Narrative:

Altitude deviation by B757 scheduled air carrier. Lax to sfo. Captain is the PF. Events leading to the altitude deviation began before we reached big sur. Our clearance was present position direct to anjee on the big sur 2 arrival into sfo. Shortly thereafter we were given clearance from FL350 to FL310. The captain selected vertical speed to descend the airplane with the autoplt engaged. Further descent clearance to cross boldr at 10000 ft was given by ZOA. I noticed we would be high at boldr if we didn't increase our rate of descent soon, so I alerted the captain that he was starting to get high on the descent profile. The captain acknowledged and selected flight level change speed which increased the rate of descent. We were still high on the profile, so the captain elected to use the speed brakes. When the speed brakes were extended, we got an unscheduled stabilizer trim EICAS message and the autoplt disconnected. The captain decided to hand fly the airplane at that point. During the descent I was giving PA's and running the appropriate checklists. The ATIS was about to change so I was rechking for the new ATIS. As the descent continued the captain asked if ATC gave us a 250 KT restr at boldr. I replied, 'no, however, it is published to cross at 250 KIAS on the STAR.' at that point the captain began some dialogue about speed restrs on the STAR. While listening to what he was saying, I noticed we were back on profile in our current confign. When the captain was done speaking, I told him I disagreed, and that we should cross boldr at 250 KTS. The captain then asked me to ask ZOA if they wanted us to cross boldr at 250 KTS. When I called ZOA there was no reply. I called ZOA again to ask if they wanted 250 KTS at boldr. I looked at the radio panel to make sure I was transmitting correctly. At that same time, ZOA replied, 'affirmative 250 KTS at boldr, contact bay approach.' the captain then called out 11000 ft for 10000 ft. I confirmed our altitude and called our 11000 ft for 10000 ft. We were slowing to 250 KTS and would be able to make our 250 KT, 10000 ft crossing restr at boldr. I tuned in bay approach frequency and reported out of 11000 ft for 10000 ft with the ATIS. There was some delay in bay's response, then he told us to turn left to a 270 degree heading and join the sfo 090 degree radial. I reached up, turned the heading bug 270 degrees, and was about to dial up the frequency for sfo VOR when the captain said, 'that can't be right, ask if that clearance was for us.' I called bay back to confirm, no reply. I looked at the chart and noticed we would have to make a right turn to intercept sfo 090 degree radial. I called bay again to confirm our clearance. About the same time, I noticed we had missed our leveloff at 10000 ft. The captain leveled off at 8500 ft and began to climb back up to 10000 ft. The MEA for our position was 6000 ft. Bay finally answered back using our flight number with a different airline name, then asked who was calling. When bay realized who we were, he told us the clearance was for someone else, and to contact bay approach on another frequency. We checked in on the next frequency and were told to continue descent to 6000 ft. No traffic conflicts existed that we know of. The remainder of the flight was uneventful. Contributing factors: starting descent late, causing us to be high on the descent profile. Autoplt disconnecting. Captain focusing too much attention on whether or not to cross boldr at 250 KTS. Late handoff from center to approach control. Slow or no response from center and approach. Our flight receiving a clearance that was meant for a different flight. Inability to get prompt clarification to an ambiguous clearance. The captain's inattn to flying the aircraft. My inattn to where the aircraft was while performing the PNF duties. Factors affecting human performance: I believe my lack of situational awareness stems from lack of rest due to my reserve schedule. The entire month of december's flying consisted of back side of the clock flying with early morning departures the following day. Calls for trip assignments were received in the middle of the night or at other times when trying to rest. My airline reserve policy allows you to be on call 24 hours a day with no scheduled rest period. This can make it difficult to plan for proper rest during a busy month. Most transport aircraft utilize an altitude warning horn. The B757 has a light on the altimeter and a light on the forward annunciator panel. If your eyes are on the altimeter the altitude warning light is visible. This doesn't help if you become distraction the way an altitude warning horn would.

