SUBROUTINE TIMER
C** ROUTINE TO UPDATE LANDING TIME
       COMMON /ALANDS/VELCTY,GRAVTY,RETROR,TMPACT,ALTUDE,FUELR
C***************************************************
       TIMEL = TMPACT
       NUMBR = 1
 10    DISTNC = VELCTY*TIMEL + 0.5*GRAVTY*TIMEL**2
       PERCNT = (ALTUDE-DISTNC) / ALTUDE
       DELTAT = 0.10
       IF(DISTNC .GT. ALTUDE) DELTAT = -0.10
       IF(ABS(PERCNT) .LE. 0.10)GO TO 900
       TIMEL = TIMEL + DELTAT
       NUMBR = NUMBR + 1
       IF(NUMBR .GT. 90)GO TO 900
        GO TO 10
 900   TMPACT = TIMEL
       RETURN
       END