Document:

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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.................................................. 11

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                                TABLE OF CONTENTS
                                  (Continued)
                                                                           PAGE

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

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

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............................ 14

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................................................ 17

        11.1  Termination of Trust Agreement............................... 17
        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........................... 18
        11.5  Trust Agreement for Benefit of Certain Parties Only.......... 18
        11.6  [Reserved]................................................... 18
        11.7  Notices...................................................... 18
        11.8  Severability................................................. 18
        11.9  Waivers, Etc................................................. 19
        11.10 Counterparts................................................. 19
        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").

                              W I T N E S S E T H :

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;

<PAGE>

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

      (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

<PAGE>

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.

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

<PAGE>

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 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 Trustee

<PAGE>

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

<PAGE>

Operative  Agreement  or of  any  supplement  to  any  thereof  or to see to the
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

<PAGE>

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 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

<PAGE>

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.

      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

<PAGE>

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
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

<PAGE>

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,
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

<PAGE>

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.

               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,

<PAGE>

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
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;

<PAGE>

           (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

           (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

<PAGE>

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.

      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.

<PAGE>

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 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.

<PAGE>

      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 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

<PAGE>

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.

      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:--------------------------------------------------------------------------------

                       TRUST INDENTURE AND MORTGAGE [___]

                        Dated as of [____________, 20___]

                                     Between

                  FIRST SECURITY BANK, NATIONAL ASSOCIATION,
                       not in its individual capacity,
                       except as expressly stated herein,
                          but solely as Owner Trustee,

                                  Owner Trustee

                                       and

                            WILMINGTON TRUST COMPANY,
                         not in its individual capacity,
                       except as expressly stated herein,
                            but solely as Mortgagee,

                                    Mortgagee

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

                            EQUIPMENT NOTES COVERING
                         ONE BOEING [________] AIRCRAFT
                     BEARING U.S. REGISTRATION MARK N[_____]
                      LEASED BY CONTINENTAL AIRLINES, INC.

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

<PAGE>

                                TABLE OF CONTENTS

                                                                            Page
GRANTING CLAUSE
                  ..........................................................2

                                    ARTICLE I

                                   DEFINITIONS

                                   ARTICLE II

                               THE EQUIPMENT NOTES
SECTION 2.01      Form of Equipment Notes................................... 8
SECTION 2.02      Issuance and Terms of Equipment Notes.....................13
SECTION 2.03      Payments from Trust Indenture Estate Only.................16
SECTION 2.04      Method of Payment.........................................18
SECTION 2.05      Application of Payments...................................20
SECTION 2.06      Termination of Interest in Trust Indenture Estate.........20
SECTION 2.07      Registration Transfer and Exchange of Equipment Notes.....20
SECTION 2.08      Mutilated, Destroyed, Lost or Stolen Equipment Notes......22
SECTION 2.09      Payment of Expenses on Transfer; Cancellation.............22
SECTION 2.10      Mandatory Redemptions of Equipment Notes..................22
SECTION 2.11      Voluntary Redemptions of Equipment Notes..................23
SECTION 2.12      Redemptions; Notice of Redemption.........................23
SECTION 2.13      Option to Purchase Equipment Notes........................24
SECTION 2.14      Subordination.............................................25

                                   ARTICLE III

         RECEIPT, DISTRIBUTION AND APPLICATION OF INCOME FROM THE TRUST
                                INDENTURE ESTATE
SECTION 3.01      Basic Rent Distribution...................................25
SECTION 3.02      Event of Loss; Replacement; Voluntary Termination;
                  Optional Redemption.......................................27
SECTION 3.03      Payments After Event of Default...........................28
SECTION 3.04      Certain Payments..........................................30
SECTION 3.05      Other Payments............................................31
SECTION 3.06      Payments to Owner Trustee.................................32

                                   ARTICLE IV

      COVENANTS OF OWNER TRUSTEE; EVENTS OF DEFAULT; REMEDIES OF MORTGAGEE
SECTION 4.01      Covenants of Owner Trustee................................32
SECTION 4.02      Event of Default..........................................33
SECTION 4.03      Certain Rights............................................35

<PAGE>

                                TABLE OF CONTENTS
                                   (Continued)
                                                                            Page

SECTION 4.04      Remedies..................................................36
SECTION 4.05      Return of Aircraft, Etc...................................39
SECTION 4.06      Remedies Cumulative.......................................40
SECTION 4.07      Discontinuance of Proceedings.............................40
SECTION 4.08      Waiver of Past Defaults...................................41
SECTION 4.09      Appointment of Receiver...................................41
SECTION 4.10      Mortgagee Authorized to Execute Bills of Sale, Etc........41
SECTION 4.11      Rights of Note Holders to Receive Payment.................41

                                    ARTICLE V

                             DUTIES OF THE MORTGAGEE
SECTION 5.01      Notice of Event of Default................................42
SECTION 5.02      Action Upon Instructions; Certain Rights and Limitations..42
SECTION 5.03      Indemnification...........................................45
SECTION 5.04      No Duties Except as Specified in Trust Indenture or
                  Instructions..............................................46
SECTION 5.05      No Action Except Under Lease, Trust Indenture or
                  Instructions..............................................46
SECTION 5.06      Replacement Airframes and Replacement Engines.............46
SECTION 5.07      Indenture Supplements for Replacements....................47
SECTION 5.08      Effect of Replacement.....................................47
SECTION 5.09      Investment of Amounts Held by Mortgagee...................47

                                   ARTICLE VI

                       THE OWNER TRUSTEE AND THE MORTGAGEE
SECTION 6.01      Acceptance of Trusts and Duties...........................48
SECTION 6.02      Absence of Duties.........................................48
SECTION 6.03      No Representations or Warranties as to Aircraft or
                  Documents.................................................49
SECTION 6.04      No Segregation of Monies; No Interest.....................49
SECTION 6.05      Reliance; Agreements; Advice of Counsel...................50
SECTION 6.06      Capacity in Which Acting..................................50
SECTION 6.07      Compensation..............................................50
SECTION 6.08      Instructions from Note Holders............................51

                                   ARTICLE VII

                INDEMNIFICATION OF MORTGAGEE BY OWNER TRUSTEE
SECTION 7.01      Scope of Indemnification..................................51

                                  ARTICLE VIII

                         SUCCESSOR AND SEPARATE TRUSTEES
SECTION 8.01      Notice of Successor Owner Trustee.........................52
SECTION 8.02      Resignation of Mortgagee; Appointment of Successor........52
SECTION 8.03      Appointment of Additional and Separate Trustees...........53

<PAGE>
                                   ARTICLE IX

          SUPPLEMENTS AND AMENDMENTS TO THIS TRUST INDENTURE AND OTHER
                                    DOCUMENTS
SECTION 9.01      Instructions of Majority; Limitations.....................55
SECTION 9.02      Trustees Protected........................................57
SECTION 9.03      Documents Mailed to Note Holders..........................57
SECTION 9.04      No Request Necessary for Lease Supplement or Trust
                  Indenture Supplement......................................57

                                    ARTICLE X

                                  MISCELLANEOUS
SECTION 10.01     Termination of Trust Indenture............................57
SECTION 10.02     No Legal Title to Trust Indenture Estate in Note Holders..58
SECTION 10.03.    Sale of Aircraft by Mortgagee Is Binding..................58
SECTION 10.04     Trust Indenture for Benefit of Owner Trustee, Mortgagee,
                  Owner Participant, Note Holders and Other Holders of
                  Secured Obligations.......................................58
SECTION 10.05.    Notices...................................................58
SECTION 10.06     Severability..............................................59
SECTION 10.07.    No Oral Modification or Continuing Waivers................59
SECTION 10.08     Successors and Assigns....................................59
SECTION 10.09     Headings..................................................59
SECTION 10.10     Normal Commercial Relations...............................59
SECTION 10.11     Governing Law; Counterpart Form...........................60
SECTION 10.12     Voting By Note Holders....................................60
SECTION 10.13     Bankruptcy................................................60

EXHIBIT A               Form of Trust Indenture and Mortgage Supplement

SCHEDULE I              Equipment Notes Amortization and Interest Rates

<PAGE>

                       TRUST INDENTURE AND MORTGAGE [___]

            TRUST INDENTURE AND MORTGAGE [___], dated as of [___________, 20___]
("Trust  Indenture"),  between FIRST  SECURITY  BANK,  NATIONAL  ASSOCIATION,  a
national  banking  association,  not  in  its  individual  capacity,  except  as
expressly  stated herein,  but solely as Owner Trustee under the Trust Agreement
referred to below (together with its successors under the Trust  Agreement,  the
"Owner Trustee"),  and WILMINGTON TRUST COMPANY, a Delaware banking corporation,
not in its individual capacity, except as expressly stated herein, but solely as
Mortgagee hereunder (together with its successors hereunder, the "Mortgagee").

                               W I T N E S S E T H
                               -------------------

            WHEREAS, all capitalized terms used herein shall have the respective
meanings set forth or referred to in Article I hereof;

            WHEREAS,  the  Owner  Participant  and  the  Owner  Trustee  in  its
individual  capacity have entered into the Trust Agreement whereby,  among other
things,  (i) the Owner  Trustee has  established a certain trust for the use and
benefit of the Owner Participant subject, however, to the Trust Indenture Estate
created  pursuant  hereto for the use and benefit  of, and with the  priority of
payment to, the holders of Equipment Notes issued hereunder,  and (ii) the Owner
Trustee has been authorized and directed to execute and deliver this Agreement;

            WHEREAS,  the parties hereto desire by this Trust  Indenture,  among
other things, (i) to provide for the issuance by the Owner Trustee of the Series
of Equipment Notes specified on Schedule I hereto (it being  understood that not
all Series may be issued,  in which case  references in this Trust  Indenture to
Series not issued shall be disregarded)  and (ii) to provide for the assignment,
mortgage and pledge by the Owner Trustee to the Mortgagee,  as part of the Trust
Indenture Estate  hereunder,  among other things,  of all of the Owner Trustee's
right,  title and interest in and to the  Aircraft  and,  except as  hereinafter
expressly provided,  all of the Owner Trustee's right, title and interest in, to
and under the Lease and the  Participation  Agreement and all payments and other
amounts received  hereunder or thereunder in accordance with the terms hereof or
thereof, as security for, among other things, the Owner Trustee's obligations to
the Note Holders;

            WHEREAS, all things have been done to make the Equipment Notes, when
executed by the Owner Trustee and  authenticated  and delivered by the Mortgagee
hereunder,  the valid, binding and enforceable obligations of the Owner Trustee;
and

            WHEREAS,  all  things  necessary  to make this Trust  Indenture  the
valid,  binding  and  legal  obligation  of the Owner  Trustee  for the uses and
purposes  herein set forth,  in  accordance  with its terms,  have been done and
performed and have happened;

<PAGE>
                                 GRANTING CLAUSE

            NOW, THEREFORE, THIS TRUST INDENTURE AND MORTGAGE WITNESSETH,  that,
to secure the prompt payment of the Original Amount of, interest on,  Make-Whole
Amount,  if any, and all other amounts due with respect to, all Equipment  Notes
from time to time outstanding  hereunder according to their tenor and effect and
to  secure  the  performance  and  observance  by the Owner  Trustee  of all the
agreements,  covenants and provisions  contained herein and in the Participation
Agreement and the Equipment Notes, for the benefit of the Note Holders, the Loan
Participants and other holders of Secured  Obligations and the prompt payment of
all amounts from time to time owing hereunder and under Participation  Agreement
to the Loan  Participants,  the Note  Holders  and/or  other  holders of Secured
Obligations  by the Owner  Trustee and for the uses and  purposes and subject to
the terms and provisions hereof, and in consideration of the premises and of the
covenants herein contained,  and of the acceptance of the Equipment Notes by the
holders thereof,  and for other good and valuable  consideration the receipt and
adequacy  whereof  are  hereby  acknowledged,  the Owner  Trustee  has  granted,
bargained,  sold,  assigned,  transferred,   conveyed,  mortgaged,  pledged  and
confirmed,  and does hereby grant,  bargain,  sell,  assign,  transfer,  convey,
mortgage,  pledge and confirm,  unto the Mortgagee,  its successors in trust and
assigns, for the security and benefit of the Loan Participants, the Note Holders
and other holders of Secured Obligations,  a first priority security interest in
and mortgage  lien on all right,  title and interest of the Owner Trustee in, to
and under the following described property,  rights and privileges,  whether now
or  hereafter  acquired,  other than  Excluded  Payments  (which,  collectively,
excluding  Excluded Payments but including all property  hereafter  specifically
subject  to the  Lien  of  this  Trust  Indenture  by the  terms  hereof  or any
supplement  hereto,  are  included  within,  and are  referred to as, the "Trust
Indenture Estate"), to wit:

            (1) The Airframe which is one Boeing [______]  aircraft with the FAA
      Registration  number of N[_____] and the  manufacturer's  serial number of
      [_______]   and   [_________]   Engines,   each  of  which  Engines  is  a
      [_______________________] engine with the manufacturer's serial numbers of
      [_____ and  _____],  is of 750 or more  rated  takeoff  horsepower  or the
      equivalent of such horsepower (such Airframe and Engines more particularly
      described in the Indenture  Supplement  executed and delivered as provided
      herein) as the same is now and will hereafter be constituted,  whether now
      owned by the Owner Trustee or hereafter acquired, leased or intended to be
      leased under the Lease,  and in the case of such  Engines,  whether or not
      any such Engine  shall be  installed in or attached to the Airframe or any
      other airframe,  together with (a) all Parts of whatever nature, which are
      from  time to time  included  within  the  definitions  of  "Airframe"  or
      "Engines",   whether  now  owned  or  hereafter  acquired,  including  all
      substitutions,  renewals and replacements of and additions,  improvements,
      accessions  and  accumulations  to the  Airframe  and Engines  (other than
      additions,  improvements,  accessions and  accumulations  which constitute
      appliances, parts, instruments, appurtenances, accessories, furnishings or
      other  equipment  excluded  from  the  definition  of  Parts)  and (b) all
      Aircraft Documents;

            (2) All right,  title,  interest,  claims  and  demands of the Owner
      Trustee, as Lessor, in, to and under the Lease,  together with all rights,

<PAGE>

      powers, privileges, options and other benefits of the Owner Trustee as
      lessor under the Lease,  including the immediate and  continuing  right to
      receive and collect all Rent, income, revenues, issues, profits, insurance
      proceeds, condemnation awards and other payments, tenders and security now
      or  hereafter  payable  to or  receivable  by the  Lessor  under the Lease
      pursuant thereto,  and, subject to Section 5.02 hereof,  the right to make
      all waivers and agreements,  to give and receive copies of all notices and
      other instruments or communications,  to accept surrender or redelivery of
      the Aircraft or any part  thereof,  as well as all the rights,  powers and
      remedies on the part of the Owner  Trustee as Lessor  under the Lease,  to
      take  such  action  upon  the  occurrence  of a  Lease  Event  of  Default
      thereunder, including the commencement, conduct and consummation of legal,
      administrative or other proceedings, as shall be permitted by the Lease or
      by Law,  and to do any and all  other  things  whatsoever  which the Owner
      Trustee or any lessor is or may be  entitled  to do under or in respect of
      the Lease and any right to restitution from the Lessee or any other Person
      in respect of any determination of invalidity of the Lease;

            [(3)] Each Permitted Sublease assignment and each assigned Permitted
      Sublease  (to  the  extent   assigned   under  such   Permitted   Sublease
      assignment),  and  including,  without  limitation,  all  rents  or  other
      payments of any kind made under such assigned  Permitted  Sublease (to the
      extent assigned under such Permitted Sublease assignment);]<F1>

            [(3)/(4)]  All right,  title,  interest,  claims and  demands of the
      Owner Trustee in, to and under:

            (a)   the Purchase Agreement and the GTA;

            (b)  the  Purchase  Agreement  Assignment,   with  the  Consent  and
Agreement and the Engine Consent and Agreement attached thereto;

            (c)   the Bills of Sale; and

            (d) any and all other contracts, agreements and instruments relating
to the  Airframe  and  Engines or any rights or  interests  therein to which the
Owner Trustee is now or may hereafter be a party;

            together with all rights, powers, privileges,  licenses,  easements,
      options  and other  benefits  of the Owner  Trustee  under each  contract,
      agreement and instrument  referred to in this clause [(3)/(4)],  including
      the right to  receive  and  collect  all  payments  to the  Owner  Trustee
      thereunder now or hereafter  payable to or receivable by the Owner Trustee
      pursuant  thereto and,  subject to Section 5.02 hereof,  the right to make
      all  waivers  and  agreements,  to give  and  receive  notices  and  other
      instruments  or  communications,  or to take any other  action under or in

--------------------
<F1>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<PAGE>

      respect of any  thereof or to take such action  upon the  occurrence  of a
      default thereunder,  including the commencement,  conduct and consummation
      of  legal,  administrative  or other  proceedings,  as shall be  permitted
      thereby  or by Law,  and to do any and all  other  things  which the Owner
      Trustee  is or  may  be  entitled  to  do  thereunder  and  any  right  to
      restitution from the Lessee,  the Owner Participant or any other Person in
      respect of any determination of invalidity of any thereof;

            [(4)/(5)] All rents, issues,  profits,  revenues and other income of
      the  property  subjected  or required to be  subjected to the Lien of this
      Trust  Indenture,  including all payments or proceeds payable to the Owner
      Trustee after termination of the Lease with respect to the Aircraft as the
      result of the sale, lease or other  disposition  thereof,  and all estate,
      right,  title and interest of every nature whatsoever of the Owner Trustee
      in and to the same;

            [(5)/(6)]  Without  limiting the  generality of the  foregoing,  all
      insurance  and  requisition  proceeds  with respect to the Aircraft or any
      part thereof,  including the  insurance  required  under Section 11 of the
      Lease;

            [(6)/(7)]  Without  limiting the  generality of the  foregoing,  all
      rights of the Owner  Trustee to  amounts  paid or payable by Lessee to the
      Owner  Trustee  under the  Participation  Agreement  and all rights of the
      Owner Trustee to enforce payments of any such amounts thereunder;

            [(7)/(8)]  Without  limiting the  generality of the  foregoing,  all
      monies  and  securities  from time to time  deposited  or  required  to be
      deposited with the Mortgagee pursuant to any terms of this Trust Indenture
      or the  Lease  or  required  hereby  or by the  Lease  to be  held  by the
      Mortgagee  hereunder as security for the  obligations  of the Lessee under
      the Lease or of the Owner Trustee hereunder; and

            [(8)/(9)] All proceeds of the foregoing;  excluding, however, in all
      events from each of foregoing clauses (1) through [(8)/(9)]  inclusive all
      Excluded Payments and the right to specifically enforce the same or to sue
      for damages for the breach thereof as provided in Section 5.02 hereof.

            Concurrently  with the delivery of this Trust  Indenture,  the Owner
Trustee will deliver to the Mortgagee the original  executed  counterpart of the
Lease and the Lease  Supplement  No. 1 (to each of which a chattel paper receipt
is attached),  and executed copies of the Participation  Agreement, the Purchase
Agreement  and the  GTA  (to  the  extent  assigned  by the  Purchase  Agreement
Assignment),  the Purchase Agreement Assignment,  with the Consent and Agreement
and the Engine Consent and Agreement attached thereto.

            TO HAVE AND TO HOLD all and singular the aforesaid property unto the
Mortgagee,  and  its  successors  and  assigns,  in  trust  for  the  equal  and
proportionate  benefit and security of the Loan  Participants,  the Note Holders
and the other holders of Secured Obligations, except as provided in Section 2.14

<PAGE>

and Article III hereof  without any  preference,  distinction or priority of any
one Equipment Note over any other by reason of priority of time of issue,  sale,
negotiation,  date of maturity  thereof or otherwise for any reason  whatsoever,
and for the uses and purposes and in all cases and as to all property  specified
in clauses  (1)  through  [(8)/(9)]  inclusive  above,  subject to the terms and
provisions set forth in this Trust Indenture.

            It is  expressly  agreed  that  anything  herein  contained  to  the
contrary  notwithstanding,  the Owner  Trustee  shall  remain  liable  under the
Indenture  Agreements,   to  perform  all  of  the  obligations  assumed  by  it
thereunder,  except to the extent  prohibited or excluded from doing so pursuant
to the terms and provisions thereof,  and the Mortgagee,  the Loan Participants,
the Note  Holders  and the other  holders of Secured  Obligations  shall have no
obligation or liability under the Indenture Agreements,  by reason of or arising
out of the assignment hereunder, nor shall the Mortgagee, the Loan Participants,
the Note  Holders or the other  holders of Secured  Obligations  be  required or
obligated  in any  manner to perform or  fulfill  any  obligations  of the Owner
Trustee  under or pursuant to the  Indenture  Agreements,  or,  except as herein
expressly provided, to make any payment, or to make any inquiry as to the nature
or sufficiency of any payment  received by it, or present or file any claim,  or
take any action to collect or enforce the payment of any amounts  which may have
been assigned to it or to which it may be entitled at any time or times.

            The Owner Trustee does hereby  constitute the Mortgagee the true and
lawful attorney of the Owner Trustee, irrevocably, granted for good and valuable
consideration  and coupled with an interest and with full power of substitution,
and with full power (in the name of the Owner  Trustee or otherwise) to ask for,
require,  demand, receive,  compound and give acquittance for any and all monies
and claims for monies (in each case including insurance and requisition proceeds
but in all cases  excluding  Excluded  Payments)  due and to become due under or
arising out of the Indenture  Agreements,  and all other  property  which now or
hereafter  constitutes part of the Trust Indenture Estate, to endorse any checks
or other instruments or orders in connection therewith and to file any claims or
to take any action or to institute any proceedings  which the Mortgagee may deem
to be necessary or advisable in the premises. Without limiting the generality of
the  foregoing,  but  subject to the rights of the Owner  Trustee  and the Owner
Participant under Sections 2.13, 4.03 and 4.04(a) hereof, during the continuance
of any Event of Default under this Trust Indenture, the Mortgagee shall have the
right under such power of attorney  to accept any offer in  connection  with the
exercise of  remedies  as set forth  herein of any  purchaser  to  purchase  the
Airframe  and Engines and upon such  purchase to execute and deliver in the name
of and on behalf  of the Owner  Trustee  an  appropriate  bill of sale and other
instruments of transfer relating to the Airframe and Engines,  when purchased by
such  purchaser,  and to perform all other  necessary or  appropriate  acts with
respect to any such  purchase,  and in its  discretion to file any claim or take
any other  action or  proceedings,  either in its own name or in the name of the
Owner  Trustee  or  otherwise,   which  the  Mortgagee  may  deem  necessary  or
appropriate  to protect  and  preserve  the  right,  title and  interest  of the
Mortgagee  in and to such Rents and other sums and the  security  intended to be
afforded hereby; provided,  however, that no action of the Mortgagee pursuant to
this  paragraph  shall  increase the  obligations  or  liabilities  of the Owner
Trustee to any Person beyond those obligations and liabilities  specifically set
forth in this Trust Indenture and in the other Operative  Agreements.  Under the
Lease,  Lessee is directed,  so long as this Trust Indenture shall not have been
fully  discharged,  to make all payments of Rent (other than Excluded  Payments)
and all other  amounts  which are required to be paid to or  deposited  with the

<PAGE>

Owner Trustee pursuant to the Lease (other than Excluded  Payments) directly to,
or as directed by, the  Mortgagee at such address or addresses as the  Mortgagee
shall specify,  for application as provided in this Trust  Indenture.  The Owner
Trustee  agrees that  promptly  upon receipt  thereof,  it will  transfer to the
Mortgagee any and all monies from time to time received by it constituting  part
of the Trust Indenture  Estate,  for  distribution by the Mortgagee  pursuant to
this  Trust   Indenture,   except  that  the  Owner  Trustee  shall  accept  for
distribution  pursuant to the Trust  Agreement any amounts  distributed to it by
the Mortgagee under this Trust Indenture.

            The  Owner  Trustee  agrees  that at any time and from time to time,
upon the written  request of the Mortgagee,  the Owner Trustee will promptly and
duly execute and deliver or cause to be duly  executed and delivered any and all
such further  instruments  and documents as the Mortgagee  may  reasonably  deem
necessary or desirable to perfect,  preserve or protect the  mortgage,  security
interests and assignments  created or intended to be created hereby or to obtain
for the  Mortgagee  the full  benefits of the  assignment  hereunder  and of the
rights and powers herein granted.

            The Owner Trustee does hereby  warrant and represent that it has not
assigned or pledged,  and hereby covenants and agrees that it will not assign or
pledge, so long as the assignment hereunder shall remain in effect, and the Lien
hereof shall not have been released pursuant to Section 10.01 hereof, any of its
right,  title or interest hereby  assigned,  to anyone other than the Mortgagee,
and that it will not,  except as otherwise  provided in this Trust Indenture and
except with respect to Excluded Payments to which it is entitled, (i) accept any
payment  from  Lessee  [or any  Permitted  Sublessee]<F2>  under  any  Indenture
Agreement, (ii) enter into any agreement amending or supplementing any Indenture
Agreement,  (iii) execute any waiver or modification  of, or consent under,  the
terms of, or exercise any rights,  powers or  privileges  under,  any  Indenture
Agreement,  (iv) settle or  compromise  any claim  arising  under any  Indenture
Agreement or (v) submit or consent to the submission of any dispute,  difference
or other  matter  arising  under or in respect  of any  Indenture  Agreement  to
arbitration thereunder.

