71-06-09 R1 BRITISH AEROSPACE: Amendment 39-1177 as amended by Amendment 39- 4737. Applies to BAC 1-11 200 and 400 series airplanes, certificated in all categories. Compliance is required as indicated. To prevent malfunction of the auxiliary power unit (APU) air delivery duct nonreturn valve, accomplish the following:
A. For airplanes having nonreturn valve P/N 525180 installed:
1. Within the next 100 hours time in service after the effective date of this AD, unless already accomplished within the previous 60 hours time in service and thereafter at intervals not to exceed 160 hours time in service, perform the actions specified by paragraphs 2.2, 2.3, 2.4, and 2.5 of Accomplishment Instructions, British Aerospace Alert Service Bulletin 49- A-PM3122, Issue 4, dated March 31, 1982. Incorporation of British Aerospace modification PM3254 or PM4912 terminates the requirements of paragraphs 2.3 and 2.4 of the service bulletin.
2. Prior to further flight, unless alreadyaccomplished, install a placard adjacent to the APU control panel in clear view of the pilot, or amend the Airplane Flight Manual limitations Section 2, to read as follows: "Close APU air delivery valve when starting engine from an external supply or by cross-feeding air from an operating engine. Close APU air delivery valve and shut down APU for takeoff and flight operations. Operational use of the APU in flight is prohibited." The placard may be removed or the amendment to the Airplane Flight Manual may be deleted upon replacement of APU air delivery duct nonreturn valve P/N 525180 with nonreturn valve P/N 1398B000 or 1398B000/1398B999 or 3031B000.
B. For airplanes having nonreturn valve P/N 1398B000 or 1398B000/1398B999 installed, within the next 750 hours time in service after the effective date of this AD, unless already accomplished within the previous 1,500 hours time in service from the last inspection, and thereafter at intervals not to exceed those specified in the service bulletin, perform the actions described by paragraphs 2.4.1, 2.4.2, and 2.4.3 of the service bulletin.
C. Incorporation of modifications PM3148, PM3177 and PM4912 constitutes terminating action for the repetitive inspections required by this AD.
D. Alternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.
E. 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 inspections and/or modifications required by this AD.
Amendment 39-1177 became effective April 16, 1971.
This Amendment 39-4737 becomes effective November 3, 1983.