AD/F50/95 Passenger Service Units (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/F50/95 Passenger Service Units 9/2006

Applicability:	F27 Mark 050 and 0502 aeroplanes equipped with Honeywell International (Grimes Aerospace) Passenger Service Units (PSU) part number (P/N) 10-1178-XX.
Requirement:	1.    Inspect the affected PSU (P/N 10-1178-XX series) panel interface connectors in accordance with Section 3 - Accomplishment Instructions of Fokker Service Bulletin SBF50-25-061 dated 31 March 2006 or later EASA approved revision.
2.    If, as a result of the Requirement 1 inspection, any discrepancies are found, rectify the discrepancy in accordance with Section 3 - Accomplishment Instructions of SBF50-25-061 or later EASA approved revision.
Note:  CAA-NL AD NL-2006-008 (EASA Approval 2006-0193) refers.
Compliance:	For Requirement 1 - Within 36 months after the effective date of this Directive.
For Requirement 2 - Before further flight after the Requirement 1 inspection.
This Airworthiness Directive becomes effective on 31 August 2006.
Background:	The Netherlands Civil Aviation Authority (CAA-NL) has advised that recently, a Fokker 100 (F28 Mark 0100) operator noted that the electrical connectors of the PSUs did not lock properly during installation in the aircraft.
Investigation revealed that the lack of locking is caused by the tolerance in thickness of the gaskets (seals) inside the PSU connectors.  This condition, if not corrected, may cause the connector to overheat, leading to electrical arcing and subsequent failure of the PSU Panels.  In such instances, smoke is likely to be emitted.  To rectify and prevent this occurring, the PSU manufacturer has narrowed the tolerances of the gaskets.

PSU panels installed in Fokker 50 (F27 Mark 050 and Mark 0502) aircraft are similar to those installed in the Fokker 100 and since an unsafe condition has been identified that is likely to exist or develop on aircraft of these type designs, this Directive requires inspection and, where necessary, replacement of the affected PSU Panel J1 and J2 interface connector gaskets.

James Coyne
Delegate of the Civil Aviation Safety Authority

21 July 2006