            The Owner  Trustee  does  hereby  agree that it will not without the
written consent of the Mortgagee:

            (a) receive or collect or agree to the receipt or  collection of any
payment (other than Excluded Payments) of Rent, including Basic Rent, Stipulated
Loss  Value,  Termination  Value or any other  payment  to be made  pursuant  to
Section 9 or 10 of the Lease prior to the date for the payment thereof  provided
for by the Lease or assign, transfer or hypothecate (other than to the Mortgagee
hereunder) any payment of Rent (other than Excluded  Payments),  including Basic

--------------------
<F2>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<PAGE>

Rent,  Stipulated Loss Value,  Termination Value or any other payment to be made
pursuant  to Section 9 or 10 of the  Lease,  then due or to accrue in the future
under the Lease in respect of the Airframe and Engines; or

            (b) except as contemplated by the Trust Agreement in connection with
the appointment of a successor owner trustee, sell, mortgage,  transfer,  assign
or  hypothecate  (other than to the  Mortgagee  hereunder)  its  interest in the
Airframe  and Engines or any part  thereof or in any amount to be received by it
from the use or  disposition  of the Airframe  and  Engines,  other than amounts
distributed to it pursuant to Article III hereof.

            It is hereby further  agreed that any and all property  described or
referred to in the granting  clauses  hereof which is hereafter  acquired by the
Owner Trustee shall ipso facto, and without any other conveyance,  assignment or
act on the part of the Owner Trustee or the Mortgagee,  become and be subject to
the Lien herein granted as fully and completely as though specifically described
herein,  but nothing  contained in this  paragraph  shall be deemed to modify or
change  the  obligations  of  the  Owner  Trustee  contained  in  the  foregoing
paragraphs.

            The Owner  Trustee does hereby ratify and confirm the Lease and does
hereby  agree that it will not violate  any  covenant  or  agreement  made by it
therein, herein or in any other Owner Trustee Agreement.

            Notwithstanding   the  Granting  Clause  or  any  of  the  preceding
paragraphs,  there  is  hereby  excluded  from  the  foregoing  sale,  transfer,
assignment,  grant, pledge and security interest all Excluded Payments. Further,
nothing in the Granting Clause or the preceding  paragraphs  shall impair any of
the rights of the Owner  Trustee or the Owner  Participant  under  Section 2.13,
4.03, 4.04, 4.08, 5.02 or 5.03 hereof.

            IT IS HEREBY COVENANTED AND AGREED by and between the parties hereto
as follows:

                                    ARTICLE I

                                   DEFINITIONS

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

<PAGE>

                                   ARTICLE II

                               THE EQUIPMENT NOTES

      SECTION 2.01.     FORM OF EQUIPMENT NOTES.

            The  Equipment  Notes shall be  substantially  in the form set forth
below:

            THIS  EQUIPMENT  NOTE  HAS  NOT  BEEN  REGISTERED  PURSUANT  TO  THE
SECURITIES  ACT OF 1933, AS AMENDED (THE "ACT"),  OR PURSUANT TO THE  SECURITIES
LAWS OF ANY  STATE.  ACCORDINGLY,  THIS  EQUIPMENT  NOTE MAY NOT BE SOLD  UNLESS
EITHER  REGISTERED  UNDER THE ACT AND SUCH APPLICABLE STATE LAWS OR AN EXEMPTION
FROM SUCH REGISTRATIONS IS AVAILABLE.

            FIRST SECURITY BANK,  NATIONAL  ASSOCIATION,  AS OWNER TRUSTEE UNDER
TRUST  AGREEMENT  [___] DATED AS OF  [_______________,  20___].  SERIES  [_____]
LIMITED RECOURSE  EQUIPMENT NOTE DUE [____] ISSUED IN CONNECTION WITH THE BOEING
MODEL [_______] AIRCRAFT BEARING UNITED STATES REGISTRATION NUMBER N[_____].

No. ____                                                     Date: [ __________,
                                                                         20___ ]

                               $__________________

       INTEREST RATE                                         MATURITY DATE

      [_____________]                                        [____________]

            FIRST SECURITY  BANK,  NATIONAL  ASSOCIATION,  not in its individual
capacity but solely as Owner Trustee  (herein in such capacity called the "Owner
Trustee") under that certain Trust Agreement [___],  dated as of  [____________,
20___],  between the Owner  Participant  named therein and First  Security Bank,
National  Association  (herein as such Trust  Agreement may be  supplemented  or
amended from time to time called the "Trust Agreement"),  hereby promises to pay
to __________________,  or the registered assignee thereof, the principal sum of
$____________ (the "Original  Amount"),  together with interest on the amount of
the Original Amount  remaining unpaid from time to time (calculated on the basis
of a year of 360 days  comprised of twelve  30-day  months) from the date hereof
until  paid in full at a rate per annum  equal to the Debt  Rate.  The  Original
Amount of this Equipment Note shall be [payable in installments on the dates set
forth in Schedule I hereto equal to the corresponding percentage of the Original
Amount of this Equipment Note set forth in Schedule I hereto.]<F3> [paid in full

--------------------
<F3>
Not included in Series A-2 or Series C-2 Equipment Notes.

<PAGE>

on  ____________.]<F4>  Accrued but unpaid  interest shall be due and payable in
semiannual installments commencing on [_____________,  20___], and thereafter on
[_______]  and  [_______]  of each  year,  to and  including  [_______________].
Notwithstanding  the  foregoing,  the final payment made on this  Equipment Note
shall be in an amount sufficient to discharge in full the unpaid Original Amount
and all accrued and unpaid  interest on, and any other  amounts due under,  this
Equipment Note.  Notwithstanding  anything to the contrary  contained herein, if
any date on which a payment under this Equipment Note becomes due and payable is
not a Business Day, then such payment shall not be made on such  scheduled  date
but shall be made on the next  succeeding  Business  Day and if such  payment is
made on such next  succeeding  Business  Day,  no interest  shall  accrue on the
amount of such payment during such extension.

            For  purposes  hereof,  the term "Trust  Indenture"  means the Trust
Indenture and Mortgage [___],  dated as of [_____________,  20___],  between the
Owner Trustee and Wilmington Trust Company (the "Mortgagee"), as the same may be
amended or supplemented  from time to time. All other  capitalized terms used in
this Equipment  Note and not defined  herein shall have the respective  meanings
assigned in the Trust Indenture.

            This Equipment Note shall bear interest,  payable on demand,  at the
Payment Due Rate  (calculated  on the basis of a year of 360 days  comprised  of
twelve 30-day months) on any overdue  Original  Amount,  any overdue  Make-Whole
Amount,  if any,  and (to the extent  permitted by  applicable  Law) any overdue
interest and any other amounts payable hereunder which are overdue, in each case
for the period the same is  overdue.  Amounts  shall be overdue if not paid when
due (whether at stated maturity, by acceleration or otherwise).

            All payments of Original Amount,  interest,  Make-Whole  Amount,  if
any, and other  amounts,  if any, to be made by the Owner Trustee  hereunder and
under the Trust Indenture or the  Participation  Agreement shall be payable only
from the income and proceeds from the Trust Estate to the extent included in the
Trust Indenture  Estate and only to the extent that the Owner Trustee shall have
sufficient  income or proceeds  from the Trust Estate to the extent  included in
the Trust  Indenture  Estate to enable the  Mortgagee  to make such  payments in
accordance  with  the  terms  of  Section  2.03  and  Article  III of the  Trust
Indenture,  and each holder hereof,  by its  acceptance of this Equipment  Note,
agrees  that it will  look  solely to the  income  and  proceeds  from the Trust
Indenture  Estate to the extent  available for distribution to the holder hereof
as above provided and that none of the Owner Participant,  the Owner Trustee and
the  Mortgagee  is  personally  liable or liable in any manner  extending to any
assets  other  than the Trust  Indenture  Estate to the  holder  hereof  for any
amounts  payable  or any  liability  under  this  Equipment  Note or,  except as
provided  in the Trust  Indenture  or in the  Participation  Agreement,  for any
liability under the Trust Indenture or the  Participation  Agreement;  provided,
however, that nothing herein contained shall limit, restrict or impair the right
of the  Mortgagee,  subject  always  to the terms  and  provisions  of the Trust
Indenture,  to accelerate the maturity of this Equipment Note upon occurrence of

--------------------
<F4>
To be inserted in the case of a Series A-2 and Series C-2 Equipment Note.

<PAGE>

an Event of Default under the Trust Indenture in accordance with Section 4.04(b)
of the Trust  Indenture,  to bring suit and obtain a judgment  against the Owner
Trustee  on this  Equipment  Note for  purposes  of  realizing  upon  the  Trust
Indenture  Estate and to exercise  all rights and  remedies  provided  under the
Trust Indenture or otherwise realize upon the Trust Indenture Estate as provided
under the Trust Indenture.

            There shall be maintained an Equipment Note Register for the purpose
of registering transfers and exchanges of Equipment Notes at the Corporate Trust
Office of the Mortgagee or at the office of any successor in the manner provided
in Section 2.07 of the Trust Indenture.

            The Original  Amount and interest  and other  amounts due  hereunder
shall be  payable in Dollars in  immediately  available  funds at the  Corporate
Trust Office of the Mortgagee,  or as otherwise provided in the Trust Indenture.
Each such payment  shall be made on the date such payment is due and without any
presentment or surrender of this Equipment Note,  except that in the case of any
final payment with respect to this  Equipment  Note, the Equipment Note shall be
surrendered promptly thereafter to the Mortgagee for cancellation.

            The holder hereof,  by its acceptance of this Equipment Note, agrees
that,  except as provided in the Trust  Indenture,  each payment of the Original
Amount,  Make-Whole  Amount, if any, and interest received by it hereunder shall
be applied, first, to the payment of accrued interest on this Equipment Note (as
well as any  interest on any overdue  Original  Amount,  any overdue  Make-Whole
Amount,  if any, or, to the extent  permitted  by Law, any overdue  interest and
other amounts hereunder) to the date of such payment,  second, to the payment of
the Original  Amount of this Equipment Note then due,  third,  to the payment of
Make-Whole Amount, if any, and any other amount due hereunder or under the Trust
Indenture, and fourth, the balance, if any, remaining thereafter, to the payment
of installments  of the Original Amount of this Equipment Note remaining  unpaid
in the inverse order of their maturity.

            This Equipment Note is one of the Equipment Notes referred to in the
Trust  Indenture  which  have  been or are to be  issued  by the  Owner  Trustee
pursuant to the terms of the Trust Indenture. The Trust Indenture Estate is held
by the Mortgagee as security,  in part, for the Equipment  Notes. The provisions
of this Equipment Note are subject to the Trust  Indenture.  Reference is hereby
made  to  the  Trust  Indenture  for a  complete  statement  of the  rights  and
obligations  of the holder of,  and the nature and extent of the  security  for,
this  Equipment  Note and the rights and  obligations of the holders of, and the
nature and extent of the security for, any other  Equipment  Notes  executed and
delivered under the Trust Indenture, as well as for a statement of the terms and
conditions  of the Trust created by the Trust  Indenture,  to all of which terms
and  conditions  in  the  Trust  Indenture  each  holder  hereof  agrees  by its
acceptance of this Equipment Note.

            As  provided  in  the  Trust   Indenture   and  subject  to  certain
limitations  therein set forth,  this Equipment Note is exchangeable  for a like
aggregate   Original   Amount  of  Equipment   Notes  of  different   authorized
denominations, as requested by the holder surrendering the same.

<PAGE>

            Prior  to due  presentment  for  registration  of  transfer  of this
Equipment  Note,  the Owner Trustee and the Mortgagee  shall treat the person in
whose  name  this  Equipment  Note is  registered  as the owner  hereof  for all
purposes,  whether or not this Equipment Note be overdue,  and neither the Owner
Trustee nor the Mortgagee shall be affected by notice to the contrary.

            This Equipment Note is subject to redemption as provided in Sections
2.10,  2.11 and 2.12 of the Trust  Indenture but not  otherwise.  This Equipment
Note is also subject to exchange and to purchase by the Owner Participant or the
Owner  Trustee  as  provided  in  Section  2.13 of the Trust  Indenture  but not
otherwise.  In addition,  this  Equipment Note may be accelerated as provided in
Section 4.04 of the Trust Indenture.

            [The indebtedness evidenced by this Equipment Note is, to the extent
and in the manner  provided in the Trust  Indenture,  subordinate and subject in
right of payment to the prior  payment in full of the  Secured  Obligations  (as
defined  in the Trust  Indenture)  in  respect  of  [Series  A-1 and  Series A-2
Equipment  Notes]<F5> [Series A-1, Series A-2 and Series B Equipment  Notes]<F6>
[Series  A-1,  Series  A-2,  Series  B,  Series  C-1 and  Series  C-2  Equipment
Notes],<F7>  and this Equipment Note is issued subject to such  provisions.  The
Note Holder of this  Equipment  Note, by accepting  the same,  (a) agrees to and
shall be bound by such  provisions,  (b) authorizes and directs the Mortgagee on
his behalf to take such action as may be necessary or  appropriate to effectuate
the  subordination  as  provided in the Trust  Indenture  and (c)  appoints  the
Mortgagee his attorney-in-fact for such purpose.]<F8>

            Unless the certificate of authentication hereon has been executed by
or on behalf of the Mortgagee by manual signature, this Equipment Note shall not
be entitled to any benefit  under the Trust  Indenture or be valid or obligatory
for any purpose.

            THIS EQUIPMENT NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE
WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK.

                                    * * *
--------------------
<F5>
To be inserted in the case of a Series B Equipment Note.

<F6>
To be inserted in the case of a Series C-1 and Series C-2 Equipment  Note.

<F7>
To be inserted in the case of a Series D Equipment Note.

<F8>
To be inserted for each  Equipment  Note other than any Series A-1 or Series A-2
Equipment Note.

<PAGE>

            IN WITNESS WHEREOF, the Owner Trustee has caused this Equipment Note
to be executed in its corporate name by its officer thereunto duly authorized on
the date hereof.

                                          FIRST SECURITY BANK, NATIONAL
                                          ASSOCIATION,
                                              not in its individual capacity
                                              but solely as Owner Trustee

                                          By:_______________________________
                                                Name:
                                                Title:

<PAGE>

                  MORTGAGEE'S CERTIFICATE OF AUTHENTICATION

            This   is  one  of  the   Equipment   Notes   referred   to  in  the
within-mentioned Trust Indenture.

                                          WILMINGTON TRUST COMPANY, as
                                          Mortgagee

                                          By__________________________________
                                                Name:
                                                Title:

                                 SCHEDULE I<F9>

                           EQUIPMENT NOTE AMORTIZATION

                                                      Percentage of
                                                     Original Amount
              Payment Date                             to be Paid
____________________________________   _________________________________________

                       [SEE SCHEDULE I TO TRUST INDENTURE

                        WHICH IS INSERTED UPON ISSUANCE]

                                    * * *

      SECTION 2.02.     ISSUANCE AND TERMS OF EQUIPMENT NOTES.

            The  Equipment  Notes shall be dated the date of  issuance  thereof,
shall be issued in up to six separate  series  consisting of Series A-1,  Series
A-2,  Series B, Series C-1,  Series C-2 and Series D and in the  maturities  and

--------------------
<F9>
Not included in Series A-2 or Series C-2 Equipment Notes.

<PAGE>

principal  amounts and shall bear interest as specified in Schedule I hereto. On
the date of the  consummation of the  Transaction,  each Equipment Note shall be
issued  to the  Subordination  Agent on behalf of the  Applicable  Pass  Through
Trustees under the Applicable Pass Through Trust Agreements. The Equipment Notes
shall be issued in registered  form only. The Equipment Notes shall be issued in
denominations  of  $1,000  and  integral  multiples  thereof,  except  that  one
Equipment  Note of  each  Series  may be in an  amount  that is not an  integral
multiple of $1,000.

            Each Equipment Note shall bear interest at the Debt Rate (calculated
on the basis of a year of 360 days  comprised  of twelve  30-day  months) on the
unpaid Original Amount thereof from time to time outstanding, payable in arrears
on [_____________,  20___], and on each [_______] and [_______] thereafter until
maturity.  The  Original  Amount  of  each  Equipment  Note  (i) in the  case of
Equipment Notes other than Series A-2 and Series C-2 Equipment  Notes,  shall be
payable  on the  dates  and  in  the  installments  equal  to the  corresponding
percentage of the Original  Amount as set forth in Schedule I hereto which shall
be attached as Schedule I to such  Equipment  Notes,  (ii) in the case of Series
A-2  Equipment  Notes,  shall be payable in full on May 1, 2010 and (iii) in the
case of Series  C-2  Equipment  Notes,  shall be payable in full on May 1, 2005.
Notwithstanding the foregoing,  the final payment made under each Equipment Note
shall be in an amount sufficient to discharge in full the unpaid Original Amount
and all accrued and unpaid  interest on, and any other  amounts due under,  such
Equipment  Note. Each Equipment Note shall bear interest at the Payment Due Rate
(calculated  on the  basis  of a year of 360 days  comprised  of  twelve  30-day
months) on any part of the Original Amount,  Make-Whole  Amount, if any, and, to
the extent  permitted by applicable Law,  interest and any other amounts payable
thereunder  not paid when due for any  period  during  which  the same  shall be
overdue,  in each case for the  period  the same is  overdue.  Amounts  shall be
overdue if not paid when due (whether at stated  maturity,  by  acceleration  or
otherwise).  Notwithstanding  anything to the contrary  contained herein, if any
date on which a payment under any Equipment  Note becomes due and payable is not
a Business Day then such payment  shall not be made on such  scheduled  date but
shall be made on the next succeeding Business Day and if such payment is made on
such next  succeeding  Business  Day, no interest  shall accrue on the amount of
such payment during such extension.

            The Owner Trustee agrees to pay to the Mortgagee for distribution in
accordance with Section 3.04 hereof: (i) any and all indemnity amounts which are
payable  by the  Lessee  to (x) WTC and the  Mortgagee,  (y)  each  separate  or
additional  Trustee  appointed  pursuant to the Trust Indenture and (z) the Pass
Through Indemnitees pursuant to Section 9 of the Participation  Agreement;  (ii)
to the extent not payable  (whether or not in fact paid) under  Section  6(a) of
the Note Purchase Agreement (as originally in effect or amended with the consent
of the Owner Participant),  an amount equal to the fees payable to the Liquidity
Provider  under  Section  2.03 of each  Liquidity  Facility  and the related Fee
Letter (as defined in the Intercreditor  Agreement) multiplied by a fraction the
numerator of which shall be the then outstanding  aggregate  principal amount of
the Series A-1 Equipment Notes,  Series A-2 Equipment Notes,  Series B Equipment
Notes,  Series  C-1  Equipment  Notes and  Series  C-2  Equipment  Notes and the
denominator of which shall be the then outstanding aggregate principal amount of
all "Series  A-1  Equipment  Notes",  "Series A-2  Equipment  Notes",  "Series B
Equipment Notes",  "Series C-1 Equipment Notes" and "Series C-2 Equipment Notes"
(each as defined in the Note Purchase Agreement);  (iii) (x) the amount equal to

<PAGE>

interest on any Downgrade  Advance  (other than any Applied  Downgrade  Advance)
payable under Section 3.07 of each Liquidity Facility minus Investment  Earnings
from such  Downgrade  Advance  multiplied  by (y) the fraction  specified in the
foregoing   clause  (ii);   (iv)  (x)  the  amount  equal  to  interest  on  any
Non-Extension  Advance (other than any Applied  Non-Extension  Advance)  payable
under Section 3.07 of each  Liquidity  Facility minus  Investment  Earnings from
such  Non-Extension  Advance  multiplied  by (y) the  fraction  specified in the
foregoing  clause (ii);  (v) any amounts owed to the Liquidity  Providers by the
Subordination  Agent as borrower  under the second  sentence of Section  7.05 of
each Liquidity Facility (other than as a result of any "prohibited  transaction"
within the meaning of Section 406 of the Employee Retirement Income Security Act
of 1974, as amended, or Section 4975(c)(1) of the Internal Revenue Code of 1986,
as amended)  multiplied by the fraction  specified in the foregoing clause (ii);
and (vi) if any payment  default  shall have  occurred  and be  continuing  with
respect to  interest on any Series A-1  Equipment  Notes,  Series A-2  Equipment
Notes,  Series B  Equipment  Notes,  Series  C-1  Equipment  Notes or Series C-2
Equipment Notes, (x) the excess,  if any, of (1) the amount equal to interest on
any Unpaid Advance,  Applied Downgrade Advance or Applied  Non-Extension Advance
payable  under  Section  3.07 of each  Liquidity  Facility  OVER  (2) the sum of
Investment  Earnings  from any Final  Advance plus any amount of interest at the
Payment  Due Rate  actually  payable  (whether or not in fact paid) by the Owner
Trustee on the overdue  scheduled  interest on the Equipment Notes in respect of
which such Unpaid Advance,  Applied Downgrade  Advance or Applied  Non-Extension
Advance was made,  multiplied  by (y) a fraction the numerator of which shall be
the then  aggregate  overdue  amounts of  interest  on the Series A-1  Equipment
Notes,  Series  A-2  Equipment  Notes,  Series B  Equipment  Notes,  Series  C-1
Equipment Notes and Series C-2 Equipment Notes (other than interest becoming due
and payable solely as a result of acceleration of any such Equipment  Notes) and
the denominator of which shall be the then aggregate overdue amounts of interest
on all "Series A-1 Equipment  Notes",  "Series A-2 Equipment  Notes",  "Series B
Equipment  Notes",  Series C-1 Equipment Notes and "Series C-2 Equipment  Notes"
(each as defined in the Note Purchase  Agreement)  (other than interest becoming
due and  payable  solely  as a result  of  acceleration  of any such  "Equipment
Notes"). For purposes of this paragraph,  the terms "Applied Downgrade Advance",
"Applied Non-Extension Advance", "Cash Collateral Account", "Downgrade Advance",
"Final  Advance",  "Investment  Earnings",  "Non-Extension  Advance" and "Unpaid
Advance"  shall have the meanings  specified in each  Liquidity  Facility or the
Intercreditor Agreement referred to therein.

            The Equipment Notes shall be executed on behalf of the Owner Trustee
by its President or one of its Vice  Presidents,  Assistant  Vice  Presidents or
Assistant  Secretaries or other authorized officer.  Equipment Notes bearing the
signatures of individuals  who were at any time the proper officers of the Owner
Trustee shall bind the Owner Trustee,  notwithstanding  that such individuals or
any of them have ceased to hold such  offices  prior to the  authentication  and
delivery of such Equipment  Notes or did not hold such offices at the respective
dates of such Equipment  Notes.  The Owner Trustee may from time to time execute
and deliver  Equipment  Notes with respect to the Aircraft to the  Mortgagee for
authentication  upon original issue and such Equipment  Notes shall thereupon be
authenticated  and  delivered by the Mortgagee  upon the written  request of the
Owner Trustee  signed by a Vice  President or Assistant  Vice President or other
authorized  officer  of the Owner  Trustee;  PROVIDED,  HOWEVER,  that each such

<PAGE>

request shall specify the aggregate Original Amount of all Equipment Notes to be
authenticated  hereunder  on original  issue with  respect to the  Aircraft.  No
Equipment  Note shall be secured by or entitled to any benefit  under this Trust
Indenture or be valid or obligatory  for any  purposes,  unless there appears on
such  Equipment Note a certificate  of  authentication  in the form provided for
herein  executed  by  the  Mortgagee  by  the  manual  signature  of  one of its
authorized  officers and such certificate upon any Equipment Notes be conclusive
evidence,  and the only  evidence,  that  such  Equipment  Note  has  been  duly
authenticated and delivered hereunder.

            The  aggregate   Original  Amount  of  the  Equipment  Notes  issued
hereunder shall not exceed [__]% of Lessor's Cost.

      SECTION 2.03.     PAYMENTS FROM TRUST INDENTURE ESTATE ONLY.

