AD/A320/188 Fuel System Twin Motor Low Pressure Valve Actuator (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.

Airbus Industrie A319, A320 and A321 Series Aeroplanes

AD/A320/188 Fuel System - Twin Motor Low
Pressure Valve Actuator 1/2006

Applicability:

AIRBUS A318, A319, A320 and A321 aircraft, equipped with Twin Motor Low Pressure (LP) valve actuator Part Number (PN): HTE190001, HTE190001-1 or HTE190001-2.

Aircraft delivered after the effective date of this Airworthiness Directive (AD) and whose MSN is above 2155 are not affected by the requirements of this AD.

Requirement:

Unless already accomplished, inspect the Twin Motor LP Valve Actuators with PN HTE190001, HTE190001-1 or HTE190001-2, in accordance with the instructions of AIRBUS Service Bulletin (SB) A320-28-1122 or later DGAC approved revision, and correct any defects if necessary.

Note 1:  The Aircraft Maintenance Manual (AMM) has been updated to introduce a systematic check of the length of the Twin Motor LP Valve Actuator locating dowel during installation of PNs HTE190001, HTE190001 -1 or HTE190001-2.

Note 2:  DGAC AD F-2005-189 EASA reference No 2005-6409 dated 15 November 2005 refers.

Compliance:

Within 5000 flight hours or within 24 months after the effective date of this AD, whichever occurs first.

This Airworthiness Directive becomes effective on 19 January 2006.

Background:

On a recent incident on an A340, a LP valve was found partially open whereas the aircraft systems indicated that it was closed.

Examination of removed parts revealed that the locating pin (dowel) in the actuator and the slot in the drive valve assembly were damaged.

The investigation showed that the locating pin in the actuator was in some cases, due to manufacturing tolerances, too short to engage with the slot, and therefore the correct location of the drive assembly.  The incorrect alignment of the actuator and the drive assembly does not guarantee complete closure of the valve.

In this situation, the combination of a fire with rupture of the line between the HP and LP valve would not prevent the fuel from flowing towards the fire.

James Coyne
Delegate of the Civil Aviation Safety Authority

29 November 2005