Document:

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                                                                   Exhibit 10.53

                                   UNDERTAKING

         THIS UNDERTAKING (the "Undertaking") is made and entered into as of
this 18th day of January 2002 by TPG Partners, L.P., a Delaware limited
partnership, TPG Parallel I L.P., a Delaware limited partnership, and Air
Partners II, L.P., a Texas limited partnership (collectively, the "TPG
Entities") and America West Holdings Corporation, a Delaware corporation (the
"Company"), for the benefit of the Air Transportation Stabilization Board (the
"ATSB").

                                    RECITALS

         WHEREAS, the TPG Entities are the beneficial owners of an aggregate of
nine hundred forty-one thousand four hundred thirty-one (941,431) shares (the
"TPG Shares") of Class A Common Stock, par value $0.01 per share (the "Class A
Common"), of the Company;

         WHEREAS, the ATSB is entering into a Guarantee Agreement of even date
herewith for the benefit of the Company's subsidiary, America West Airlines,
Inc. (the "Guarantee");

         WHEREAS, the Company is issuing to the ATSB that certain warrant of
even date herewith (the "Warrant") to purchase eighteen million seven hundred
fifty thousand (18,750,000) shares (as adjusted pursuant to the terms of the
Warrant, the "Warrant Shares") of the Class B Common Stock, par value $0.01 per
share (the "Class B Common") of the Company; and

         WHEREAS, the ATSB has required the execution and delivery of this
Undertaking as a condition to entering into the Guarantee.

         NOW, THEREFORE, in consideration of these premises and for other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the TPG Entities agree as follows:

1.       REPRESENTATIONS.

         The TPG Entities jointly and severally represent and warrant that:

         (i) the TPG Entities are the beneficial owners of the TPG Shares, which
represent all of the outstanding shares of Class A Common of the Company;

         (ii) each TPG Entity is duly organized, validly existing and in good
standing under the laws of the state of its formation;

         (iii) the execution, delivery and performance by each TPG Entity of
this Undertaking and the consummation of the transactions contemplated hereby:
(a) are within the powers of each TPG Entity and have been duly authorized by
all necessary partnership action on the part of the TPG Entities and all
necessary corporate action on the part of any general partner of any TPG Entity
or any general partner thereof; (b) do not contravene the constituent documents
of any TPG Entity or any law, rule, regulation or administrative or court order
binding on or affecting any TPG Entity or its property; and (c) do not conflict
with or constitute a breach of, or default under, or result in the creation or
imposition of any lien, charge or encumbrance upon any property or assets of any
TPG Entity pursuant to any contract, indenture, mortgage, loan

                                       1.

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agreement, note or other instrument to which any TPG Entity is a party or by
which any TPG Entity may be bound or to which the assets of any TPG Entity may
be subject;

         (iv) this Undertaking constitutes a valid and binding obligation of
each TPG Entity, enforceable against it in accordance with its terms, except as
the enforceability thereof may be subject to or limited by bankruptcy,
insolvency, reorganization, arrangement, moratorium or other similar laws
relating to or affecting the rights of creditors generally and general
principles (whether applied in an action at law or a suit in equity); and

         (v) no authorization, approval, consent or order of any court or
governmental authority or agency or any other person or entity is required in
connection with the execution and delivery by any TPG Entity of this Undertaking
or its performance hereunder.

