Airworthiness Directive · Amendment 39-9743 · AlliedSignal Inc. TSCP700-4B, -4E, and -5 Auxiliary Power Units
AlliedSignal Inc. TSCP700-4B, -4E, and -5 Auxiliary Power Units
AlliedSignal Inc. (formerly Garrett) Models TSCP700-4B, -4E, and -5 auxiliary power units (APUs), with high pressure turbine (HPT) disks identified by serial number in AlliedSignal Aerospace Service Bulletin (SB) No. TSCP700-49-A7168, dated November 7, 1995. These APUs are installed on, but not limited to, McDonnell Douglas DC-10, KC-10 (military), and MD-11 series, and Airbus A300 series aircraft. Note: This airworthiness directive (AD) applies to each APU identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For APUs that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment adopts a new airworthiness directive (AD), applicable to AlliedSignal Inc. (formerly Garrett) TSCP700-4B, -4E, and -5 auxiliary power units (APUs), that requires removal from service of certain high pressure turbine (HPT) disks identified by serial number, and replacement with serviceable parts. This amendment is prompted by the discovery of a material defect in certain HPT disk forgings that may result in HPT disk rupture prior to reaching the disk cyclic life limit. The actions specified by this AD are intended to prevent an HPT disk rupture.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Appliances and equipment
