AD/BAe 146/115 Elevator Bearings (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.

British Aerospace BAe 146 Series Aeroplanes

AD/BAe 146/115 Elevator Bearings 8/2005

Applicability:

All model BAe 146 and AVRO 146-RJ series aeroplanes.

Requirement:

Replace the flight control system bearings detailed in Table 1 of this Directive, in accordance with BAE Systems (Operations) Ltd Service Bulletin ISB.27-177 Initial Issue or later EASA approved revision.

Table 1

Elevator Servo Tab Hinge Bearings	BAE Systems (Operations) Service Bulletin ISB.27- 177 Para 2.B (2).
Elevator Servo Tab Mechanism Bearings	BAE Systems (Operations) Service Bulletin ISB.27- 177 Para 2. B (3).
Elevator Trim Tab Hinge Bearings	BAE Systems (Operations) Service Bulletin ISB.27- 177 Para 2. B (4).
Elevator Trim Tab Drive Rod Bearings	BAE Systems (Operations) Service Bulletin ISB.27- 177 Para 2. B (5).

Note:  UK CAA AD G-2005-0014 (as approved by EASA approval number 2005-4654) refers.

Compliance:

Before 31 October 2006 or before each bearing achieves 8 years time in service, whichever occurs later.

This Airworthiness Directive becomes effective on 4 August 2005.

Background: Reported instances of flight control surface restrictions have been associated with the deterioration of control surface bearings.  The current bearings are a “sealed-for-life” type with a light dust shield and have no provisions for re-greasing.  Over time, the original lubrication is lost and moisture can enter the bearing assembly.  This can be exacerbated by the use of pressure washing.  This deterioration can lead to bearing corrosion and will eventually lead to control restrictions, particularly when moisture in the bearing freezes.  This could result in a catastrophic event.

James Coyne
Delegate of the Civil Aviation Safety Authority

24 June 2005