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B727 flight crew has altitude deviation when autoplt disengaged to re-trim aircraft and not reengaged.
| Attributes | |
| ACN | 335130 |
| Time | |
| Date | 199605 |
| Day | Sat |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : lit |
| State Reference | AR |
| Altitude | msl bound lower : 30600 msl bound upper : 31000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zme |
| Operator | common carrier : air carrier |
| Make Model Name | B727 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : second officer |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 150 flight time total : 6000 flight time type : 2000 |
| ASRS Report | 335130 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : far non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
At cruise altitude (FL310) on long flight, center controller stated that it appeared we were 400 ft low. Indeed we were at 30600 ft. Captain (PF) disengaged autoplt and climbed back to assigned altitude. Captain had recently disengaged autoplt to re- trim aircraft and apparently did not reengage altitude hold mode and none of us caught it. Two main contributing factors were 1) apparently none of the three crew members were monitoring flight instruments closely and, 2) company policy and procedure is to verbally announce any change to autoplt mode. This did not happen, but if followed could have drawn my attention to autoplt control panel where it would have been obvious that the altitude hold was not engaged.
Original NASA ASRS Text
Title: B727 FLC HAS ALTDEV WHEN AUTOPLT DISENGAGED TO RE-TRIM ACFT AND NOT REENGAGED.
Narrative: AT CRUISE ALT (FL310) ON LONG FLT, CTR CTLR STATED THAT IT APPEARED WE WERE 400 FT LOW. INDEED WE WERE AT 30600 FT. CAPT (PF) DISENGAGED AUTOPLT AND CLBED BACK TO ASSIGNED ALT. CAPT HAD RECENTLY DISENGAGED AUTOPLT TO RE- TRIM ACFT AND APPARENTLY DID NOT REENGAGE ALT HOLD MODE AND NONE OF US CAUGHT IT. TWO MAIN CONTRIBUTING FACTORS WERE 1) APPARENTLY NONE OF THE THREE CREW MEMBERS WERE MONITORING FLT INSTS CLOSELY AND, 2) COMPANY POLICY AND PROC IS TO VERBALLY ANNOUNCE ANY CHANGE TO AUTOPLT MODE. THIS DID NOT HAPPEN, BUT IF FOLLOWED COULD HAVE DRAWN MY ATTN TO AUTOPLT CTL PANEL WHERE IT WOULD HAVE BEEN OBVIOUS THAT THE ALT HOLD WAS NOT ENGAGED.
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.