AD 66-16-06

final rule

PRATT & WHITNEY Models JT3C-7 and JT3C-12 Engines

AD Number
66-16-06
Status
final_rule
Effective Date
Product Category
engine
Docket
Unknown
FR Citation
This information is not available.
Technical illustration of an aircraft turbine engine assembly
Problem area Engine

Applicability

TypeManufacturerModelDetails
engine Pratt & Whitney Division JT3C-12 PRATT & WHITNEY Models JT3C-7 and JT3C-12 Engines
engine Pratt & Whitney Division JT3C-7 PRATT & WHITNEY Models JT3C-7 and JT3C-12 Engines

Unsafe Condition

Failure of fourth stage compressor rotor disc spacer assemblies due to cracks in visible areas of the spacer.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Drill an inspection hole and install a plug in the compressor case and fourth stage vane and shroud assembly. Inspect the spacer assembly using a specified cystoscope for cracks. Replace cracked spacers with P/N 359413 or 429177 before further flight. Remove engine and reinspect if cracks are found during inspection.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within the next 50 hours' time in service after the effective date, unless already accomplished within the last 575 hours' time in service, and thereafter at intervals not to exceed 625 hours' time in service from the last inspection until installation of assembly P/N 429177.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Pratt & Whitney Models JT3C-7 and JT3C-12 Turbojet Engines.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

Rotor Disc Spacer Assemblies

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_66-16-06.html
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AD Number:
66-16-06
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
PRATT & WHITNEY Models JT3C-7 and JT3C-12 Engines
Subject:
Rotor Disc Spacer Assemblies
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
07/02/1966
Make:
Pratt & Whitney Division
Model:
JT3C-12 | JT3C-7
Product Type:
Engine
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Superseded AD: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Superseded By: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: 66-16-06
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-256

AD NUMBER:   66-16-06

SUBJECT HEADING:   PRATT & WHITNEY Models JT3C-7 and JT3C-12 Engines

ACTION:  

SUMMARY:  

DATES:   Effective July 2, 1966.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
66-16-06 PRATT & WHITNEY: Amdt. 39-256 Part 39 Federal Register July 2, 1966. Applies to Models JT3C-7 and JT3C-12 Turbojet Engines.

Compliance required as indicated.

To prevent further failures of fourth stage compressor rotor disc spacer assemblies, accomplish the following:

(a) For fourth stage compressor rotor disc spacer assemblies, P/N 359413, with 1,000 or more hours' time in service since last overhaul, comply with (c) within the next 50 hours' time in service after the effective date of this AD, unless already accomplished within the last 575 hours' time in service, and thereafter at intervals not to exceed 625 hours' time in service from the last inspection until installation of assembly, P/N 429177.

(b) For fourth stage compressor rotor disc spacer assemblies, P/N 359413, with less than 1,000 hours' time in service since last overhaul, comply with (c) before the accumulation of 1,050 hours' time in service since last overhaul, unless already accomplished after the accumulation of 425 hours' time in service since last overhaul, and thereafter at intervals not to exceed 625 hours' time in service from the last inspection until installation of assembly, P/N 429177.

(c) Drill an inspection hole and install a plug in the compressor case and fourth stage vane and shroud assembly in accordance with Pratt & Whitney Aircraft letter dated April 15, 1966, and sketches PWA 15814 and SL61447. Using an American Cystoscope Makers Incorporated Model B-175-AS-15, B-110-AS-15 instrument (or FAA-approved equivalent) inserted through this hole, inspect the fourth stage compressor rotor disc spacer assembly for indication of cracks in visible areas of the spacer. If any indications of cracks are found, remove the engine before further flight, disassemble, and reinspect. If, after disassembly, no cracks are found, the engine may be returned to service. Replace any cracked spacer assemblies before further flight with an assembly of the same part number or P/N 429177.

NOTE: During the inspection required by (c), particular attention should be directed to the front and rear seal edges.

(d) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.

This directive effective July 2, 1966.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_66-16-06.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
66-16-06
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
PRATT & WHITNEY Models JT3C-7 and JT3C-12 Engines
Subject:
Rotor Disc Spacer Assemblies
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
07/02/1966
Make:
Pratt & Whitney Division
Model:
JT3C-12 | JT3C-7
Product Type:
Engine
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: 66-16-06
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-256

AD NUMBER:   66-16-06

SUBJECT HEADING:   PRATT & WHITNEY Models JT3C-7 and JT3C-12 Engines

ACTION:  

SUMMARY:  

DATES:   Effective July 2, 1966.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
66-16-06 PRATT & WHITNEY: Amdt. 39-256 Part 39 Federal Register July 2, 1966. Applies to Models JT3C-7 and JT3C-12 Turbojet Engines.

Compliance required as indicated.

To prevent further failures of fourth stage compressor rotor disc spacer assemblies, accomplish the following:

(a) For fourth stage compressor rotor disc spacer assemblies, P/N 359413, with 1,000 or more hours' time in service since last overhaul, comply with (c) within the next 50 hours' time in service after the effective date of this AD, unless already accomplished within the last 575 hours' time in service, and thereafter at intervals not to exceed 625 hours' time in service from the last inspection until installation of assembly, P/N 429177.

(b) For fourth stage compressor rotor disc spacer assemblies, P/N 359413, with less than 1,000 hours' time in service since last overhaul, comply with (c) before the accumulation of 1,050 hours' time in service since last overhaul, unless already accomplished after the accumulation of 425 hours' time in service since last overhaul, and thereafter at intervals not to exceed 625 hours' time in service from the last inspection until installation of assembly, P/N 429177.

(c) Drill an inspection hole and install a plug in the compressor case and fourth stage vane and shroud assembly in accordance with Pratt & Whitney Aircraft letter dated April 15, 1966, and sketches PWA 15814 and SL61447. Using an American Cystoscope Makers Incorporated Model B-175-AS-15, B-110-AS-15 instrument (or FAA-approved equivalent) inserted through this hole, inspect the fourth stage compressor rotor disc spacer assembly for indication of cracks in visible areas of the spacer. If any indications of cracks are found, remove the engine before further flight, disassemble, and reinspect. If, after disassembly, no cracks are found, the engine may be returned to service. Replace any cracked spacer assemblies before further flight with an assembly of the same part number or P/N 429177.

NOTE: During the inspection required by (c), particular attention should be directed to the front and rear seal edges.

(d) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.

This directive effective July 2, 1966.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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