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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Flight crew of a cpr execute jet distracted by system problems and possible divert, overshot descent altitude. Autoplt altitude preselect drifted off setting and leveled the aircraft 500 ft lower than assigned. ATC intervened and advised them of their mistake, whereupon the captain climbed back to assigned altitude.
| Attributes | |
| ACN | 387979 |
| Time | |
| Date | 199712 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : hmv |
| State Reference | TN |
| Altitude | msl bound lower : 36500 msl bound upper : 37000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : ztl |
| Operator | general aviation : corporate |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other descent other |
| Route In Use | enroute : direct enroute other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 65 flight time total : 7300 flight time type : 500 |
| ASRS Report | 387979 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 60 flight time total : 5500 flight time type : 500 |
| ASRS Report | 387890 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Aircraft leveled off 500 ft below assigned altitude on autoplt. The crew had been given a cruise altitude change and started a descent from FL390 to FL370. The altitude selector was set to FL370 and the descent began. The crew was also working an aircraft malfunction and trying to find a suitable alternate airport. The altitude selector moved off the selected altitude by 500 ft, which it does if not carefully set and crosschecked. The crew then started work on the aircraft malfunction. I called home base while the first officer called for WX. With all the distraction of phone calls and radio work to get WX, the aircraft leveled off 500 ft low. The center asked us to confirm our altitude at which time we noticed the deviation. The crew had become preoccupied with the aircraft malfunction and didn't monitor the autoplt. The crew should always xchk the autoplt and be sure one of the crew members is monitoring the autoplt. The autoplts are so reliable that we forget that we are still responsible to monitor and fly the aircraft.
Original NASA ASRS Text
Title: FLC OF A CPR EXECUTE JET DISTRACTED BY SYS PROBS AND POSSIBLE DIVERT, OVERSHOT DSCNT ALT. AUTOPLT ALT PRESELECT DRIFTED OFF SETTING AND LEVELED THE ACFT 500 FT LOWER THAN ASSIGNED. ATC INTERVENED AND ADVISED THEM OF THEIR MISTAKE, WHEREUPON THE CAPT CLBED BACK TO ASSIGNED ALT.
Narrative: ACFT LEVELED OFF 500 FT BELOW ASSIGNED ALT ON AUTOPLT. THE CREW HAD BEEN GIVEN A CRUISE ALT CHANGE AND STARTED A DSCNT FROM FL390 TO FL370. THE ALT SELECTOR WAS SET TO FL370 AND THE DSCNT BEGAN. THE CREW WAS ALSO WORKING AN ACFT MALFUNCTION AND TRYING TO FIND A SUITABLE ALTERNATE ARPT. THE ALT SELECTOR MOVED OFF THE SELECTED ALT BY 500 FT, WHICH IT DOES IF NOT CAREFULLY SET AND XCHKED. THE CREW THEN STARTED WORK ON THE ACFT MALFUNCTION. I CALLED HOME BASE WHILE THE FO CALLED FOR WX. WITH ALL THE DISTR OF PHONE CALLS AND RADIO WORK TO GET WX, THE ACFT LEVELED OFF 500 FT LOW. THE CTR ASKED US TO CONFIRM OUR ALT AT WHICH TIME WE NOTICED THE DEV. THE CREW HAD BECOME PREOCCUPIED WITH THE ACFT MALFUNCTION AND DIDN'T MONITOR THE AUTOPLT. THE CREW SHOULD ALWAYS XCHK THE AUTOPLT AND BE SURE ONE OF THE CREW MEMBERS IS MONITORING THE AUTOPLT. THE AUTOPLTS ARE SO RELIABLE THAT WE FORGET THAT WE ARE STILL RESPONSIBLE TO MONITOR AND FLY THE ACFT.
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.