2.       RESTRICTIONS AGAINST TRANSFER.

         During the term of this Undertaking, the TPG Entities shall not assign,
transfer, sell or otherwise dispose of, directly or indirectly, any TPG Shares,
other than pursuant to or in connection with a transaction or series of related
transactions in which the holders of all outstanding shares of the Class B
Common are entitled to participate with respect to all shares of Class B Common
in such transaction or series of related transactions and the holders of greater
than fifty percent (50%) of the Company's Class B Common then outstanding either
(i) vote their shares of Class B Common in favor of such transaction or series
of related transactions or (ii) tender their shares of Class B Common for sale
in such transaction or series of related transactions; provided, however, that
nothing herein shall be deemed to require that the form or amount of
consideration payable for the shares of Class B Common be the same as the form
or amount of consideration payable to the TPG Entities for the TPG Shares. For
purposes of determining whether the holders of greater than fifty percent (50%)
of the outstanding Class B Common have voted in favor of the transaction or
series of related transactions or tender their shares in such transaction or
series of related transactions, if the ATSB consents in writing to the
transaction or series of related transactions, the actual number of outstanding
shares of Class B Common shall be deemed to be outstanding, and if the ATSB does
not consent in writing to the transaction or series of related transactions, the
number of outstanding shares deemed to be outstanding shall equal the sum of the
actual number of shares outstanding plus the number of shares issuable upon
exercise of the Warrant. The closing of any transaction or series of related
transactions shall be simultaneous for the TPG Shares and any shares of Class B
Common. The TPG Entities agree that the Company may instruct its transfer agent
to impose transfer restrictions on the TPG Shares to enforce the provisions of
this Agreement.

3.       AGREEMENT OF THE COMPANY.

         The Company agrees to take all commercially reasonable actions not to
permit any transfer by any TPG Entity, which does not comply with the provisions
of Section 2 and 4 hereof.

4.       EXEMPT TRANSFERS.

         Notwithstanding the foregoing but subject to the further provisions of
this Section 4, the restriction against transfer set forth in Section 2 above
shall not apply to (i) any transfer by a

                                       2.

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TPG Entity to an affiliate (as defined below), (ii) any transfer by a TPG
Entity, which is a limited or general partnership, limited liability company or
similar entity, by way of a distribution to any or all of its partners or former
partners or member or former members, (iii) any transfer without consideration
to any descendants or spouse of a person to whom a transfer is permitted by
clauses (i) or (ii) above or to trusts for the benefit such descendants or
spouse, (iv) any transfer by a TPG Entity to the Company and (v) any conversion
by a TPG Entity of the TPG Shares into shares of Class B Common and any
subsequent transfer of such shares of Class B Common; provided that in the event
of any transfer made pursuant to clauses (i), (ii) or (iii) above, (A) the TPG
Entity shall inform the Company and the ATSB of such transfer prior to effecting
it and (B) as a condition to any such transfer, the transferee(s) shall enter
into a written agreement to be bound by and comply with all provisions of this
Undertaking, as if it were an original signatory hereunder. Such transferred TPG
Shares shall remain "TPG Shares" hereunder, and such transferee shall be treated
as a "TPG Entity" for purposes of this Undertaking (including Section 3 hereof).
An "affiliate" of a TPG Entity is a person or entity that directly or indirectly
through one or more intermediaries controls, is controlled by, or is under
common control with such TPG Entity. None of the TPG Entities shall pledge or
otherwise encumber any of the TPG Shares unless the conditions set forth in
clauses (A) and (B) above are satisfied.

5.       MISCELLANEOUS.

         5.1 GOVERNING LAW. This Undertaking shall be governed by and construed
under the laws of the State of New York as applied to agreements among New York
residents entered into and to be performed entirely within New York, provided
that the rights of the ATSB hereunder shall be governed and construed in
accordance with Federal law, if and to the extent such Federal law is
applicable, and otherwise in accordance with the laws of the State of New York.

         5.2 AMENDMENT AND WAIVER. Any provision of this Undertaking may be
amended and the observance thereof may be waived (either generally or in a
particular instance and either retroactively or prospectively), or this
Undertaking terminated, only by the written consent of (i) with respect to
rights of the ATSB (and its successors and assigns), only by the ATSB (and its
successors and assigns) and (ii) with respect to rights of the TPG Entities,
only by TPG Partners, L.P. To the extent that the Warrant becomes exercisable
for shares other than shares of Class B Common or the shares of Class A Common
are changed or reclassified into, or exchanged for other shares of the Company
or any other issuer (other than shares of Class B Common or shares of the same
security that the shares of Class B Common are changed or reclassified into or
exchanged for) as a result of any reclassification, reorganization, merger,
consolidation or other corporate transaction, the TPG Entities shall be subject
to such undertakings and agreements with respect to such other shares and the
holders thereof as shall be necessary to achieve the intended purposes of this
Undertaking and shall enter into such amendments or additional undertakings as
the ATSB (and its successors and assigns) may reasonably request.

