant, Owner Trustee shall not approve any
such matter as satisfactory to it; (d) subject to the rights of Lessee under the
Operative Agreements, after the expiration or earlier termination of the Lease,
convey all of Owner Trustee's right, title and interest in and to the Aircraft
for such amount, on such terms and to such purchaser or purchasers as shall be
designated in such instructions, or retain, lease or otherwise dispose of, or
from time to time take such other action with respect to, the Aircraft on such
terms as shall be designated in such instructions; and (e) take or refrain from
taking such other action or actions as may be specified in such instructions.


<PAGE>

      5.3 LIMITATIONS ON DUTIES

      Owner Trustee shall not be required to take any action under
Section 5.1 (other than the giving of the notices referred to therein) or 5.2
if Owner Trustee shall reasonably believe such action is not adequately
indemnified by Owner Participant under Section 7, unless Lessee or Owner
Participant agrees to furnish such additional indemnity as shall reasonably
be required, in manner and form satisfactory to Owner Trustee, and, in
addition to the extent not otherwise paid pursuant to the provisions of the
Lease or of the Participation Agreement, to pay the reasonable compensation
of Owner Trustee for the services performed or to be performed by it pursuant
to such direction and any reasonable fees and disbursements of counsel or
agents employed by Owner Trustee in connection therewith.  Owner Trustee
shall not be required to take any action under Section 5.1 or 5.2 (other than
the giving of the notices referred to therein) if Owner Trustee shall have
been advised by counsel that such action is contrary to the terms of any of
the Owner Trustee Agreements or is otherwise contrary to Law and Owner
Trustee has delivered to Owner Participant written notice of the basis for
its refusal to act.

      5.4 NO DUTIES EXCEPT AS SPECIFIED; NO ACTION EXCEPT AS SPECIFIED

            5.4.1 NO DUTIES EXCEPT AS SPECIFIED

      Owner Trustee shall not have any duty or obligation to manage, control,
use, sell, dispose of or otherwise deal with the Aircraft or any other part
of the Trust Estate or to otherwise take or refrain from taking any action
under, or in connection with, any of the Owner Trustee Agreements, except as
expressly required by the terms of any of the Owner Trustee Agreements, or
(to the extent not inconsistent with the provisions of the Trust Indenture)
as expressly provided by the terms hereof or in a written instruction from
Owner Participant received pursuant to the terms of Section 5.1 or 5.2, and
no implied duties or obligations shall be read into this Trust Agreement
against Owner Trustee.  First Security agrees that it will, in its individual
capacity and at its own cost or expense (but without any right of indemnity
in respect of any such cost or expense hereunder or under the Participation
Agreement), promptly take such action as may be necessary to duly discharge
and satisfy in full all Lessor Liens attributable to it in its individual
capacity which it is required to discharge pursuant to Section 7.3.1 of the
Participation Agreement and otherwise comply with the terms of said Section
binding upon it.

            5.4.2 NO ACTION EXCEPT AS SPECIFIED

      Owner Trustee shall have no power, right or authority to, and agrees
that it will not, manage, control, use, sell, dispose of or otherwise deal
with the Aircraft or any other part of the Trust Estate except (a) as
expressly required by the terms of any of the Owner Trustee Agreements,
(b) as expressly provided by the terms hereof or (c) as expressly provided in
written instructions from Owner Participant pursuant to Section 5.1 or 5.2.

      5.5 SATISFACTION OF CONDITIONS PRECEDENT

      Anything in this Trust Agreement to the contrary notwithstanding, Owner
Trustee shall, subject to the satisfaction of special counsel for Owner

<PAGE>

Trustee of the occurrence of all the applicable conditions precedent
specified in Section 3.2, comply with the provisions of Section 3.1.

      5.6 FIXED INVESTMENT TRUST

      Notwithstanding anything in this Trust Agreement to the contrary, Owner
Trustee shall not be authorized and shall have no power to "vary the
investment" of Owner Participant within the meaning of Treasury Regulations
Section 301.7701-4(c)(1), it being understood that Owner Trustee shall have
the power and authority to fulfill its obligations under Section 4.3 hereof
and Section 4.4 of the Lease.

SECTION 6. OWNER TRUSTEE

      6.1 ACCEPTANCE OF TRUSTS AND DUTIES

      First Security accepts the trusts hereby created and agrees to perform
the same as Owner Trustee but only upon the terms hereof and the Trust
Indenture applicable to it.  Owner Trustee also agrees to receive and
disburse all monies received by it constituting part of the Trust Estate
pursuant to the terms hereof.  First Security shall not be answerable or
accountable under any circumstances, except for (a) its own willful
misconduct or gross negligence (including, without limitation, in connection
with any activities of Owner Trustee in violation of Section 5.4.2), (b) its
failure (in its individual capacity) to perform its obligations under
Section 5.4.1, (c) its or Owner Trustee's failure to use ordinary care to
receive or disburse funds or to comply with the first sentence of
Section 6.8, (d) liabilities that may result from the inaccuracy of any
representation or breach of warranty of it in its individual capacity (or
from the failure by it in its individual capacity to perform any covenant) in
this Trust Agreement, the Trust Indenture, the Lease or the Participation
Agreement or elsewhere in any of the other Operative Agreements, (e) taxes,
fees or other charges on, based on or measured by any fees, commissions or
compensation received by First Security in connection with the transactions
contemplated by this Trust Agreement and the other Operative Agreements to
which it (in its individual capacity or as Owner Trustee) is a party, (f) its
or Owner Trustee's failure to use ordinary care in receiving or disbursing
funds or in connection with its obligation to invest funds pursuant to
Section 4.4 of the Lease or Section 4.3 hereof, (g) for any liability on the
part of Owner Trustee arising out of its negligence or willful or negligent
misconduct in connection with its obligations under Section 5.1 (other than
the first sentence thereof), 6.8 or 9.2 hereof or Section 4.01 of the Trust
Indenture.  First Security shall have no obligation to advance its individual
funds for any purpose, and Owner Trustee shall have no obligation to
distribute to Owner Participant, Lessee or any third party any amounts to be
paid to Owner Trustee until such amounts are collected by Owner Trustee.

