AD/AL 250/31 Fuel System Check Valve Assembly Installation Cancelled (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive AD/AL 250/31.

Allison Turbine Engines - 250 Series

AD/AL 250/31 Fuel System - Check Valve
Assembly - Installation 6/2009

Requirement:

CANCELLED.

This AD is cancelled on 4 June 2009.

Background:

This unique Australian AD raised in 1978 against Allison Commercial Engine Bulletin (CEB) 250-C20B CEB-1101R1 and 250-B17/B17B TP CEB-1078R1, as appropriate, required a modification of the engine fuel system by introducing a check valve to prevent the pressurising valve in the CECO fuel control from oscillating under certain altitude conditions and to improve in-flight starting at altitude.

Compliance was:  Before 30 November 1978.

This AD has been sufficiently promulgated for the affected engines to have been modified by now; therefore this AD is considered to be no longer required.

James Coyne
Delegate of the Civil Aviation Safety Authority

24 April 2009