         5.3 ENTIRE AGREEMENT. This Undertaking constitutes the entire agreement
between the parties relative to the specific subject matter hereof. Any previous
agreement among the parties relative to the specific subject matter hereof is
superseded by this Undertaking.

                                       3.

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         5.4 SUCCESSORS. This Undertaking and the rights and obligations of the
parties hereunder shall inure to the benefit of, and be binding upon the parties
hereto and their respective successors, assigns and legal representatives.

         5.5 NO THIRD PARTY BENEFICIARIES. None of the provisions of this
Undertaking is intended to provide any rights or remedies to any person or
entity other than the ATSB and its successors, assigns and legal
representatives.

         5.6 NOTICES. All notices required or permitted hereunder shall be in
writing and shall be deemed effectively given: (i) upon personal delivery to the
party to be notified, (ii) when sent by confirmed electronic mail or facsimile
if sent during normal business hours of the recipient; if not, then on the next
business day, (iii) five (5) days after having been sent by registered or
certified mail, return receipt requested, postage prepaid, or (iv) one (1) day
after deposit with a nationally recognized overnight courier, specifying next
day delivery, with written verification of receipt. All communications shall be
sent to the party to be notified at the address as set forth on the signature
page hereof or at such other address as such party may designate by ten (10)
days advance written notice to the other parties hereto.

         5.7 SEVERABILITY. In the event one or more of the provisions of this
Undertaking should, for any reason, be held to be invalid, illegal or
unenforceable in any respect, such invalidity, illegality, or unenforceability
shall not affect any other provisions of this Undertaking, and this Undertaking
shall be construed as if such invalid, illegal or unenforceable provision had
never been contained herein, and the parties hereto shall use their best efforts
to find and employ an alternative means to achieve the same or substantially the
same result as that contemplated by such term, provision, covenant or
restriction, it being intended that all of the rights and privileges of the
parties shall be enforceable to the fullest extent permitted by law.

         5.8 COUNTERPARTS. This Undertaking may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

         5.9 TERM. The provisions of this Undertaking shall continue in full
force and effect until the earlier of (i) such time as the TPG Entities cease to
own any shares of Class A Common, (ii) the expiration of the Warrant, and (iii)
the exercise in full of the Warrant and the sale of all the Warrant Shares
received upon exercise.

                                       4.

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         The foregoing UNDERTAKING is hereby executed as of the date first above
written.

TPG PARTNERS, L.P.

BY:  TPG GENPAR, A DELAWARE LIMITED PARTNERSHIP,
     ITS GENERAL PARTNER

BY:  TPG ADVISORS, INC., A DELAWARE CORPORATION,
     ITS GENERAL PARTNER

By: /s/ Richard A. Ekleberry
   --------------------------------------------------

Name:   Richard A. Ekleberry
     ------------------------------------------------

Title:  Vice President
      -----------------------------------------------

Address: 301 Commerce Street, Suite 3300
        ---------------------------------------------
         Fort Worth, Texas 76102
        ---------------------------------------------

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

TPG PARALLEL I L.P.

BY:  TPG GENPAR, A DELAWARE LIMITED PARTNERSHIP,
     ITS GENERAL PARTNER

BY:  TPG ADVISORS, INC., A DELAWARE CORPORATION,
     ITS GENERAL PARTNER

By: /s/ Richard A. Ekleberry
   --------------------------------------------------

Name:   Richard A. Ekleberry
     ------------------------------------------------

Title:  Vice President
      -----------------------------------------------

Address: 301 Commerce Street, Suite 3300
        ---------------------------------------------
         Fort Worth, Texas, 76102
        ---------------------------------------------

        ---------------------------------------------
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AIR PARTNERS II, L.P.