           (a)  Without  impairing  any of the other rights,  powers,  remedies,
privileges,  liens or security  interests of the Note  Holders  under this Trust
Indenture, each Note Holder, by its acceptance of an Equipment Note, agrees that
as between it and the Owner Trustee,  except as expressly provided in this Trust
Indenture, the Participation Agreement or any other Operative Agreement, (i) the
obligation  to make  all  payments  of the  Original  Amount  of,  interest  on,
Make-Whole  Amount,  if any,  and all  other  amounts  due with  respect  to the
Equipment Notes, and the performance by the Owner Trustee of every obligation or
covenant contained in this Trust Indenture and in the Participation Agreement or
any of the other Operative Agreements, shall be payable only from the income and
proceeds  from the Trust  Estate to the extent  included in the Trust  Indenture
Estate  and only to the extent  that the Owner  Trustee  shall  have  sufficient
income or  proceeds  from the Trust  Estate to the extent  included in the Trust
Indenture  Estate to enable the  Mortgagee to make such  payments in  accordance
with  the  terms  of   Article   III   hereof,   and  all  of  the   statements,
representations,  covenants and agreements  made by the Owner Trustee (when made
in such capacity)  contained in this Trust Indenture and any agreement  referred
to herein other than the Trust Agreement, unless expressly otherwise stated, are
made and  intended  only  for the  purpose  of  binding  the  Trust  Estate  and
establishing  the  existence of rights and remedies  which can be exercised  and
enforced against the Trust Estate;  therefore,  anything contained in this Trust
Indenture or such other agreements to the contrary  notwithstanding  (except for
any express provisions or representations  that the Owner Trustee is responsible
for, or is making, in its individual capacity, for which there would be personal
liability of the Owner  Trustee),  no recourse shall be had with respect to this
Trust  Indenture  or such  other  agreements  against  the Owner  Trustee in its
individual  capacity  or  against  any  institution  or person  which  becomes a
successor trustee or co-trustee or any officer,  director,  trustee,  servant or
direct or indirect  parent or controlling  Person or Persons of any of them, and
(ii)  none  of  the  Owner  Trustee,  in  its  individual  capacity,  the  Owner
Participant,   the  Mortgagee  and  any  officer,  director,  trustee,  servant,
employee, agent or direct or indirect parent or controlling Person or Persons of
any of them shall have any personal liability for any amounts payable hereunder,
under the  Participation  Agreement or any of the other Operative  Agreements or
under the Equipment Notes except as expressly  provided herein,  in the Lease or
in the Participation  Agreement;  provided,  however,  that nothing contained in
this Section 2.03(a) shall be construed to limit the exercise and enforcement in
accordance  with the terms of this Trust  Indenture or such other  agreements of
rights and remedies against the Trust Indenture Estate. These provisions are not
intended as any release or  discharge  of the  indebtedness  represented  by the
Equipment Notes and the Trust Indenture, but are intended only as a covenant not

<PAGE>

to sue the  Owner  Participant,  the Owner  Trustee  or the  Mortgagee  in their
individual   capacities,   except  as  expressly   provided  herein  or  in  the
Participation Agreement, for a deficiency with respect to such indebtedness, the
indebtedness  represented  by this Trust  Indenture and the  Equipment  Notes to
remain in full force and  effect as fully as though  these  provisions  were not
contained in this Trust Indenture.  The Owner Trustee hereby  acknowledges  that
the Note Holders have expressly  reserved all their rights and remedies  against
the Trust  Indenture  Estate,  including the right, in the event of a default in
the payment of all or part of the Original  Amount of,  interest on,  Make-Whole
Amount,  if any,  or any other  amount due with  respect to any  Equipment  Note
within  the  periods  provided  for in  Section  4.02(b)  hereof,  or  upon  the
occurrence  and  continuation  of any other  Event of  Default  under this Trust
Indenture,  to  foreclose  upon this  Trust  Indenture,  and/or to  receive  the
proceeds  from the Trust  Indenture  Estate and  otherwise  to enforce any other
right under this Trust  Indenture.  Nothing in this  Section  2.03(a)  shall (x)
release the Owner Participant from personal liability,  or constitute a covenant
not to sue the Owner Participant,  for any breach by it of any of its covenants,
representations  or warranties  contained in the Participation  Agreement or for
any  of the  payments  it has  agreed  to  make  pursuant  to the  Participation
Agreement or (y) release the Owner  Trustee or  constitute a covenant not to sue
the Owner  Trustee for any breach by it of any  representations,  warranties  or
covenants of the Owner  Trustee  contained in the  Operative  Agreements  or (z)
release the Owner Trustee in its individual capacity from personal liability, or
constitute a covenant not to sue the Owner  Trustee in its  individual  capacity
for any breach by it of any  representations,  warranties  or  covenants  of the
Owner Trustee made in its individual capacity in the Operative Agreements.

            (b) If (i) all or any part of the Trust Estate  becomes the property
of, or the Owner Trustee or Owner Participant  becomes,  a debtor subject to the
reorganization  provisions  of  the  Bankruptcy  Code,  (ii)  pursuant  to  such
reorganization provisions, including Section 1111(b) of the Bankruptcy Code, the
Owner Trustee (in its individual capacity) or the Owner Participant is required,
by  reason  of the  Owner  Trustee  (in its  individual  capacity)  or the Owner
Participant  being held to have  recourse  liability  to any Note  Holder or the
Mortgagee,  directly or  indirectly  (other than the  recourse  liability of the
Owner Trustee (in its individual  capacity) or the Owner  Participant  under the
Participation  Agreement,  the  Lease or this  Trust  Indenture  or by  separate
agreement),  to make  payment on account  of any  amount  payable as  principal,
Make-Whole  Amount, if any, interest or other amounts on the Equipment Notes and
(iii) any Note Holder or the Mortgagee  actually  receives any Excess Amount (as
hereinafter  defined)  which  reflects any payment by the Owner  Trustee (in its
individual  capacity) or the Owner  Participant on account of clause (ii) above,
then  such Note  Holder or the  Mortgagee,  as the case may be,  shall  promptly
refund  to  the  Owner  Trustee  (in  its  individual  capacity)  or  the  Owner
Participant (whichever shall have made such payment) such Excess Amount.

            For  purposes of this Section  2.03(b),  "Excess  Amount"  means the
amount by which such payment exceeds the amount that would have been received by
a Note Holder or the Trustee if the Owner Trustee (in its  individual  capacity)
or the Owner  Participant  had not  become  subject  to the  recourse  liability
referred to in clause (ii) above.  Nothing  contained  in this  Section  2.03(b)
shall  prevent a Note  Holder  or the  Mortgagee  from  enforcing  any  personal
recourse  obligation  (and retaining the proceeds  thereof) of the Owner Trustee
(in its individual  capacity) or the Owner  Participant  under the Participation
Agreement, the Lease or this Trust Indenture (and any exhibits or annexes hereto

<PAGE>

or thereto) or from retaining any amount paid by Owner Participant under Section
2.13 or 4.03 hereof.

      SECTION 2.04.     METHOD OF PAYMENT.

            (a) The Original Amount of, interest on, Make-Whole  Amount, if any,
and other amounts due under each  Equipment Note or hereunder will be payable in
Dollars by wire  transfer of  immediately  available  funds not later than 12:30
p.m.,  New York City time,  on the due date of payment to the  Mortgagee  at the
Corporate  Trust  Office for  distribution  among the Note Holders in the manner
provided  herein.  The Owner Trustee shall not have any  responsibility  for the
distribution of such payment to any Note Holder.  Notwithstanding  the foregoing
or any provision in any Equipment  Note to the contrary,  the Mortgagee will use
reasonable  efforts to pay or cause to be paid, if so directed in writing by any
Note Holder  (with a copy to the Owner  Trustee),  all amounts paid by the Owner
Trustee  hereunder and under such holder's  Equipment Note or Equipment Notes to
such holder or a nominee therefor (including all amounts distributed pursuant to
Article  III  of  this  Trust  Indenture)  by  transferring,  or  causing  to be
transferred,  by wire transfer of immediately available funds in Dollars,  prior
to 2:00 p.m.,  New York City  time,  on the due date of  payment,  to an account
maintained by such holder with a bank located in the  continental  United States
the amount to be distributed  to such holder,  for credit to the account of such
holder  maintained at such bank.  If the  Mortgagee  shall fail to make any such
payment as provided in the immediately  foregoing  sentence after its receipt of
funds at the place and prior to the time specified above, the Mortgagee,  in its
individual  capacity and not as trustee,  agrees to compensate  such holders for
loss of use of  funds  at the  Debt  Rate  until  such  payment  is made and the
Mortgagee  shall be  entitled  to any  interest  earned on such funds until such
payment  is  made.  Any  payment  made  hereunder  shall  be  made  without  any
presentment or surrender of any Equipment Note,  except that, in the case of the
final payment in respect of any Equipment  Note,  such  Equipment  Note shall be
surrendered  to the  Mortgagee  for  cancellation  promptly  after such payment.
Notwithstanding any other provision of this Trust Indenture to the contrary, the
Mortgagee  shall not be required to make, or cause to be made, wire transfers as
aforesaid  prior to the first  Business Day on which it is  practicable  for the
Mortgagee  to do so in  view  of  the  time  of  day  when  the  funds  to be so
transferred  were received by it if such funds were  received  after 12:30 p.m.,
New York City time, at the place of payment.  Prior to the due  presentment  for
registration  of  transfer  of any  Equipment  Note,  the Owner  Trustee and the
Mortgagee  shall deem and treat the Person in whose name any  Equipment  Note is
registered  on the Equipment  Note Register as the absolute  owner and holder of
such Equipment Note for the purpose of receiving  payment of all amounts payable
with respect to such Equipment Note and for all other purposes,  and none of the
Owner Trustee or the Mortgagee  shall be affected by any notice to the contrary.
So long as any signatory to the Participation Agreement or nominee thereof shall
be a registered Note Holder,  all payments to it shall be made to the account of
such Note Holder  specified  in Schedule I thereto and  otherwise  in the manner
provided  in or  pursuant to the  Participation  Agreement  unless it shall have
specified  some other  account  or manner of payment by notice to the  Mortgagee
consistent with this Section 2.04.

            (b) The Mortgagee, as agent for the Owner Trustee, shall exclude and
withhold  at the  appropriate  rate from each  payment  of  Original  Amount of,
interest on, Make-Whole Amount, if any, and other amounts due hereunder or under

<PAGE>

each Equipment Note (and such exclusion and withholding shall constitute payment
in respect of such Equipment Note) any and all United States  withholding  taxes
applicable  thereto as  required  by Law.  The  Mortgagee  agrees to act as such
withholding agent and, in connection  therewith,  whenever any present or future
United States taxes or similar  charges are required to be withheld with respect
to any  amounts  payable  hereunder  or in respect of the  Equipment  Notes,  to
withhold  such amounts and timely pay the same to the  appropriate  authority in
the name of and on behalf of the Note  Holders,  that it will file any necessary
United  States  withholding  tax  returns or  statements  when due,  and that as
promptly as  possible  after the  payment  thereof it will  deliver to each Note
Holder (with a copy to the Owner  Trustee and the Lessee)  appropriate  receipts
showing the payment thereof,  together with such additional documentary evidence
as any such Note Holder may reasonably request from time to time.

            If a Note Holder  which is a Non-U.S.  Person has  furnished  to the
Mortgagee a properly  completed,  accurate and currently effective U.S. Internal
Revenue  Service  Form  1001 or W-8 (or such  successor  form or forms as may be
required by the United States Treasury  Department)  during the calendar year in
which the payment  hereunder or under the Equipment  Note(s) held by such holder
is made  (but  prior to the  making  of such  payment),  or in either of the two
preceding  calendar years,  and has not notified the Mortgagee of the withdrawal
or  inaccuracy of such form prior to the date of such payment (and the Mortgagee
has no  reason  to  believe  that any  information  set  forth  in such  form is
inaccurate),  the Mortgagee shall withhold only the amount,  if any, required by
Law (after taking into account any applicable exemptions properly claimed by the
Note Holder) to be withheld from payments hereunder or under the Equipment Notes
held by such holder in respect of United  States  federal  income tax. If a Note
Holder (x) which is a Non-U.S.  Person has furnished to the Mortgagee a properly
completed,  accurate and currently  effective U.S. Internal Revenue Service Form
W-8ECI in  duplicate  (or such  successor  certificate,  form or forms as may be
required by the United  States  Treasury  Department  as  necessary  in order to
properly  avoid  withholding  of United  States  federal  income tax),  for each
calendar year in which a payment is made (but prior to the making of any payment
for  such  year),  and has not  notified  the  Mortgagee  of the  withdrawal  or
inaccuracy  of such  certificate  or form prior to the date of such payment (and
the  Mortgagee has no reason to believe that any  information  set forth in such
form is inaccurate) or (y) which is a U.S. Person has furnished to the Mortgagee
a properly  completed,  accurate and currently  effective U.S.  Internal Revenue
Service  Form W-9,  if  applicable,  prior to a payment  hereunder  or under the
Equipment  Notes held by such holder,  no amount shall be withheld from payments
in respect of United States  federal income tax. If any Note Holder has notified
the Mortgagee that any of the foregoing  forms or  certificates  is withdrawn or
inaccurate,  or if such holder has not filed a form  claiming an exemption  from
United States  withholding tax or if the Code or the  regulations  thereunder or
the administrative  interpretation  thereof is at any time after the date hereof
amended to require such  withholding  of United States federal income taxes from
payments under the Equipment Notes held by such holder,  the Mortgagee agrees to
withhold from each payment due to the relevant Note Holder  withholding taxes at
the  appropriate  rate  under  Law and  will,  on a timely  basis as more  fully
provided above, deposit such amounts with an authorized depository and make such
returns,  statements,  receipts  and other  documentary  evidence in  connection
therewith as required by Law.

<PAGE>

            Neither the Owner Trustee nor the Owner  Participant  shall have any
liability  for the  failure of the  Mortgagee  to  withhold  taxes in the manner
provided for herein or for any false,  inaccurate or untrue evidence provided by
any Note Holder hereunder,  and Mortgagee shall pay, indemnify,  protect, defend
and hold the Owner  Participant  and the Owner Trustee  harmless on an after-tax
basis against any Taxes imposed as a result of such failure by the Mortgagee.

      SECTION 2.05.     APPLICATION OF PAYMENTS.

            In the case of each Equipment Note, each payment of Original Amount,
Make-Whole Amount, if any, and interest due thereon shall be applied:

            First: to the payment of accrued interest on such Equipment Note (as
      well  as  any  interest  on  any  overdue  Original  Amount,  any  overdue
      Make-Whole Amount, if any, and to the extent permitted by Law, any overdue
      interest and any other  overdue  amounts  thereunder)  to the date of such
      payment;

            Second: to the payment of the Original Amount of such Equipment Note
     (or a portion thereof) then due thereunder;

            Third:  to the payment of Make-Whole  Amount,  if any, and any other
     amount due hereunder or under such Equipment Note; and

            Fourth: the balance, if any, remaining thereafter, to the payment of
      the Original Amount of such Equipment Note remaining unpaid (provided that
      such Equipment Note shall not be subject to redemption  except as provided
      in Sections 2.10, 2.11 and 2.12 hereof).

The  amounts  paid  pursuant  to clause  "Fourth"  above shall be applied to the
installments  of Original  Amount of such Equipment Note in the inverse order of
their normal maturity.

      SECTION 2.06.     TERMINATION OF INTEREST IN TRUST INDENTURE ESTATE.

            No Note Holder  shall,  as such,  have any further  interest  in, or
other right with respect to, the Trust Indenture Estate when and if the Original
Amount of,  Make-Whole  Amount,  if any, and  interest on and other  amounts due
under all  Equipment  Notes held by such Note Holder and all other sums then due
and payable hereunder (including,  without limitation, under the third paragraph
of Section 2.02 hereof) and under the other  Operative  Agreements  by the Owner
Trustee (collectively, the "Secured Obligations") shall have been paid in full.

      SECTION 2.07.     REGISTRATION TRANSFER AND EXCHANGE OF EQUIPMENT NOTES.

            The Mortgagee  shall keep a register (the "Equipment Note Register")
in which the Mortgagee shall provide for the registration of Equipment Notes and
the  registration  of transfers of Equipment  Notes.  No such transfer  shall be
given effect unless and until  registration  hereunder shall have occurred.  The
Equipment  Note  Register  shall be kept at the  Corporate  Trust  Office of the
Mortgagee.  The Mortgagee is hereby appointed "Equipment Note Registrar" for the

<PAGE>

purpose of  registering  Equipment  Notes and  transfers of  Equipment  Notes as
herein  provided.  A holder of any  Equipment  Note  intending to exchange  such
Equipment  Note shall  surrender  such  Equipment  Note to the  Mortgagee at the
Corporate  Trust  Office,  together with a written  request from the  registered
holder thereof for the issuance of a new Equipment Note, specifying, in the case
of a surrender for transfer,  the name and address of the new holder or holders.
Upon  surrender for  registration  of transfer of any Equipment  Note, the Owner
Trustee shall execute,  and the Mortgagee shall authenticate and deliver, in the
name of the  designated  transferee  or  transferees,  one or more new Equipment
Notes of a like aggregate  Original Amount and of the same series. At the option
of the Note Holder,  Equipment  Notes may be exchanged for other Equipment Notes
of any  authorized  denominations  of a like  aggregate  Original  Amount,  upon
surrender  of the  Equipment  Notes  to be  exchanged  to the  Mortgagee  at the
Corporate  Trust Office.  Whenever any Equipment  Notes are so  surrendered  for
exchange,  the Owner Trustee shall execute, and the Mortgagee shall authenticate
and deliver,  the  Equipment  Notes which the Note Holder making the exchange is
entitled  to receive.  All  Equipment  Notes  issued  upon any  registration  of
transfer or exchange of  Equipment  Notes  (whether  under this  Section 2.07 or
under Section 2.08 hereof or otherwise under this Trust  Indenture) shall be the
valid   obligations  of  the  Owner  Trustee   evidencing  the  same  respective
obligations,  and entitled to the same  security  and benefits  under this Trust
Indenture, as the Equipment Notes surrendered upon such registration of transfer
or exchange.  Every Equipment Note presented or surrendered for  registration of
transfer  shall  (if so  required  by the  Mortgagee)  be duly  endorsed,  or be
accompanied  by a written  instrument  of transfer in form  satisfactory  to the
Mortgagee  duly  executed  by the Note  Holder or such  holder's  attorney  duly
authorized in writing, and the Mortgagee shall require evidence  satisfactory to
it as to the  compliance of any such transfer with the  Securities  Act, and the
securities Laws of any applicable  state. The Mortgagee shall make a notation on
each new  Equipment  Note of the  amount  of all  payments  of  Original  Amount
previously  made on the old  Equipment  Note or Equipment  Notes with respect to
which such new Equipment  Note is issued and the date to which  interest on such
old Equipment Note or Equipment Notes has been paid. Interest shall be deemed to
have been paid on such new Equipment  Note to the date on which  interest  shall
have been paid on such old  Equipment  Note,  and all  payments of the  Original
Amount marked on such new Equipment Note, as provided above,  shall be deemed to
have been made thereon.  The Owner Trustee shall not be required to exchange any
surrendered  Equipment  Notes  as  provided  above  during  the  ten-day  period
preceding the due date of any payment on such Equipment  Note. The Owner Trustee
shall in all cases deem the Person in whose name any  Equipment  Note shall have
been issued and  registered as the absolute  owner and holder of such  Equipment
Note for the purpose of  receiving  payment of all amounts  payable by the Owner
Trustee with respect to such  Equipment Note and for all purposes until a notice
stating otherwise is received from the Mortgagee and such change is reflected on
the  Equipment  Note  Register.  The Mortgagee  will  promptly  notify the Owner
Trustee and the Lessee of each  registration of a transfer of an Equipment Note.
Any such  transferee  of an Equipment  Note,  by its  acceptance of an Equipment
Note, agrees to the provisions of the Participation Agreement applicable to Note
Holders,  and  shall  be  deemed  to  have  covenanted  to  the  parties  to the
Participation  Agreement  as to the  matters  covenanted  by the  original  Loan
Participant in the  Participation  Agreement.  Subject to compliance by the Note
Holder and its transferee (if any) of the requirements set forth in this Section
2.07,  Mortgagee and Owner Trustee shall use all reasonable efforts to issue new

<PAGE>

Equipment Notes upon transfer or exchange within 10 Business Days of the date an
Equipment Note is surrendered for transfer or exchange.

      SECTION 2.08.     MUTILATED, DESTROYED, LOST OR STOLEN EQUIPMENT NOTES.

            If any Equipment  Note shall become  mutilated,  destroyed,  lost or
stolen,  the Owner Trustee shall, upon the written request of the holder of such
Equipment  Note,  execute and the Mortgagee  shall  authenticate  and deliver in
replacement  thereof a new Equipment  Note,  payable in the same Original Amount
dated the same date and captioned as issued in connection with the Aircraft.  If
the Equipment  Note being  replaced has become  mutilated,  such  Equipment Note
shall be surrendered to the Mortgagee and a photocopy thereof shall be furnished
to the Owner Trustee.  If the Equipment Note being replaced has been  destroyed,
lost or stolen,  the holder of such  Equipment  Note shall  furnish to the Owner
Trustee and the Mortgagee  such security or indemnity as may be required by them
to save the Owner Trustee and the Mortgagee  harmless and evidence  satisfactory
to the Owner Trustee and the Mortgagee of the destruction, loss or theft of such
Equipment  Note and of the  ownership  thereof.  If a  "qualified  institutional
buyer" of the type  referred to in  paragraph  (a)(1)(i)(A),  (B), (D) or (E) of
Rule  144A  under  the  Securities  Act (a  "QIB")  is the  holder  of any  such
destroyed,  lost or stolen  Equipment Note,  then the written  indemnity of such
QIB, signed by an authorized  officer thereof,  in favor of, delivered to and in
form  reasonably  satisfactory  to Lessee,  Owner Trustee and Mortgagee shall be
accepted as  satisfactory  indemnity  and security  and no further  indemnity or
security  shall be required as a condition to the execution and delivery of such
new  Equipment  Note.  Subject  to  compliance  by  the  Note  Holder  with  the
requirements  set forth in this Section 2.08,  Mortgagee and Owner Trustee shall
use all reasonable  efforts to issue new Equipment Notes within 10 Business Days
of the date of the written request therefor from the Note Holder.

      SECTION 2.09.     PAYMENT OF EXPENSES ON TRANSFER; CANCELLATION.

            (a) No  service  charge  shall  be  made  to a Note  Holder  for any
registration of transfer or exchange of Equipment Notes,  but the Mortgagee,  as
Equipment Note  Registrar,  may require payment of a sum sufficient to cover any
tax or other  governmental  charge  that may be imposed in  connection  with any
registration of transfer or exchange of Equipment Notes.

            (b) The Mortgagee shall cancel all Equipment  Notes  surrendered for
replacement,  redemption,  transfer, exchange, payment or cancellation and shall
destroy the canceled Equipment Notes.

      SECTION 2.10.     MANDATORY REDEMPTIONS OF EQUIPMENT NOTES.

            (a) On the date on which  Lessee is  required  pursuant  to  Section
10.1.2 of the Lease to make  payment  for an Event of Loss with  respect  to the
Aircraft,  all of the Equipment Notes shall be redeemed in whole at a redemption
price equal to 100% of the unpaid  Original  Amount  thereof,  together with all
accrued  interest  thereon  to the  date of  redemption  and all  other  Secured
Obligations  owed or then  due and  payable  to the  Note  Holders  but  without
Make-Whole Amount.

<PAGE>

            (b) If the Lease is  terminated  with  respect  to the  Aircraft  by
Lessee  pursuant to Section 9 thereof,  on the date the Lease is so  terminated,
all the Equipment  Notes shall be redeemed in whole at a redemption  price equal
to 100% of the unpaid Original Amount  thereof,  together with accrued  interest
thereon to the date of  redemption  and all other  amounts  then due and payable
hereunder  and  under  the  Participation  Agreement  and  all  other  Operative
Agreements to the Note Holders plus Make-Whole Amount, if any.

      SECTION 2.11.     VOLUNTARY REDEMPTIONS OF EQUIPMENT NOTES.

            All (but not less than all) of the  Equipment  Notes may be redeemed
by the Owner Trustee in connection with a transaction  described in, and subject
to the terms and conditions of, Section 11 of the  Participation  Agreement upon
at least 30 days'  revocable  prior written notice to the Mortgagee and the Note
Holders,  and such  Equipment  Notes  shall,  as  provided  in Section 11 of the
Participation  Agreement,  be redeemed in whole at a  redemption  price equal to
100% of the unpaid  Original  Amount  thereof,  together  with accrued  interest
thereon to the date of redemption and all other Secured Obligations owed or then
due and payable to the Note  Holders  plus  (except as provided in Section 11 of
the Participation Agreement) Make-Whole Amount, if any.

      SECTION 2.12.     REDEMPTIONS; NOTICE OF REDEMPTION.

            (a) Neither any redemption of any Equipment Note nor any purchase by
the Owner Trustee of any Equipment  Note may be made except to the extent and in
the manner  expressly  permitted  by this Trust  Indenture.  No  purchase of any
Equipment Note may be made by the Mortgagee.

            (b) Notice of redemption  with respect to the Equipment  Notes shall
be given by the Mortgagee by first-class mail, postage prepaid,  mailed not less
than 20 nor more than 60 days prior to the applicable  redemption  date, to each
Note  Holder of such  Equipment  Notes to be  redeemed,  at such  Note  Holder's
address appearing in the Equipment Note Register;  provided that, in the case of
a redemption to be made pursuant to Section 2.10(b) or Section 2.11, such notice
shall be revocable and shall be deemed  revoked in the event that the Lease does
not in fact  terminate on the  specified  termination  date or if notice of such
redemption  shall have been given in connection  with a refinancing of Equipment
Notes and the Mortgagee  receives  written  notice of such  revocation  from the
Lessee or the Owner  Trustee  not later than three days prior to the  redemption
date. All notices of redemption  shall state:  (1) the redemption  date, (2) the
applicable  basis  for  determining  the  redemption  price,  (3)  that  on  the
redemption date, the redemption price will become due and payable upon each such
Equipment  Note,  and that, if any such  Equipment  Notes are then  outstanding,
interest  on such  Equipment  Notes  shall  cease to accrue  on and  after  such
redemption  date, and (4) the place or places where such Equipment  Notes are to
be surrendered for payment of the redemption price.