      6.2 ABSENCE OF CERTAIN DUTIES

      (a) Except in accordance with written instructions furnished pursuant to
Section 5.1 or 5.2 and except as provided in, and without limiting the
generality of, Sections 3.1 and 5.4.1 and the last sentence of Section 9.1.2,
and subject to Section 4.01 of the Trust Indenture, neither Owner Trustee nor
First Security shall have any duty (i) to see to any recording or filing of any
Operative Agreement or of any supplement to any thereof or to see to the

<PAGE>

maintenance of any such recording or filing or any other filing of reports with
the FAA or other governmental agencies, except that of First Security to comply
with the FAA reporting requirements set forth in 14 C.F.R. ss. 47.45 and 14
C.F.R. ss. 47.51, and Owner Trustee shall, to the extent that information for
that purpose is timely supplied by Lessee pursuant to any of the Operative
Agreements, complete and timely submit (and furnish Owner Participant with a
copy of) any and all reports relating to the Aircraft that may from time to time
be required by the FAA or any government or governmental authority having
jurisdiction, (ii) to see to any insurance on the Aircraft or to effect or
maintain any such insurance, whether or not Lessee shall be in default with
respect thereto, other than to forward to Owner Participant copies of all
reports and other written information which Owner Trustee receives from Lessee
pursuant to Section 11 of the Lease, (iii) except as provided in Section 7.3.1
or 7.3.2 of the Participation Agreement, Section 4.01 of the Trust Indenture or
Section 5.4 or 6.1 hereof, to see to the payment or discharge of any tax,
assessment or other governmental charge or any lien or encumbrance of any kind
owing with respect to or assessed or levied against any part of the Trust
Indenture Estate or the Trust Estate, except as provided in Section 6.3.9 of the
Participation Agreement or (iv) to inspect Lessee's books and records with
respect to the Aircraft at any time permitted pursuant to the Lease.

      (b) Notwithstanding clause (a), Owner Trustee will furnish to Mortgagee
and Owner Participant, promptly upon receipt thereof, duplicates or copies of
all reports, notices, requests, demands, certificates, financial statements and
other instruments furnished to Owner Trustee under the Lease or any other
Operative Agreement except to the extent to which a responsible officer of Owner
Trustee reasonably believes (and confirms by telephone call with Owner
Participant) that duplicates or copies thereof have already been furnished to
Owner Participant by some other person.

      6.3 NO REPRESENTATIONS OR WARRANTIES AS TO CERTAIN MATTERS

      NEITHER FIRST SECURITY NOR OWNER TRUSTEE MAKES OR SHALL BE DEEMED TO
HAVE MADE (a) ANY REPRESENTATION OR WARRANTY, EXPRESS OR IMPLIED, AS TO THE
TITLE, AIRWORTHINESS, VALUE, CONDITION, DESIGN, OPERATION, MERCHANTABILITY OR
FITNESS FOR USE FOR A PARTICULAR PURPOSE OF THE AIRCRAFT OR ANY PART THEREOF,
AS TO THE ABSENCE OF LATENT OR OTHER DEFECTS, WHETHER OR NOT DISCOVERABLE, AS
TO THE ABSENCE OF ANY INFRINGEMENT OF ANY PATENT, TRADEMARK OR COPYRIGHT, THE
ABSENCE OF ANY STRICT LIABILITY OBLIGATION OR ANY OTHER REPRESENTATION OR
WARRANTY, EXPRESS OR IMPLIED, WITH RESPECT TO THE AIRCRAFT OR ANY PART
THEREOF WHATSOEVER, except that First Security warrants to Owner Participant
that on the Delivery Date Owner Trustee shall have received whatever title to
the Aircraft that was conveyed to it and that the Aircraft shall, on the
Delivery Date and during the Term, be free of Lessor Liens attributable to
First Security or (b) any representation or warranty as to the validity,
legality or enforceability of this Trust Agreement or any other Operative
Agreement to which First Security, in its individual capacity or as Owner
Trustee, is a party, or any other document or instrument, or as to the
correctness of any statement contained in any thereof except to the extent
that any such statement is expressly made herein or therein by such party as
a representation by First Security, in its individual capacity or as Owner
Trustee, as the case may be, and except that First Security hereby represents

<PAGE>

and warrants that it has all corporate power and authority to execute,
deliver and perform this Trust Agreement and that this Trust Agreement has
been, and (assuming due authorization, execution and delivery by Owner
Participant of this Trust Agreement) the other Operative Agreements to which
it or Owner Trustee is a party have been (or at the time of execution and
delivery of any such instrument by it or Owner Trustee under this Trust
Agreement or pursuant to the terms of the Participation Agreement that such
an instrument will be) duly executed and delivered by one of its officers who
is or will be, as the case may be, duly authorized to execute and deliver
such instruments on behalf of itself or Owner Trustee, as the case may be,
and that this Trust Agreement constitutes the legal, valid and binding
obligation of First Security or Owner Trustee, as the case may be,
enforceable against First Security or Owner Trustee, as the case may be, in
accordance with its terms.