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Original NASA ASRS Text

Title: A DSNDING B757 CREW OVERSHOT THEIR ASSIGNED ALT WHEN BECOMING CONFUSED OVER CALL SIGNS AND CLRNC.

Narrative: ALTDEV BY B757 SCHEDULED ACR. LAX TO SFO. CAPT IS THE PF. EVENTS LEADING TO THE ALTDEV BEGAN BEFORE WE REACHED BIG SUR. OUR CLRNC WAS PRESENT POS DIRECT TO ANJEE ON THE BIG SUR 2 ARR INTO SFO. SHORTLY THEREAFTER WE WERE GIVEN CLRNC FROM FL350 TO FL310. THE CAPT SELECTED VERT SPD TO DSND THE AIRPLANE WITH THE AUTOPLT ENGAGED. FURTHER DSCNT CLRNC TO CROSS BOLDR AT 10000 FT WAS GIVEN BY ZOA. I NOTICED WE WOULD BE HIGH AT BOLDR IF WE DIDN'T INCREASE OUR RATE OF DSCNT SOON, SO I ALERTED THE CAPT THAT HE WAS STARTING TO GET HIGH ON THE DSCNT PROFILE. THE CAPT ACKNOWLEDGED AND SELECTED FLT LEVEL CHANGE SPD WHICH INCREASED THE RATE OF DSCNT. WE WERE STILL HIGH ON THE PROFILE, SO THE CAPT ELECTED TO USE THE SPD BRAKES. WHEN THE SPD BRAKES WERE EXTENDED, WE GOT AN UNSCHEDULED STABILIZER TRIM EICAS MESSAGE AND THE AUTOPLT DISCONNECTED. THE CAPT DECIDED TO HAND FLY THE AIRPLANE AT THAT POINT. DURING THE DSCNT I WAS GIVING PA'S AND RUNNING THE APPROPRIATE CHKLISTS. THE ATIS WAS ABOUT TO CHANGE SO I WAS RECHKING FOR THE NEW ATIS. AS THE DSCNT CONTINUED THE CAPT ASKED IF ATC GAVE US A 250 KT RESTR AT BOLDR. I REPLIED, 'NO, HOWEVER, IT IS PUBLISHED TO CROSS AT 250 KIAS ON THE STAR.' AT THAT POINT THE CAPT BEGAN SOME DIALOGUE ABOUT SPD RESTRS ON THE STAR. WHILE LISTENING TO WHAT HE WAS SAYING, I NOTICED WE WERE BACK ON PROFILE IN OUR CURRENT CONFIGN. WHEN THE CAPT WAS DONE SPEAKING, I TOLD HIM I DISAGREED, AND THAT WE SHOULD CROSS BOLDR AT 250 KTS. THE CAPT THEN ASKED ME TO ASK ZOA IF THEY WANTED US TO CROSS BOLDR AT 250 KTS. WHEN I CALLED ZOA THERE WAS NO REPLY. I CALLED ZOA AGAIN TO ASK IF THEY WANTED 250 KTS AT BOLDR. I LOOKED AT THE RADIO PANEL TO MAKE SURE I WAS XMITTING CORRECTLY. AT THAT SAME TIME, ZOA REPLIED, 'AFFIRMATIVE 250 KTS AT BOLDR, CONTACT BAY APCH.' THE CAPT THEN CALLED OUT 11000 FT FOR 10000 FT. I CONFIRMED OUR ALT AND CALLED OUR 11000 FT FOR 10000 FT. WE WERE SLOWING TO 250 KTS AND WOULD BE ABLE TO MAKE OUR 250 KT, 10000 FT XING RESTR AT BOLDR. I TUNED IN BAY APCH FREQ AND RPTED OUT OF 11000 FT FOR 10000 FT WITH THE ATIS. THERE WAS SOME DELAY IN BAY'S RESPONSE, THEN HE TOLD US TO TURN L TO