AD/F50/85 Amdt 1 Feathering Pump Gasket (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/F50/85 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/F50/85 Amdt 1 Feathering Pump Gasket 4/2005

Applicability:

Model F.27 Mk.50, 0502 and 0604 aeroplanes all serial numbers.

Requirement:

1.    For aircraft Serial Numbers (S/Ns) 20103 through 20195, if in post-SB F50-61-014 configuration; and S/N’s 20196 and up:

Replace feathering pump gasket Part Number (P/N) F8200-200-001 with improved gasket P/N W8200-200-001 in accordance with Fokker Services B.V. Service Bulletin (SB) F50-61-022 dated 31 March 2003 including Change Notification (SBCN) SBF50-61-022/01 dated 20 December 2004, or later CAA-NL approved revision of the referenced SB.

Note 1:  The SBCN introduces changes to SBF50-61-022 as a result of Fokker Service Manual Change Notification-Maintenance (MCNM) F50-035 Revision 1 and MCNM F50-040 Revision 1, both dated 15 December 2004.  It also requires replacement of the original issue of MCNM F50-040 attached SBF50-61-022 with Revision 1 of MCNM F50-040. Fokker Services All Operator Message AOF50.037#02 dated 15 December 2004 also pertains to this subject.

2.    Unless modified into P/N W8200-200-001 in accordance with Fokker Services B.V. SB F50-61-022, no feathering pump gasket P/N F8200-200-001 may be installed on any aircraft or Quick Engine Change (QEC) unit as a replacement part.

Note 2:  Netherlands CAA AD 2003-089/2 EASA approval No 2004-12540 dated 27 December 2003 refers.

Compliance:

For Requirement 1:  At first opportunity eg. scheduled or unscheduled feathering pump or engine change, after the effective date of this Directive.

For Requirement 2:  Remains unchanged as detailed in the original issue of this Directive as; After 30 October 2003.

This Amendment becomes effective on 14 April 2005.

Background:

This amendment expands the applicability to all aeroplanes that may be fitted with the gasket and also gives more detail to the required tasks.

In-service experience and safety analysis has indicated that if a bobbin seal gets damaged during installation of the feathering pump, any oil leakage may remain undetected during the post-installation ground test/leak check until the feathering pump gasket P/N F8200-200-001 gets soaked with oil and bursts.  These particular gaskets were introduced during production on aircraft serial number 20196 and up and may have been retrofitted on earlier aircraft through application of (optional) Fokker SB F50-61-014.  This SB has now been cancelled and is superseded by SB F50-61-022 that introduces an improved gasket.

The original issue of this Directive became effective on 30 October 2003.

James Coyne
Delegate of the Civil Aviation Safety Authority

2 March 2005