      6.4 NO SEGREGATION OF MONIES; INTEREST

      Monies received by Owner Trustee under this Trust Agreement need not be
segregated in any manner except to the extent required by Law, or except as
provided in written instructions from Owner Participant, and shall be
invested as provided in Section 4.3 hereof or Section 4.4 of the Lease.

      6.5 RELIANCE UPON CERTIFICATES, COUNSEL AND AGENTS

      Owner Trustee shall incur no liability to anyone in acting in good
faith in reliance upon and in accordance with any signature, instrument,
notice, resolution, request, consent, order, certificate, report, opinion,
bond or other document or paper reasonably believed by it to be genuine and
reasonably believed by it to be signed by the proper party or parties.
Unless other evidence in respect thereof is specifically prescribed in this
Trust Agreement, any request, direction, order or demand of Owner Participant
or Lessee mentioned in this Trust Agreement or in any of the other Owner
Trustee Agreements shall be sufficiently evidenced by written instruments
signed by the Chairman of the Board, the President, any Vice President or any
other officer and in the name of Owner Participant or Lessee, as the case may
be.  Owner Trustee may accept a copy of a resolution of the Board of
Directors or Executive Committee of Lessee, certified by the Secretary or an
Assistant Secretary of Lessee as duly adopted and in full force and effect,
as conclusive evidence that such resolution has been duly adopted by said
Board of Directors or Executive Committee and that the same is in full force
and effect.  As to any fact or matter the manner of ascertainment of which is
not specifically described in this Trust Agreement, Owner Trustee may, absent
Actual Knowledge to the contrary, for all purposes rely on a certificate
signed by the Chairman of the Board, the President, any Vice President or any
other officer of Lessee, and the Treasurer or an Assistant Treasurer or the
Secretary or an Assistant Secretary of Lessee, as to such fact or matter, and
such certificate shall constitute full protection to Owner Trustee for any
action taken or omitted to be taken by it in good faith in reliance thereon
and in accordance therewith.  In the administration of trusts under this
Trust Agreement, Owner Trustee may execute any of the trusts or powers and
perform its powers and duties under this Trust Agreement directly or through
agents or attorneys and may, at the expense of the Trust Estate, consult with
counsel, accountants and other skilled persons to be selected and employed by
it.  Owner Trustee shall not be liable for anything done, suffered or omitted
in good faith by it in accordance with the advice or opinion of any such
counsel, accountants or other skilled persons.


<PAGE>

      6.6 NOT ACTING IN INDIVIDUAL CAPACITY

      In acting under this Trust Agreement, First Security acts solely as Owner
Trustee and not in its individual capacity except as otherwise expressly
provided in this Trust Agreement or in the other Operative Agreements to which
it is a party; and, except as may be otherwise expressly provided in this Trust
Agreement, the Lease, the Participation Agreement and the Trust Indenture, all
persons, other than the Owner Participant as provided in this Trust Agreement or
the Trust Indenture, having any claim against Owner Trustee by reason of the
transactions contemplated hereby shall look only to the Trust Estate for payment
or satisfaction thereof except to the extent provided in Section 6.1 or
otherwise as Owner Trustee shall expressly agree otherwise in writing.

      6.7 FEES; COMPENSATION

      Lessee or Owner Participant shall pay the Transaction Expenses of Owner
Trustee pursuant to Section 9.2 of the Participation Agreement.  The Trust
Estate shall not have any liability for any such fees and expenses; PROVIDED,
that the foregoing shall not limit the obligations of Owner Participant under
Sections 5.3 and 7; PROVIDED, that Owner Trustee shall have a Lien upon the
Trust Estate for any such fee not paid by Lessee or Owner Participant, as the
case may be, as contemplated by Section 9.2 of the Participation Agreement
and such Lien shall entitle Owner Trustee to priority as to payment thereof
over payment to any other Person under this Trust Agreement; PROVIDED, that
such Lien shall be subject and subordinate in all events to the Lien of the
Trust Indenture; and PROVIDED, FURTHER, that Owner Trustee shall have no
right to exercise, and shall not exercise, any rights or remedies Owner
Trustee may have with respect to such Lien unless and until the Secured
Obligations have been paid and performed in full.

