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A B757 was given an arrival without the usual speed restrs. During the attempt to remove the speeds from the FMC the flight crew descended below the assigned altitude.
| Attributes | |
| ACN | 433130 |
| Time | |
| Date | 199904 |
| Day | Wed |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : cqy.vortac |
| State Reference | TX |
| Altitude | msl bound lower : 10560 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : approach |
| Route In Use | arrival star : cqy4 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| ASRS Report | 433130 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 25000 flight time type : 8000 |
| ASRS Report | 433134 |
| Events | |
| Anomaly | altitude deviation : undershoot non adherence : clearance |
| Independent Detector | other controllera other flight crewa other flight crewb |
| Resolutory Action | controller : issued alert flight crew : returned to original clearance |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
The clearance was to descend to 11000 ft and ignore speeds on the arrival except 210 KTS at dietz. We had just slowed to 280 KTS to meet the first restr on the arrival. Approach control deleted speeds until dietz and captain selected 300 KTS in FMS. The FMC would not command the bug to 300 KTS after several attempts on several different pages, ie, crz, desc. Finally the FMC commanded 300 KTS and the airplane began a high rate of descent (approximately 4000 FPM) to obtain 300 KTS. I called out of 12000 ft for 11000 ft and began again to focus on the captain trying to program computer. At that point the captain disconnected the autoplt to return to 11000 ft. We had descended to 10560 ft. 11000 ft was in the window with autoplt on and the autoplt did not capture the altitude. We returned to 11000 ft immediately with the approach controller querying our altitude. No loss of separation occurred. Contributing factors: engrossed in automation from both pilots.
Original NASA ASRS Text
Title: A B757 WAS GIVEN AN ARR WITHOUT THE USUAL SPD RESTRS. DURING THE ATTEMPT TO REMOVE THE SPDS FROM THE FMC THE FLC DSNDED BELOW THE ASSIGNED ALT.
Narrative: THE CLRNC WAS TO DSND TO 11000 FT AND IGNORE SPDS ON THE ARR EXCEPT 210 KTS AT DIETZ. WE HAD JUST SLOWED TO 280 KTS TO MEET THE FIRST RESTR ON THE ARR. APCH CTL DELETED SPDS UNTIL DIETZ AND CAPT SELECTED 300 KTS IN FMS. THE FMC WOULD NOT COMMAND THE BUG TO 300 KTS AFTER SEVERAL ATTEMPTS ON SEVERAL DIFFERENT PAGES, IE, CRZ, DESC. FINALLY THE FMC COMMANDED 300 KTS AND THE AIRPLANE BEGAN A HIGH RATE OF DSCNT (APPROX 4000 FPM) TO OBTAIN 300 KTS. I CALLED OUT OF 12000 FT FOR 11000 FT AND BEGAN AGAIN TO FOCUS ON THE CAPT TRYING TO PROGRAM COMPUTER. AT THAT POINT THE CAPT DISCONNECTED THE AUTOPLT TO RETURN TO 11000 FT. WE HAD DSNDED TO 10560 FT. 11000 FT WAS IN THE WINDOW WITH AUTOPLT ON AND THE AUTOPLT DID NOT CAPTURE THE ALT. WE RETURNED TO 11000 FT IMMEDIATELY WITH THE APCH CTLR QUERYING OUR ALT. NO LOSS OF SEPARATION OCCURRED. CONTRIBUTING FACTORS: ENGROSSED IN AUTOMATION FROM BOTH PLTS.
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.