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A B737, lost 800 ft in the holding pattern at FL410 when the captain selected LNAV for the turn back inbound to the VOR. The autoplt had disengaged during the ensuing 30 degree bank.
| Attributes | |
| ACN | 411791 |
| Time | |
| Date | 199808 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : lib |
| State Reference | NC |
| Altitude | msl bound lower : 40200 msl bound upper : 41000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 240 flight time total : 14000 flight time type : 600 |
| ASRS Report | 411791 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance non adherence other other anomaly |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course flight crew : overcame equipment problem flight crew : regained aircraft control |
| Consequence | Other |
Narrative:
After passing glovr and while on the outbound holding leg, the LNAV was engaged and aircraft turned into a 30 degree angle of bank to get on the inbound leg. Suddenly, the autoplt disengaged, the nose dropped and aircraft lost 800 ft in seconds. I disengaged the autothrottle climbed up to 41000 ft and resumed holding.
Original NASA ASRS Text
Title: A B737, LOST 800 FT IN THE HOLDING PATTERN AT FL410 WHEN THE CAPT SELECTED LNAV FOR THE TURN BACK INBOUND TO THE VOR. THE AUTOPLT HAD DISENGAGED DURING THE ENSUING 30 DEG BANK.
Narrative: AFTER PASSING GLOVR AND WHILE ON THE OUTBOUND HOLDING LEG, THE LNAV WAS ENGAGED AND ACFT TURNED INTO A 30 DEG ANGLE OF BANK TO GET ON THE INBOUND LEG. SUDDENLY, THE AUTOPLT DISENGAGED, THE NOSE DROPPED AND ACFT LOST 800 FT IN SECONDS. I DISENGAGED THE AUTOTHROTTLE CLBED UP TO 41000 FT AND RESUMED HOLDING.
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.