BY:  TPG GENPAR, A DELAWARE LIMITED PARTNERSHIP,
     ITS GENERAL PARTNER

BY:  TPG ADVISORS, INC., A DELAWARE CORPORATION,
     ITS GENERAL PARTNER

By: /s/ Richard A. Ekleberry
   --------------------------------------------------

Name:   Richard A. Ekleberry
     ------------------------------------------------

Title:  Vice President
      -----------------------------------------------

Address: 301 Commerce Street, Suite 3300
        ---------------------------------------------
         Fort Worth, Texas 76102
        ---------------------------------------------

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

AMERICA WEST HOLDINGS CORPORATION

By: /s/ Bernard Han
   --------------------------------------------------

Name: Bernard Han
     ------------------------------------------------

Title: Executive Vice President and Chief Financial
      -----------------------------------------------
       Officer
      -----------------------------------------------

Address:   111 West Rio Salado Parkway
           Tempe, AZ  85281

ACKNOWLEDGED TO AND AGREED BY:

AIR TRANSPORTATION STABILIZATION BOARD

By: /s/ Joseph P. Adams, Jr.
   --------------------------------------------------

Name: Joseph P. Adams, Jr.
     ------------------------------------------------

Title: Executive Director
      -----------------------------------------------

Address:   1120 Vermont Avenue, Suite 970
           Washington, D.C.  20005

With a copy to:
           United States Department of the Treasury
           1500 Pennsylvania Avenue, N.W.
           Washington, D.C.  20220
           Attn:  Deputy Assistant Secretary (Government Financial Policy)EXHIBIT 10.1
                                                                    ------------

                             INSIGHTFUL CORPORATION

                 SATISFACTION, TERMINATION AND RELEASE AGREEMENT
                 -----------------------------------------------

     This Satisfaction, Termination and Release Agreement (this "Agreement"), is
                                                                 ---------
made as of January 8, 2002, by and between Insightful Corporation, a Delaware
corporation (the "Company"), and Charles Digate ("Digate").
                  -------                         ------

                                    RECITALS

     A.   The Company and Digate are parties to that certain Promissory Note,
dated as of June 19, 2000 (the "Note"), whereby the Company agreed to lend to
                                ----
Digate an amount equal to $550,000 to purchase 275,000 shares of the Company's
Common Stock (the "Shares"),
                   ------

     B.   The Company and Digate are parties to that certain Pledge Agreement,
dated as of June 19, 2000 (the "Pledge Agreement"), whereby Digate agreed to
                                ----------------
pledge the Shares to the Company as security for the repayment of the principal
and interest outstanding under the Note.

     C.   As of the date hereof, 167,800 Shares remain pledged pursuant to the
Pledge Agreement, and $307,959.05 in principal and interest are outstanding
under the Note.

     D.   The Company desires to accept as full payment of all of Digate's
outstanding obligations under the Note, and Digate desires to secure all rights,
title and interest in and to, the remaining Shares pledged pursuant to the
Pledge Agreement, upon the terms and subject to the conditions set forth herein.

     NOW, THEREFORE, in consideration of the mutual promises set forth herein,
the receipt and sufficiency of which are hereby acknowledged, the parties hereto
agree as follows:

     1.   SATISFACTION OF DEBT. Subject to the terms and conditions of this
          --------------------
Agreement, Digate shall pay to the Company, and the Company agrees to accept as
full payment of all of Digate's outstanding obligations under the Note,
$307,959.05 (the "Payoff Amount"), which amount represents the principal and
interest outstanding under the Note.

     2.   CLOSING.
          -------

          (a)  The transfer of the Payoff Amount as full payment of all of
Digate's outstanding obligations under the Note shall occur at the principal
office of the Company simultaneously with the execution of this Agreement by the
parties or on such other date as the Company and Digate shall agree (the
"Closing Date").
 ------------

          (b)  On the Closing Date,

               (i)  Digate shall deliver to the Company a negotiable instrument
effecting the transfer of the Payoff Amount to the Company;

               (ii) the Company shall deliver a letter to First Albany
Corporation, the escrow agent for the Shares authorizing the release of, or the
taking of any action to release, any and all remaining Shares covered by the
Pledge Agreement; and

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               (iii) the Company shall cancel the Note and deliver the cancelled
Note to Digate.

