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B767 crew experienced a leading edge flap anomaly shortly after takeoff and elects to return to the departure airport.
| Attributes | |
| ACN | 732254 |
| Time | |
| Date | 200703 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 13000 |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Controlling Facilities | tracon : zzz.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B767-300 and 300 ER |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : intermediate altitude |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 150 flight time total : 12500 flight time type : 600 |
| ASRS Report | 732254 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Experience | flight time last 90 days : 200 flight time total : 17700 flight time type : 6000 |
| ASRS Report | 732255 |
| Events | |
| Anomaly | aircraft equipment problem : less severe |
| Independent Detector | aircraft equipment other aircraft equipment : eicas other flight crewa other flight crewb |
| Resolutory Action | flight crew : landed as precaution flight crew : declared emergency other |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
During the after takeoff checklist the flap indicator started flickering between 0 and 1. An electrical noise was coming from the overhead panel in unison with the flap indicator movement. Received an EICAS message 'le flap asym' off and on with the noise and needle indication. Then got EICAS message 'le flap disagree.' both messages appeared only in conjunction with the sound in the overhead panel and the needle movement. Talked with maintenance and dispatch and decided to return to ZZZ. Accomplished the irregular checklists for flap asymmetry and flap disagree; declared an emergency and landed without incident with flaps 20 degrees. Callback conversation with reporter revealed the following information: the reporter believes that all the indications can be explained by a faulty micro-switch that senses the leading edge flaps are fully retracted. Leading edge flap position sensed by this micro-switch is what determines when the engine igniters are automatically activated and the relay that controls the igniters which is in the overhead; was rapidly opening and closing making a sound. Once on the ground the leading edge flaps operated normally although the indication was still erratic.
Original NASA ASRS Text
Title: B767 CREW EXPERIENCED A LEADING EDGE FLAP ANOMALY SHORTLY AFTER TKOF AND ELECTS TO RETURN TO THE DEP ARPT.
Narrative: DURING THE AFTER TKOF CHKLIST THE FLAP INDICATOR STARTED FLICKERING BTWN 0 AND 1. AN ELECTRICAL NOISE WAS COMING FROM THE OVERHEAD PANEL IN UNISON WITH THE FLAP INDICATOR MOVEMENT. RECEIVED AN EICAS MESSAGE 'LE FLAP ASYM' OFF AND ON WITH THE NOISE AND NEEDLE INDICATION. THEN GOT EICAS MESSAGE 'LE FLAP DISAGREE.' BOTH MESSAGES APPEARED ONLY IN CONJUNCTION WITH THE SOUND IN THE OVERHEAD PANEL AND THE NEEDLE MOVEMENT. TALKED WITH MAINT AND DISPATCH AND DECIDED TO RETURN TO ZZZ. ACCOMPLISHED THE IRREGULAR CHKLISTS FOR FLAP ASYMMETRY AND FLAP DISAGREE; DECLARED AN EMER AND LANDED WITHOUT INCIDENT WITH FLAPS 20 DEGS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR BELIEVES THAT ALL THE INDICATIONS CAN BE EXPLAINED BY A FAULTY MICRO-SWITCH THAT SENSES THE LEADING EDGE FLAPS ARE FULLY RETRACTED. LEADING EDGE FLAP POS SENSED BY THIS MICRO-SWITCH IS WHAT DETERMINES WHEN THE ENG IGNITERS ARE AUTOMATICALLY ACTIVATED AND THE RELAY THAT CTLS THE IGNITERS WHICH IS IN THE OVERHEAD; WAS RAPIDLY OPENING AND CLOSING MAKING A SOUND. ONCE ON THE GND THE LEADING EDGE FLAPS OPERATED NORMALLY ALTHOUGH THE INDICATION WAS STILL ERRATIC.
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.