Narrative:

While climbing out through 13000 ft with a cruise altitude of 16000 ft; the captain recommended we go to flch due to an unable cruise message that I did not see. Shortly thereafter the airspeed bug rolled back to 250 KTS so I stepped into flch as recommended. After leveling at 16000 ft I went back into VNAV and the airspeed bug rolled back one more time to 250 KTS and I speed intervened back to 300 KTS. Checking the cruise page I saw a cruise airspeed of .604 mach or something very close to that; with no IAS; so I entered 300 KTS for a cruise airspeed. I questioned myself that a mach was displayed vice an IAS at 16000 ft and checked that 16000 ft was our cruise altitude. It was; I closed the airspeed window and returned to the descent page and changed our descent speed to 300 KTS from 277 KTS. At the same time we were deviating for a cell and cleared to an off flight plan point; when able; to dunkk intersection at 11000 ft; altimeter 29.75. The captain entered it and we added 250 KTS for the speed restr; I verified; and he executed. The captain placed 11000 ft in the altitude window. A top of descent was present just prior to dunkk on both maps and dunkk 250 KTS at 11000 ft was in the descent page. Thinking everything looked good and I turned my attention to setting up for the ILS runway 25L approach at phx. I saw us getting close to top of descent and asked if the captain was ready for a brief. While giving my approach brief center asked if we had been given 11000 ft as a restr. We said yes and realized we were now 6 mi outside dunkk and 16000 ft still outside the top of descent point. I started down immediately and deployed the speed brakes. While passing 14000 ft we got an unable cruise message again. At 4 mi it was clear we would not make the restr and center said what I heard as delete speed restr and continue descent to 8000 ft. The captain heard delete altitude vice speed. We passed dunkk at 12000 ft and 270 KTS and continued our descent to 8000 ft. The rest of the flight was normal. I could have easily prevented this error by flying the airplane first. I trusted the automation and touchdown point without observing the DME to dunkk or paying much attention to my map scale. I was in a lower scale so it looked further than it actually was and I neglected to back up with 3 to 1 as I normally do. I was also focused on getting the approach brief done and descent checklist completed before our top of descent point. I also should have xferred control of the aircraft prior to giving the approach brief; or briefed the approach while on the ground due to the limited time airborne. Additionally; I could have clicked off the automation to make the descent altitude. I'm still not sure what happened with our automation failure or why we got the unable cruise in the descent; but bottom-line is I relied too heavily on automation and I didn't fly the airplane first.

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Original NASA ASRS Text

Title: B757 FLT CREW FAILED TO MEET CROSSING RESTRICTION ON ARRIVAL; RELYING ON FMC GENERATED 'TOP OF DESCENT' POINT; WHICH WAS IN ERROR.

Narrative: WHILE CLBING OUT THROUGH 13000 FT WITH A CRUISE ALT OF 16000 FT; THE CAPT RECOMMENDED WE GO TO FLCH DUE TO AN UNABLE CRUISE MESSAGE THAT I DID NOT SEE. SHORTLY THEREAFTER THE AIRSPD BUG ROLLED BACK TO 250 KTS SO I STEPPED INTO FLCH AS RECOMMENDED. AFTER LEVELING AT 16000 FT I WENT BACK INTO VNAV AND THE AIRSPD BUG ROLLED BACK ONE MORE TIME TO 250 KTS AND I SPD INTERVENED BACK TO 300 KTS. CHKING THE CRUISE PAGE I SAW A CRUISE AIRSPD OF .604 MACH OR SOMETHING VERY CLOSE TO THAT; WITH NO IAS; SO I ENTERED 300 KTS FOR A CRUISE AIRSPD. I QUESTIONED MYSELF THAT A MACH WAS DISPLAYED VICE AN IAS AT 16000 FT AND CHKED THAT 16000 FT WAS OUR CRUISE ALT. IT WAS; I CLOSED THE AIRSPD WINDOW AND RETURNED TO THE DSCNT PAGE AND CHANGED OUR DSCNT SPD TO 300 KTS FROM 277 KTS. AT THE SAME TIME WE WERE DEVIATING FOR A CELL AND CLRED TO AN OFF FLT PLAN POINT; WHEN ABLE; TO DUNKK INTXN AT 11000 FT; ALTIMETER 29.75. THE CAPT ENTERED IT AND WE ADDED 250 KTS FOR THE SPD RESTR; I VERIFIED; AND HE EXECUTED. THE CAPT PLACED 11000 FT IN THE ALT WINDOW. A TOP OF DSCNT WAS PRESENT JUST PRIOR TO DUNKK ON BOTH MAPS AND DUNKK 250 KTS AT 11000 FT WAS IN THE DSCNT PAGE. THINKING EVERYTHING LOOKED GOOD AND I TURNED MY ATTN TO SETTING UP FOR THE ILS RWY 25L APCH AT PHX. I SAW US GETTING CLOSE TO TOP OF DSCNT AND ASKED IF THE CAPT WAS READY FOR A BRIEF. WHILE GIVING MY APCH BRIEF CTR ASKED IF WE HAD BEEN GIVEN 11000 FT AS A RESTR. WE SAID YES AND REALIZED WE WERE NOW 6 MI OUTSIDE DUNKK AND 16000 FT STILL OUTSIDE THE TOP OF DSCNT POINT. I STARTED DOWN IMMEDIATELY AND DEPLOYED THE SPD BRAKES. WHILE PASSING 14000 FT WE GOT AN UNABLE CRUISE MESSAGE AGAIN. AT 4 MI IT WAS CLR WE WOULD NOT MAKE THE RESTR AND CTR SAID WHAT I HEARD AS DELETE SPD RESTR AND CONTINUE DSCNT TO 8000 FT. THE CAPT HEARD DELETE ALT VICE SPD. WE PASSED DUNKK AT 12000 FT AND 270 KTS AND CONTINUED OUR DSCNT TO 8000 FT. THE REST OF THE FLT WAS NORMAL. I COULD HAVE EASILY PREVENTED THIS ERROR BY FLYING THE AIRPLANE FIRST. I TRUSTED THE AUTOMATION AND TOUCHDOWN POINT WITHOUT OBSERVING THE DME TO DUNKK OR PAYING MUCH ATTN TO MY MAP SCALE. I WAS IN A LOWER SCALE SO IT LOOKED FURTHER THAN IT ACTUALLY WAS AND I NEGLECTED TO BACK UP WITH 3 TO 1 AS I NORMALLY DO. I WAS ALSO FOCUSED ON GETTING THE APCH BRIEF DONE AND DSCNT CHKLIST COMPLETED BEFORE OUR TOP OF DSCNT POINT. I ALSO SHOULD HAVE XFERRED CTL OF THE ACFT PRIOR TO GIVING THE APCH BRIEF; OR BRIEFED THE APCH WHILE ON THE GND DUE TO THE LIMITED TIME AIRBORNE. ADDITIONALLY; I COULD HAVE CLICKED OFF THE AUTOMATION TO MAKE THE DSCNT ALT. I'M STILL NOT SURE WHAT HAPPENED WITH OUR AUTOMATION FAILURE OR WHY WE GOT THE UNABLE CRUISE IN THE DSCNT; BUT BOTTOM-LINE IS I RELIED TOO HEAVILY ON AUTOMATION AND I DIDN'T FLY THE AIRPLANE FIRST.

Data retrieved from NASA's ASRS site as of January 2009 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.