            (c) On or before the  redemption  date,  the Owner  Trustee  (or any
person on behalf of the Owner Trustee)  shall,  to the extent an amount equal to
the  redemption  price for the Equipment  Notes to be redeemed on the redemption
date shall not then be held in the Trust Indenture  Estate,  deposit or cause to
be  deposited  with  the  Mortgagee  by  12:00  noon on the  redemption  date in

<PAGE>

immediately  available  funds the redemption  price of the Equipment Notes to be
redeemed.

            (d) Notice of  redemption  having been given as  aforesaid  (and not
deemed revoked as contemplated in the proviso to Section 2.12(b)), the Equipment
Notes to be redeemed  shall, on the redemption  date,  become due and payable at
the  Corporate  Trust  Office  of the  Mortgagee  or at  any  office  or  agency
maintained  for such purposes  pursuant to Section 2.07, and from and after such
redemption  date  (unless  there  shall  be a  default  in  the  payment  of the
redemption  price) any such Equipment Notes then outstanding shall cease to bear
interest. Upon surrender of any such Equipment Note for redemption in accordance
with said notice, such Equipment Note shall be redeemed at the redemption price.
If any Equipment Note called for redemption  shall not be so paid upon surrender
thereof for redemption, the principal amount thereof shall, until paid, continue
to bear interest  from the  applicable  redemption  date at the interest rate in
effect for such Equipment Note as of such redemption date.

      SECTION 2.13.     OPTION TO PURCHASE EQUIPMENT NOTES.

            The Owner Trustee and the Owner Participant may, upon the events and
subject to the terms and  conditions and for the price set forth in this Section
2.13,  purchase  all but not less than all of the  Equipment  Notes  outstanding
hereunder,  and each Note  Holder  agrees  that it will,  upon such  events  and
subject to such terms and  conditions  and upon  receipt  of such  price,  sell,
assign,  transfer and convey to such purchaser or its nominee (without  recourse
or warranty of any kind except against Liens on such Equipment Notes arising by,
through or under such holder), all of the right, title and interest of such Note
Holder in and to the  Equipment  Notes  held by it,  and such  purchaser  or its
nominee shall assume all of such holder's  obligations  under the  Participation
Agreement and hereunder.

            Such option to purchase the Equipment  Notes may be exercised by the
Owner Trustee or the Owner  Participant  at any time following the occurrence of
any of the following  events,  and in any such event the purchase  price thereof
shall equal for each  Equipment  Note,  the  aggregate  unpaid  Original  Amount
thereof,  plus accrued and unpaid  interest  thereon to, but not including,  the
date of purchase and all other Secured Obligations owed, or then due and payable
hereunder, to the holder thereof (including under the third paragraph of Section
2.02 hereof).  Such option to purchase the Equipment  Notes may be exercised (x)
upon a  Mortgagee  Event or (y) in the event there  shall have  occurred  and be
continuing  a Lease Event of Default  provided  that if such option is exercised
pursuant  to  clause  (y)  at a time  when  there  shall  have  occurred  and be
continuing  for less than 120 days a Lease Event of Default,  the purchase price
thereof  shall  equal the price  provided  in the  preceding  sentence  plus the
Make-Whole Amount, if any.

            Such option to purchase the Equipment  Notes may be exercised by the
Owner Trustee or the Owner Participant  giving written notice of its election of
such  option  to the  Mortgagee,  which  notice  shall  specify  a date for such
purchase within 30 days of the date of such notice. The Mortgagee shall promptly
send a copy of such notice to each Note Holder. The Mortgagee shall not exercise
any of the remedies  hereunder and,  without the consent of the Owner Trustee or
the Owner Participant,  under the Lease, during the period from the time that an

<PAGE>

exercise by the Owner Participant of such option to purchase becomes irrevocable
until the date on which such purchase is required to occur pursuant to the terms
of the preceding  sentence.  Such election to purchase the Equipment Notes shall
become irrevocable upon the sixteenth day following the giving of written notice
as provided above.

            If the Owner Trustee or the Owner  Participant on or before the date
of such  purchase  shall so request,  the Note  Holders will comply with all the
provisions  of Section  2.07 to enable new  Equipment  Notes to be issued to the
Owner Trustee or the Owner  Participant or its nominee in such  denominations as
the Owner Trustee or the Owner Participant shall request. All taxes, charges and
expenses  required  pursuant to Section 2.09 in connection  with the issuance of
such new Equipment Note shall be borne by the Owner Participant.

      SECTION 2.14.     SUBORDINATION.

            (a) The Owner Trustee and, by  acceptance of its Equipment  Notes of
any Series,  each Note Holder of such  Series,  hereby  agree that no payment or
distribution  shall be made on or in respect of the Secured  Obligations owed to
such Note Holder of such Series,  including any payment or distribution of cash,
property  or  securities  after the  commencement  of a  proceeding  of the type
referred to in Section 4.02(g) hereof,  except as expressly  provided in Article
III hereof.

            (b) By the  acceptance of its  Equipment  Notes of any Series (other
than Series A-1 and Series A-2),  each Note Holder of such Series agrees that in
the event that such Note Holder, in its capacity as a Note Holder, shall receive
any payment or distribution on any Secured Obligations in respect of such Series
which it is not  entitled  to receive  under this  Section  2.14 or Article  III
hereof,  it will hold any amount so received in trust for the Senior  Holder (as
defined in Section  2.14(c) hereof) and will forthwith turn over such payment to
the  Mortgagee  in the form  received  to be applied as  provided in Article III
hereof.

            (c) As used in this Section  2.14,  the term "Senior  Holder"  shall
mean,  (i) the Note  Holders  of Series  A-1 and  Series  A-2 until the  Secured
Obligations  in respect of Series A-1 and Series A-2  Equipment  Notes have been
paid in full,  (ii) after the Secured  Obligations  in respect of Series A-1 and
Series A-2 Equipment  Notes have been paid in full, the Note Holders of Series B
until the Secured  Obligations in respect of Series B Equipment  Notes have been
paid in full and (iii)  after the  Secured  Obligations  in  respect of Series B
Equipment  Notes  have been paid in full,  the Note  Holders  of Series  C-1 and
Series C-2 until the Secured Obligations in respect of Series C-1 and Series C-2
Equipment Notes have been paid in full.

                                   ARTICLE III

                   RECEIPT, DISTRIBUTION AND APPLICATION OF
                     INCOME FROM THE TRUST INDENTURE ESTATE

      SECTION 3.01.     BASIC RENT DISTRIBUTION.

            Except as otherwise provided in Sections 3.02 and 3.03 hereof,  each
installment  of Basic Rent, any payment of interest on overdue  installments  of

<PAGE>

Basic Rent and any payment  received by the  Mortgagee  pursuant to Section 4.03
hereof shall be promptly distributed in the following order of priority:

FIRST,  (i) so much of such  installment  or payment as shall be required to pay
            in full the aggregate  amount of the payment or payments of Original
            Amount and interest (as well as any interest on any overdue Original
            Amount and, to the extent permitted by Law, on any overdue interest)
            then due under all Series A-1 and Series A-2  Equipment  Notes shall
            be  distributed  to the Note  Holders  of Series  A-1 and Series A-2
            ratably,  without  priority of one over the other, in the proportion
            that the  amount of such  payment  or  payments  then due under each
            Series  A-1 and  Series A-2  Equipment  Note bears to the  aggregate
            amount of the payments  then due under all Series A-1 and Series A-2
            Equipment Notes;

       (ii) after  giving  effect  to  paragraph  (i)  above,  so  much  of such
            installment or payment remaining as shall be required to pay in full
            the aggregate  amount of the payment or payments of Original  Amount
            and interest (as well as any interest on any overdue Original Amount
            and, to the extent permitted by Law, on interest) then due under all
            Series B Equipment Notes shall be distributed to the Note Holders of
            Series B ratably,  without  priority  of one over the other,  in the
            proportion  that the  amount of such  payment or  payments  then due
            under each Series B Equipment Note bears to the aggregate  amount of
            the payments then due under all Series B Equipment Notes;

      (iii) after  giving  effect  to  paragraph  (ii)  above,  so  much of such
            installment or payment remaining as shall be required to pay in full
            the aggregate  amount of the payment or payments of Original  Amount
            and interest (as well as any interest on any overdue Original Amount
            and, to the extent  permitted by Law, on any overdue  interest) then
            due under all Series C-1 and Series  C-2  Equipment  Notes  shall be
            distributed  to the  Note  Holders  of  Series  C-1 and  Series  C-2
            ratably,  without  priority of one over the other, in the proportion
            that the  amount of such  payment  or  payments  then due under each
            Series  C-1 and  Series C-2  Equipment  Note bears to the  aggregate
            amount of the payments  then due under all Series C-1 and Series C-2
            Equipment Notes; and

       (iv) after  giving  effect  to  paragraph  (iii)  above,  so much of such
            payment  remaining as shall be required to pay in full the aggregate
            amount of the payment or payments  of Original  Amount and  interest
            (as well as any interest on any overdue  Original Amount and, to the
            extent permitted by Law, on any overdue interest) then due under all
            Series D Equipment Notes shall be distributed to the Note Holders of
            Series D ratably,  without  priority  of one over the other,  in the
            proportion  that the  amount of such  payment or  payments  then due
            under each Series D Equipment Note bears to the aggregate  amount of
            the payments then due under all Series D Equipment Notes; and

SECOND,     the balance, if any, of such installment  remaining thereafter shall
            be distributed to the Owner Trustee; provided, however,

<PAGE>

            that if an Event of Default shall have  occurred and be  continuing,
            then such  balance  shall not be  distributed  as  provided  in this
            clause  "Second"  but shall be held by the  Mortgagee as part of the
            Trust Indenture  Estate and invested in accordance with Section 5.09
            hereof until whichever of the following  shall first occur:  (i) all
            Events of Default  shall have been cured or waived,  in which  event
            such  balance  shall  be  distributed  as  provided  in this  clause
            "Second",  (ii) Section 3.03 hereof  shall be  applicable,  in which
            event such  balance  shall be  distributed  in  accordance  with the
            provisions  of such Section  3.03,  or (iii) the 120th day after the
            receipt  of such  payment  in  which  case  such  payment  shall  be
            distributed as provided in this clause "Second".

      SECTION 3.02.     EVENT OF LOSS; REPLACEMENT; VOLUNTARY TERMINATION;
                        OPTIONAL REDEMPTION.

            Except as otherwise  provided in Section  3.03 hereof,  any payments
received by the  Mortgagee  (i) with respect to the Airframe or the Airframe and
one or more  Engines  as the  result  of an Event of Loss,  (ii)  pursuant  to a
voluntary  termination  of the Lease  pursuant  to Section 9  thereof,  or (iii)
pursuant to an optional redemption of the Equipment Notes pursuant to Section 11
of the  Participation  Agreement shall be applied to redemption of the Equipment
Notes  and to all  other  Secured  Obligations  by  applying  such  funds in the
following order of priority:

FIRST,      (a) to  reimburse  the  Mortgagee  and  the  Note  Holders  for  any
            reasonable  costs or  expenses  incurred  in  connection  with  such
            redemption  for  which  they  are  entitled  to  reimbursement,   or
            indemnity by Lessee,  under the Operative Agreements and then (b) to
            pay any other amounts then due to the Mortgagee and the Note Holders
            under this  Trust  Indenture,  the  Participation  Agreement  or the
            Equipment  Notes and any and all  amounts  payable  pursuant  to the
            third  paragraph of Section  2.02 (other than  amounts  specified in
            clause Second below);

SECOND, (i) to pay the amounts  specified in paragraph (i) of clause  "Third" of
            Section 3.03 hereof plus  Make-Whole  Amount,  if any,  then due and
            payable in respect of the Series A-1 and Series A-2 Equipment Notes;

       (ii) after  giving  effect to  paragraph  (i) above,  to pay the  amounts
            specified in paragraph (ii) of clause "Third" of Section 3.03 hereof
            plus Make-Whole  Amount,  if any, then due and payable in respect of
            the Series B Equipment Notes;

      (iii) after  giving  effect to  paragraph  (ii) above,  to pay the amounts
            specified  in  paragraph  (iii) of clause  "Third" of  Section  3.03
            hereof  plus  Make-Whole  Amount,  if any,  then due and  payable in
            respect of the Series C-1 and Series C-2 Equipment Notes; and

       (iv) after  giving  effect to paragraph  (iii) above,  to pay the amounts
            specified in paragraph (iv) of clause "Third" of Section 3.03 hereof
            plus Make-Whole  Amount,  if any, then due and payable in respect of
            the Series D Equipment Notes; and

<PAGE>

THIRD,      as provided in clause "Fourth" of Section 3.03 hereof;

PROVIDED, HOWEVER, that if a Replacement Airframe or Replacement Engine shall be
substituted for the Airframe or Engine subject to such Event of Loss as provided
in Section 10 of the Lease and in  accordance  with  Section  5.06  hereof,  any
insurance, condemnation or similar proceeds which result from such Event of Loss
and are paid over to the  Mortgagee  shall be held by the Mortgagee as permitted
by Section 6.04 hereof  (provided that such moneys shall be invested as provided
in Section 5.09 hereof) as  additional  security for the  obligations  of Lessee
under the Lessee Operative  Agreements and, unless otherwise applied pursuant to
the Lease, such proceeds (and such investment earnings) shall be released to the
Lessee at the Lessee's written request upon the release of such damaged Airframe
or Engine and the replacement thereof as provided in the Lease.

      SECTION 3.03.     PAYMENTS AFTER EVENT OF DEFAULT.

            Except as otherwise  provided in Section  3.04 hereof,  all payments
received and amounts held or realized by the  Mortgagee  (including  any amounts
realized by the Mortgagee from the exercise of any remedies  pursuant to Section
15 of the Lease or  Article  IV  hereof)  after an Event of  Default  shall have
occurred  and be  continuing  and after the  declaration  specified  in  Section
4.04(b) hereof, as well as all payments or amounts then held by the Mortgagee as
part of the  Trust  Indenture  Estate,  shall  be  promptly  distributed  by the
Mortgagee in the following order of priority:

FIRST,      so much of such  payments  or  amounts as shall be  required  to (i)
            reimburse  the  Mortgagee  or WTC for any tax  (except to the extent
            resulting from a failure of the Mortgagee to withhold taxes pursuant
            to  Section  2.04(b)  hereof),  expense  or other  loss  (including,
            without limitation, all amounts to be expended at the expense of, or
            charged upon the rents, revenues,  issues,  products and profits of,
            the  property  included  in the  Trust  Indenture  Estate  (all such
            property being herein called the "Mortgaged  Property")  pursuant to
            Section  4.05(b)  hereof)  incurred by the  Mortgagee or WTC (to the
            extent not  previously  reimbursed),  the  expenses of any sale,  or
            other  proceeding,  reasonable  attorneys' fees and expenses,  court
            costs,  and any  other  expenditures  incurred  or  expenditures  or
            advances  made by the  Mortgagee,  WTC or the  Note  Holders  in the
            protection, exercise or enforcement of any right, power or remedy or
            any damages  sustained  by the  Mortgagee,  WTC or any Note  Holder,
            liquidated or otherwise, upon such Event of Default shall be applied
            by the  Mortgagee  as between  itself,  WTC and the Note  Holders in
            reimbursement  of such expenses and any other expenses for which the
            Mortgagee,  WTC or the Note  Holders are  entitled to  reimbursement
            under  any  Operative  Agreement  and (ii)  pay any and all  amounts
            payable to WTC or the  Mortgagee  hereunder  and any and all amounts
            payable  pursuant to the third paragraph of Section 2.02 (other than
            amounts  specified in clauses  Second and Third  below);  and in the
            case the aggregate  amount to be so distributed is  insufficient  to
            pay as  aforesaid  in clauses (i) and (ii),  then  ratably,  without
            priority of one over the other,  in  proportion  to the amounts owed
            each hereunder;

<PAGE>

SECOND,     so much of such  payments or amounts  remaining as shall be required
            to  reimburse  the then  existing or prior Note Holders for payments
            made  pursuant to Section 5.03 hereof (to the extent not  previously
            reimbursed) shall be distributed to such then existing or prior Note
            Holders  ratably,  without  priority  of  one  over  the  other,  in
            accordance  with the amount of the payment or payments  made by each
            such then  existing  or prior Note Holder  pursuant to said  Section
            5.03 hereof;

THIRD, (i)  so much of such  payments or amounts  remaining as shall be required
            to pay in full the aggregate  unpaid  Original  Amount of all Series
            A-1 and Series  A-2  Equipment  Notes,  and the  accrued  but unpaid
            interest and other amounts due thereon (other than Make-Whole Amount
            which  shall  not  be  due  and  payable)  and  all  other   Secured
            Obligations  in respect  of the Series A-1 and Series A-2  Equipment
            Notes (other than  Make-Whole  Amount) to the date of  distribution,
            shall be  distributed  to the Note  Holders of Series A-1 and Series
            A-2, and in case the aggregate amount so to be distributed  shall be
            insufficient  to pay in full as  aforesaid,  then  ratably,  without
            priority of one over the other, in the proportion that the aggregate
            unpaid  Original  Amount of all Series A-1 and Series A-2  Equipment
            Notes held by each holder plus the accrued but unpaid  interest  and
            other  amounts due hereunder or  thereunder  (other than  Make-Whole
            Amount, if any) to the date of distribution,  bears to the aggregate
            unpaid  Original  Amount of all Series A-1 and Series A-2  Equipment
            Notes held by all such holders plus the accrued but unpaid  interest
            and other amounts due thereon (other than Make-Whole  Amount) to the
            date of distribution;

      (ii)  after giving effect to paragraph (i) above, so much of such payments
            or  amounts  remaining  as  shall  be  required  to pay in full  the
            aggregate  unpaid Original  Amount of all Series B Equipment  Notes,
            and the accrued but unpaid  interest  and other  amounts due thereon
            (other than  Make-Whole  Amount  which shall not be due and payable)
            and all  other  Secured  Obligations  in  respect  of the  Series  B
            Equipment  Notes  (other  than  Make-Whole  Amount)  to the  date of
            distribution,  shall be distributed to the Note Holders of Series B,
            and in case  the  aggregate  amount  so to be  distributed  shall be
            insufficient  to pay in full as  aforesaid,  then  ratably,  without
            priority of one over the other, in the proportion that the aggregate
            unpaid  Original Amount of all Series B Equipment Notes held by each
            holder plus the accrued but unpaid  interest  and other  amounts due
            hereunder or thereunder  (other than the Make-Whole  Amount, if any)
            to the date of distribution,  bears to the aggregate unpaid Original
            Amount of all Series B Equipment Notes held by all such holders plus
            the accrued but unpaid interest and other amounts due thereon (other
            than the Make-Whole Amount) to the date of distribution;

      (iii) after  giving  effect  to  paragraph  (ii)  above,  so  much of such
            payments  or amounts  remaining  as shall be required to pay in full
            the aggregate  unpaid  Original  Amount of all Series C-1 and Series
            C-2 Equipment  Notes,  and the accrued but unpaid interest and other
            amounts due thereon (other than Make-Whole Amount which shall not be
            due and payable) and all other Secured Obligations in respect of the

<PAGE>

            Series C-1 and Series C-2  Equipment  Notes  (other than  Make-Whole
            Amount) to the date of  distribution,  shall be  distributed  to the
            Note Holders of Series C-1 and Series C-2, and in case the aggregate
            amount so to be distributed  shall be insufficient to pay in full as
            aforesaid,  then ratably, without priority of one over the other, in
            the  proportion  that the aggregate  unpaid  Original  Amount of all
            Series C-1 and Series C-2  Equipment  Notes held by each holder plus
            the accrued but unpaid  interest and other  amounts due hereunder or
            thereunder (other than the Make-Whole Amount, if any) to the date of
            distribution,  bears to the aggregate  unpaid Original Amount of all
            Series C-1 and Series C-2  Equipment  Notes held by all such holders
            plus the accrued but unpaid  interest and other  amounts due thereon
            (other than the Make-Whole Amount) to the date of distribution; and

      (iv)  after  giving  effect  to  paragraph  (iii)  above,  so much of such
            payments  or amounts  remaining  as shall be required to pay in full
            the  aggregate  unpaid  Original  Amount of all  Series D  Equipment
            Notes,  and the accrued but unpaid  interest  and other  amounts due
            thereon  (other than  Make-Whole  Amount  which shall not be due and
            payable) and all other Secured  Obligations in respect of the Series
            D  Equipment  Notes  (other than  Make-Whole  Amount) to the date of
            distribution,  shall be distributed to the Note Holders of Series D,
            and in case  the  aggregate  amount  so to be  distributed  shall be
            insufficient  to pay in full as  aforesaid,  then  ratably,  without
            priority of one over the other, in the proportion that the aggregate
            unpaid  Original Amount of all Series D Equipment Notes held by each
            holder plus the accrued but unpaid  interest  and other  amounts due
            hereunder or thereunder  (other than the Make-Whole  Amount, if any)
            to the date of distribution,  bears to the aggregate unpaid Original
            Amount of all Series D Equipment Notes held by all such holders plus
            the accrued but unpaid interest and other amounts due thereon (other
            than the Make-Whole Amount) to the date of distribution; and

FOURTH,     the  balance,   if  any,  of  such  payments  or  amounts  remaining
            thereafter shall be distributed to the Owner Trustee.

            No Make-Whole Amount shall be due and payable on the Equipment Notes
as a consequence of the  acceleration  of the Equipment  Notes as a result of an
Event of Default.

      SECTION 3.04.     CERTAIN PAYMENTS.

            (a) Any payments received by the Mortgagee for which no provision as
to the  application  thereof is made in this Trust  Indenture and for which such
provision is made in the Lease or the  Participation  Agreement shall be applied
forthwith to the purpose for which such payment was made in accordance  with the
terms of the Lease or the Participation Agreement, as the case may be.

            (b)  Notwithstanding  anything  to the  contrary  contained  in this
Article III, the Mortgagee will  distribute  promptly upon receipt any indemnity
payment  received  by it from the Owner  Trustee  or Lessee  in  respect  of the
Mortgagee in its individual capacity, any Note Holder, WTC, the Mortgagee,  each
separate or additional  Trustee appointed pursuant to the Trust Indenture or the

<PAGE>

Pass  Through  Indemnitees,  in each case  whether  pursuant to Section 9 of the
Participation Agreement or as Supplemental Rent, directly to the Person entitled
thereto.  Subject to the foregoing sentence of this Section 3.04(b), any payment
received by the  Mortgagee  under the third  paragraph  of Section 2.02 shall be
distributed to the Subordination  Agent to be distributed in accordance with the
terms of the Intercreditor Agreement.

            (c)  Notwithstanding  anything  to the  contrary  contained  in this
Article III, any payments  received by the Mortgagee which  constitute  Excluded
Payments shall be distributed promptly upon receipt by the Mortgagee directly to
the Person or Persons entitled thereto.

            (d)  Notwithstanding  any  provision of this Trust  Indenture to the
contrary,  any amounts held by Mortgagee  pursuant to the terms of the Lease [or
any  Permitted  Sublease  assignment]<F10>  shall  be held by the  Mortgagee  as
security for the  obligations  of Lessee under the Lessee  Operative  Agreements
and, if and when required by the Lease,  paid and/or applied in accordance  with
the applicable provisions of the Lease.

      SECTION 3.05.     OTHER PAYMENTS.

            Any payments  received by the Mortgagee for which no provision as to
the  application  thereof is made in the  Lease,  the  Participation  Agreement,
elsewhere in this Trust Indenture or in any other  Operative  Agreement shall be
distributed by the Mortgagee to the extent  received or realized at any time (i)
prior to the payment in full of all Secured Obligations due the Note Holders, in
the order of priority  specified in Section  3.01 hereof  subject to the proviso
thereto,  and (ii) after  payment  in full of all  Secured  Obligations,  in the
following order of priority:

FIRST,      to the extent  payments or amounts  described  in clause  "First" of
            Section 3.03 hereof are  otherwise  obligations  of Lessee under the
            Operative  Agreements  or for  which  the  Lessee  is  obligated  to
            indemnify  against  thereunder,  in the  manner  provided  in clause
            "First" of Section 3.03 hereof, and

SECOND,     in the manner provided in clause "Fourth" of Section 3.03 hereof.

            Further, and except as otherwise provided in Sections 3.02, 3.03 and
3.04 hereof,  all payments  received and amounts realized by the Mortgagee under
the  Lease  or  otherwise  with  respect  to the  Aircraft  (including,  without
limitation,  all amounts realized upon the sale or release of the Aircraft after
the  termination of the Lease with respect  thereto),  to the extent received or
realized at any time after  payment in full of all Secured  Obligations  due the
Note  Holders,  shall be  distributed  by the Mortgagee in the order of priority
specified in clause (ii) of the immediately  preceding  sentence of this Section
3.05.

--------------------
<F10>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<PAGE>

      SECTION 3.06.     PAYMENTS TO OWNER TRUSTEE.