      6.8 TAX RETURNS

      Owner Trustee shall be responsible for the keeping of all appropriate
books and records relating to the receipt and disbursement of all monies
under this Trust Agreement or any agreement contemplated hereby.  Owner
Participant shall be responsible for causing to be prepared and filed all
income tax returns required to be filed by Owner Participant.  Owner Trustee
shall be responsible for causing to be prepared, at the request of Owner
Participant and at the expense of Lessee, all income tax returns required to
be filed with respect to the trust created hereby and shall execute and file
such returns; PROVIDED, that Owner Trustee shall send promptly a completed
copy of such return to Owner Participant not more than sixty nor less than
fifteen days prior to the due date of the return, PROVIDED, that Owner
Trustee shall have timely received all necessary information to complete and
deliver to Owner Participant such return.  Owner Participant, upon request,
will furnish Owner Trustee with all such information as may be reasonably
required from Owner Participant in connection with the preparation of such
income tax returns.  Owner Trustee shall keep copies of all returns delivered
to or filed by it.

SECTION 7. INDEMNIFICATION OF FIRST SECURITY BY OWNER PARTICIPANT

      Owner Participant hereby agrees, whether or not any of the transactions
contemplated hereby shall be consummated, to assume liability for, and hereby

<PAGE>

indemnifies, protects, saves and keeps harmless, First Security and its
successors, assigns, agents and servants, from and against any and all
liabilities, obligations, losses, damages, penalties, taxes (excluding any Taxes
which are not required to be indemnified by Lessee pursuant to Section 9.1 or
9.3 of the Participation Agreement and excluding any taxes payable by First
Security on or measured by any compensation received by First Security for its
services under this Trust Agreement), claims, actions, suits, costs, expenses or
disbursements (including, without limitation, reasonable legal fees and
expenses, but excluding internal costs and expenses such as salaries and
overhead, and including, without limitation, any liability of an owner, any
strict liability and any liability without fault) of any kind and nature
whatsoever which may be imposed on, incurred by or asserted against First
Security (whether or not also indemnified against by Lessee under the Lease or
under the Participation Agreement or also indemnified against by any other
Person; PROVIDED, that Owner Participant shall be subrogated to the rights of
Owner Trustee against Lessee or any other indemnitor) in any way relating to or
arising out of this Trust Agreement or any of the other Operative Agreements or
the enforcement of any of the terms of any thereof, or in any way relating to or
arising out of the manufacture, purchase, acceptance, nonacceptance, rejection,
ownership, delivery, lease, possession, use, operation, condition, sale, return
or other disposition of the Aircraft (including, without limitation, latent and
other defects, whether or not discoverable, and any claim for patent, trademark
or copyright infringement), or in any way relating to or arising out of the
administration of the Trust Estate or the action or inaction of Owner Trustee,
under this Trust Agreement, except (a) in the case of gross negligence or
willful misconduct on the part of First Security, in its individual capacity or
as Owner Trustee, in the performance or nonperformance of its duties under this
Trust Agreement or under any of the other Owner Trustee Agreements or (b) those
Claims resulting from the inaccuracy of any representation or warranty of First
Security (or from the failure of First Security to perform any of its covenants)
in Section 6.3, in Section 6.03 of the Trust Indenture, in Section 4 of the
Lease, in Section 6.3 of the Participation Agreement or elsewhere in any of the
Operative Agreements or (c) as may result from a breach by First Security of its
covenant in the last sentence of Section 5.4.1 or (d) in the case of the failure
to use ordinary care on the part of First Security, in its individual capacity
or as Owner Trustee, in the receipt or disbursement of funds or in connection
with its obligation to invest funds pursuant to Section 4.4 of the Lease or
Section 4.3 hereof or in compliance with the provisions of the first sentence of
Section 6.8 or (e) any liability on the part of Owner Trustee arising out of its
negligence or willful or negligent misconduct in connection with its obligations
under Section 5.1, 6.8 or 9.2 hereof or Section 4.01 of the Trust Indenture, or
(f) those claims arising under any circumstances or upon any terms where Lessee
would not have been required to indemnify First Security pursuant to Section 9.1
or 9.3 of the Participation Agreement (disregarding for purposes of this
paragraph Sections 9.1.2(b) and 9.3.2(j)); PROVIDED, that before asserting its
right to indemnification, if any, pursuant to this Section 7, First Security
shall first demand its corresponding right to indemnification pursuant to
Section 9 of the Participation Agreement (but need not exhaust any or all
remedies available thereunder). The indemnities contained in this Section 7
extend to First Security only in its individual capacity and shall not be
construed as indemnities of the Trust Indenture Estate or the Trust Estate
(except to the extent, if any, that First Security has been reimbursed by the
Trust Indenture Estate or the Trust Estate for amounts covered by the
indemnities contained in this Section 7). The indemnities contained in this
Section 7 shall survive the termination of this Trust Agreement. In addition, if
necessary, First Security shall be entitled to indemnification from the Trust
Estate, subject to the Lien of the Trust Indenture, for any liability,

<PAGE>

obligation, loss, damage, penalty, tax, claim, action, suit, cost, expense or
disbursement indemnified against pursuant to this Section 7 to the extent not
reimbursed by Lessee, Owner Participant or others, but without releasing any of
them from their respective agreements of reimbursement; and, to secure the same
First Security shall have a lien on the Trust Estate, subject to the lien of the
Trust Indenture and subject further to the provisions of Section 6.7, which
shall be prior to any interest therein of Owner Participant. The payor of any
indemnity under this Section 7 shall be subrogated to any right of the person
indemnified in respect of the matter as to which such indemnity was paid.

