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A lear 25B flight crew experienced multiple failures involving their autopilot; stall warning system; and pitch trim control. They exited rvsm environment and elected to return to departure airport.
| Attributes | |
| ACN | 786965 |
| Time | |
| Date | 200805 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 41000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zzz.artcc tower : zzz.tower |
| Operator | general aviation : corporate |
| Make Model Name | Learjet 25 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 25 flight time total : 6200 flight time type : 800 |
| ASRS Report | 786965 |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | other flight crewa |
| Resolutory Action | other |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
Upon leveloff and engagement of autoplt; both stall warnings failed -- pitch trim control failed -- afcss breakers popped. After several seconds; we requested return to origin and descent. Upon realizing failures caused autoplt failure; we requested descent below FL290. Ran failure checklist while descending. We did not advise ATC of autoplt problem because multiple failures were very time consuming to accommodate and sort out. Landed back at ZZZ on emergency trim and all breakers associated with failures popped. In retrospect; upon realizing autoplt failed; we should have advised ATC immediately of failure to meet rvsm standards but aircraft was descending for balance of flight and no known conflicts occurred.
Original NASA ASRS Text
Title: A LEAR 25B FLT CREW EXPERIENCED MULTIPLE FAILURES INVOLVING THEIR AUTOPILOT; STALL WARNING SYSTEM; AND PITCH TRIM CONTROL. THEY EXITED RVSM ENVIRONMENT AND ELECTED TO RETURN TO DEP ARPT.
Narrative: UPON LEVELOFF AND ENGAGEMENT OF AUTOPLT; BOTH STALL WARNINGS FAILED -- PITCH TRIM CTL FAILED -- AFCSS BREAKERS POPPED. AFTER SEVERAL SECONDS; WE REQUESTED RETURN TO ORIGIN AND DSCNT. UPON REALIZING FAILURES CAUSED AUTOPLT FAILURE; WE REQUESTED DSCNT BELOW FL290. RAN FAILURE CHKLIST WHILE DSNDING. WE DID NOT ADVISE ATC OF AUTOPLT PROB BECAUSE MULTIPLE FAILURES WERE VERY TIME CONSUMING TO ACCOMMODATE AND SORT OUT. LANDED BACK AT ZZZ ON EMER TRIM AND ALL BREAKERS ASSOCIATED WITH FAILURES POPPED. IN RETROSPECT; UPON REALIZING AUTOPLT FAILED; WE SHOULD HAVE ADVISED ATC IMMEDIATELY OF FAILURE TO MEET RVSM STANDARDS BUT ACFT WAS DSNDING FOR BAL OF FLT AND NO KNOWN CONFLICTS OCCURRED.
Data retrieved from NASA's ASRS site as of May 2009 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.