            Any amounts  distributed  hereunder  by the  Mortgagee  to the Owner
Trustee shall be paid to the Owner Trustee (within the time limits  contemplated
by  Section  2.04(a))  by wire  transfer  of funds of the type  received  by the
Mortgagee  at such  office and to such  account or  accounts  of such  entity or
entities  as  shall be  designated  by  notice  from the  Owner  Trustee  to the
Mortgagee  from time to time.  The Owner Trustee  hereby  notifies the Mortgagee
that unless and until the  Mortgagee  receives  notice to the contrary  from the
Owner Trustee,  all amounts to be  distributed to the Owner Trustee  pursuant to
clause  "Second" of Section 3.01 or clause "Fourth" of Section 3.03 hereof shall
be  distributed  by wire transfer of funds of the type received by the Mortgagee
to the Owner  Participant's  account  (within  the time limits  contemplated  by
Section 2.04(a)) specified in Schedule 1 to the Participation Agreement.

                                   ARTICLE IV

                      COVENANTS OF OWNER TRUSTEE; EVENTS OF
                         DEFAULT; REMEDIES OF MORTGAGEE

      SECTION 4.01.     COVENANTS OF OWNER TRUSTEE.

            The Owner Trustee  hereby  covenants  and agrees (the  covenants and
agreements  only in clause  (b) below  being  made by the Owner  Trustee  in its
individual capacity) as follows:

            (a) the Owner  Trustee  will duly and  punctually  pay the  Original
Amount of,  Make-Whole  Amount,  if any, and  interest on and other  amounts due
under the  Equipment  Notes and  hereunder in  accordance  with the terms of the
Equipment Notes and this Trust Indenture and all amounts,  if any, payable by it
to the Note Holders under the Participation Agreement or Section 9 of the Lease;

            (b) the Owner  Trustee  in its  individual  capacity  covenants  and
agrees  that it shall not,  directly or  indirectly,  cause or permit to exist a
Lessor Lien  attributable  to it in its individual  capacity with respect to the
Aircraft or any other portion of the Trust Estate; that it will promptly, at its
own expense,  take such action as may be necessary to duly discharge such Lessor
Lien  attributable  to it in its  individual  capacity;  and  that it will  make
restitution  to the Trust  Indenture  Estate  for any actual  diminution  of the
assets of the Trust Estate  resulting from such Lessor Liens  attributable to it
in its individual capacity;

            (c) in the event the Owner Trustee shall have Actual Knowledge of an
Event of Default,  a Default or an Event of Loss,  the Owner  Trustee  will give
prompt written notice of such Event of Default,  Default or Event of Loss to the
Mortgagee, each Note Holder, Lessee and the Owner Participant;

            (d) the Owner  Trustee  will  furnish  to the Note  Holders  and the
Mortgagee,  promptly upon receipt thereof,  duplicates or copies of all reports,
notices, requests, demands,  certificates and other instruments furnished to the
Owner Trustee under the Lease,  including,  without  limitation,  a copy of each

<PAGE>

report or notice  received  pursuant to Section 9 or 8.2 or Annex D, Paragraph E
of the Lease to the extent that the same shall not have been furnished or is not
required  to be  furnished  by the Lessee to the Note  Holders or the  Mortgagee
pursuant to the Lease;

            (e) except with the  consent of the  Mortgagee  (acting  pursuant to
instructions  given in  accordance  with  Section 9.01 hereof) or as provided in
Sections 2, 11 and 16 of the Participation Agreement, the Owner Trustee will not
contract for,  create,  incur,  assume or suffer to exist any Debt, and will not
guarantee  (directly  or  indirectly  or by an  instrument  having the effect of
assuring  another's payment or performance on any obligation or capability of so
doing,  or otherwise),  endorse or otherwise be or become  contingently  liable,
directly or indirectly, in connection with the Debt of any other person; and

            (f) the Owner  Trustee  will not enter  into any  business  or other
activity other than the business of owning the Aircraft,  the leasing thereof to
Lessee and the carrying out of the transactions  contemplated  hereby and by the
Lease,  the  Participation  Agreement  and the  Trust  Agreement  and the  other
Operative Agreements.

      SECTION 4.02.     EVENT OF DEFAULT.

            "Event of Default" means any of the following  events  (whatever the
reason for such Event of Default and whether  such event shall be  voluntary  or
involuntary  or come about or be effected by  operation of Law or pursuant to or
in compliance with any judgment, decree or order of any court or any order, rule
or regulation of any administrative or governmental body):

            (a) any Lease Event of Default  (provided  that any such Lease Event
of Default  caused  solely by a failure of Lessee to pay to the Owner Trustee or
the Owner  Participant when due any amount that is included in the definition of
Excluded  Payments  shall not  constitute  an Event of Default  unless notice is
given by the Owner Trustee to the Mortgagee  that such failure shall  constitute
an Event of Default); or

            (b) the failure of the Owner  Trustee to pay when due any payment of
Original Amount of, interest on, Make-Whole  Amount, if any, or other amount due
and payable under any Equipment  Note or hereunder  (other than as a result of a
Lease Event of Default or a Lease Default) and such failure shall have continued
unremedied  for ten Business Days in the case of any payment of Original  Amount
or interest or Make-Whole  Amount, if any, thereon and, in the case of any other
amount,  for ten Business Days after the Owner Trustee or the Owner  Participant
receives written demand from the Mortgagee or any Note Holder; or

            (c) any Lien required to be discharged by the Owner Trustee,  in its
individual  capacity  pursuant to Section 4.01(b) hereof or in its individual or
trust capacity pursuant to Section 7.3.1 of the Participation  Agreement,  or by
the Owner Participant  pursuant to Section 7.2.1 of the Participation  Agreement
shall remain undischarged for a period of 30 days after the Owner Trustee or the
Owner  Participant,  as the case may be, shall have received written notice from
the Mortgagee or any Note Holder of such Lien; or

<PAGE>

            (d) any  representation or warranty made by the Owner Participant or
the Owner Trustee in the  Participation  Agreement or this Trust Indenture or in
any certificate  furnished by the Owner  Participant or the Owner Trustee to the
Mortgagee or any Note Holder in connection with the transactions contemplated by
the Operative  Agreements  shall prove to have been false or incorrect when made
in any  material  respect  and  continues  to be  material  and  adverse  to the
interests of the Mortgagee or the Note Holders; and if such misrepresentation is
capable of being  corrected and if such  correction is being sought  diligently,
such misrepresentation shall not have been corrected within 60 days (or, without
affecting  Section 4.02(f)  hereof,  in the case of the  representation  made in
Section 6.3.6 or 6.2.6 of the  Participation  Agreement as to citizenship of the
Owner  Trustee  in  its  individual   capacity  or  of  the  Owner  Participant,
respectively,  as soon as is reasonably  practicable  but in any event within 60
days)  following  notice  thereof  from the  Mortgagee or any Note Holder to the
Owner Trustee or the Owner Participant, as the case may be; or

            (e) other than as provided in (c) above or (f) below, any failure by
the Owner Trustee or Owner  Participant to observe or perform any other covenant
or obligation of the Owner Trustee or Owner Participant, as the case may be, for
the benefit of the Mortgagee or the Note Holders  contained in the Participation
Agreement,  Section 4.2.1 of the Trust  Agreement,  the Equipment  Notes or this
Trust  Indenture  which is not remedied  within a period of 60 days after notice
thereof has been given to the Owner Trustee and the Owner Participant; or

            (f) if at any time when the Aircraft is registered under the Laws of
the United States,  the Owner  Participant shall not be a "citizen of the United
States" within the meaning of Section  40102(a)(15) of Part A of Subtitle VII of
Title 49, United States Code, and as the result thereof the  registration of the
Aircraft  under the  Federal  Aviation  Act,  and  regulations  then  applicable
thereunder, shall cease to be effective; provided that no Event of Default shall
be deemed to have occurred  under this  paragraph (f) unless such  circumstances
continue unremedied for more than 60 days after the Owner Participant has Actual
Knowledge  of the state of facts that  resulted in such  ineffectiveness  and of
such loss of citizenship; or

            (g) at any time either (i) the  commencement of an involuntary  case
or other proceeding in respect of the Owner Participant,  the Owner Trustee, the
Trust or the Trust Estate under the federal  bankruptcy Laws, as now constituted
or  hereafter  amended,  or any other  applicable  federal or state  bankruptcy,
insolvency or other similar Law in the United States or seeking the  appointment
of a  receiver,  liquidator,  assignee,  custodian,  trustee,  sequestrator  (or
similar official) of the Owner Participant,  the Owner Trustee, the Trust or the
Trust Estate or for all or  substantially  all of its  property,  or seeking the
winding-up or liquidation of its affairs and the  continuation  of any such case
or other  proceeding  undismissed  and unstayed  for a period of 60  consecutive
days; or (ii) the commencement by the Owner Participant,  the Owner Trustee, the
Trust or the Trust Estate of a voluntary  case or  proceeding  under the federal
bankruptcy  Laws,  as  now  constituted  or  hereafter  amended,  or  any  other
applicable  federal or state bankruptcy,  insolvency or other similar Law in the
United States, or the consent by the Owner Participant,  the Owner Trustee,  the
Trust or the  Trust  Estate to the  appointment  of or  taking  possession  by a
receiver,  liquidator,  assignee,  trustee,  custodian,  sequestrator  (or other
similar official) of the Owner Participant,  the Owner Trustee, the Trust or the
Trust Estate or for all or substantially  all of its property,  or the making by
the Owner Participant,  the Owner Trustee,  the Trust or the Trust Estate of any

<PAGE>

assignment  for the benefit of creditors or the Owner  Participant  or the Owner
Trustee  shall  take any action to  authorize  any of the  foregoing;  PROVIDED,
HOWEVER,  that an event referred to in this Section  4.02(g) with respect to the
Owner  Participant shall not constitute an Event of Default if within 30 days of
the  commencement  of the  case  or  proceeding  a final  non-appealable  order,
judgment or decree shall be entered in such case or  proceeding  by a court or a
trustee,  custodian,  receiver or liquidator, to the effect that, no part of the
Trust Estate (except for the Owner  Participant's  beneficial  interest therein)
and no  right,  title or  interest  under the Trust  Indenture  Estate  shall be
included  in,  or  be  subject  to,  any  declaration  or  adjudication  of,  or
proceedings  with respect to, the  bankruptcy,  insolvency or liquidation of the
Owner Participant referred to in this Section 4.02(g).

      SECTION 4.03.     CERTAIN RIGHTS.

            The Mortgagee shall give the Note Holders, the Owner Trustee and the
Owner  Participant  prompt  written  notice of any Event of Default of which the
Mortgagee  has  Actual  Knowledge  and shall  give the Note  Holders,  the Owner
Trustee and the Owner Participant not less than ten Business Days' prior written
notice of the date (the "Enforcement Date") on or after which the Mortgagee may,
subject to the limitation set forth in Section 4.04(a),  commence and consummate
the exercise of any remedy or remedies  described in Section 4.04,  4.05 or 4.06
hereof;  provided,  however,  that in the event the Mortgagee shall have validly
terminated the Lease, the Mortgagee shall not sell or lease, or otherwise afford
the use of, the Aircraft or any portion  thereof to the Lessee or any  Affiliate
thereof.  Without limiting the generality of the foregoing,  the Mortgagee shall
give the  Owner  Trustee,  the  Owner  Participant  and the  Lessee at least ten
Business Days' prior written notice (which may be given concurrently with notice
of the  Enforcement  Date) of any  declaration  of the  Lease  to be in  default
pursuant to Sections 14 and 15 of the Lease or any  termination  of the Lease or
of the  exercise of any remedy or remedies  pursuant to Section 15 of the Lease.
If an Event of Default shall have occurred and be continuing,  the Owner Trustee
shall have the rights set forth below, any of which may be exercised directly by
the Owner Participant.

            If as a result of the  occurrence  of an Event of Default in respect
of the  nonpayment  by Lessee of Basic Rent due under the Lease,  the  Mortgagee
shall  have  insufficient  funds to make any  payment  of  Original  Amount  and
interest on any Equipment Note on the day it becomes due and payable,  the Owner
Trustee  may,  but  shall not be  obligated  to pay the  Mortgagee  prior to the
Enforcement Date, in the manner provided in Section 2.04 hereof, for application
in  accordance  with Section 3.01 hereof,  an amount equal to the portion of the
Original  Amount  and  interest  (including  interest,  if any,  on any  overdue
payments of such portion of Original  Amount and interest)  then due and payable
on the  Equipment  Notes,  and,  unless the Owner  Trustee  has cured  Events of
Default in respect of  payments  of Basic Rent on each of the three  immediately
preceding  Basic Rent  payment  dates (or,  for so long as any  Affiliate of The
Boeing Company is the Owner  Participant,  six immediately  preceding Basic Rent
payment  dates),  or the Owner Trustee has cured six previous  Events of Default
(or for so long as any Affiliate of The Boeing Company is the Owner Participant,
eight  previous  Events of Default)  in respect of payments of Basic Rent,  such
payment by the Owner Trustee shall,  solely for purposes of this Trust Indenture
be deemed to cure any Event of Default  which  would  otherwise  have  arisen on
account of the  nonpayment by Lessee of such  installment of Basic Rent (but not

<PAGE>

any  other  Default  or  Event of  Default  which  shall  have  occurred  and be
continuing).

            If any Event of Default  (other than in respect of the nonpayment of
Basic  Rent by the  Lessee)  which  can be cured  by the  payment  of money  has
occurred,  the Owner Trustee may, but shall not be obligated to, cure such Event
of Default by making such payment prior to the Enforcement  Date as is necessary
to accomplish the observance or performance of the defaulted covenant, condition
or agreement to the party entitled to the same.

            Except as  hereinafter  in this  Section  4.03  provided,  the Owner
Trustee shall not, as a result of exercising the right to cure any such Event of
Default,  obtain any Lien on any of the  Mortgaged  Property or any Rent payable
under the Lease for or on account of costs or expenses  incurred  in  connection
with the  exercise  of such  right,  nor shall  any  claim of the Owner  Trustee
against  Lessee or any other party for the  repayment  of such costs or expenses
impair the prior  right and  security  interest of the  Mortgagee  in and to the
Mortgaged Property.  Upon any payment by the Owner Trustee pursuant to the first
or second preceding  paragraphs of this Section 4.03, the Owner Trustee shall be
subrogated to the rights of the Mortgagee and the Note Holders in respect of the
Basic Rent which was overdue at the time of such payment and interest payable by
the Lessee on account of its being overdue and any Supplemental  Rent in respect
of  the  reimbursement  of  amounts  paid  by  Owner  Trustee  pursuant  to  the
immediately  preceding  paragraph  (but in either case shall have no rights as a
secured party  hereunder),  and thereafter,  the Owner Trustee shall be entitled
(so long as the  application  thereof shall not give rise to an Event of Default
hereunder) to receive such overdue Basic Rent or Supplemental  Rent, as the case
may be, and interest  thereon upon receipt  thereof by the Mortgagee;  PROVIDED,
HOWEVER,  that (i) if the Original  Amount and interest on the  Equipment  Notes
shall have  become due and  payable  pursuant to Section  4.04(b)  hereof,  such
subrogation shall,  until the Secured  Obligations shall have been paid in full,
be  subordinate  to the  rights of the  Mortgagee,  the Note  Holders  and other
holders of Secured Obligations in respect of such payment of overdue Basic Rent,
Supplemental  Rent and such  interest  and (ii) the Owner  Trustee  shall not be
entitled  to seek to recover any such  payment (or any payment in lieu  thereof)
except pursuant to the foregoing right of subrogation.

            Neither the Owner Trustee nor the Owner  Participant  shall have the
right to cure any Lease Event of Default or Lease Default except as specified in
this Section 4.03.

      SECTION 4.04.     REMEDIES.

            (a) If an Event of Default shall have occurred and be continuing and
so long as the same shall continue  unremedied,  then and in every such case the
Mortgagee  may,  subject  to the  second and third  paragraphs  of this  Section
4.04(a),  exercise any or all of the rights and powers and pursue any and all of
the remedies  pursuant to this Article IV and shall have and may exercise all of
the rights and  remedies of a secured  party under the Uniform  Commercial  Code
and, in the event such Event of Default is also a Lease  Event of  Default,  any

<PAGE>

and all of the remedies pursuant to Section 15 of the Lease [and pursuant to any
Permitted Sublease  assignment]<F11>  and may take possession of all or any part
of the  properties  covered or intended to be covered by the Lien created hereby
or pursuant hereto and may exclude the Owner Participant,  the Owner Trustee and
Lessee and all persons  claiming  under any of them wholly or partly  therefrom;
provided,  that  the  Mortgagee  shall  give the  Owner  Trustee  and the  Owner
Participant  twenty  days' prior  written  notice of its  intention  to sell the
Aircraft,  and provided,  further,  that in the event the  Mortgagee  shall have
validly  terminated  the  Lease,  the  Mortgagee  shall  not sell or  lease,  or
otherwise  afford the use of, the Aircraft or any portion  thereof to the Lessee
or any  Affiliate  thereof.  Unless an Event of Default  not  resulting  from or
relating to a Lease Event of Default has occurred and is  continuing,  the Owner
Participant may bid at the sale and become the purchaser.  Without  limiting any
of the  foregoing,  it is understood  and agreed that the Mortgagee may exercise
any right of sale of the Aircraft available to it, even though it shall not have
taken  possession of the Aircraft and shall not have  possession  thereof at the
time of such sale.

            Anything in this Trust  Indenture to the  contrary  notwithstanding,
the Mortgagee shall not be entitled to exercise any remedy hereunder as a result
of an Event of Default  which  arises  solely by reason of one or more events or
circumstances  which constitute a Lease Event of Default unless the Mortgagee as
security  assignee of the Owner Trustee shall have exercised or  concurrently be
exercising one or more of the dispossessory  remedies provided for in Section 15
of the  Lease  with  respect  to the  Aircraft;  PROVIDED,  HOWEVER,  that  such
requirement  to exercise one or more of such remedies  under the Lease shall not
apply in  circumstances  where the Mortgagee is, and has been,  for a continuous
period in excess of 60 days or such other  period as may be specified in Section
1110(a)(1)(A) of the Bankruptcy Code (such 60-day or other period being the "New
Section 1110 Period"),  involuntarily  stayed or prohibited by applicable law or
court order from  exercising  such remedies under the Lease (a "Continuous  Stay
Period");  PROVIDED  FURTHER,  HOWEVER,  that the requirement to exercise one or
more of such remedies under the Lease shall  nonetheless be applicable  during a
Continuous  Stay Period  subsequent  to the  expiration  of the New Section 1110
Period to the  extent  that the  continuation  of such  Continuous  Stay  Period
subsequent to the  expiration of the New Section 1110 Period (A) results from an
agreement by the trustee or the  debtor-in-possession  in such proceeding during
the New Section 1110 Period with the  approval of the relevant  court to perform
the Lease in accordance  with Section  1110(a)(1)(A)  of the Bankruptcy Code and
continues to perform as required by Section  1110(a)(1)(A-B)  of the  Bankruptcy
Code or (B) is an  extension  of the New Section 1110 Period with the consent of
the Mortgagee  pursuant to Section 1110(b) of the Bankruptcy Code or (C) results
from the  Lessee's  assumption  during  the New  Section  1110  Period  with the
approval  of the  relevant  court of the Lease  pursuant  to Section  365 of the
Bankruptcy Code and Lessee's  continuous  performance of the Lease as so assumed
or (D) is the  consequence of the  Mortgagee's own failure to give any requisite
notice to any person. In the event that the applicability of Section 1110 of the
Bankruptcy  Code to the  Aircraft  is being  contested  by  Lessee  in  judicial
proceedings, both of the Mortgagee and the Owner Trustee

--------------------
<F11>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<PAGE>

shall have the right to participate in such proceedings;  provided that any such
participation  by the Owner  Trustee  shall not  affect in any way any rights or
remedy of the Mortgagee hereunder.

            It is expressly  understood and agreed that, subject only to the two
preceding  paragraphs,  the  inability,  described  in such  paragraphs,  of the
Mortgagee  to exercise any right or remedy under the Lease shall in no event and
under no  circumstances  prevent the Mortgagee from exercising any or all of its
rights,  powers and  remedies  under this Trust  Indenture,  including,  without
limitation, this Article IV.

            (b) If an Event of Default  shall have  occurred and be  continuing,
then and in every such case the  Mortgagee  may (and  shall,  upon  receipt of a
written demand therefor from a Majority in Interest of Note Holders), subject to
Section 4.03 hereof,  at any time,  by delivery of written  notice or notices to
the Owner Trustee and the Owner Participant,  declare all the Equipment Notes to
be due and payable,  whereupon the unpaid Original Amount of all Equipment Notes
then  outstanding,  together with accrued but unpaid interest  thereon  (without
Make-Whole  Amount) and other amounts due thereunder,  shall immediately  become
due and payable without presentment, demand, protest or notice, all of which are
hereby waived; provided that if an Event of Default referred to in clause (g) of
Section 4.02 hereof shall have occurred,  then and in every such case the unpaid
Original Amount then outstanding,  together with accrued but unpaid interest and
all other amounts due thereunder  and hereunder  shall  immediately  and without
further  act become due and  payable  without  presentment,  demand,  protest or
notice, all of which are hereby waived;  provided further that in the event of a
reorganization  proceeding  involving the Lessee  instituted under Chapter 11 of
the  Bankruptcy  Code, if no other Lease Event of Default  (including  any Lease
Event of Default  set forth in Section  14.3 of the Lease) and no other Event of
Default  (other than the  failure to pay the  Original  Amount of the  Equipment
Notes which by such  declaration  shall have become  payable) exists at any time
after  the   consummation  of  such  proceeding,   such  declaration   shall  be
automatically  rescinded  without  any  further  action  on the part of any Note
Holder.

            This Section 4.04(b),  however, is subject to the condition that, if
at any time after the Original  Amount of the Equipment  Notes shall have become
so due and  payable,  and before any  judgment  or decree for the payment of the
money so due, or any thereof, shall be entered, all overdue payments of interest
upon the Equipment Notes and all other amounts payable under the Equipment Notes
(except the Original  Amount of the  Equipment  Notes which by such  declaration
shall have become  payable)  shall have been duly paid,  and every other Default
and Event of Default  with  respect to any  covenant or  provision of this Trust
Indenture  shall have been  cured,  then and in every  such case a  Majority  in
Interest  of Note  Holders  may (but  shall not be  obligated  to),  by  written
instrument  filed  with  the  Mortgagee,   rescind  and  annul  the  Mortgagee's
declaration (or such automatic  acceleration) and its consequences;  but no such
rescission  or  annulment  shall extend to or affect any  subsequent  Default or
Event of Default or impair any right consequent thereon.

            Any   acceleration   pursuant  to  this  Section  4.04(b)  shall  be
automatically  rescinded  and any  related  declaration  of an Event of  Default
annulled in the event that the Owner  Trustee  shall have cured,  in  accordance
with  Section  4.03  hereof,   the  Event  of  Default  that  resulted  in  such
acceleration or declaration.

<PAGE>

            (c) The Note  Holders  shall be  entitled,  at any sale  pursuant to
Section 15 of the Lease or this  Section  4.04,  to credit  against any purchase
price bid at such sale by such holder all or any part of the unpaid  obligations
owing to such Note Holder and secured by the Lien of this Trust  Indenture (only
to the extent that such purchase  price would have been paid to such Note Holder
pursuant to Article III hereof if such purchase  price were paid in cash and the
foregoing provisions of this subsection (c) were not given effect).

            (d) In the event of any sale of the Trust Indenture  Estate,  or any
part  thereof,  pursuant to any  judgment or decree of any court or otherwise in
connection with the enforcement of any of the terms of this Trust Indenture, the
unpaid Original Amount of all Equipment  Notes then  outstanding,  together with
accrued  interest  thereon (without  Make-Whole  Amount),  and other amounts due
thereunder,  shall  immediately  become  due and  payable  without  presentment,
demand, protest or notice, all of which are hereby waived.

            (e)  Notwithstanding  anything contained herein, so long as the Pass
Through  Trustee under any Pass Through  Trust  Agreement (or its designee) is a
Note Holder,  the Mortgagee will not be authorized or empowered to acquire title
to any  Mortgaged  Property  or take any action  with  respect to any  Mortgaged
Property so acquired by it if such  acquisition  or action would cause any Trust
to fail to qualify as a "grantor trust" for federal income tax purposes.

      SECTION 4.05.     RETURN OF AIRCRAFT, ETC.

            (a) If an Event of Default shall have occurred and be continuing and
the Equipment  Notes have been  accelerated,  subject to Section 4.03 hereof and
unless the Owner Trustee or the Owner Participant shall have elected to purchase
the Equipment  Notes,  at the request of the Mortgagee,  the Owner Trustee shall
promptly  execute and deliver to the  Mortgagee  such  instruments  of title and
other  documents as the Mortgagee may deem  necessary or advisable to enable the
Mortgagee or an agent or  representative  designated by the  Mortgagee,  at such
time or times  and  place or  places as the  Mortgagee  may  specify,  to obtain
possession  of all or any part of the Mortgaged  Property  included in the Trust
Indenture Estate to which the Mortgagee shall at the time be entitled hereunder.
If the Owner  Trustee  shall for any reason  fail to execute  and  deliver  such
instruments and documents after such request by the Mortgagee, the Mortgagee may
(i)  obtain a  judgment  conferring  on the  Mortgagee  the  right to  immediate
possession  and  requiring  the  Owner  Trustee  to  execute  and  deliver  such
instruments  and documents to the Mortgagee,  to the entry of which judgment the
Owner Trustee hereby  specifically  consents to the fullest extent  permitted by
Law, and (ii) pursue all or part of such Mortgaged  Property  wherever it may be
found  and,  in the event  that a Lease  Event of Default  has  occurred  and is
continuing,  may enter any of the  premises of Lessee  wherever  such  Mortgaged
Property may be or be supposed to be and search for such Mortgaged  Property and
take possession of and remove such Mortgaged Property. All expenses of obtaining
such  judgment or of pursuing,  searching  for and taking such  property  shall,
until paid, be secured by the Lien of this Trust Indenture.

