AD/BAe 146/119 Hydraulic System Accumulators with Suspect Defect (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 146/119 Hydraulic System - Accumulators
with Suspect Defect 5/2006 TX

Applicability:

BAE SYSTEMS - BAe 146 and AVRO 146-RJ series aircraft.

Requirement:

1.    Identify suspect batch number accumulators in accordance with BAe 146 series / Avro 146-RJ series aircraft Inspection Service Bulletin ISB.29-A046 initial issue dated 14 March 2006 or later EASA approved revisions.

Only one suspect accumulator is allowed to be installed on an individual aircraft.

2.    Where such an accumulator is identified, inspect accumulator in accordance with ISB.29-A046.

3.    Replace identified accumulator in accordance with para 2.D. of ISB.29-A046

Terminating action:  Replacement of identified accumulator with serviceable accumulator is considered terminating action from the requirements of this AD.

Note:  EASA Emergency AD number 2006-0061-E dated 17 March 2006 refers.

Compliance:

1.    Within 48 hours after the effective date of this AD.

2.    On identification of the suspect accumulator and thereafter, repetitively, at 48 hour inspection intervals, until terminated as detailed in ISB.29-A046.

3.    Not later than 31 May 2006.

This Airworthiness Directive becomes effective on 23 March 2006.

Background:

Following an in-service failure of a hydraulic accumulator, the manufacturer has identified two suspect batches of accumulator cylinders.  Suspect hydraulic accumulators are identified in BAE Systems ISB.29-A046.  These accumulators may burst in service with the potential to cause a hazardous event on the aircraft, with an unacceptable probability of occurrence.

Hazardous event being the resultant flight crew workload associated with the loss of one or more hydraulic circuits, combined with possible fuselage pressure vessel rupture and possible cabin contamination with hydraulic mist.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

21 March 2006