Narrative:

We were given an altitude crossing restriction of 10 west of stillwater VOR at FL230. We were cruising at FL370 at about 600 KTS gndspd due to good tailwind. The descent was programmed into the FMC. Due to engine compressor problems at high altitude, we generally start down 10 mi earlier than the FMC generated top of descent point. The PF decided to brief the approach prior to descent. During the brief the throttles started coming back for the descent. PF had to stop throttles at 1.1 EPR for 30 seconds to prevent possible flame-out. This engine restriction made it impossible to make altitude restriction. We called ATC and advised them of the fact that we would cross 10 west of stillwater at FL270 and would continue to FL230. We made FL230 by stillwater VOR (stw). The problem could be solved by better attention by the flight crew to descend prior to top of descent point. A more positive solution would be to have the FMC generated top of descent point include the 1.1 EPR restriction, or to fix the engines where compressor problems would be solved. Supplemental information from acn 130861: notified ZNY that we would be some 3000' high. Center did not seem concerned. Crossed 10 west of stw out of FL260 and stw at FL230. Mistake was allowing fmcs to initiate descent. A manual descent should have been initiated prior to top of descent point.

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Original NASA ASRS Text

Title: ACR WDB FAILS TO MEET CROSSING RESTRICTION IN DESCENT. CITES INSUFFICIENT LEAD TIME FOR TOP OF DESCENT BY FMS, AND HAMPERED BY ENGINE LOW EPR LIMITATIONS.

Narrative: WE WERE GIVEN AN ALT XING RESTRICTION OF 10 W OF STILLWATER VOR AT FL230. WE WERE CRUISING AT FL370 AT ABOUT 600 KTS GNDSPD DUE TO GOOD TAILWIND. THE DSCNT WAS PROGRAMMED INTO THE FMC. DUE TO ENG COMPRESSOR PROBS AT HIGH ALT, WE GENERALLY START DOWN 10 MI EARLIER THAN THE FMC GENERATED TOP OF DSCNT POINT. THE PF DECIDED TO BRIEF THE APCH PRIOR TO DSCNT. DURING THE BRIEF THE THROTTLES STARTED COMING BACK FOR THE DSCNT. PF HAD TO STOP THROTTLES AT 1.1 EPR FOR 30 SECS TO PREVENT POSSIBLE FLAME-OUT. THIS ENG RESTRICTION MADE IT IMPOSSIBLE TO MAKE ALT RESTRICTION. WE CALLED ATC AND ADVISED THEM OF THE FACT THAT WE WOULD CROSS 10 W OF STILLWATER AT FL270 AND WOULD CONTINUE TO FL230. WE MADE FL230 BY STILLWATER VOR (STW). THE PROB COULD BE SOLVED BY BETTER ATTN BY THE FLT CREW TO DSND PRIOR TO TOP OF DSCNT POINT. A MORE POSITIVE SOLUTION WOULD BE TO HAVE THE FMC GENERATED TOP OF DSCNT POINT INCLUDE THE 1.1 EPR RESTRICTION, OR TO FIX THE ENGS WHERE COMPRESSOR PROBS WOULD BE SOLVED. SUPPLEMENTAL INFO FROM ACN 130861: NOTIFIED ZNY THAT WE WOULD BE SOME 3000' HIGH. CENTER DID NOT SEEM CONCERNED. CROSSED 10 W OF STW OUT OF FL260 AND STW AT FL230. MISTAKE WAS ALLOWING FMCS TO INITIATE DSCNT. A MANUAL DSCNT SHOULD HAVE BEEN INITIATED PRIOR TO TOP OF DSCNT POINT.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.