            (b) Upon every such taking of  possession,  the Mortgagee  may, from
time  to  time,  at the  expense  of  the  Mortgaged  Property,  make  all  such
expenditures for  maintenance,  use,  operation,  storage,  insurance,  leasing,
control,  management,  disposition,  modifications  or alterations to and of the

<PAGE>

Mortgaged  Property,  as it may deem proper.  In each such case,  the  Mortgagee
shall have the right to maintain,  use, operate,  store, insure, lease, control,
manage,  dispose of, modify or alter the Mortgaged  Property and to carry on the
business and to exercise all rights and powers of the Owner  Participant and the
Owner Trustee  relating to the Mortgaged  Property,  as the Mortgagee shall deem
best, including the right to enter into any and all such agreements with respect
to the  maintenance,  use,  operation,  storage,  insurance,  leasing,  control,
management, disposition, modification or alteration of the Mortgaged Property or
any part thereof as the Mortgagee  may  determine,  and the  Mortgagee  shall be
entitled to collect and receive  directly  all tolls,  rents  (including  Rent),
revenues,  issues,  income,  products and profits of the Mortgaged  Property and
every part thereof, except Excluded Payments, without prejudice, however, to the
right of the Mortgagee  under any  provision of this Trust  Indenture to collect
and receive all cash held by, or required to be deposited  with,  the  Mortgagee
hereunder other than Excluded  Payments.  Such tolls,  rents  (including  Rent),
revenues,  issues,  income,  products  and  profits  shall be applied to pay the
expenses  of the  maintenance,  use,  operation,  storage,  insurance,  leasing,
control, management, disposition, improvement, modification or alteration of the
Mortgaged  Property  and of  conducting  the business  thereof,  and to make all
payments  which the  Mortgagee may be required or may elect to make, if any, for
taxes,  assessments,  insurance  or other  proper  charges  upon  the  Mortgaged
Property  or any  part  thereof  (including  the  employment  of  engineers  and
accountants  to examine,  inspect and make reports upon the properties and books
and records of the Owner  Trustee),  and all other  payments which the Mortgagee
may be  required  or  authorized  to make  under  any  provision  of this  Trust
Indenture,  as well as just and reasonable  compensation for the services of the
Mortgagee,  and of all persons  properly  engaged and employed by the  Mortgagee
with respect hereto.

      SECTION 4.06.     REMEDIES CUMULATIVE.

            Each and  every  right,  power  and  remedy  given to the  Mortgagee
specifically  or otherwise in this Trust Indenture shall be cumulative and shall
be in addition to every other right, power and remedy herein  specifically given
or now or hereafter existing at Law, in equity or by statute, and each and every
right, power and remedy whether  specifically herein given or otherwise existing
may be  exercised  from  time to time and as often  and in such  order as may be
deemed  expedient by the  Mortgagee,  and the  exercise or the  beginning of the
exercise  of any power or remedy  shall not be  construed  to be a waiver of the
right to  exercise  at the same time or  thereafter  any other  right,  power or
remedy.  No delay or omission  by the  Mortgagee  in the  exercise of any right,
remedy or power or in the  pursuance  of any remedy shall impair any such right,
power or remedy or be construed to be a waiver of any default on the part of the
Owner Trustee or Lessee or to be an acquiescence therein.

      SECTION 4.07.     DISCONTINUANCE OF PROCEEDINGS.

            In case the  Mortgagee  shall  have  instituted  any  proceeding  to
enforce any right,  power or remedy under this Trust  Indenture by  foreclosure,
entry or  otherwise,  and such  proceedings  shall  have  been  discontinued  or
abandoned  for any  reason  or  shall  have  been  determined  adversely  to the
Mortgagee,  then and in every such case the Owner  Trustee,  the  Mortgagee  and
Lessee shall,  subject to any determination in such proceedings,  be restored to

<PAGE>

their  former  positions  and rights  hereunder  with  respect to the  Mortgaged
Property,  and all  rights,  remedies  and  powers  of the  Owner  Trustee,  the
Mortgagee  or  Lessee  shall  continue  as  if  no  such  proceedings  had  been
instituted.

      SECTION 4.08.     WAIVER OF PAST DEFAULTS.

            Upon  written  instruction  from a  Majority  in  Interest  of  Note
Holders,   the  Mortgagee  shall  waive  any  past  Default  hereunder  and  its
consequences  and upon any such waiver such Default shall cease to exist and any
Event of Default arising  therefrom shall be deemed to have been cured for every
purpose  of  this  Trust  Indenture,  but no such  waiver  shall  extend  to any
subsequent or other Default or impair any right  consequent  thereon;  provided,
that in the  absence  of written  instructions  from all the Note  Holders,  the
Mortgagee shall not waive any Default (i) in the payment of the Original Amount,
Make-Whole  Amount,  if any,  and  interest  and  other  amounts  due  under any
Equipment Note then  outstanding,  or (ii) in respect of a covenant or provision
hereof which, under Article IX hereof, cannot be modified or amended without the
consent of each Note Holder.

      SECTION 4.09.     APPOINTMENT OF RECEIVER.

            The  Mortgagee  shall,  as a matter of  right,  be  entitled  to the
appointment  of a receiver (who may be the Mortgagee or any successor or nominee
thereof)  for  all  or  any  part  of  the  Mortgaged  Property,   whether  such
receivership  be incidental to a proposed sale of the Mortgaged  Property or the
taking of possession thereof or otherwise, and the Owner Trustee hereby consents
to the appointment of such a receiver and will not oppose any such  appointment.
Any receiver  appointed for all or any part of the Mortgaged  Property  shall be
entitled to exercise all the rights and powers of the Mortgagee  with respect to
the Mortgaged Property.

      SECTION 4.10.     MORTGAGEE AUTHORIZED TO EXECUTE BILLS OF SALE, ETC.

            Subject to the provisions of this Trust Indenture, the Owner Trustee
irrevocably  appoints the Mortgagee the true and lawful  attorney-in-fact of the
Owner Trustee  (which  appointment  is coupled with an interest) in its name and
stead and on its behalf,  for the purpose of effectuating any sale,  assignment,
transfer or delivery for the  enforcement  of the Lien of this Trust  Indenture,
whether  pursuant  to  foreclosure  or  power  of sale,  assignments  and  other
instruments as may be necessary or appropriate, with full power of substitution,
the Owner Trustee hereby  ratifying and confirming all that such attorney or any
substitute  shall  do by  virtue  hereof  in  accordance  with  applicable  law.
Nevertheless,  if so requested  by the  Mortgagee  or any  purchaser,  the Owner
Trustee  shall  ratify  and  confirm  any such  sale,  assignment,  transfer  or
delivery,  by executing and  delivering  to the Mortgagee or such  purchaser all
bills of sale, assignments, releases and other proper instruments to effect such
ratification and confirmation as may be designated in any such request.

      SECTION 4.11.     RIGHTS OF NOTE HOLDERS TO RECEIVE PAYMENT.

            Notwithstanding  any other  provision of this Trust  Indenture,  the
right of any Note Holder to receive  payment of principal  of, and  premium,  if
any,  and  interest on an Equipment  Note on or after the  respective  due dates
expressed in such  Equipment  Note, or to bring suit for the  enforcement of any

<PAGE>

such  payment on or after such  respective  dates in  accordance  with the terms
hereof,  shall not be  impaired  or  affected  without  the consent of such Note
Holder.

                                    ARTICLE V

                             DUTIES OF THE MORTGAGEE

      SECTION 5.01.     NOTICE OF EVENT OF DEFAULT.

            If the Mortgagee shall have Actual  Knowledge of an Event of Default
or of a Default  arising from a failure to pay Rent,  the  Mortgagee  shall give
prompt  written  notice  thereof to the Owner  Trustee,  the Owner  Participant,
Lessee, and each Note Holder. Subject to the terms of Sections 2.13, 4.03, 4.04,
4.08,  5.02 and 5.03 hereof,  the Mortgagee  shall take such action,  or refrain
from  taking  such  action,  with  respect  to such  Event of Default or Default
(including with respect to the exercise of any rights or remedies  hereunder) as
the  Mortgagee  shall be instructed in writing by a Majority in Interest of Note
Holders.  Subject to the provisions of Section 5.03, if the Mortgagee  shall not
have received instructions as above provided within 20 days after mailing notice
of such Event of Default to the Note  Holders,  the  Mortgagee  may,  subject to
instructions  thereafter  received pursuant to the preceding  provisions of this
Section 5.01, take such action, or refrain from taking such action, but shall be
under no duty to take or refrain  from taking any action,  with  respect to such
Event  of  Default  or  Default  as it  shall  determine  advisable  in the best
interests of the Note  Holders;  PROVIDED,  HOWEVER,  that the Mortgagee may not
sell the Aircraft or any Engine without the consent of a Majority in Interest of
Note Holders. For all purposes of this Trust Indenture, in the absence of Actual
Knowledge  on  the  part  of the  Mortgagee,  the  Owner  Trustee  or the  Owner
Participant,  the Mortgagee, the Owner Trustee or the Owner Participant,  as the
case may be,  shall not be deemed to have  knowledge of a Default or an Event of
Default (except, in the case of the Mortgagee,  the failure of Lessee to pay any
installment  of Basic Rent within one  Business  Day after the same shall become
due,  if any  portion of such  installment  was then  required to be paid to the
Mortgagee,  which  failure  shall  constitute  knowledge  of a  Default)  unless
notified in writing by Lessee,  the Owner Trustee,  the Owner Participant or one
or more Note Holders.

      SECTION 5.02.     ACTION UPON INSTRUCTIONS; CERTAIN RIGHTS AND
                        LIMITATIONS.

            (a) Subject to the terms of Sections  2.13,  4.03,  4.04(a) and (b),
4.08, 5.01 and 5.03 hereof,  upon the written  instructions at any time and from
time to time of a Majority in Interest of Note  Holders,  the  Mortgagee  shall,
subject to the terms of this Section 5.02, take such of the following actions as
may be  specified  in such  instructions:  (i) give such notice or  direction or
exercise  such right,  remedy or power  hereunder  as shall be specified in such
instructions;  (ii) give such notice or direction or exercise such right, remedy
or power under the Lease, the Participation  Agreement,  the Purchase Agreement,
the  Purchase  Agreement  Assignment,  or any other part of the Trust  Indenture
Estate  as shall  be  specified  in such  instructions;  and  (iii)  approve  as
satisfactory to the Mortgagee all matters  required by the terms of the Lease to

<PAGE>

be  satisfactory  to the Owner  Trustee,  it being  understood  that without the
written  instructions  of a Majority in Interest of Note Holders,  the Mortgagee
shall not approve any such matter as  satisfactory  to the Mortgagee;  provided,
that  anything  contained  in this  Trust  Indenture,  the  Lease  or the  other
Operative  Agreements to the contrary  notwithstanding,  but subject to the next
paragraph hereof:

            (1) the Owner  Trustee or the Owner  Participant,  may,  without the
      consent of the Mortgagee, demand, collect, sue for or otherwise obtain all
      amounts  included  in  Excluded  Payments  from  Lessee  and seek legal or
      equitable  remedies to require  Lessee to maintain the insurance  coverage
      referred to in Section 11 of the Lease [(or the  comparable  provisions of
      any assigned Permitted  Sublease)]<F12> provided, that the rights referred
      to in this clause (1) shall not be deemed to include  the  exercise of any
      remedies  provided  for in Section 15 of the Lease other than the right to
      proceed  by  appropriate  court  action,  either at Law or in  equity,  to
      enforce payment by Lessee of such amounts included in Excluded Payments or
      performance by Lessee of such insurance covenant or to recover damages for
      the breach  thereof or for specific  performance  of any other term of the
      Lease  [(or  the   comparable   provisions   of  any  assigned   Permitted
      Sublease)]<F13>;

            (2) (A) the  Mortgagee  shall not,  without the consent of the Owner
      Trustee,  enter into,  execute or deliver  amendments or  modifications in
      respect of any of the  provisions  of the Lease[,  any assigned  Permitted
      Sublease  or any  Permitted  Sublease  assignment]<F14>,  and (B) unless a
      Mortgagee Event shall have occurred and be continuing, the Mortgagee shall
      not, without the consent of the Owner Trustee,  which consent shall not be
      withheld  if no  right or  interest  of the  Owner  Trustee  or the  Owner
      Participant  shall be  diminished  or  impaired  thereby,  (i) enter into,
      execute or deliver waivers or consents in respect of any of the provisions
      of the Lease, or (ii) approve any  accountants,  engineers,  appraisers or
      counsel as  satisfactory  to render  services for or issue opinions to the
      Owner Trustee pursuant to the Operative Agreements,  provided that whether
      or not any  Mortgagee  Event has  occurred  and is  continuing,  the Owner
      Trustee's  consent  shall be  required  with  respect  to any  waivers  or
      consents in respect of any of the  provisions of Section 5, 7 or 11 of the
      Lease,  or of any other  Section  of the Lease to the extent  such  action
      shall affect (y) the amount or timing of, or the right to enforce  payment
      of any Excluded Payment or (z) the amount or timing of any amounts payable
      by the Lessee under the Lease as originally  executed (or as  subsequently
      modified  with  the  consent  of the  Owner  Trustee)  which,  absent  the
      occurrence  and  continuance  of an Event of Default  hereunder,  would be
      distributable to the Owner Trustee under Article III hereof;

            (3)  whether or not a Default  or Event of  Default  under the Trust
      Indenture has occurred and is continuing,  the Owner Trustee and the Owner
      Participant  shall have the right,  together  with the  Mortgagee,  (i) to

--------------------
<F12>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<F13>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<F14>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<PAGE>

      receive from Lessee [or any  Permitted  Sublessee]<F15>  certificates  and
      other  documents  and  information  which  Lessee is  required  to give or
      furnish  to the Owner  Trustee  or the Lessor  pursuant  to any  Operative
      Agreement  and (ii) to inspect in  accordance  with the Lease the Airframe
      and Engines and all Aircraft Documents;

            (4)  whether or not a Default  or Event of  Default  under the Trust
      Indenture has occurred and is continuing, the Owner Trustee shall have the
      right to adjust  upwards  Rent,  Stipulated  Loss  Values and  Termination
      Values as provided in Section 3.2.1 of the Lease or pursuant to a transfer
      under Section 10.1.1 of the Participation Agreement;

            (5) so long as no Mortgagee  Event has  occurred and is  continuing,
      the Owner Trustee shall have the right, to the exclusion of the Mortgagee,
      to adjust Basic Rent,  Stipulated  Loss Values and  Termination  Values as
      provided in Section 3.2 of the Lease or to adjust downward any installment
      or amount of Basic Rent,  Stipulated  Loss Value or Termination  Value, as
      such  installments  and  amounts  are set forth in  Schedules  2, 3 and 4,
      respectively,  to  the  Lease,  to  the  extent  of the  portion  of  such
      installment or amount that would, under Section 3.01, 3.02 or 3.03 hereof,
      as the case may be, be  distributable  to the Owner  Trustee  or the Owner
      Participant;

            (6)  whether or not a Default  or Event of  Default  under the Trust
      Indenture has occurred and is continuing,  the Owner Trustee may,  without
      the consent of the  Mortgagee,  (i) solicit and make bids with  respect to
      the Aircraft  under Section 9 of the Lease in respect of a termination  of
      the Lease by Lessee  pursuant to Section 9 thereof,  (ii)  determine  Fair
      Market Sales Value and Fair Market  Rental  Value under  Section 17 of the
      Lease for all  purposes  except  following a Mortgagee  Event  pursuant to
      Section 15 of the Lease,  and (iii) make an  election  pursuant  to and in
      accordance  with the  provisions  of Sections  9.1(b),  9.2 and 9.3 of the
      Lease; and

            (7) so  long  as no  Mortgagee  Event  shall  have  occurred  and be
      continuing,  all  other  rights  of the  "Lessor"  under the Lease [or any
      assigned Permitted  Sublease]<F16> shall be exercised by the Owner Trustee
      to the exclusion of the Mortgagee including, without limitation, the right
      to (i) exercise  all rights with  respect to Lessee's  use and  operation,
      modification or maintenance of the Aircraft and any Engine which the Lease
      specifically  confers on the Lessor,  and (ii)  consent to and approve any
      assignment  pursuant  to  Section  13 of  the  Lease;  PROVIDED  that  the
      foregoing  shall not (x) limit (A) any  rights  separately  granted to the
      Mortgagee under the Operative Agreements or (B) the right of the Mortgagee
      to  receive  any funds to be  delivered  to the  "Lessor"  under the Lease
      (except  with  respect  to  Excluded  Payments)  and  under  the  Purchase
      Agreement  or (y) confer  upon the Owner  Trustee  the right to  adversely
      affect  the  validity  or  enforceability  of the lien of this  Indenture.

--------------------
<F15>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<F16>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<PAGE>

            Notwithstanding anything to the contrary contained herein (including
this Section 5.02),  the Mortgagee shall have the right, to the exclusion of the
Owner  Trustee  and the Owner  Participant,  to (A)  declare  the Lease to be in
default  under  Section 15 thereof and (B)  subject  only to the  provisions  of
Sections 4.03, 4.04(a) and (b) and 2.13 hereof,  exercise the remedies set forth
in such Section 15 (other than in connection with Excluded Payments and provided
that  each  of  the  Owner  Trustee,   Owner  Participant  and  Mortgagee  shall
independently  retain the rights set forth in clause  (ii) of Section  15.1.5 of
the Lease) at any time that a Lease Event of Default  shall have occurred and be
continuing. Further and for the avoidance of doubt, and anything to the contrary
contained  herein  (including  this  Section  5.02),  in no event  may the Owner
Trustee  amend or otherwise  modify the  provisions  of Section  3.2.1(e) of the
Lease or of the final  sentence of the  definition of  Stipulated  Loss Value or
Termination  Value,  in any such case,  without the prior written consent of the
Mortgagee.

            The Mortgagee  will execute and the Owner Trustee will file or cause
to be filed such  continuation  statements with respect to financing  statements
relating to the  security  interest  created  hereunder  in the Trust  Indenture
Estate  as may be  specified  from  time to time in  written  instructions  of a
Majority in Interest of Note Holders (which instructions shall be accompanied by
the form of such  continuation  statement so to be filed).  The  Mortgagee  will
furnish to each Note Holder (and,  during the continuation of a Mortgagee Event,
to the Owner  Trustee and Owner  Participant),  promptly  upon receipt  thereof,
duplicates or copies of all reports, notices,  requests,  demands,  certificates
and other  instruments  furnished to the Mortgagee under the Lease or hereunder,
including, without limitation, a copy of each report or notice received pursuant
to Section 9 and Paragraph E of Annex D of the Lease, respectively to the extent
that the same shall not have been  furnished to such holder  pursuant  hereto or
the Lease.

            (b) If any  Lease  Event  of  Default  shall  have  occurred  and be
continuing  and the Owner Trustee shall not have cured fully such Lease Event of
Default  under and in  accordance  with  Section  4.03  hereof,  on request of a
Majority in Interest of Note Holders,  the Mortgagee  shall declare the Lease to
be in  default  pursuant  to  Section 15 thereof  and  exercise  those  remedies
specified  by such Note  Holders.  The  Mortgagee  agrees to provide to the Note
Holders,  the Owner  Trustee and the Owner  Participant  concurrently  with such
declaration by the Mortgagee, notice of such declaration by the Mortgagee.

      SECTION 5.03.     INDEMNIFICATION.

            The  Mortgagee  shall not be  required to take any action or refrain
from  taking  any action  under  Section  5.01  (other  than the first  sentence
thereof),  5.02 or  Article  IV hereof  unless  the  Mortgagee  shall  have been
indemnified  to its  reasonable  satisfaction  against  any  liability,  cost or
expense (including  counsel fees) which may be incurred in connection  therewith
pursuant to a written  agreement  with one or more Note  Holders.  The Mortgagee
agrees that it shall look solely to the Note Holders for the satisfaction of any
indemnity  (except  expenses for  foreclosure  of the type referred to in clause

<PAGE>

"First" of Section 3.03 hereof)  owed to it pursuant to this Section  5.03.  The
Mortgagee  shall not be under any obligation to take any action under this Trust
Indenture or any other  Operative  Agreement and nothing herein or therein shall
require the  Mortgagee  to expend or risk its own funds or  otherwise  incur the
risk of any  financial  liability  in the  performance  of any of its  rights or
powers if it shall have reasonable  grounds for believing that repayment of such
funds or adequate  indemnity  against such risk or  liability is not  reasonably
assured to it (the written  indemnity of any Note Holder who is a QIB, signed by
an authorized officer thereof,  in favor of, delivered to and in form reasonably
satisfactory  to the  Mortgagee  shall be accepted as  reasonable  assurance  of
adequate  indemnity).  The  Mortgagee  shall not be  required to take any action
under Section 5.01 (other than the first sentence thereof) or 5.02 or Article IV
hereof,  nor shall any other  provision  of this  Trust  Indenture  or any other
Operative  Agreement  be deemed to  impose a duty on the  Mortgagee  to take any
action,  if the Mortgagee shall have been advised by counsel that such action is
contrary to the terms hereof or of the Lease or is otherwise contrary to Law.

      SECTION 5.04.     NO DUTIES EXCEPT AS SPECIFIED IN TRUST INDENTURE OR
                        INSTRUCTIONS.

            The Mortgagee shall not have any duty or obligation to use, operate,
store,  lease,  control,  manage,  sell,  dispose of or otherwise  deal with the
Aircraft or any other part of the Trust Indenture  Estate,  or to otherwise take
or refrain  from taking any action  under,  or in  connection  with,  this Trust
Indenture  or any  part of the  Trust  Indenture  Estate,  except  as  expressly
provided  by the terms of this  Trust  Indenture  or as  expressly  provided  in
written instructions from Note Holders as provided in this Trust Indenture;  and
no implied duties or obligations shall be read into this Trust Indenture against
the Mortgagee.  The Mortgagee agrees that it will in its individual capacity and
at its own cost and expense  (but  without any right of  indemnity in respect of
any such cost or expense under  Section 7.01 hereof),  promptly take such action
as may be necessary duly to discharge all liens and  encumbrances on any part of
the Trust Indenture Estate which result from claims against it in its individual
capacity not related to the ownership of the Aircraft or the  administration  of
the Trust  Indenture  Estate or any other  transaction  pursuant  to this  Trust
Indenture or any document included in the Trust Indenture Estate.

      SECTION 5.05.     NO ACTION EXCEPT UNDER LEASE, TRUST INDENTURE OR
                        INSTRUCTIONS.

            The Owner  Trustee and the  Mortgagee  agree that they will not use,
operate, store, lease, control,  manage, sell, dispose of or otherwise deal with
the  Aircraft  or any other  part of the Trust  Indenture  Estate  except (i) as
required by the terms of the Lease or (ii) in accordance with the powers granted
to, or the  authority  conferred  upon,  the  Owner  Trustee  and the  Mortgagee
pursuant  to this Trust  Indenture  and in  accordance  with the  express  terms
hereof.

      SECTION 5.06.     REPLACEMENT AIRFRAMES AND REPLACEMENT ENGINES.

            At any  time an  Airframe  or  Engine  is to be  replaced  under  or
pursuant to Section 10 of the Lease by a  Replacement  Airframe  or  Replacement
Engine,  if no Lease Event of Default is  continuing,  the Owner  Trustee  shall
direct the Mortgagee to execute and deliver to the Owner Trustee an  appropriate
instrument releasing such Airframe and/or Engine as appropriate from the Lien of

<PAGE>

this Trust Indenture and the Mortgagee shall execute and deliver such instrument
as aforesaid,  but only upon compliance by Lessee with the applicable provisions
of Section 10 of the Lease.

      SECTION 5.07.     INDENTURE SUPPLEMENTS FOR REPLACEMENTS.

            If a Replacement Airframe or Replacement Engine is being substituted
as contemplated by Section 10 of the Lease,  the Owner Trustee and the Mortgagee
agree for the benefit of the Note Holders and Lessee,  subject to fulfillment of
the conditions precedent and compliance by Lessee with its obligations set forth
in Section 10 of the Lease and the  requirements  of Section  5.06  hereof  with
respect to such  Replacement  Airframe  or  Replacement  Engine,  to execute and
deliver a Lease Supplement and a Trust Indenture Supplement,  as applicable,  as
contemplated by Section 10 of the Lease.

      SECTION 5.08.     EFFECT OF REPLACEMENT.

