AD/B747/80 Equipment Cooling System E30 Cooling Rack Orifice 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/B747/80.

Boeing 747 Series Aeroplanes

AD/B747/80 Equipment Cooling System
E30 Cooling Rack Orifice 12/2009

Requirement:

CANCELLED.

This AD is cancelled on 19 November 2009.

Background:

This AD, raised in 1990 against Boeing Alert Service Bulletin 747-21A2285, required a check to ensure sufficient pressure in the E30 equipment cooling rack to prevent possible overheating of the main transformer rectifier units (TRU's).  Compliance was required prior to 6 December 1990.

As all affected aircraft would have been inspected and modified long ago, this AD is no longer required.

David Villiers
Delegate of the Civil Aviation Safety Authority

27 September 2009