SECTION 8. TRANSFER OF OWNER PARTICIPANT'S INTEREST

      8.1 TRANSFER OF INTEREST

      All provisions of Section 10 of the Participation Agreement shall (with
the same force and effect as if set forth in full in this Section 8.1) be
applicable to any assignment, conveyance or other transfer by Owner
Participant of any of its right, title or interest in and to the
Participation Agreement, the Trust Estate or this Trust Agreement.

SECTION 9. SUCCESSOR OWNER TRUSTEES; CO-TRUSTEES

      9.1 RESIGNATION OF OWNER TRUSTEE; APPOINTMENT OF SUCCESSOR

            9.1.1 RESIGNATION OR REMOVAL

      Owner Trustee or any successor Owner Trustee (a) shall resign if
required to do so pursuant to Section 13.3 of the Participation Agreement or
upon obtaining Actual Knowledge of any facts that would cast doubt upon its
continuing status as a Citizen of the United States and (b) may resign at any
time without cause by giving at least 60 days' prior written notice to Owner
Participant, Mortgagee and Lessee, such resignation to be effective upon the
assumption of the trusts hereunder by the successor Owner Trustee under
Section 9.1.2.  In addition, Owner Participant may at any time remove Owner
Trustee, with or without cause by a notice in writing delivered to Owner
Trustee, Mortgagee and Lessee, such removal to be effective upon the
assumption of the trusts hereunder by the successor Owner Trustee under
Section 9.1.2, PROVIDED, that, in the case of a removal without cause, unless
a Lease Event of Default shall have occurred and be continuing, such removal
shall be subject to the consent of Lessee (which consent shall not be
unreasonably withheld).  In the case of the resignation or removal of Owner
Trustee, Owner Participant may appoint a successor Owner Trustee by an
instrument signed by Owner Participant, with, unless a Lease Event of Default
shall have occurred and be continuing, the consent of Lessee (which consent
shall not be unreasonably withheld).  If a successor Owner Trustee shall not
have been appointed within 30 days after such notice of resignation or
removal, Owner Trustee, any Owner Participant, Lessee or Mortgagee may apply
to any court of competent jurisdiction to appoint a successor Owner Trustee
to act until such time, if any, as a successor shall have been appointed as
above provided.  Any successor Owner Trustee so appointed by such court shall
immediately and without further act be superseded by any successor Owner
Trustee appointed as above provided within one year from the date of the
appointment by such court.


<PAGE>

            9.1.2 EXECUTION AND DELIVERY OF DOCUMENTS, ETC.

      Any successor Owner Trustee, however appointed, shall execute and
deliver to the predecessor Owner Trustee, with a copy to Owner Participant,
Lessee and Mortgagee, an instrument accepting such appointment and assuming
the obligations of Owner Trustee, in its individual capacity and as Owner
Trustee, under the Owner Trustee Agreements, and thereupon such successor
Owner Trustee, without further act, shall become vested with all the estates,
properties, rights, powers, duties and trusts of the predecessor Owner
Trustee in the trusts under this Trust Agreement with like effect as if
originally named Owner Trustee in this Trust Agreement; but nevertheless,
upon the written request of such successor Owner Trustee, such predecessor
Owner Trustee shall execute and deliver an instrument transferring to such
successor Owner Trustee, upon the trusts herein expressed, all the estates,
properties, rights, powers and trusts of such predecessor Owner Trustee, and
such predecessor Owner Trustee shall duly assign, transfer, deliver and pay
over to such successor Owner Trustee all monies or other property then held
by such predecessor Owner Trustee upon the trusts herein expressed.  Upon the
appointment of any successor Owner Trustee under this Section 9.1, the
predecessor Owner Trustee will execute such documents as are provided to it
by such successor Owner Trustee and will take such further actions as are
requested of it by such successor Owner Trustee as are required to cause
registration of the Aircraft included in the Trust Estate to be transferred
upon the records of the FAA, or other governmental authority having
jurisdiction, into the name of the successor Owner Trustee.

            9.1.3 QUALIFICATIONS

      Any successor Owner Trustee, however appointed, shall be a Citizen of
the United States and shall also be a bank or trust company organized under
the Laws of the United States or any state thereof having a combined capital
and surplus of at least $100,000,000, if there be such an institution
willing, able and legally qualified to perform the duties of Owner Trustee
under this Trust Agreement upon reasonable or customary terms.  No such
successor Owner Trustee shall be located in a jurisdiction which creates
material adverse consequences for Lessee (unless such material adverse
consequences would be created by substantially all jurisdictions where major
banking or trust institutions are located).

            9.1.4 MERGER, ETC.

      Any corporation into which First Security may be merged or converted or
with which it may be consolidated, or any corporation resulting from any
merger, conversion or consolidation to which First Security shall be a party,
or any corporation to which substantially all the corporate trust business of
First Security may be transferred, shall, subject to the terms of
Section 9.1.3, be Owner Trustee under this Trust Agreement without further
act, PROVIDED, that such corporation shall not also be the Mortgagee.