            In the event of the  substitution of an Airframe or of a Replacement
Engine  pursuant  to  Section  10 of the  Lease,  all  provisions  of this Trust
Indenture  relating to the Airframe or Engine or Engines being replaced shall be
applicable to such  Replacement  Airframe or Replacement  Engine or Engines with
the same force and effect as if such Replacement  Airframe or Replacement Engine
or Engines were the same  airframe or engine or engines,  as the case may be, as
the Airframe or Engine or Engines being  replaced but for the Event of Loss with
respect to the Airframe or Engine or Engines being replaced.

      SECTION 5.09.     INVESTMENT OF AMOUNTS HELD BY MORTGAGEE.

            Any amounts held by the Mortgagee as assignee of the Owner Trustee's
rights to hold monies for security pursuant to Section 4.4 of the Lease shall be
held in accordance with the terms of such Section and the Mortgagee agrees,  for
the  benefit of Lessee,  to perform the duties of the Owner  Trustee  under such
Section.  Any amounts held by the Mortgagee pursuant to the proviso to the first
sentence of Section 3.01, pursuant to Section 3.02, or pursuant to any provision
of any  other  Operative  Agreement  providing  for  amounts  to be  held by the
Mortgagee which are not distributed  pursuant to the other provisions of Article
III  hereof  shall  be  invested  by the  Mortgagee  from  time  to time in Cash
Equivalents  as  directed  by the Owner  Trustee  so long as the  Mortgagee  may
acquire  the same  using  its best  efforts.  All Cash  Equivalents  held by the
Mortgagee pursuant to Section 4.4 of the Lease or this Section 5.09 shall either
be (a) registered in the name of, payable to the order of, or specially indorsed
to,  the  Mortgagee,  or (b)  held  in an  Eligible  Account.  Unless  otherwise
expressly  provided in this Trust Indenture,  any income realized as a result of
any such  investment,  net of the  Mortgagee's  reasonable  fees and expenses in
making such  investment,  shall be held and applied by the Mortgagee in the same
manner as the  principal  amount of such  investment  is to be  applied  and any
losses, net of earnings and such reasonable fees and expenses,  shall be charged
against the principal amount invested. The Mortgagee shall not be liable for any
loss resulting  from any  investment  required to be made by it under this Trust
Indenture  other than by reason of its willful  misconduct or gross  negligence,
and any such  investment  may be sold  (without  regard to its  maturity) by the
Mortgagee  without  instructions  whenever  such  sale  is  necessary  to make a
distribution required by this Trust Indenture.

<PAGE>

                                   ARTICLE VI

                       THE OWNER TRUSTEE AND THE MORTGAGEE

      SECTION 6.01.     ACCEPTANCE OF TRUSTS AND DUTIES.

            The Mortgagee accepts the duties hereby created and applicable to it
and agrees to perform  the same but only upon the terms of this Trust  Indenture
and agrees to receive and  disburse  all monies  constituting  part of the Trust
Indenture Estate in accordance with the terms hereof. The Owner Trustee,  in its
individual capacity, and the Mortgagee, in its individual capacity, shall not be
answerable  or  accountable  under any  circumstances,  except (i) for their own
willful  misconduct or gross  negligence  (other than for the handling of funds,
for  which  the  standard  of  accountability  shall be  willful  misconduct  or
negligence),  (ii) in the  case of the  Mortgagee,  as  provided  in the  fourth
sentence of Section 2.04(a) hereof and the last sentence of Section 5.04 hereof,
and (iii) for  liabilities  that may result,  in the case of the Owner  Trustee,
from the  inaccuracy  of any  representation  or warranty  of the Owner  Trustee
expressly made in its individual  capacity in the Participation  Agreement or in
Section 4.01(b) or 6.03 hereof (or in any certificate furnished to the Mortgagee
or any Note  Holder in  connection  with the  transactions  contemplated  by the
Operative  Agreements)  or,  in the  case of the  Mortgagee  (in its  individual
capacity),  from  the  inaccuracy  of  any  representation  or  warranty  of the
Mortgagee  (in  its  individual  capacity)  in the  Participation  Agreement  or
expressly made  hereunder.  Neither the Owner Trustee nor the Mortgagee shall be
liable for any action or inaction of the other or of the Owner Participant.

      SECTION 6.02.     ABSENCE OF DUTIES.

            In the case of the  Mortgagee,  except in  accordance  with  written
instructions  furnished  pursuant to Section 5.01 or 5.02 hereof,  and except as
provided in, and without  limiting the  generality of,  Sections 5.03,  5.04 and
6.08 hereof and, in the case of the Owner Trustee, except as provided in Section
4.01(b)  hereof,  the Owner Trustee and the Mortgagee  shall have no duty (i) to
see to any  registration of the Aircraft or any recording or filing of the Lease
or of this Trust Indenture or any other  document,  or to see to the maintenance
of any such registration,  recording or filing,  (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,  (iii) to see to the  payment  or
discharge of any lien or  encumbrance  of any kind against any part of the Trust
Estate or the Trust Indenture  Estate,  (iv) to confirm,  verify or inquire into
the failure to receive any financial  statements from Lessee,  or (v) to inspect
the  Aircraft  at any time or  ascertain  or  inquire as to the  performance  or
observance of any of Lessee's covenants under the Lease [or any of the Permitted
Sublessee's  covenants under any assigned Permitted  Sublease]<F17> with respect

--------------------
<F17>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<PAGE>

to the Aircraft. The Owner Participant shall not have any duty or responsibility
hereunder, including, without limitation, any of the duties mentioned in clauses
(i) through (v) above;  provided,  that nothing contained in this sentence shall
limit any obligations of the Owner Participant under the Participation Agreement
or relieve the Owner Participant from any restriction under Section 4.03 hereof.

      SECTION 6.03.     NO REPRESENTATIONS OR WARRANTIES AS TO AIRCRAFT OR
                        DOCUMENTS.

            NEITHER THE MORTGAGEE IN ITS  INDIVIDUAL  OR TRUST  CAPACITY NOR THE
OWNER  TRUSTEE IN ITS  INDIVIDUAL  CAPACITY OR AS OWNER  TRUSTEE UNDER THE TRUST
AGREEMENT,  MAKES OR SHALL BE  DEEMED  TO HAVE  MADE AND EACH  HEREBY  EXPRESSLY
DISCLAIMS ANY REPRESENTATION OR WARRANTY,  EXPRESS OR IMPLIED,  AS TO THE TITLE,
AIRWORTHINESS,   VALUE,  COMPLIANCE  WITH  SPECIFICATIONS,   CONDITION,  DESIGN,
QUALITY,  DURABILITY,  OPERATION,  MERCHANTABILITY  OR  FITNESS  FOR  USE  FOR A
PARTICULAR PURPOSE OF THE AIRCRAFT OR ANY ENGINE, 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,  AS TO THE  ABSENCE  OF
OBLIGATIONS  BASED ON STRICT  LIABILITY IN TORT OR ANY OTHER  REPRESENTATION  OR
WARRANTY  WHATSOEVER,  except  the  Owner  Trustee  in its  individual  capacity
warrants  that (i) the Owner  Trustee has received on the Delivery Date whatever
title was  conveyed  to it,  and (ii) the  Aircraft  is free and clear of Lessor
Liens attributable to the Owner Trustee in its individual capacity.  Neither the
Owner Trustee,  in its  individual  capacity or as Owner Trustee under the Trust
Agreement,  nor the Mortgagee,  in its individual or trust capacities,  makes or
shall be deemed to have made any  representation or warranty as to the validity,
legality or  enforceability  of this Trust Indenture,  the Trust Agreement,  the
Participation  Agreement, the Equipment Notes, the Lease, the Purchase Agreement
or the Purchase  Agreement  Assignment  with the Consent and  Agreement  and the
Engine Consent and Agreement  attached thereto,  or as to the correctness of any
statement  contained  in  any  thereof,   except  for  the  representations  and
warranties  of the  Owner  Trustee  made  in its  individual  capacity  and  the
representations and warranties of the Mortgagee in its individual  capacity,  in
each  case  expressly  made  in this  Trust  Indenture  or in the  Participation
Agreement.  The Loan  Participants,  the Note Holders and the Owner  Participant
make no representation or warranty hereunder whatsoever.

      SECTION 6.04.     NO SEGREGATION OF MONIES; NO INTEREST.

            Any monies  paid to or  retained  by the  Mortgagee  pursuant to any
provision  hereof and not then required to be  distributed  to the Note Holders,
Lessee or the Owner  Trustee  as  provided  in Article  III  hereof  need not be
segregated in any manner except to the extent  required by Law or Section 4.4 of
the Lease and Section  5.09  hereof,  and may be  deposited  under such  general
conditions as may be  prescribed  by Law, and the Mortgagee  shall not be liable
for any interest thereon (except that the Mortgagee shall invest all monies held
as directed by Lessee so long as no Lease Event of Default or Lease  Default has
occurred and is continuing (or in the absence of such direction, by the Majority
In Interest of Note Holders) in Cash Equivalents;  PROVIDED,  HOWEVER,  that any
payments received, or applied hereunder, by the Mortgagee shall be accounted for

<PAGE>

by the  Mortgagee so that any portion  thereof paid or applied  pursuant  hereto
shall be identifiable as to the source thereof.

      SECTION 6.05.     RELIANCE; AGREEMENTS; ADVICE OF COUNSEL.

            Neither  the  Owner  Trustee  nor  the  Mortgagee  shall  incur  any
liability  to  anyone  in  acting  upon  any  signature,   instrument,   notice,
resolution, request, consent, order, certificate, report, opinion, bond or other
document or paper  believed by it to be genuine and  believed by it to be signed
by the proper party or parties. The Owner Trustee and the Mortgagee may accept a
copy of a resolution of the Board of Directors (or Executive  Committee thereof)
of any party to the  Participation  Agreement,  certified by the Secretary or an
Assistant  Secretary  thereof as duly  adopted and in full force and effect,  as
conclusive evidence that such resolution has been duly adopted and that the same
is in full force and  effect.  As to the  aggregate  unpaid  Original  Amount of
Equipment  Notes  outstanding  as of any  date,  the Owner  Trustee  may for all
purposes  hereof rely on a  certificate  signed by any Vice  President  or other
authorized  corporate  trust officer of the Mortgagee.  As to any fact or matter
relating  to Lessee the  manner of  ascertainment  of which is not  specifically
described  herein,  the Owner  Trustee and the  Mortgagee  may for all  purposes
hereof rely on a certificate,  signed by a duly authorized officer of Lessee, as
to such fact or matter, and such certificate shall constitute full protection to
the Owner  Trustee and the Mortgagee for any action taken or omitted to be taken
by them in good faith in reliance thereon. The Mortgagee shall assume, and shall
be fully  protected in assuming,  that the Owner  Trustee is  authorized  by the
Trust  Agreement to enter into this Trust Indenture and to take all action to be
taken by it pursuant to the  provisions  hereof,  and shall not inquire into the
authorization of the Owner Trustee with respect thereto.  In the  administration
of the trusts  hereunder,  the Owner Trustee and the Mortgagee  each may execute
any of the trusts or powers  hereof and perform its powers and duties  hereunder
directly  or through  agents or  attorneys  and may, at the expense of the Trust
Indenture Estate, advise with counsel,  accountants and other skilled persons to
be selected and retained by it, and the Owner  Trustee and the  Mortgagee  shall
not be liable for  anything  done,  suffered or omitted in good faith by them in
accordance  with the  written  advice or written  opinion  of any such  counsel,
accountants or other skilled persons.

      SECTION 6.06.     CAPACITY IN WHICH ACTING.

            The Owner Trustee acts hereunder  solely as trustee as herein and in
the Trust  Agreement  provided,  and not in its individual  capacity,  except as
otherwise  expressly  provided  herein,  in  the  Trust  Agreement  and  in  the
Participation Agreement.

      SECTION 6.07.     COMPENSATION.

            The  Mortgagee   shall  be  entitled  to  reasonable   compensation,
including expenses and disbursements (including the reasonable fees and expenses
of counsel), for all services rendered hereunder and shall, on and subsequent to
an Event of  Default  hereunder,  have a priority  claim on the Trust  Indenture
Estate  for  the  payment  of  such  compensation,   to  the  extent  that  such
compensation  shall not be paid by  Lessee,  and shall  have the  right,  on and
subsequent to an Event of Default hereunder,  to use or apply any monies held by

<PAGE>

it hereunder in the Trust Indenture  Estate toward such payments.  The Mortgagee
agrees  that it shall  have no right  against  the Loan  Participants,  the Note
Holders,  the Owner Trustee or the Owner Participant for any fee as compensation
for its services as trustee under this Trust Indenture.

      SECTION 6.08.     INSTRUCTIONS FROM NOTE HOLDERS.

            In the administration of the trusts created hereunder, the Mortgagee
shall have the right to seek  instructions  from a Majority  in Interest of Note
Holders should any provision of this Trust Indenture appear to conflict with any
other provision herein or should the Mortgagee's duties or obligations hereunder
be unclear, and the Mortgagee shall incur no liability in refraining from acting
until it receives such instructions.  The Mortgagee shall be fully protected for
acting in accordance with any instructions received under this Section 6.08.

                                   ARTICLE VII

                INDEMNIFICATION OF MORTGAGEE BY OWNER TRUSTEE

      SECTION 7.01.     SCOPE OF INDEMNIFICATION.

            The Owner  Trustee,  not in its individual  capacity,  but solely as
Owner  Trustee,   hereby  agrees,   whether  or  not  any  of  the  transactions
contemplated  hereby shall be  consummated,  except as to matters covered by any
indemnity  furnished  as  contemplated  by  Section  5.03  hereof  and except as
otherwise  provided in Section 2.03 or 2.04(b) hereof,  to assume liability for,
and does hereby indemnify, protect, save and keep harmless the Mortgagee (in its
individual  and trust  capacities),  and its  successors,  assigns,  agents  and
servants,  from  and  against  any and  all  liabilities,  obligations,  losses,
damages,  penalties,  taxes  (excluding any taxes payable by the Mortgagee on or
measured by any  compensation  received by the Mortgagee for its services  under
this Trust Indenture),  claims, actions, suits, costs, expenses or disbursements
(including legal fees and expenses) of any kind and nature whatsoever, which may
be imposed on,  incurred by or asserted  against the  Mortgagee  (whether or not
also  indemnified  against by any other person under any other  document) in any
way relating to or arising out of this Trust  Indenture  or any other  Operative
Agreement to which it is a party 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,  non-acceptance,  rejection, ownership, delivery, lease, possession,
use, operation,  condition, sale, return or other disposition of the Aircraft or
any Engine (including,  without limitation,  latent or 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 Indenture Estate or the action or inaction of the Mortgagee  hereunder
except only in the case of willful misconduct or gross negligence (or negligence
in the case of handling funds) of the Mortgagee in the performance of its duties
hereunder or resulting from the inaccuracy of any  representation or warranty of
the Mortgagee (in its individual  capacity)  referred to in Section 6.03 hereof,
or as provided in Section  6.01 hereof or in the last  sentence of Section  5.04
hereof,  or as  otherwise  excluded  by the terms of  Section  9.1 or 9.3 of the
Participation  Agreement  from  Lessee's  indemnities  under such  Sections.  In
addition, if necessary,  the Mortgagee shall be entitled to indemnification from
the Trust Indenture Estate for any liability, obligation, loss, damage, penalty,
claim, action, suit, cost, expense or disbursement  indemnified against pursuant
to this  Section  7.01 to the extent  not  reimbursed  by Lessee or others,  but

<PAGE>

without releasing any of them from their respective agreements of reimbursement;
and to  secure  the same the  Mortgagee  shall  have a prior  Lien on the  Trust
Indenture  Estate.  Without  limiting the foregoing,  the Mortgagee agrees that,
prior to  seeking  indemnification  from the  Trust  Indenture  Estate,  it will
demand,  and  diligently  pursue in good faith (but with no duty to exhaust  all
legal remedies therefor), indemnification available to the Mortgagee from Lessee
under the Lease or the Participation Agreement.

                                  ARTICLE VIII

                         SUCCESSOR AND SEPARATE TRUSTEES

      SECTION 8.01.     NOTICE OF SUCCESSOR OWNER TRUSTEE.

            In the case of any  appointment  of a successor to the Owner Trustee
pursuant  to  the  Trust  Agreement  including  upon  any  merger,   conversion,
consolidation  or sale of  substantially  all of the corporate trust business of
the Owner Trustee pursuant to the Trust  Agreement,  the successor Owner Trustee
shall give prompt written  notice thereof to the Mortgagee,  Lessee and the Note
Holders.

      SECTION 8.02.     RESIGNATION OF MORTGAGEE; APPOINTMENT OF SUCCESSOR.

            (a) The  Mortgagee or any  successor  thereto may resign at any time
without  cause by giving at least 30 days' prior written  notice to Lessee,  the
Owner Trustee,  the Owner Participant and each Note Holder,  such resignation to
be effective upon the acceptance of the trusteeship by a successor Mortgagee. In
addition,  a Majority in Interest of Note Holders may at any time (but only with
the consent of the Lessee,  which  consent shall not be  unreasonably  withheld,
except that such  consent  shall not be necessary if a Lease Event of Default is
continuing)  remove the  Mortgagee  without  cause by an  instrument  in writing
delivered to the Owner Trustee, Lessee, the Owner Participant and the Mortgagee,
and the Mortgagee  shall  promptly  notify each Note Holder  thereof in writing,
such  removal  to be  effective  upon the  acceptance  of the  trusteeship  by a
successor Mortgagee. In the case of the resignation or removal of the Mortgagee,
a Majority in Interest of Note  Holders may appoint a successor  Mortgagee by an
instrument signed by such holders, which successor, so long as no Lease Event of
Default  shall have  occurred  and be  continuing,  shall be subject to Lessee's
reasonable  approval.  If a successor  Mortgagee  shall not have been  appointed
within 30 days after such notice of resignation or removal,  the Mortgagee,  the
Owner Trustee,  the Owner  Participant or any Note Holder may apply to any court
of  competent  jurisdiction  to appoint a successor  Mortgagee to act until such
time, if any, as a successor  shall have been appointed as above  provided.  The
successor  Mortgagee so appointed  by such court shall  immediately  and without
further  act be  superseded  by  any  successor  Mortgagee  appointed  as  above
provided.

            (b) Any successor  Mortgagee,  however appointed,  shall execute and
deliver  to the Owner  Trustee,  the  predecessor  Mortgagee  and the  Lessee an
instrument  accepting  such  appointment  and  assuming the  obligations  of the
Mortgagee under the  Participation  Agreement arising from and after the time of
such appointment,  and thereupon such successor Mortgagee,  without further act,

<PAGE>

shall become vested with all the estates, properties,  rights, powers and duties
of the predecessor  Mortgagee hereunder in the trust hereunder  applicable to it
with like effect as if originally named the Mortgagee  herein;  but nevertheless
upon the written request of such successor Mortgagee, such predecessor Mortgagee
shall  execute  and  deliver  an  instrument   transferring  to  such  successor
Mortgagee,  upon the trusts herein expressed  applicable to it, all the estates,
properties,   rights  and  powers  of  such  predecessor  Mortgagee,   and  such
predecessor Mortgagee shall duly assign, transfer,  deliver and pay over to such
successor  Mortgagee all monies or other property then held by such  predecessor
Mortgagee hereunder.

            (c) Any successor Mortgagee,  however appointed,  shall be a bank or
trust  company  having  its  principal  place  of  business  in the  Borough  of
Manhattan, City and State of New York; Chicago, Illinois; Hartford, Connecticut;
Wilmington,  Delaware; or Boston, Massachusetts and having (or whose obligations
under the Operative  Agreements are guaranteed by an affiliated entity 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 the
Mortgagee hereunder upon reasonable or customary terms.

            (d) Any  corporation  into  which  the  Mortgagee  may be  merged or
converted or with which it may be  consolidated,  or any  corporation  resulting
from any merger,  conversion or  consolidation to which the Mortgagee shall be a
party,  or any  corporation  to  which  substantially  all the  corporate  trust
business of the Mortgagee  may be  transferred,  shall,  subject to the terms of
paragraph (c) of this Section  8.02, be a successor  Mortgagee and the Mortgagee
under this Trust Indenture without further act.

      SECTION 8.03.     APPOINTMENT OF ADDITIONAL AND SEPARATE TRUSTEES.

            (a) Whenever (i) the Mortgagee  shall deem it necessary or desirable
in order to conform to any Law of any  jurisdiction  in which all or any part of
the Trust  Indenture  Estate shall be situated or to make any claim or bring any
suit with respect to or in  connection  with the Trust  Indenture  Estate,  this
Trust Indenture,  any other Indenture  Agreement,  the Equipment Notes or any of
the transactions contemplated by the Participation Agreement, (ii) the Mortgagee
shall be  advised  by  counsel  satisfactory  to it that it is so  necessary  or
prudent in the interests of the Note Holders (and the Mortgagee  shall so advise
the Owner Trustee and Lessee),  or (iii) the Mortgagee shall have been requested
to do so by a Majority in Interest of Note Holders,  then in any such case,  the
Mortgagee  and, upon the written  request of the  Mortgagee,  the Owner Trustee,
shall  execute  and  deliver  an  indenture  supplemental  hereto and such other
instruments  as may from time to time be necessary  or  advisable  either (1) to
constitute one or more bank or trust  companies or one or more persons  approved
by the Mortgagee, either to act jointly with the Mortgagee as additional trustee
or  trustees  of all or any part of the  Trust  Indenture  Estate,  or to act as
separate  trustee or trustees of all or any part of the Trust Indenture  Estate,
in each case with such rights,  powers,  duties and obligations  consistent with
this Trust Indenture as may be provided in such supplemental  indenture or other
instruments  as the Mortgagee or a Majority in Interest of Note Holders may deem
necessary or advisable,  or (2) to clarify,  add to or subtract from the rights,
powers,  duties and  obligations  theretofore  granted  any such  additional  or
separate  trustee,  subject  in each case to the  remaining  provisions  of this
Section 8.03. If the Owner Trustee shall not have taken any action  requested of
it under this Section  8.03(a) that is permitted or required by its terms within

<PAGE>

15 days after the receipt of a written  request from the  Mortgagee so to do, or
if an Event of Default shall have occurred and be continuing,  the Mortgagee may
act  under  the  foregoing  provisions  of  this  Section  8.03(a)  without  the
concurrence  of the Owner  Trustee,  and the Owner  Trustee  hereby  irrevocably
appoints  (which  appointment  is coupled with an interest) the  Mortgagee,  its
agent and  attorney-in-fact to act for it under the foregoing provisions of this
Section  8.03(a) in either of such  contingencies.  The  Mortgagee  may, in such
capacity,  execute,  deliver and perform any such supplemental indenture, or any
such  instrument,  as may be required for the appointment of any such additional
or separate trustee or for the clarification of, addition to or subtraction from
the  rights,  powers,  duties or  obligations  theretofore  granted  to any such
additional  or separate  trustee.  In case any  additional  or separate  trustee
appointed  under this Section  8.03(a)  shall die,  become  incapable of acting,
resign or be moved, all the assets, property, rights, powers, trusts, duties and
obligations of such additional or separate trustee shall revert to the Mortgagee
until a successor  additional  or separate  trustee is  appointed as provided in
this Section 8.03(a).

            (b) No additional or separate  trustee shall be entitled to exercise
any of the rights,  powers,  duties and obligations conferred upon the Mortgagee
in  respect  of the  custody,  investment  and  payment of monies and all monies
received by any such additional or separate trustee from or constituting part of
the Trust Indenture Estate or otherwise payable under any Operative Agreement to
the  Mortgagee  shall be promptly  paid over by it to the  Mortgagee.  All other
rights,  powers, duties and obligations conferred or imposed upon any additional
or separate  trustee  shall be exercised or performed by the  Mortgagee and such
additional or separate  trustee jointly except to the extent that applicable Law
of any  jurisdiction in which any particular act is to be performed  renders the
Mortgagee  incompetent  or  unqualified to perform such act, in which event such
rights, powers, duties and obligations (including the holding of title to all or
part of the Trust Indenture Estate in any such jurisdiction)  shall be exercised
and performed by such additional or separate trustee.  No additional or separate
trustee shall take any  discretionary  action except on the  instructions of the
Mortgagee or a Majority in Interest of Note Holders.  No trustee hereunder shall
be  personally  liable  by reason of any act or  omission  of any other  trustee
hereunder, except that the Mortgagee shall be liable for the consequences of its
lack of reasonable care in selecting,  and the Mortgagee's own actions in acting
with, any additional or separate  trustee.  Each additional or separate  trustee
appointed  pursuant to this Section 8.03 shall be subject to, and shall have the
benefit of Articles IV through  VIII and Article X hereof  insofar as they apply
to the  Mortgagee.  The powers of any additional or separate  trustee  appointed
pursuant  to this  Section  8.03  shall  not in any  case  exceed  those  of the
Mortgagee hereunder.

            (c) If at any time the Trustee shall deem it no longer  necessary or
in order to conform to any such Law or take any such  action or shall be advised
by such  counsel  that it is no longer so necessary or desirable in the interest
of the  Note  Holders,  or in the  event  that the  Mortgagee  shall  have  been
requested  to do so in writing by a Majority in Interest  of Note  Holders,  the
Mortgagee  and, upon the written  request of the  Mortgagee,  the Owner Trustee,
shall  execute  and  deliver  an  indenture  supplemental  hereto  and all other
instruments  and  agreements  necessary  or proper to remove any  additional  or
separate  trustee.  The  Mortgagee  may act on behalf of the Owner Trustee under
this  Section  8.03(c)  when and to the  extent  it could so act  under  Section
8.03(a) hereof.

