| AD Number | 75-16-12 | Status | Active |
| Effective Date | August 28, 1975 | Issue Date | Not specified |
| Docket Number | Unknown | Amendment | 39-2285 |
| Product Type | ["Aircraft"] | Product Subtype | ["Large Airplane"] |
| CFR Part | --- - Part 39 | CFR Section | N/A |
| Citation | This information is not available. | ||
| Manufacturer(s) | Airbus SAS |
| Model(s) | BAC 1-11 200 Series BAC 1-11 400 Series |
75-16-12 BRITISH AIRCRAFT CORPORATION: Amendment 39-2285. Applies to Model BAC 1-11 200 and 400 Series Airplanes Equipped with AiResearch Model GTCP-85-115, -115C, -115K, or -115CK Auxiliary Power Units (APU).
Compliance is required as indicated. To prevent possible overheat damage of the rear fuselage tail cone structure due to fire resulting from an APU or jet pipe assembly failure, accomplish the following:
(a) Check the condition of the APU turbine bearing seals either -
(1) In accordance with an oil sampling analysis program that detects progressive deterioration of the bearing seals and that must be approved by an FAA maintenance inspector within the nest 25 APU hours' time in service after the effective date of this AD; or
(2) In accordance with paragraphs 2.2.1, 2.2.2, and 2.2.3, BAC 1-11 Alert Service Bulletin No. 49-A-PM 4714, Issue 4, dated March 8, 1971, or an FAA-approved equivalent, within the next 25 APU hours' time in service after the effective date of this AD, and thereafter at intervals not to exceed 25 APU hours' time in service from the last inspection.
(b) If a defective turbine bearing seal is found during a check required by paragraph (a), before further flight, either -
(1) Repair the APU in accordance with the applicable AiResearch Maintenance Manual or an FAA-approved equivalent; or
(2) Mechanically disconnect the APU so that it is not possible to operate the APU on the ground or in flight and install a placard in the cockpit in clear view of the pilot stating that the APU is not to be operated.
(c) Within the next 1,000 APU hours' time in service after the effective date of this AD, unless already accomplished, either -
(1) Mechanically disconnect the APU so that it is not possible to operate the APU on the ground or in flight and install a placard on the APU cockpit controls stating that the APU is not to be operated; or
(2) Modify the APU installation and tail cone assembly to provide ameans that automatically shuts down the APU when an overheat condition occurs, as follows:
(i) For airplanes equipped with a premodification PM 3520 tail cone installation, modify the APU installation and tail cone assembly in accordance with BAC 1-11 Service Bulletin No. 49-PM 4714, Part 1, Revision 1, dated November 9, 1970, and Parts 2(a), (b), and (d), dated November 16, 1970, or an FAA- approved equivalent.
(ii) For airplanes equipped with a post-modification PM 3520 tail cone installation, modify the APU installation and tail cone assembly in accordance with BAC 1- 11 Service Bulletin No. 49-PM-4714, Part 1, Revision 1, dated November 9, 1970, and Parts 2(a), (b), (c), and (d), dated November 16, 1970, or an FAA- approved equivalent.
(d) The checks required by paragraph (a) may be discontinued after the APU has been disconnected in accordance with subparagraph (b)(2), or subparagraph (c)(1) or after the modification specified in subparagraph (c)(2) has been accomplished.
(e) Placards installed in accordance with subparagraph (b)(2), or subparagraph (c)(1) may be removed after the modification specified in subparagraph (c)(2) has been accomplished.
(f) The checks required by paragraph (e) constitute preventive maintenance under FAR 43.
This amendment becomes effective August 28, 1975.