AD 89-18-13

89-18-13 BRITISH AEROSPACE: Amendment 39-6309. (Docket No. 89-NM-24-AD) Applicability: Model DH/HS/BH/BAe 125 series airplanes certificated in any category, equipped with Sundstrand Turbomach Titan Gas Turbine Auxiliary Power (APU) Unit, Model T- 62T Series, installed in the aft equipment compartment of the airplane.

NOTE: Installation of the subject APU's has been in accordance with, but are not limited to, the following Supplemental Type Certificates (STC):

SA674CE SA1143EA SA1176EA SA1196EA SA440NE SA1173EA

SA4710SW SA1923SW

This AD applies to all Sundstrand Turbomach Titan APU installations in the aft equipment compartment.

Compliance: Required as indicated unless previously accomplished.

To prevent a fire in the aft equipment compartment, puncture of the aft pressure bulkhead, and severance of the control cables, due to an uncontained APU rotor failure, accomplish the following:

A. Within the next 10 days after the effective date of this AD:

1. Revise the Limitations Section in the FAA-approved Airplane Flight Manual (AFM) Supplement to include the following statement. This may be accomplished by inserting a copy of this AD in the AFM Supplement Limitations Section: "OPERATION OF THE APU DURING FLIGHT IS PROHIBITED, EXCEPT DURING AN EMERGENCY."

2. Install a placard next to the APU start switch in the cockpit to state: "OPERATION OF THE APU DURING FLIGHT IS PROHIBITED, EXCEPT DURING AN EMERGENCY."

B. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM-113, FAA, Northwest Mountain Region, Transport Airplane Directorate.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, Standardization Branch, ANM-113.

C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of modifications required by this AD.

This amendment (39-6309, AD 89-18-13) becomes effective on September 28, 1989.