     3.   CANCELLATION OF PLEDGE AGREEMENT. Upon the delivery of the Payoff
          --------------------------------
Amount, the Pledge Agreement shall be terminated effective immediately.

     4.   MUTUAL RELEASE. The Company and Digate hereby fully, forever,
          --------------
irrevocably and unconditionally release and discharge each other from any and
all claims and liabilities, whether or not currently known, that either party
asserted or could have asserted, had or may now have or may hereafter have
against the other relating to or arising under the Pledge Agreement or the Note.

     5.   RELEASE OF UNKNOWN CLAIMS. The Company and Digate intentionally and
          -------------------------
voluntarily waive and relinquish the benefits of any statutes or decisions
providing that a general release does not extend to claims which the creditor
does not know or suspect to exist in its favor at the time of executing the
release, which if known by it must have materially affected its settlement with
the debtor.

     6.   NO ASSIGNMENTS OF RELEASED CLAIMS. The Company and Digate represent
          ---------------------------------

and warrant that they have not previously assigned or transferred, nor will they
assign or transfer, any claim, demand, or cause of being released by them in
this Agreement.

     7.   MISCELLANEOUS.
          -------------

          (a)  GOVERNING LAW. This Agreement and all acts and transactions
               -------------
pursuant hereto and the rights and obligations of the parties hereto shall be
governed, construed and interpreted in accordance with the laws of the state of
Delaware, without giving effect to principles of conflicts of law.

          (b)  ENTIRE AGREEMENT; ENFORCEMENT OF RIGHTS. This Agreement sets
               ---------------------------------------
forth the entire agreement and understanding of the parties relating to the
subject matter herein and merges all prior discussions between them. No
modification of or amendment to this Agreement, nor any waiver of any rights
under this Agreement, shall be effective unless in writing signed by the parties
to this Agreement. The failure by either party to enforce any rights under this
Agreement shall not be construed as a waiver of any rights of such party.

          (c)  SEVERABILITY. If one or more provisions of this Agreement are
               ------------
held to be unenforceable under applicable law, the parties agree to renegotiate
such provision in good faith. In the event that the parties cannot reach a
mutually agreeable and enforceable replacement for such provision, then (i) such
provision shall be excluded from this Agreement, (ii) the balance of the
Agreement shall be interpreted as if such provision were so excluded and (iii)
the balance of the Agreement shall be enforceable in accordance with its terms.

          (d)  CONSTRUCTION. This Agreement is the result of negotiations
               ------------
between and has been reviewed by each of the parties hereto and their respective
counsel, if any; accordingly, this Agreement shall be deemed to be the product
of all of the parties hereto, and no ambiguity shall be construed in favor of or
against any one of the parties hereto.

          (e)  NOTICES. Any notice required or permitted by this Agreement shall
               -------
be in writing and shall be deemed sufficient when delivered personally or sent
by telegram or fax or 48 hours after being deposited in the U.S. mail, as

<PAGE>
certified or registered mail, with postage prepaid, and addressed to the party
to be notified at such party's address or fax number as set forth below or as
subsequently modified by written notice.

          (f)  COUNTERPARTS. This Agreement may be executed in two or more
               ------------
counterparts, each of which shall be deemed an original and all of which
together shall constitute one instrument.

     The parties have executed this Satisfaction, Termination and Release
Agreement as of the date first set forth above.

                                    COMPANY:

                                    INSIGHTFUL CORPORATION

                                    By: /s/ Sarwat H. Ramadan
                                       -----------------------------
                                    Name: Sarwat H. Ramadan
                                    Title: CFO and Treasurer

                                    PURCHASER:

                                    CHARLES DIGATE

                                    /s/ Charles J. Digate
                                    ---------------------
                                    (Signature)

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