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A C172 left inboard lower flap rudder sheared; jamming the left flap and ailerons. The pilot was able to control the aircraft using just the rudder.
| Attributes | |
| ACN | 734744 |
| Time | |
| Date | 200704 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 2800 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | general aviation : personal |
| Make Model Name | Skyhawk 172/Cutlass 172 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | cruise : level ground : maintenance |
| Flight Plan | None |
| Person 1 | |
| Affiliation | other |
| Function | flight crew : single pilot |
| Qualification | pilot : private pilot : instrument |
| Experience | flight time last 90 days : 8.6 flight time total : 330 flight time type : 330 |
| ASRS Report | 734744 |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Resolutory Action | flight crew : landed in emergency condition |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
During practice for the commercial license test; after simulating an emergency descent; power off; full flaps; wind 70 KTS; then leveling off. On retracting flaps; the left inboard lower roller sheared the bolt and the roller came off and jammed the flap mechanism. The flap therefore seized at an angle which also caused seizure of the ailerons when the outboard end of the flap pressed into the left aileron. Rudder was sufficient to maintain aircraft control for a safe return to ZZZ.callback conversation with reporter revealed the following information: reporter stated that the initial failure was the bolt holding the pulley on which the flap slot rides. This particular bearing assembly was inspected at the 100 hour inspection less than 40 hours previously. The assembly had approximately 14000 hours on it at the time of failure.
Original NASA ASRS Text
Title: A C172 LEFT INBOARD LOWER FLAP RUDDER SHEARED; JAMMING THE LEFT FLAP AND AILERONS. THE PLT WAS ABLE TO CTL THE ACFT USING JUST THE RUDDER.
Narrative: DURING PRACTICE FOR THE COMMERCIAL LICENSE TEST; AFTER SIMULATING AN EMER DESCENT; POWER OFF; FULL FLAPS; WIND 70 KTS; THEN LEVELING OFF. ON RETRACTING FLAPS; THE LEFT INBOARD LOWER ROLLER SHEARED THE BOLT AND THE ROLLER CAME OFF AND JAMMED THE FLAP MECHANISM. THE FLAP THEREFORE SEIZED AT AN ANGLE WHICH ALSO CAUSED SEIZURE OF THE AILERONS WHEN THE OUTBOARD END OF THE FLAP PRESSED INTO THE LEFT AILERON. RUDDER WAS SUFFICIENT TO MAINTAIN ACFT CTL FOR A SAFE RETURN TO ZZZ.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE INITIAL FAILURE WAS THE BOLT HOLDING THE PULLEY ON WHICH THE FLAP SLOT RIDES. THIS PARTICULAR BEARING ASSEMBLY WAS INSPECTED AT THE 100 HOUR INSPECTION LESS THAN 40 HOURS PREVIOUSLY. THE ASSEMBLY HAD APPROX 14000 HOURS ON IT AT THE TIME OF FAILURE.
Data retrieved from NASA's ASRS site as of January 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.