
                                 Exhibit 10.10a

                               SECOND AMENDMENT TO
                     THE PINNACLE WEST CAPITAL CORPORATION,
                         ARIZONA PUBLIC SERVICE COMPANY
                           SUNCOR DEVELOPMENT COMPANY
                        AND EL DORADO INVESTMENT COMPANY
                           DEFERRED COMPENSATION PLAN

     Effective  January  1,  1992,   Pinnacle  West  Capital   Corporation  (the
"Company"),  Arizona Public Service Company,  SunCor Development  Company and El
Dorado Investment Company adopted the Pinnacle West Capital Corporation, Arizona
Public Service  Company,  SunCor  Development  Company and El Dorado  Investment
Company Deferred Compensation Plan (the "Plan"). The Plan was thereafter amended
several  times and was amended and restated in its entirety on December 1, 1995,
and thereafter amended September 15, 1999.

     By this  instrument,  the Company  intends to amend the Plan to clarify the
definition  of "Change in  Control."

     1. This Amendment  shall amend only those sections of the Plan as set forth
herein and those  sections  not  expressly  amended  hereby shall remain in full
force and effect.

     2. Sections 11.3(a) of the Plan is hereby amended to read as follows:

          (a) CHANGE IN  CONTROL.  A "Change in  Control"  shall mean one (1) or
     more of the following events:

               (1) Any Person, other than an Affiliate, through a transaction or
          series of transactions,  is or becomes the Beneficial Owner,  directly
          or indirectly, of securities of the Company or APS representing twenty
          percent  (20%)  or more  of the  combined  voting  power  of the  then
          outstanding securities of the Company or APS, as the case may be;

               (2) A merger or  consolidation  of (i) the Company with any other
          corporation which would result in the voting securities of the Company
          outstanding immediately prior to such merger or consoli-
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          dation continuing to represent (either by remaining  outstanding or by
          being converted into voting  securities of the surviving entity or any
          parent  thereof),  in combination with the ownership of any trustee or
          other fiduciary  holding  securities under an employee benefit plan of
          the  Company or an  Affiliate,  less than sixty  percent  (60%) of the
          combined  voting  power  of the  securities  of the  Company  or  such
          surviving entity or any parent thereof  outstanding  immediately after
          such merger or  consolidation,  or (ii) APS with any other corporation
          which  would  result  in the  voting  securities  of  APS  outstanding
          immediately  prior  to such  merger  or  consolidation  continuing  to
          represent (either by remaining  outstanding or by being converted into
          voting  securities of the surviving entity or any parent thereof),  in
          combination  with the  ownership  of any  trustee  or other  fiduciary
          holding securities under an employee benefit plan of the Company or an
          Affiliate,  less than sixty percent (60%) of the combined voting power
          of the  securities  of APS or  such  surviving  entity  or any  parent
          thereof  outstanding  immediately  after such merger or consolidation;
          provided  that,  for  purposes of this  subparagraph  (2), a merger or
          consolidation  effected to implement a recapitalization of the Company
          or of APS (or  similar  transaction)  in which no Person is or becomes
          the Beneficial  Owner,  directly or  indirectly,  of securities of the
          Company or of APS  representing  twenty  percent  (20%) or more of the
          combined  voting  power  of the  then  outstanding  securities  of the
          Company or of APS (excluding  any  securities  acquired by that Person
          directly  from the  Company  or an  Affiliate)  shall not  result in a
          Change of Control;

               (3) The shareholders of either the Company or APS approve a sale,
          transfer  or  other  disposition  of all or  substantially  all of the
          assets of either the Company or APS to a Person other than the Company
          or an Affiliate; or

               (4) Individuals who, as of July 31, 1999, constitute the board of
          directors of the Company  (the  "Company  Incumbent  Board") or of APS
          (the "APS  Incumbent  Board")  cease for any reason to  constitute  at
          least  two-thirds  (2/3) of the members of the Company or APS board of
          directors, as the case may be; provided, however, that for purposes of
          this  subparagraph  (4),  (i)(A) any  person  becoming a member of the
          Company  board of  directors  after July 31, 1999 whose  election,  or
          nomination for election by the Company's shareholders, was approved by
          a vote of at least two-thirds (2/3) of the members then comprising the
          Company  Incumbent Board will be considered as though such person were
          a member of the Company  Incumbent Board and (B) the Company Incumbent
          Board shall not include a director whose initial assumption

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          of office as a director was in connection with an actual or threatened
          election  contest  relating to the election of directors;  and (ii)(A)
          any person  becoming a member of the APS board of directors after July
          31,  1999  whose   election,   or  nomination  for  election  by  APS'
          shareholder(s), was approved by a vote of at least two-thirds (2/3) of
          the members then comprising the APS Incumbent Board or by the Company,
          as a majority  shareholder  of APS,  will be considered as though such
          person  were a  member  of the  APS  Incumbent  Board  and (B) the APS
          Incumbent Board shall not include a director whose initial  assumption
          of office as a director was in connection with an actual or threatened
          election contest relating to the election of directors.

          For purposes of this Section 11.3(a),

               (A) "Act" shall mean the  Securities and Exchange Act of 1934, as
          amended from time to time.

               (B)  "Affiliate"  shall  mean (i) a  corporation  other  than the
          Company  that is a member  of a  "controlled  group  of  corporations"
          (within  the  meaning of  Section  414(b) of the Code as  modified  by
          Section  415(h) of the  Code) or (ii) a group of trades or  businesses
          under common control (within the meaning of Section 414(c) of the Code
          as  modified  by Section  415(h) of the Code) that also  includes  the
          Company as a member. For purposes of determining whether a transaction
          or event  constitutes  a Change of Control  within the meaning of this
          Section  13(d),  "Affiliate"  status  shall be  determined  on the day
          immediately preceding the date of the transaction or event.

               (C) "APS" shall mean Arizona Public Service Company.

               (D)  "Beneficial  Owner"  shall have the same meaning as given to
          that term in Rule 13d-3 of the General  Rules and  Regulations  of the
          Act, provided that any pledgee of the voting securities of the Company
          or APS shall not be deemed to be the Beneficial Owner thereof prior to
          its  disposition  of, or acquisition of voting rights with respect to,
          such securities.

               (E)  "Code"  shall mean the  Internal  Revenue  Code of 1986,  as
          amended from time to time.

               (F)  "Person"  shall  mean  any  individual,  partnership,  joint
          venture, association,  trust, corporation or other entity (including a
          "group" as defined in Section 13(d)(3) of the Act), other than an

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<PAGE>
          employee  benefit  plan of the  Company or an  Affiliate  or an entity
          organized,  appointed or established pursuant to the terms of any such
          benefit plan.

               3. A new Section  11.3(c) is hereby added to the Plan which shall
          read as follows:

               (c) EFFECTIVE  DATE OF A CHANGE IN CONTROL.  Notwithstanding  any
          provision to the contrary herein,  for purposes of this Plan, a Change
          in Control  shall be deemed to have  occurred  six (6) months prior to
          the date on which one (1) or more of the  events  set forth in Section
          11.3(a) occurred.

               4. This Amendment shall be effective as of January 1, 2000.

     IN WITNESS WHEREOF, the Company has caused this Amendment to be executed by
its duly authorized officer this 7 day of December, 1999.


                                        PINNACE WEST CAPITAL CORPORATION


                                        By Armando Flores
                                          --------------------------------------
                                        Its EVP Corp Bus Svcs
                                           -------------------------------------

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