AD/S-92/2 Main Gearbox Lubrication Pump Vespel Spline Adapters (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.

Sikorsky S-92 Series Helicopters

AD/S-92/2 Main Gearbox Lubrication Pump
Vespel Spline Adapters 2/2007 TX

Applicability:

Sikorsky Model S-92A helicopters with main gearbox (MGB) lubrication/scavenge pump, part number (P/N) 92351-15800-101, with vespel spline adapter, P/N 1584000-1, installed.

Requirement:

Remove and replace each MGB lubrication/scavenge pump vespel spline adapter in accordance with paragraph 3.A., steps (1) through (6) of the Accomplishment Instructions in Sikorsky Aircraft Corporation Alert Service Bulletin No. 92-63-001, dated 1 April 2005.

Note:  FAA AD 2005-12-03 Amdt 39-14119 dated 1 June 2005 refers.

Compliance:

Before further flight, unless accomplished previously, and thereafter, at intervals not to exceed 50 hours time-in-service.

This Airworthiness Directive becomes effective on 18 December 2006.

Background:

This AD requires replacing the MGB lubrication/scavenge pump vespel spline adapters before further flight, and thereafter, replacing them at certain intervals.  This is prompted by a reported incident of an in-flight loss of oil pressure.  The actions specified in this AD are intended to prevent loss of lubrication to the MGB, which could cause failure of one or both engine input drives, or planetary gear to sun gear tooth mesh failure, resulting in loss of power to the rotor system and subsequent loss of control of the helicopter.

James Coyne
Delegate of the Civil Aviation Safety Authority

13 December 2006