1AD/APU/13 - Augmentation Containment Ring

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Auxiliary Power Units

AD/APU/13 Augmentation Containment Ring 8/97

Applicability: AlliedSignal Inc., GTCP85 series auxiliary power units (APUs) incorporating a one piece cast turbine wheel, P/No 968095-xx, 3604604-xx, 3606982-xx, or 3842072-xx

Requirement: Install a containment augmentation ring in accordance with either AlliedSignal Aerospace Alert Service Bulletin GTCP85-49-A6706 Revision 2 (or earlier revision) or AlliedSignal Aerospace Alert Service Bulletin GTCP85-49-A7189 Revision 2 (or earlier revision)

Note 1. FAA AD 97-04-04 also refers.

Note 2. This Directive supersedes AD/APU/6 Amdt1.

Compliance: For flight operable APUs, within 24 months of the effective date of this directive, or for APUs that are ground operable only, within 36 months of the effective date of this directive.

This airworthiness directive becomes effective on 17 July 1997.

Background: The FAA has advised that the Hastelloy S containment shield introduced by AlliedSignal SB GTCP85-49-5700 failed to contain fragments following the rupture of a one-piece cast turbine wheel.

Non-containment of high energy rotor fragments can result in penetration of the APU compartment, thereby reducing the fire protection capability of the APU and potentially causing damage to the aircraft structure.