      9.2 CO-TRUSTEES AND SEPARATE TRUSTEES

      (a) If at any time it shall be necessary or prudent in order to conform to
any Law of any jurisdiction in which all or any part of the Trust Estate is
located, or Owner Trustee being advised by counsel shall determine that it is so
necessary or prudent in the interest of Owner Participant or Owner Trustee, or

<PAGE>

Owner Trustee shall have been directed to do so by Owner Participant, Owner
Trustee and Owner Participant shall execute and deliver an agreement
supplemental hereto and all other instruments and agreements necessary or proper
to constitute another bank or trust company or one or more persons (any or all
of which shall be a Citizen of the United States) approved by Owner Trustee and
Owner Participant, either to act as co-trustee, jointly with Owner Trustee, or
to act as separate trustee under this Trust Agreement (any such co-trustee or
separate trustee being herein sometimes referred to as an "additional trustee").
In the event Owner Participant shall not have joined in the execution of such
agreements' supplemental hereto within ten days after the receipt of a written
request from Owner Trustee so to do, or in case a Lease Event of Default or
Indenture Event of Default shall occur and be continuing, Owner Trustee may act
under the foregoing provisions of this Section 9.2 without the concurrence of
Owner Participant; and Owner Participant hereby appoints Owner Trustee its agent
and attorney-in-fact to act for it under the foregoing provisions of this
Section 9.2 in either of such contingencies.

      (b) Every additional trustee under this Trust Agreement shall, to the
extent permitted by Law, be appointed and act, and Owner Trustee and its
successors shall act, subject to the following provisions and conditions:

            (i) All powers, duties, obligations and rights conferred upon Owner
      Trustee in respect of the custody, control and management of monies, the
      Aircraft or documents authorized to be delivered under this Trust
      Agreement or under the Participation Agreement shall be exercised solely
      by Owner Trustee;

            (ii) All other rights, powers, duties and obligations conferred or
      imposed upon Owner Trustee shall be conferred or imposed upon and
      exercised or performed by Owner Trustee and such additional trustee
      jointly, except to the extent that under any Law of any jurisdiction in
      which any particular act or acts are to be performed (including the
      holding of title to the Trust Estate) Owner Trustee shall be incompetent
      or unqualified to perform such act or acts, in which event such rights,
      powers, duties and obligations shall be exercised and performed by such
      additional trustee;

            (iii) No power given to, or which it is provided hereby may be
      exercised by, any such additional trustee shall be exercised under this
      Trust Agreement by such additional trustee, except jointly with, or with
      the consent in writing of, Owner Trustee;

            (iv) No trustee under this Trust Agreement shall be personally
      liable by reason of any action or omission of any other trustee under this
      Trust Agreement;

            (v) Owner Participant, at any time, by an instrument in writing may
      remove any such additional trustee. In the event that Owner Participant
      shall not have joined in the execution of any such instrument within ten
      days after the receipt of a written request from Owner Trustee so to do,
      Owner Trustee shall have the power to remove any such additional trustee
      without the concurrence of Owner Participant; and Owner Participant hereby
      appoints Owner Trustee its agent and attorney-in-fact to act for it in
      such connection in such contingency; and

<PAGE>

            (vi) No appointment of, or action by, any additional trustee will
      relieve Owner Trustee of any of its obligations under, or otherwise affect
      any of the terms of, the Trust Indenture or affect the interests of
      Mortgagee or the Certificate Holders in the Trust Indenture Estate.

      (c) In case any separate trustee under this Section 9.2 shall die, become
incapable of acting, resign or be removed, the title to the Trust Estate and all
rights and duties of such separate trustee shall, so far as permitted by Law,
vest in and be exercised by Owner Trustee, without the appointment of a
successor to such separate trustee.

SECTION 10. SUPPLEMENTS AND AMENDMENTS TO TRUST AGREEMENT AND OTHER DOCUMENTS

      10.1 SUPPLEMENTS AND AMENDMENTS AND DELIVERY THEREOF

            10.1.1 SUPPLEMENTS AND AMENDMENTS

      Subject to Section 7.2.2 of the Participation Agreement, this Trust
Agreement may not be amended, supplemented or otherwise modified except by an
instrument in writing signed by Owner Trustee and Owner Participant. Subject to
Section 10.2, Section 9.01 of the Trust Indenture and Section 7.6.7 of the
Participation Agreement, Owner Trustee will execute any amendment, supplement or
other modification of this Trust Agreement or of any other Owner Trustee
Agreement which it is requested in writing to execute by Owner Participant,
except that Owner Trustee shall not execute any such amendment, supplement or
other modification which, by the express provisions of any of the above
documents, requires the consent of any other party unless such consent shall
have been obtained; and PROVIDED, that, without the prior written consent of
Owner Participant, (a) no such supplement, amendment or modification shall (i)
modify any of the provisions of Section 4 or this Section 10.1, (ii) reduce,
modify or amend any indemnities in favor of Owner Participant as set forth in
Section 9 of the Participation Agreement or in the Tax Indemnity Agreement,
(iii) reduce the amount or extend the time of payment of Basic Rent,
Supplemental Rent, Stipulated Loss Value or Termination Value as set forth in
the Lease (except in accordance with Section 3 of the Lease) or (iv) modify any
of the rights of Owner Participant under the Trust Indenture and (b) no such
supplement, amendment or modification shall require Owner Participant to invest
or advance funds or shall entail any additional personal liability or the
surrender of any indemnification, claim or individual right on the part of Owner
Participant with respect to any agreement or obligation.