A 270 DEG HDG AND JOIN THE SFO 090 DEG RADIAL. I REACHED UP, TURNED THE HDG BUG 270 DEGS, AND WAS ABOUT TO DIAL UP THE FREQ FOR SFO VOR WHEN THE CAPT SAID, 'THAT CAN'T BE RIGHT, ASK IF THAT CLRNC WAS FOR US.' I CALLED BAY BACK TO CONFIRM, NO REPLY. I LOOKED AT THE CHART AND NOTICED WE WOULD HAVE TO MAKE A R TURN TO INTERCEPT SFO 090 DEG RADIAL. I CALLED BAY AGAIN TO CONFIRM OUR CLRNC. ABOUT THE SAME TIME, I NOTICED WE HAD MISSED OUR LEVELOFF AT 10000 FT. THE CAPT LEVELED OFF AT 8500 FT AND BEGAN TO CLB BACK UP TO 10000 FT. THE MEA FOR OUR POS WAS 6000 FT. BAY FINALLY ANSWERED BACK USING OUR FLT NUMBER WITH A DIFFERENT AIRLINE NAME, THEN ASKED WHO WAS CALLING. WHEN BAY REALIZED WHO WE WERE, HE TOLD US THE CLRNC WAS FOR SOMEONE ELSE, AND TO CONTACT BAY APCH ON ANOTHER FREQ. WE CHKED IN ON THE NEXT FREQ AND WERE TOLD TO CONTINUE DSCNT TO 6000 FT. NO TFC CONFLICTS EXISTED THAT WE KNOW OF. THE REMAINDER OF THE FLT WAS UNEVENTFUL. CONTRIBUTING FACTORS: STARTING DSCNT LATE, CAUSING US TO BE HIGH ON THE DSCNT PROFILE. AUTOPLT DISCONNECTING. CAPT FOCUSING TOO MUCH ATTN ON WHETHER OR NOT TO CROSS BOLDR AT 250 KTS. LATE HDOF FROM CTR TO APCH CTL. SLOW OR NO RESPONSE FROM CTR AND APCH. OUR FLT RECEIVING A CLRNC THAT WAS MEANT FOR A DIFFERENT FLT. INABILITY TO GET PROMPT CLARIFICATION TO AN AMBIGUOUS CLRNC. THE CAPT'S INATTN TO FLYING THE ACFT. MY INATTN TO WHERE THE ACFT WAS WHILE PERFORMING THE PNF DUTIES. FACTORS AFFECTING HUMAN PERFORMANCE: I BELIEVE MY LACK OF SITUATIONAL AWARENESS STEMS FROM LACK OF REST DUE TO MY RESERVE SCHEDULE. THE ENTIRE MONTH OF DECEMBER'S FLYING CONSISTED OF BACK SIDE OF THE CLOCK FLYING WITH EARLY MORNING DEPS THE FOLLOWING DAY. CALLS FOR TRIP ASSIGNMENTS WERE RECEIVED IN THE MIDDLE OF THE NIGHT OR AT OTHER TIMES WHEN TRYING TO REST. MY AIRLINE RESERVE POLICY ALLOWS YOU TO BE ON CALL 24 HRS A DAY WITH NO SCHEDULED REST PERIOD. THIS CAN MAKE IT DIFFICULT TO PLAN FOR PROPER REST DURING A BUSY MONTH. MOST TRANSPORT ACFT UTILIZE AN ALT WARNING HORN. THE B757 HAS A LIGHT ON THE ALTIMETER AND A LIGHT ON THE FORWARD ANNUNCIATOR PANEL. IF YOUR EYES ARE ON THE ALTIMETER THE ALT WARNING LIGHT IS VISIBLE. THIS DOESN'T HELP IF YOU BECOME DISTR THE WAY AN ALT WARNING HORN WOULD.

Data retrieved from NASA's ASRS site as of July 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.