
                                  Exhibit 10.8a

                             FOURTH AMENDMENT TO THE
                         ARIZONA PUBLIC SERVICE COMPANY
                      DIRECTORS DEFERRED COMPENSATION PLAN


                  Effective January 1, 1978, Arizona Public Service Company (the
     "Company") adopted the Arizona Public Service Company Directors Deferred
Compensation Plan (the "Plan").  The Plan was subsequently  amended and restated
several times,  the most recent  amendment and  restatement  becoming  effective
January  1,  1986.  The Plan  was  thereafter  amended  several  times.  By this
instrument,  the Company intends to amend the Plan to allow benefit  payments to
begin after a director attains age 70.

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

     2. Section VI.B is hereby amended in its entirety to read as follows:

     B. Time of Distribution of Benefits Under Deferral Option II

          No payment of benefits  shall be made under  Deferral  Option II until
     the  Participant  is no  longer a  Director  of the  Company  or any of its
     Affiliates.  No Participant or Beneficiary of a Participant  shall have any
     right to payment of any amounts under Deferral  Option II prior to the date
     on which the  Participant  ceases to be a Director of the Company or any of
     its  Affiliates.  Amounts shall be payable under Deferral Option II only in
     accordance  with the terms and  provisions of Deferral  Option II.  Amounts
     payable under  Deferral  Option II shall be paid to the  Participant or his
     Beneficiary  in  equal  annual   installments  for  ten  (10)  years.  Each
     Participant  shall have the right to elect,  prior to the  commencement  of
     payments,   the  year  he  desires  to  commence   receipt  of  his  annual
     installments.  The  Participant  may  elect  to  commence  receipt  of  the
     installments in any year during the period beginning with the year in which
     the  Participant  attains  the age of sixty (60) years and ending  with the
     year  in  which  the  Participant  retires  from  the  Board.  The  initial
     installment will be paid on the Participant's birthday provided that if the
     Participant's  retirement from the Board occurs after his birthday for that
     year, the initial  installment  shall be paid on the first day of the month
     following  the  month in which  the  Participant  retired  from the  Board.
     Subsequent  installments  will  be  paid  on the  Participant's  subsequent
     birthdays.  Each Participant shall have the right to select the Beneficiary
     of payments in the event of his death, as provided in Sections VI.D and E.

     3. Section VI.E is hereby amended in its entirety to read as follows:

     E. Death of a Participant Not Yet Receiving  Benefits Under Deferral Option
II.

          In the event  that a  Participant  not yet  receiving  Annual  Benefit
     payments under  Deferral  Option II shall die, the Company shall pay to the
     Participant's  Beneficiary or Beneficiaries,  in equal annual  installments
     for ten (10) years, the Annual Survivor Benefit for the year in which death
     occurred as stated on the Director's Death Benefit Summary Document for the
     Participant,  which shall be provided to the Participant from time to time.
     The  initial  installment  of the Annual  Survivor  Benefit for the year in
     which death occurs will be paid within sixty (60) days of the Participant's
     death.  Subsequent installments of the Annual Survivor Benefit will be paid
     on the anniversary of the Participant's  death. Each Participant shall have
     the right to designate a Beneficiary  or  Beneficiaries  of benefits in the
     event of his death;  provided  that, in the event that the  Participant  is
     married and designates a Beneficiary other than his spouse, his spouse must
     consent  in  writing  to such  designation.  If the  Participant  fails  to
     designate a Beneficiary,  the Annual Survivor  Benefit shall be paid to the
     Participant's estate.

     4. The  provisions  of this  Amendment  shall be effective as of January 1,
1999.

     Except as amended and supplemented by this  instrument,  the Company hereby
     ratifies the Plan as amended and restated  effective January 1, 1986 and as
     thereafter amended.


 Dated: December 28 , 1999             Arizona Public Service Company


                                        By Jack Davis
                                           -------------------------------------
                                        Its President
                                            ------------------------------------