            10.1.2 DELIVERY OF AMENDMENTS AND SUPPLEMENTS TO CERTAIN PARTIES

      A signed copy of each amendment or supplement referred to in
Section 10.1.1 to which Lessee is not a party shall be delivered promptly by
Owner Trustee to Lessee, and a signed copy of each amendment or supplement
referred to in Section 10.1.1 shall be delivered promptly by Owner Trustee to
Mortgagee.


<PAGE>

      10.2 DISCRETION AS TO EXECUTION OF DOCUMENTS

      Prior to executing any document required to be executed by it pursuant to
the terms of Section 10.1, Owner Trustee shall be entitled to receive an opinion
of its counsel to the effect that the execution of such document is authorized
under this Trust Agreement. If in the opinion of Owner Trustee any such document
adversely affects any right, duty, immunity or indemnity in favor of Owner
Trustee under this Trust Agreement or under any other Owner Trustee Agreement,
Owner Trustee may in its discretion decline to execute such document unless
Owner Trustee is furnished with indemnification from Lessee or any other party
upon terms and in amounts reasonably satisfactory to Owner Trustee to protect
the Trust Estate and the Owner Trustee against any and all liabilities, costs
and expenses arising out of the execution of such documents.

      10.3 ABSENCE OF REQUIREMENTS AS TO FORM

      It shall not be necessary for any written request furnished pursuant to
Section 10.1 to specify the particular form of the proposed documents to be
executed pursuant to such Section 10.1, but it shall be sufficient if such
request shall indicate the substance thereof.

      10.4 DISTRIBUTION OF DOCUMENTS

      Promptly after the execution by Owner Trustee of any document entered
into pursuant to Section 10.1, Owner Trustee shall mail, by certified mail,
postage prepaid, a conformed copy thereof to Owner Participant, but the
failure of Owner Trustee to mail such conformed copy shall not impair or
affect the validity of such document.

      10.5  NO REQUEST NEEDED AS TO LEASE SUPPLEMENT AND TRUST INDENTURE
            SUPPLEMENT

      No written request pursuant to Section 10.1 shall be required to enable
Owner Trustee to enter into, pursuant to Section 3.1 and the Lease or the
Trust Indenture, as the case may be, the Lease Supplement with Lessee and the
Trust Indenture Supplement.

SECTION 11. MISCELLANEOUS

      11.1 TERMINATION OF TRUST AGREEMENT

      This Trust Agreement and the trusts created hereby shall be of no
further force or effect upon the earlier of (a) both the final discharge of
the Trust Indenture pursuant to Section 10.01 thereof and the sale or other
final disposition by Owner Trustee of all property constituting part of the
Trust Estate and the final distribution by Owner Trustee of all monies or
other property or proceeds constituting part of the Trust Estate in
accordance with Section 4, PROVIDED, that at such time Lessee shall have
fully complied with all of the terms of the Lease and the Participation
Agreement or (b) 21 years less one day after the death of the last survivor
of all of the descendants of the grandparents of David C. Rockefeller living
on the date of the earliest execution of this Trust Agreement by any party
hereto, but if this Trust Agreement and the trusts created hereby shall be or
become authorized under applicable Law to be valid for a period commencing on

<PAGE>

the 21st anniversary of the death of such last survivor (or, without limiting
the generality of the foregoing, if legislation shall become effective
providing for the validity of this Trust Agreement and the trusts created
hereby for a period in gross exceeding the period for which this Trust
Agreement and the trusts created hereby are hereinabove stated to extend and
be valid), then this Trust Agreement and the trusts created hereby shall not
terminate under this clause (b) but shall extend to and continue in effect,
but only if such nontermination and extension shall then be valid under
applicable Law, until the day preceding such date as the same shall, under
applicable Law, cease to be valid; otherwise this Trust Agreement and the
trusts created hereby shall continue in full force and effect in accordance
with the terms hereof.  Except as expressly set forth in Section 11.2, this
Trust Agreement and the trusts created hereby may not be revoked by Owner
Participant.

      11.2 TERMINATION AT OPTION OF THE OWNER PARTICIPANT

      Notwithstanding Section 11.1 hereof, this Agreement and trust created
hereby shall terminate and the Trust Estate shall be distributed to the Owner
Participant, and this Agreement shall be of no further force and effect, upon
the election of the Owner Participant by notice to the Owner Trustee, if such
notice shall be accompanied by the written agreement (in form and substance
satisfactory to the Owner Trustee) of the Owner Participant assuming all
obligations of the Owner Trustee under or contemplated by the Operative
Agreements or incurred by it as trustee hereunder and releasing the Owner
Trustee therefrom; provided, however, that such notice may be given only
after the time the Lien of the Trust Indenture is discharged under
Section 10.01 of the Trust Indenture and after the Lease shall no longer be
in effect.

      11.3 OWNER PARTICIPANT HAS NO LEGAL TITLE IN TRUST ESTATE

      No Owner Participant shall have legal title to any part of the Trust
Estate.  No transfer, by operation of Law or otherwise, of any right, title
and interest of Owner Participant in and to the Trust Estate under this Trust
Agreement shall operate to terminate this Trust Agreement or the trusts under
this Trust Agreement or entitle any successors or transferees of Owner
Participant to an accounting or to the transfer of legal title to any part of
the Trust Estate.

