AD/AL 250/50 Amdt 1 N2 Overspeed Control Assembly Addition of Lockwashers to Ground Jumper Lead 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 250/50 Amdt 1.

Allison Turbine Engines - 250 Series

AD/AL 250/50 Amdt 1 N2 Overspeed Control Assembly - Addition
of Lockwashers to Ground Jumper Lead 6/2009

Requirement:

CANCELLED.

This AD is cancelled on 4 June 2009.

Background:

This unique Australian AD raised in 1983 against Allison Commercial Engine Bulletin (CEB) 250-C28C CEB-A73-2024 Rev 2, and 250-C30S CEB-A-73-3015 Rev.2, as appropriate, required a modification by adding a lockwasher under the ground jumper wire attaching screw on the N2 overspeed control assembly to prevent a loose ground connection that could cause spurious activation of the N2 overspeed control.

Compliance was:  As per the requirement document.

The requirement document required: compliance at the next scheduled maintenance event or when access to the N2 overspeed governor control assembly is achieved, but in no case later than the next 50 hours TIS.

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

James Coyne
Delegate of the Civil Aviation Safety Authority

24 April 2009