AD/F100/74 Fire Protection Engine Fire Extinguishing Line Shuttle Valve (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 F100 (F28 Mk 100) Series Aeroplanes

AD/F100/74 Fire Protection - Engine Fire
Extinguishing Line Shuttle Valve 3/2006

Applicability:

Fokker Aircraft B.V. Model F28 Mark 0070 and Mark 0100 aircraft.

Requirement:

1.    Inspect the nuts on the affected shuttle valves in accordance with Section 3. Accomplishment Instructions of Fokker Service Bulletin SBF100-26-019 dated
6 January 2006 or later CAA-NL approved revision.

If no discrepancies are found no further action is required by this AD.

2.    When discrepancies are found during the inspection, detailed in Requirement 1 of this AD, tighten or replace the affected nuts, or replace the shuttle valves in accordance with Section 3.  Accomplishment Instructions of Fokker
SBF100-26-019 or later CAA-NL approved revision.

3.    Report all discrepancies, if any have been found, to the TC-holder as detailed in SBF100-26-019 or later CAA-NL approved revision.

Note 1:  Fokker 70/100 Maintenance Manual Task 26-21-03-400-814A also pertains to this subject.

Note 2:  CAA AD Netherlands NL-2006-002 EASA approval 2006-018 dated
23 January 2006 refers.

Compliance:

1.    Within 6 months after the effective date of this AD.

2.    Before further flight.

3.    Within 7 days after the inspection is completed.

This Airworthiness Directive becomes effective on 16 March 2006.

Background: One Fokker 100 (F28 Mark 0100) operator reported that during maintenance in the APU compartment, a disconnected nut was discovered on one of the shuttle valves in the deployment lines of the engine fire-extinguishing system.  An additional check by the operator revealed that on more aircraft in its fleet, the nuts of the shuttle valves were incorrectly tightened.  This condition, if not corrected, could result in failure or reduced efficiency of the engine fire-extinguishing system in case of an engine fire.  Since a potentially unsafe condition has been identified that is likely to exist or develop on other aircraft of this type design, this AD requires a one-time inspection of the nuts and shuttle valves in the deployment lines of the engine fire-extinguishing system in the APU compartment and corrective actions, as necessary.

James Coyne
Delegate of the Civil Aviation Safety Authority

1 February 2006