AD/AL 250/55 Amdt 3 Gas Producer Rotor Assembly Tie Bolt P/N 6843388, 6876991 and 6889320 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 250/55 Amdt 3.

Allison Turbine Engines - 250 Series

AD/AL 250/55 Amdt 3 Gas Producer Rotor Assembly - Tie
Bolt P/N 6843388, 6876991 and 6889320 6/2009

Requirement:

CANCELLED.

This AD is cancelled on 4 June 2009.

Background:

This unique Australian AD raised in 1989 against Allison Commercial Engine Bulletin (CEB) 250-C18 CEB-234R2, 250-C20 CEB-1212R2, 250-B15G CEB-TP CEB-104R2, 250-B17 TP CEB-1173R2, 250-C28 CEB-72-2093 and 250-C30
CEB-72-3109, as appropriate, required replacement of gas producer rotor assembly tie bolts due fatigue cracks in threaded area.

Compliance was:  Remove from service:

Tie bolts P/No. 6843388 at next turbine repair or overhaul or by 28 February 1990, whichever is sooner; and

Tie bolts P/No's 6876991 and 6889320 at next turbine repair or overhaul or by
28 February 1992, whichever is sooner.

The contents of this AD are superseded by AD/AL 250/89; therefore this AD is considered to be no longer required.

James Coyne
Delegate of the Civil Aviation Safety Authority

24 April 2009