<PAGE>

                                   ARTICLE IX

              SUPPLEMENTS AND AMENDMENTS TO THIS TRUST INDENTURE
                               AND OTHER DOCUMENTS

      SECTION 9.01.     INSTRUCTIONS OF MAJORITY; LIMITATIONS.

            (a) Except as provided in Section  5.02  hereof,  the Owner  Trustee
agrees it shall not enter into any amendment of or supplement to the Lease,  the
Purchase Agreement, the Purchase Agreement Assignment, the Consent and Agreement
or the Engine Consent and  Agreement,  or execute and deliver any written waiver
or  modification  of, or consent  under,  the terms of the Lease,  the  Purchase
Agreement,  the Purchase Agreement Assignment,  the Consent and Agreement or the
Engine  Consent  and  Agreement,  unless  such  supplement,  amendment,  waiver,
modification  or consent is  consented  to in  writing  by the  Mortgagee  and a
Majority in Interest of Note Holders.  Anything to the contrary contained herein
notwithstanding, without the necessity of the consent of any of the Note Holders
or the Mortgagee, (i) any Excluded Payments payable to the Owner Participant may
be modified,  amended, changed or waived in such manner as shall be agreed to by
the Owner Participant and Lessee and (ii) the Owner Trustee and Lessee may enter
into  amendments of or additions to the Lease to modify Section 5 (except to the
extent that such amendment would affect the rights or exercise of remedies under
Section 15 of the Lease) or Section 17 of the Lease so long as such  amendments,
modifications and changes do not and would not affect the time of, or reduce the
amount of, Rent payments  (except to the extent  expressly  permitted by Section
5.02  hereof)  until  after the payment in full of all  Secured  Obligations  or
otherwise adversely affect the Note Holders.

            (b) Without  limiting the  provisions  of Section  9.01 hereof,  the
Mortgagee  agrees  with  the  Note  Holders  that it shall  not  enter  into any
amendment,  waiver or  modification  of,  supplement  or  consent  to this Trust
Indenture, the Lease, the Purchase Agreement, the Purchase Agreement Assignment,
the Consent and Agreement, the Engine Consent and Agreement or the Participation
Agreement, or any other agreement included in the Trust Indenture Estate, unless
such supplement,  amendment,  waiver, modification or consent is consented to in
writing by a Majority in Interest of Note Holders,  but upon the written request
of a Majority in Interest of Note Holders, the Mortgagee shall from time to time
enter into any such  supplement  or  amendment,  or execute and deliver any such
waiver,  modification or consent, as may be specified in such request and as may
be (in the case of any  such  amendment,  supplement  or  modification),  to the
extent such agreement is required, agreed to by the Owner Trustee and Lessee or,
as may be appropriate,  the Airframe  Manufacturer  or the Engine  Manufacturer;
provided,  however,  that,  without  the  consent of each  holder of an affected
Equipment Note then outstanding and of the Liquidity Provider, no such amendment
of or supplement to this Trust Indenture, the Lease, the Purchase Agreement, the
Purchase Agreement Assignment, the Consent and Agreement, the Engine Consent and
Agreement or the Participation  Agreement or waiver or modification of the terms
of, or consent  under,  any thereof,  shall (i) modify any of the  provisions of
this Section 9.01, or of Article II or III or Section  4.02,  4.04(c),  4.04(d),
5.02 or 5.06 hereof,  Section 13.3, 14 (except to add an Event of Default) or 16
of the Lease,  Section 15.1 of the Participation  Agreement,  the definitions of
"Event of  Default,"  "Default,"  "Lease  Event of  Default,"  "Lease  Default,"

<PAGE>

"Majority in Interest of Note Holders," "Make-Whole Amount" or "Note Holder," or
the percentage of Note Holders required to take or approve any action hereunder,
(ii) reduce the amount,  or change the time of payment or method of  calculation
of any amount, of Original Amount,  Make-Whole  Amount, if any, or interest with
respect to any Equipment  Note, or alter or modify the provisions of Article III
hereof with respect to the order of priorities in which distribution  thereunder
shall be made as among the Note  Holders,  the Owner  Trustee and Lessee,  (iii)
reduce,  modify or amend any  indemnities  in favor of the  Owner  Trustee,  the
Mortgagee or the Note Holders  (except that the Owner Trustee (in its individual
capacity)  or the  Mortgagee,  as the case may be, may  consent to any waiver or
reduction of an indemnity payable to it) or the Pass Through  Indemnitees,  (iv)
consent to any change in the Trust  Indenture  or the Lease which  would  permit
redemption of Equipment  Notes earlier than permitted under Section 2.10 or 2.11
hereof  or the  purchase  or  exchange  of the  Equipment  Notes  other  than as
permitted by Section 2.13 hereof, (v) except as contemplated by the Lease or the
Participation  Agreement,  reduce  the  amount or extend  the time of payment of
Basic Rent, Stipulated Loss Value, or Termination Value for the Aircraft in each
case as set forth in the Lease,  or  modify,  amend or  supplement  the Lease or
consent to any assignment of the Lease, in either case releasing Lessee from its
obligations  in respect of the payment of Basic Rent,  Stipulated  Loss Value or
Termination  Value for the Aircraft or altering  the absolute and  unconditional
character  of the  obligations  of Lessee to pay Rent as set forth in Sections 3
and 16 of the  Lease  or (vi)  permit  the  creation  of any  Lien on the  Trust
Indenture  Estate or any part thereof other than Permitted  Liens or deprive any
Note  Holder of the  benefit  of the Lien of this Trust  Indenture  on the Trust
Indenture Estate, except as provided in connection with the exercise of remedies
under Article IV hereof.

            (c) At any time after the date  hereof,  the Owner  Trustee  and the
Mortgagee may enter into one or more agreements  supplemental hereto without the
consent of any Note Holder for any of the  following  purposes:  (i) (a) to cure
any defect or  inconsistency  herein or in the Equipment  Notes,  or to make any
change not  inconsistent  with the provisions  hereof (PROVIDED that such change
does not  adversely  affect the  interests  of any Note  Holder in its  capacity
solely as Note Holder) or (b) to cure any ambiguity or correct any mistake; (ii)
to evidence the  succession  of another party as the Owner Trustee in accordance
with the terms of the Trust  Agreement  or to evidence the  succession  of a new
trustee hereunder  pursuant hereto,  the removal of the trustee hereunder or the
appointment  of any  co-trustee  or  co-trustees  or any separate or  additional
trustee or trustees; (iii) to convey,  transfer,  assign, mortgage or pledge any
property to or with the Mortgagee or to make any other  provisions  with respect
to matters or  questions  arising  hereunder  so long as such  action  shall not
adversely  affect the  interests of the Note  Holders in its capacity  solely as
Note Holder;  (iv) to correct or amplify the  description of any property at any
time subject to the Lien of this Trust Indenture or better to assure, convey and
confirm unto the Mortgagee any property subject or required to be subject to the
Lien of this  Trust  Indenture,  the  Airframe  or  Engines  or any  Replacement
Airframe or Replacement Engine; (v) to add to the covenants of the Owner Trustee
for the benefit of the Note Holders,  or to surrender any rights or power herein
conferred upon the Owner Trustee,  the Owner Participant or the Lessee;  (vi) to
add to the rights of the Note  Holders;  and (vii) to  include on the  Equipment
Notes any legend as may be required by Law.

<PAGE>

      SECTION 9.02.     TRUSTEES PROTECTED.

            If, in the opinion of the institution  acting as Owner Trustee under
the Trust  Agreement  or the  institution  acting as  Mortgagee  hereunder,  any
document  required to be  executed  by it pursuant to the terms of Section  9.01
hereof  affects any right,  duty,  immunity or  indemnity  with  respect to such
institution under this Trust Indenture or the Lease, such institution may in its
discretion decline to execute such document.

      SECTION 9.03.     DOCUMENTS MAILED TO NOTE HOLDERS.

            Promptly  after the  execution by the Owner Trustee or the Mortgagee
of any document  entered into  pursuant to Section  9.01 hereof,  the  Mortgagee
shall mail, by first class mail,  postage prepaid,  a copy thereof to Lessee and
to each  Note  Holder  at its  address  last  set  forth in the  Equipment  Note
Register,  but the failure of the Mortgagee to mail such copies shall not impair
or affect the validity of such document.

      SECTION 9.04.     NO REQUEST NECESSARY FOR LEASE SUPPLEMENT OR TRUST
                        INDENTURE SUPPLEMENT.

            No written request or consent of the Mortgagee,  the Note Holders or
the Owner  Participant  pursuant  to Section  9.01  hereof  shall be required to
enable  the  Owner  Trustee  to enter  into any  Lease  Supplement  specifically
required by the terms of the Lease or to execute  and deliver a Trust  Indenture
Supplement specifically required by the terms hereof.

                                    ARTICLE X

                                  MISCELLANEOUS

      SECTION 10.01.    TERMINATION OF TRUST INDENTURE.

            Upon (or at any time after)  payment in full of the Original  Amount
of,  Make-Whole  Amount, if any, and interest on and all other amounts due under
all  Equipment  Notes and  provided  that there  shall then be no other  Secured
Obligations due to the Note Holders,  the Mortgagee and other holders of Secured
Obligations  hereunder  or  under  the  Participation  Agreement  or  any  other
Operative Agreement, the Owner Trustee shall direct the Mortgagee to execute and
deliver  to or as  directed  in  writing  by the Owner  Trustee  an  appropriate
instrument  releasing  the  Aircraft and the Engines from the Lien of this Trust
Indenture  and  releasing  the  Lease,  the  Purchase  Agreement,  the  Purchase
Agreement  Assignment  with the Consent and Agreement and the Engine Consent and
Agreement  attached thereto from the assignment and pledge thereof hereunder and
the Mortgagee  shall  execute and deliver such  instrument as aforesaid and give
written notice thereof to Lessee;  PROVIDED,  HOWEVER, that this Trust Indenture
and the trusts created hereby shall earlier  terminate and this Trust  Indenture
shall be of no further force or effect upon any sale or other final  disposition
by the Mortgagee of all property constituting part of the Trust Indenture Estate
and the final  distribution  by the Mortgagee of all monies or other property or
proceeds  constituting part of the Trust Indenture Estate in accordance with the
terms hereof.  Except as aforesaid otherwise provided,  this Trust Indenture and

<PAGE>

the trusts  created hereby shall continue in full force and effect in accordance
with the terms hereof.

      SECTION 10.02.    NO LEGAL TITLE TO TRUST INDENTURE ESTATE IN NOTE
                        HOLDERS.

            No holder of an Equipment Note shall have legal title to any part of
the Trust Indenture  Estate. No transfer,  by operation of law or otherwise,  of
any Equipment Note or other right,  title and interest of any Note Holder in and
to the Trust Indenture Estate or hereunder shall operate to terminate this Trust
Indenture or entitle such holder or any  successor or  transferee of such holder
to an  accounting or to the transfer to it of any legal title to any part of the
Trust Indenture Estate.

      SECTION 10.03.    SALE OF AIRCRAFT BY MORTGAGEE IS BINDING.

            Any sale or other conveyance of the Trust Indenture  Estate,  or any
part thereof (including any part thereof or interest therein),  by the Mortgagee
made pursuant to the terms of this Trust  Indenture  shall bind the Note Holders
and shall be  effective  to transfer or convey all right,  title and interest of
the Trustee, the Owner Trustee, the Owner Participant and such holders in and to
such Trust Indenture Estate or part thereof. No purchaser or other grantee shall
be  required  to  inquire  as to the  authorization,  necessity,  expediency  or
regularity of such sale or conveyance  or as to the  application  of any sale or
other proceeds with respect thereto by the Mortgagee.

      SECTION 10.04.    TRUST  INDENTURE  FOR BENEFIT OF  OWNER  TRUSTEE,
                        MORTGAGEE,  OWNER  PARTICIPANT, NOTE  HOLDERS AND
                        OTHER HOLDERS OF SECURED OBLIGATIONS.

            Nothing in this Trust Indenture,  whether express or implied,  shall
be construed to give any person other than the Owner Trustee, the Mortgagee, the
Owner  Participant,  the Note Holders and other holders of Secured  Obligations,
any legal or equitable right,  remedy or claim under or in respect of this Trust
Indenture.

      SECTION 10.05.    NOTICES.

            Unless  otherwise  expressly  specified  or  permitted  by the terms
hereof, all notices, requests, demands,  authorizations,  directions,  consents,
waivers or documents  provided or permitted by this Trust  Indenture to be made,
given, furnished or filed shall be in writing, personally delivered or mailed by
certified mail, postage prepaid,  or by facsimile or confirmed telex, and (i) if
to the Owner Trustee,  addressed to it at 79 South Main Street,  3rd Floor, Salt
Lake City, Utah 84111 with a copy to the Owner Participant addressed as provided
in clause (iii) below,  (ii) if to  Mortgagee,  addressed to it at its office at
Rodney Square  North,  1100 North Market  Street,  Wilmington,  Delaware  19890,
Attention:  Corporate  Trust  Administration,  facsimile  number (302) 651-8882,
(iii) if to any Participant, Lessee, or any Note Holder, addressed to such party
at such  address  as such  party  shall  have  furnished  by notice to the Owner
Trustee and the  Mortgagee,  or, until an address is so furnished,  addressed to
the address of such party (if any) set forth on Schedule 1 to the  Participation

<PAGE>

Agreement or in the Equipment Note  Register.  Whenever any notice in writing is
required to be given by the Owner Trustee,  any  Participant or the Mortgagee or
any Note Holder to any of the other of them,  such notice  shall be deemed given
and such requirement  satisfied when such notice is received,  or if such notice
is mailed by certified mail,  postage  prepaid,  three Business Days after being
mailed,  addressed as provided above. Any party hereto may change the address to
which  notices to such party will be sent by giving notice of such change to the
other parties to this Trust Indenture.

      SECTION 10.06.    SEVERABILITY.

            Any  provision  of this  Trust  Indenture  which  is  prohibited  or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such prohibition or unenforceability  without  invalidating the
remaining  provisions  hereof. Any such prohibition or  unenforceability  in any
particular  jurisdiction  shall  not  invalidate  or render  unenforceable  such
provision in any other jurisdiction.

      SECTION 10.07.    NO ORAL MODIFICATION OR CONTINUING WAIVERS.

            No term or provision of this Trust  Indenture or the Equipment Notes
may be  changed,  waived,  discharged  or  terminated  orally,  but  only  by an
instrument  in  writing  signed  by the  Owner  Trustee  and the  Mortgagee,  in
compliance  with Section  9.01 hereof.  Any waiver of the terms hereof or of any
Equipment  Note shall be  effective  only in the  specific  instance and for the
specific purpose given.

      SECTION 10.08.    SUCCESSORS AND ASSIGNS.

            All covenants and agreements contained herein shall be binding upon,
and inure to the  benefit  of,  each of the  parties  hereto  and the  permitted
successors and assigns of each,  all as herein  provided.  Any request,  notice,
direction,  consent,  waiver or other  instrument  or action by any Note  Holder
shall bind the successors and assigns of such holder.  This Trust  Indenture and
the Trust Indenture  Estate shall not be affected by any amendment or supplement
to the Trust  Agreement  or by any other action taken under or in respect of the
Trust Agreement, except that each reference in this Trust Indenture to the Trust
Agreement shall mean the Trust Agreement as amended and  supplemented  from time
to  time  to the  extent  permitted  hereby,  thereby  and by the  Participation
Agreement.  Each Note Holder by its acceptance of an Equipment Note agrees to be
bound by this Trust Indenture and all provisions of the Participation  Agreement
applicable to a Loan Participant or a Note Holder.

      SECTION 10.09.    HEADINGS.

            The headings of the various  Articles and sections herein and in the
table of contents  hereto are for  convenience  of reference  only and shall not
define or limit any of the terms or provisions hereof.

      SECTION 10.10.    NORMAL COMMERCIAL RELATIONS.

            Anything   contained  in  this  Trust   Indenture  to  the  contrary
notwithstanding,  Owner Trustee, Mortgagee, any Participant or any bank or other

<PAGE>

Affiliate  of such  Participant  may  conduct  any  banking  or other  financial
transactions,  and have banking or other commercial  relationships,  with Lessee
[or any  Permitted  Sublessee]<F18>, fully to the same  extent as if this  Trust
Indenture were not in effect,  including without  limitation the making of loans
or other  extensions  of credit to Lessee for any  purpose  whatsoever,  whether
related to any of the transactions contemplated hereby or otherwise.

      SECTION 10.11.    GOVERNING LAW; COUNTERPART FORM.

            THIS TRUST  INDENTURE  SHALL IN ALL  RESPECTS  BE  GOVERNED  BY, AND
CONSTRUED  IN  ACCORDANCE  WITH,  THE  INTERNAL  LAWS OF THE  STATE OF NEW YORK,
INCLUDING  ALL MATTERS OF  CONSTRUCTION,  VALIDITY AND  PERFORMANCE.  THIS TRUST
INDENTURE IS BEING  DELIVERED IN THE STATE OF NEW YORK. This Trust Indenture may
be executed by the parties  hereto in separate  counterparts  (or upon  separate
signature  pages bound  together into one or more  counterparts),  each of which
when so executed and delivered shall be an original,  but all such  counterparts
shall together constitute but one and the same instrument.

      SECTION 10.12.    VOTING BY NOTE HOLDERS.

            All  votes of the Note  Holders  shall  be  governed  by a vote of a
Majority in Interest of Note Holders, except as otherwise provided herein.

      SECTION 10.13.    BANKRUPTCY.

            It is the intention of the parties that the Owner Trustee, as lessor
under the Lease (and the Mortgagee as assignee of the Owner Trustee  hereunder),
shall be entitled to the  benefits of Section  1110 with respect to the right to
take possession of the Aircraft,  Airframe, Engines and Parts as provided in the
Lease in the event of a case under  Chapter 11 of the  Bankruptcy  Code in which
Lessee is a debtor,  and in any  instance  where more than one  construction  is
possible of the terms and  conditions  hereof or any other  pertinent  Operative
Agreement,  each such party agrees that a construction which would preserve such
benefits  shall  control over any  construction  which would not  preserve  such
benefits.

--------------------
<F18>
Insert  bracketed  language  if the  Lease  provides  for  the  assignment  of a
permitted sublease.

<PAGE>

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

                                          FIRST SECURITY BANK, NATIONAL
                                          ASSOCIATION,
                                              not in its individual capacity,
                                              except as expressly provided
                                              herein, but solely as Owner
                                              Trustee, as Owner Trustee

                                          By:_________________________________
                                             Name:
                                             Title:

                                          WILMINGTON TRUST COMPANY, as
                                              Mortgagee

                                          By:_________________________________
                                             Name:
                                             Title:

<PAGE>

                                                                       EXHIBIT A
                                           TO TRUST INDENTURE AND MORTGAGE [___]

                TRUST INDENTURE AND MORTGAGE [___] SUPPLEMENT

            This TRUST  INDENTURE  AND MORTGAGE  [___]  SUPPLEMENT  NO. 1, dated
[___________,  20___] (herein called this "Trust Indenture Supplement") of FIRST
SECURITY BANK, NATIONAL ASSOCIATION,  not in its individual capacity, but solely
as Owner Trustee  (herein called the "Owner  Trustee")  under that certain Trust
Agreement  [___]  dated as of  [___________,  20___]  (the  "Trust  Agreement"),
between the Owner Trustee and the Owner Participant named therein.

                             W I T N E S S E T H:

            WHEREAS,  the  Trust  Indenture  and  Mortgage  [___],  dated  as of
[____________,  20___] (as  amended and  supplemented  to the date  hereof,  the
"Trust  Indenture")  between the Owner Trustee and Wilmington Trust Company,  as
Mortgagee  (the  "Mortgagee"),  provides  for the  execution  and  delivery of a
supplement  thereto  substantially in the form hereof,  which shall particularly
describe the  Aircraft,  and shall  specifically  mortgage  such Aircraft to the
Mortgagee; and

            WHEREAS,  each of the Trust Agreement and Trust Indenture relates to
the  Airframe  and  Engines  described  below,  and a  counterpart  of the Trust
Indenture  is attached  hereto and made a part  hereof and this Trust  Indenture
Supplement,  together with such  counterpart  of the Trust  Indenture,  is being
filed for recordation on the date hereof with the FAA as one document;

            NOW, THEREFORE,  this Trust Indenture Supplement witnesseth that the
Owner Trustee hereby  confirms that the Lien of the Trust Indenture on the Trust
Indenture Estate covers all of Owner Trustee's right,  title and interest in and
to the following described property:

                                    AIRFRAME

            One airframe identified as follows:
                                                    FAA
                                               Registration     Manufacturer's
     Manufacturer              Model              Number         Serial Number
---------------------  -------------------    ---------------  -----------------

The Boeing Company

together with all of the Owner Trustee's right, title and interest in and to all
Parts of whatever  nature,  whether now owned or hereinafter  acquired and which
are from time to time incorporated or installed in or attached to said airframe.

<PAGE>

                                AIRCRAFT ENGINES

            Two  aircraft  engines,  each such  engine  having 750 or more rated
take-off horsepower or the equivalent thereof, identified as follows:

     Manufacturer              Model              Number         Serial Number
---------------------  -------------------    ---------------  -----------------

together  with all of Owner  Trustee's  right,  title and interest in and to all
Parts of whatever nature,  whether now owned or hereafter acquired and which are
from time to time  incorporated  or  installed  in or attached to either of such
engines.

            Together with all of Owner  Trustee's  right,  title and interest in
and to (a) all Parts of whatever  nature,  which from time to time are  included
within the definition of "Airframe" or "Engine",  whether now owned or hereafter
acquired,  including  all  substitutions,   renewals  and  replacements  of  and
additions,  improvements,  accessions  and  accumulations  to the  Airframe  and
Engines (other than additions, improvements,  accessions and accumulations which
constitute   appliances,   parts,   instruments,   appurtenances,   accessories,
furnishings  or other  equipment  excluded from the definition of Parts) and (b)
all Aircraft Documents.

            As  further  security  for the  obligations  referred  to above  and
secured by the Trust  Indenture  and  hereby,  the Owner  Trustee  has  granted,
bargained,  sold,  assigned,  transferred,   conveyed,  mortgaged,  pledged  and
confirmed,  and does hereby grant,  bargain,  sell,  assign,  transfer,  convey,
mortgage,  pledge and confirm,  unto the Mortgagee,  its successors and assigns,
for the security and benefit of the Loan Participants,  the Note Holders and the
other  holders  of  Secured  Obligations,  in the  trust  created  by the  Trust
Indenture,  all of the right, title and interest of the Owner Trustee in, to and
under the Lease Supplement of even date herewith covering the property described
above.

            Notwithstanding  any  provision  hereof,  no Excluded  Payment shall
constitute security for any of the aforementioned obligations.

            TO HAVE AND TO HOLD all and singular the aforesaid property unto the
Mortgagee,  its successors and assigns, in trust for the equal and proportionate
benefit and  security of the Loan  Participants,  the Note Holders and the other
holders of Secured  Obligations,  except as provided in Section 2.14 and Article
III of the Trust Indenture  without any  preference,  distinction or priority of
any one  Equipment  Note over any other by reason of  priority of time of issue,
sale,  negotiation,  date of  maturity  thereof  or  otherwise  for  any  reason

<PAGE>

whatsoever,  and  for the  uses  and  purposes  and  subject  to the  terms  and
provisions set forth in the Trust Indenture.

            This Trust Indenture  Supplement  shall be construed as supplemental
to the Trust  Indenture  and shall form a part thereof.  The Trust  Indenture is
each hereby  incorporated by reference herein and is hereby  ratified,  approved
and confirmed.

            AND,  FURTHER,  the  Owner  Trustee  hereby  acknowledges  that  the
Aircraft referred to in this Trust Indenture  Supplement and the aforesaid Lease
Supplement  has been  delivered  to the Owner  Trustee  and is  included  in the
property of the Owner  Trustee  covered by all the terms and  conditions  of the
Trust  Agreement,  subject to the pledge and  mortgage  thereof  under the Trust
Indenture.

                                    * * *

            IN  WITNESS  WHEREOF,  the  Owner  Trustee  has  caused  this  Trust
Indenture Supplement to be duly executed by one of its officers,  thereunto duly
authorized, on the day and year first above written.

                                          FIRST SECURITY BANK, NATIONAL
                                          ASSOCIATION, not in its individual
                                              capacity, but solely as Owner
                                              Trustee, Owner Trustee

                                          By:_________________________________
                                                Name:
                                                Title:

<PAGE>

                                                  TRUST INDENTURE AND MORTGAGE

                                   SCHEDULE I

                                 Original Amount             Interest Rate
                            -------------------------  -------------------------
Series A-1:

Series A-2:

Series B:

Series C-1:

Series C-2:

Series D:

<PAGE>

                           Equipment Note Amortization

                                                 Percentage of Original
              Payment Date                          Amount to be Paid
---------------------------------------  ---------------------------------------

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