AD/F50/100 - Flap Mechanical Drive (Cth)

AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Fokker F50 (F27 Mk 50) Series Aeroplanes AD/F50/100 Flap Mechanical Drive 5/2009

Applicability: Model F27 Mark 050, Mark 0502 and Mark 0604 aircraft, all serial numbers, if in a post-SBF50-27-030 configuration. Requirement: Action in accordance with the requirements of EASA AD 2009-0047.

Note: Fokker Services SBF50-27-043 original issue, or later EASA approved revision, refers. Compliance: As specified in the requirement document, with a revised effective date of 7 May 2009. This Airworthiness Directive becomes effective on 7 May 2009. Background: Extensive damage was found on a Fokker 50 left hand inner flap and nacelle during a walk-around check. The damage had been caused by a broken fork of the inner flap outboard driveshaft; and resulted in asymmetric flap extension, and interference between the flap and nacelle. A metallurgical investigation revealed that the fork end failed in a fatigue mode, and most probably caused by the "cyclic load" as a result of regularly reaching the mechanical end stop position. This condition, if not corrected, could lead to further cases of asymmetric flap extension, possibly resulting in loss of control of the aircraft.