AD 75-05-17
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airesearch | The Boeing Company | Auxiliary Power Units | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-100 Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-100B Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-100B SUD Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-200B Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-200C Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-200F Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-300 Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-400 Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| aircraft | Airesearch | The Boeing Company | 747-400D Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | Auxiliary Power Units | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-100 Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-100B Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-100B SUD Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-200B Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-200C Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-200F Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-300 Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-400 Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-400D Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747-400F Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747SP Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
| appliance | Airesearch | The Boeing Company | 747SR Series | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's |
Unsafe Condition
Development of a hazardous condition during flight due to APU operation.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Issue flight crew instructions prohibiting in-flight APU operation and install a placard within 72 hours. Inspect APU and compartment for damage or verify turbine rotor rotation after shutdowns. Incorporate modifications and inspections per AiResearch Bulletin by July 1, 1976.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Prior to further flight, within 72 hours after receipt, and on or before July 1, 1976.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
AiResearch Model GTCP660-4 (S/N P-37501-P-37723) and GTCP660-4R (S/N P-101-P-124) APU's installed in Boeing Model B-747 Series airplanes unless modified with improved compressor assemblies.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Auxiliary Power Units
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_75-05-17.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 75-05-17 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model...Show more Subject: Auxiliary Power Units Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 10/06/1975 Make: Airesearch | The Boeing Company Model: Auxiliary Power Units | 747-100 Series | 747-100B Series | 747-100B SUD Series | 747-200B Series | 7...Show more Product Type: Appliance Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 75-05-17 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-2357 AD NUMBER: 75-05-17 SUBJECT HEADING: Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's ACTION: SUMMARY: DATES: Effective October 6, 1975. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 75-05-17 AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Amendment 39-2108 as amended by Amendment 39-2224 is further amended by Amendment 39-2357. Applies to AiResearch Model GTCP660-4 and -4R APU's of the following listed serial numbers, installed in Boeing Model B-747 Series airplanes, unless modified to incorporate improved compressor assemblies in accordance with AiResearch Service Bulletin GTCP660-49-3039, Revision 1, 2, or 3, or later FAA approved revisions: Model GTCP660-4, S/N's P-37501 through P-37723 inclusive, and GTCP660-4R, S/N's P-101 through P-124 inclusive. To prevent development of a hazardous condition during flight, accomplish the following: (a) Prior to further flight, unless already accomplished, operators shall issue instructions to flight crews that the APU is not to be operated in flight. Within 72 hours after receipt of this Airworthiness Directive, unless already accomplished, install a placard in full view of the flight crew which reads: "INFLIGHT OPERATION OF THE APU IS PROHIBITED." (b) Prior to further flight, unless already accomplished, operators shall issue instructions to determine that damage hazardous to the aircraft has not occurred prior to flight after an automatic shutdown or manual shutdown to correct operating discrepancies of the APU after the completion of a successful APU start has been accomplished. This determination may be made by the following means: (1) Inspect the APU and APU compartment for damage; or (2) Inspect the exterior surfaces of the APU compartment for evidence of damage and verify that the APU turbine rotor can be rotated manually from the exhaust tailpipe; or, (3) Perform the procedures described in Boeing Operations Manual Bulletin No. 75-1, dated January 17, 1975, or later FAA approved revision. (c) The modifications and inspections described in AiResearch Bulletin GTCP660-49-3713, dated May 15, 1975, or later FAA-approved revisions must be incorporated on or before July 1, 1976. Upon completion of these modifications and inspections, the placard required by paragraph (a), above, may be removed and the inspections required by (b), above, may be discontinued. (d) Equivalent procedures may be approved by the Chief, Aircraft Engineering Division, FAA Western Region, upon submission of adequate substantiating data. Amendment 39-2108 supersedes the AD adopted January 10, 1975, and distributed by individual telegrams dated January 11, 1975. Amendment 39-2108 was effective March 5, 1975 and was effective upon receipt for all recipients of the airmail letter dated January 22, 1975 which contained this amendment. Amendment 39-2224 became effective June 5, 1975. This amendment 39-2357 becomes effective October 6, 1975. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_75-05-17.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 75-05-17 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model...Show more Subject: Auxiliary Power Units Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 10/06/1975 Make: Airesearch | The Boeing Company Model: Auxiliary Power Units | 747-100 Series | 747-100B Series | 747-100B SUD Series | 747-200B Series | 7...Show more Product Type: Appliance Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 75-05-17 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-2357 AD NUMBER: 75-05-17 SUBJECT HEADING: Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Applies to AiResearch Model GTCP660-4 and -4R APU's ACTION: SUMMARY: DATES: Effective October 6, 1975. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 75-05-17 AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Amendment 39-2108 as amended by Amendment 39-2224 is further amended by Amendment 39-2357. Applies to AiResearch Model GTCP660-4 and -4R APU's of the following listed serial numbers, installed in Boeing Model B-747 Series airplanes, unless modified to incorporate improved compressor assemblies in accordance with AiResearch Service Bulletin GTCP660-49-3039, Revision 1, 2, or 3, or later FAA approved revisions: Model GTCP660-4, S/N's P-37501 through P-37723 inclusive, and GTCP660-4R, S/N's P-101 through P-124 inclusive. To prevent development of a hazardous condition during flight, accomplish the following: (a) Prior to further flight, unless already accomplished, operators shall issue instructions to flight crews that the APU is not to be operated in flight. Within 72 hours after receipt of this Airworthiness Directive, unless already accomplished, install a placard in full view of the flight crew which reads: "INFLIGHT OPERATION OF THE APU IS PROHIBITED." (b) Prior to further flight, unless already accomplished, operators shall issue instructions to determine that damage hazardous to the aircraft has not occurred prior to flight after an automatic shutdown or manual shutdown to correct operating discrepancies of the APU after the completion of a successful APU start has been accomplished. This determination may be made by the following means: (1) Inspect the APU and APU compartment for damage; or (2) Inspect the exterior surfaces of the APU compartment for evidence of damage and verify that the APU turbine rotor can be rotated manually from the exhaust tailpipe; or, (3) Perform the procedures described in Boeing Operations Manual Bulletin No. 75-1, dated January 17, 1975, or later FAA approved revision. (c) The modifications and inspections described in AiResearch Bulletin GTCP660-49-3713, dated May 15, 1975, or later FAA-approved revisions must be incorporated on or before July 1, 1976. Upon completion of these modifications and inspections, the placard required by paragraph (a), above, may be removed and the inspections required by (b), above, may be discontinued. (d) Equivalent procedures may be approved by the Chief, Aircraft Engineering Division, FAA Western Region, upon submission of adequate substantiating data. Amendment 39-2108 supersedes the AD adopted January 10, 1975, and distributed by individual telegrams dated January 11, 1975. Amendment 39-2108 was effective March 5, 1975 and was effective upon receipt for all recipients of the airmail letter dated January 22, 1975 which contained this amendment. Amendment 39-2224 became effective June 5, 1975. This amendment 39-2357 becomes effective October 6, 1975. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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