      11.4 ASSIGNMENT, SALE, ETC. OF AIRCRAFT

      Any assignment, sale, transfer or other conveyance of the Aircraft by
Owner Trustee made pursuant to the terms of this Trust Agreement or of the
Lease or the Participation Agreement shall bind Owner Participant and shall
be effective to transfer or convey all right, title and interest of Owner
Trustee and Owner Participant in and to the Aircraft.  No purchaser or other
grantee shall be required to inquire as to the authorization, necessity,
expediency or regularity of such assignment, sale, transfer or conveyance or
as to the application of any sale or other proceeds with respect thereto by
Owner Trustee.

      11.5 TRUST AGREEMENT FOR BENEFIT OF CERTAIN PARTIES ONLY

      Except for the terms of Section 10 of the Participation Agreement
incorporated in Section 8 and except as otherwise provided in Sections 5.1,
6.7, 9, 10.1 and 11.1, nothing in this Trust Agreement, whether express or
implied, shall be construed to give any person other than Owner Trustee and

<PAGE>

Owner Participant any legal or equitable right, remedy or claim under or in
respect of this Trust Agreement; and this Trust Agreement shall be held to be
for the sole and exclusive benefit of Owner Trustee and Owner Participant.

      11.6 [RESERVED]

      11.7 NOTICES

      Unless otherwise expressly permitted by the terms of this Trust
Agreement, all notices, requests, demands, authorizations, directions,
consents, waivers and other communications required or permitted to be made,
given, furnished or filed under this Trust Agreement shall be in writing,
shall refer specifically to this Trust Agreement and shall be personally
delivered, sent by telecopy, telex or other means of electronic facsimile or
telecommunication transmission, sent by registered mail or certified mail,
return receipt requested, postage prepaid, or sent by overnight courier
service, in each case to the respective telex, telecopy or other number or
address set forth for such party in Schedule 1 to the Participation
Agreement, or to such other telex, telecopy or other number or address as
each party hereto may hereafter specify by notice to the other parties
hereto.  Each such notice, request, demand, authorization, direction,
consent, waiver or other communication shall be effective when received or,
if made, given, furnished or filed (a) by telecopy or other means of
electronic facsimile or telecommunication transmission, when confirmed, or
(b) by registered or certified mail, three Business Days after being
deposited, properly addressed, in the U.S. mail.

      11.8 SEVERABILITY

      If any provision of this Trust Agreement shall be held invalid, illegal
or unenforceable in any respect in any jurisdiction, then, to the extent
permitted by Law, (a) all other provisions hereof shall remain in full force
and effect in such jurisdiction and (b) such invalidity, illegality or
unenforceability shall not affect the validity, legality or enforceability of
such provision in any other jurisdiction.  If, however, any Law pursuant to
which such provisions are held invalid, illegal or unenforceable may be
waived, such Law is hereby waived by the parties hereto to the full extent
permitted, to the end that this Trust Agreement shall be deemed to be a valid
and binding agreement in all respects, enforceable in accordance with its
terms.

      11.9 WAIVERS, ETC.

      No term or provision hereof may be changed, waived, discharged or
terminated orally, but only by an instrument in writing entered into in
compliance with the terms of Section 10; and any waiver of the terms hereof
shall be effective only in the specific instance and for the specific purpose
given.

      11.10 COUNTERPARTS

      This Trust Agreement and any amendments, waivers, consents or
supplements hereto may be executed in any number of counterparts, each of
which when so executed shall be deemed to be an original, and all of which
counterparts, taken together, shall constitute one and the same instrument.

<PAGE>

      11.11 BINDING EFFECT, ETC.

      All covenants and agreements contained in this Trust Agreement shall be
binding upon, and inure to the benefit of, Owner Trustee and its successors
and assigns, and Owner Participant and its successors and, to the extent
permitted by Section 8, assigns.  Any request, notice, direction, consent,
waiver or other instrument or action by Owner Participant shall bind its
successors and assigns.

      11.12 HEADINGS; REFERENCES

      The headings and the table of contents used in this Trust Agreement are
for convenience of reference only and shall not define or limit any of the
terms or provisions hereof and shall not in any way affect the construction
of, or be taken into consideration in interpreting, this Trust Agreement.

      11.13 GOVERNING LAW

      THIS TRUST AGREEMENT SHALL IN ALL RESPECTS BE GOVERNED BY THE LAWS OF
THE STATE OF UTAH , INCLUDING ALL MATTERS OF CONSTRUCTION, VALIDITY AND
PERFORMANCE, WITHOUT GIVING EFFECT TO PRINCIPLES OF CONFLICTS OF LAWS.


                    [This space intentionally left blank.]

<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Trust Agreement to
be duly executed by their respective officers thereunto duly authorized as of
the day and year first above written.


                                          [                                  ]


                                          By
                                            ----------------------------------
                                            Name:
                                            Title:


                                          FIRST SECURITY BANK, NATIONAL
                                          ASSOCIATION


                                          By
                                            ----------------------------------
                                            Name:
                                            Title: