Incident Details
On 20 May 2013, an Embraer 170-100 operating a flight from Gdańsk to Frankfurt experienced a FLAP FAIL warning after takeoff at an altitude of 4000 feet. The flight crew executed the FLAP FAIL checklist and decided to return to Gdańsk. The aircraft landed in a flaps 2, slats 3 configuration. Following the landing, the aircraft was withdrawn from service for inspection.
Maintenance Findings
Post-flight maintenance performed troubleshooting procedure FIM 27-51-00-810-802-A00. The inspection revealed a fault in the left-hand (L/H) inboard flap assembly outboard actuator. The actuator was replaced in accordance with Aircraft Maintenance Manual 27-51-01-400-801-A. Subsequent operational tests per Aircraft Maintenance Manual 27-50-00-710-801-A and 27-50-00-730-801-A were satisfactory, and the aircraft was returned to service.
The defective actuator (part number C154811-2, serial number 1020) had been installed on the aircraft since its manufacture on 25 June 2004. The aircraft manufacturer had issued Service Bulletin SB170-27-0037 in 2009, recommending regreasing and inspection of flap actuators; this bulletin had been incorporated by the operator's maintenance organization. Another bulletin, SB170-27-0025, recommended replacement of certain flap actuators by part number and serial number, but it was categorized as non-mandatory and not adopted by the operator. The failed actuator was not listed in SB170-27-0025 for replacement. The replacement actuator installed was from a list of components approved by the manufacturer for use on Embraer aircraft, meeting requirements after modifications described in SB170-27-0025 and SB170-27-0037.
Cause
The cause of the incident was a flap actuator malfunction.