AD/F50/59 Amdt 1 Engine Electronic Control System (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/F50/59 and issues the following 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/F50/59 Amdt 1 Engine Electronic Control System 5/2008

Applicability:	F27 Mk 050 aircraft Serial Numbers 20103 to 20242 inclusive.
Requirement:	If not previously accomplished, action in accordance with Fokker Service Bulletin F50-73-013 dated 6 July 1992 or later revision approved by the Rijksluchtvaartdienst (RLD) of The Netherlands or its successor.  Fokker Component Service Bulletin F7941-006-73-03 also refers.
Note:  RLD BLA 92-086 refers.
Compliance:	No later than 8 June 2008.
This Amendment becomes effective on 8 May 2008.
Background:	The engine electronic control (EEC) is designed in such a way that if an EEC failure occurs, the affected engine fuel control will remain at the last selected power setting.  This means that there is no power response from the affected engine when the power levers are moved forward (fail-fixed feature) unless manual mode is selected by the pilot.
The original issue of this Directive required that the EEC be replaced with a modified version which automatically selects manual mode if an EEC failure occurs below the 17 degrees power lever angle (approach position).  This Amendment continues that requirement and corrects a typographical error in the affected serial number range.  At the same time the Amendment allows compliance with later approved revisions of the Fokker service bulletin.
The original issue of this Directive became effective on 4 February 1993.

James Coyne
Delegate of the Civil Aviation Safety Authority

27 March 2008