AD 93-08-16

final rule

PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines

AD Number
93-08-16
Status
final_rule
Effective Date
Product Category
engine
Docket
92-ANE-06
FR Citation
This information is not available.
Technical illustration of an aircraft turbine engine assembly
Problem area Engine

Applicability

TypeManufacturerModelDetails
engine Pratt & Whitney Division PW4050 PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines
engine Pratt & Whitney Division PW4052 PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines
engine Pratt & Whitney Division PW4056 PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines
engine Pratt & Whitney Division PW4060 PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines
engine Pratt & Whitney Division PW4060A PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines

Unsafe Condition

High pressure compressor (HPC) failure caused by excessive blade tip to airseal interference, which can result in total loss of engine thrust.

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

Required Actions

Incorporate Boeing ASB 747-73A2055 to limit low pressure rotor speed to Approach Idle rpm on PW4000 powered Boeing 747-400 aircraft. Incorporate Boeing ASB 767-73A0033 to limit low pressure rotor speed to Approach Idle rpm on PW4000 powered Boeing 767-200/-300 aircraft. Alternative methods of compliance may be approved by the Manager, Engine Certification Office.

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

Compliance Time

within 30 calendar days after the effective date of this airworthiness directive (July 12, 1993), unless accomplished previously

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

Affected Aircraft

Pratt & Whitney PW4050, PW4052, PW4056, PW4060, and PW4060A engines equipped with EEC Part Numbers 50D437, 50D821, 50D823, 51D011, and 51D012, installed on Boeing 747 and 767 aircraft.

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

Federal Register Abstract

Fuel Pump

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_93-08-16.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
93-08-16
Document Type:
AD Final Rules
Docket Number:
92-ANE-06
Subject Heading:
PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines
Subject:
Fuel Pump
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
07/12/1993
Make:
Pratt & Whitney Division
Model:
PW4050 | PW4052 | PW4056 | PW4060 | PW4060A
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: 93-08-16
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   92-ANE-06

AMENDMENT:   39-8564

AD NUMBER:   93-08-16

SUBJECT HEADING:   PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines

ACTION:  

SUMMARY:  

DATES:   Effective July 12, 1993.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   93-08-16 PRATT & WHITNEY: Amendment 39-8564. Docket 92-ANE-06. Supersedes AD 90-20-11, Amendment 39-6682.
Applicability: Pratt & Whitney PW4050, PW4052, PW4056, PW4060, and PW4060A model turbofan engines equipped with electronic engine control (EEC) Part Numbers 50D437, 50D821, 50D823, 51D011, and 51D012, installed on but not limited to Boeing 747 and 767 aircraft.
Compliance: Required within 30 calendar days after the effective date of this airworthiness directive (AD), unless accomplished previously.
To prevent a high pressure compressor (HPC) failure caused by excessive blade tip to airseal interference, which can result in total loss of engine thrust, accomplish the following:
(a) Incorporate the requirements of Boeing Commercial Airplanes Alert Service Bulletin (ASB) 747-73A2055, dated June 8, 1990, on PW4000 powered Boeing 747-400 aircraft, so that the minimum inflight rotational speed (rpm) of the low pressure rotor is limited to Approach Idle rpm.
(b) Incorporate the requirements of Boeing Commercial Airplanes ASB 767-73A0033, dated June 5, 1990, on PW4000 powered Boeing 767-200/-300 aircraft, so that the minimum inflight rotational speed of the low pressure rotor inflight is limited to Approach Idle rpm.
(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(d) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.
(e) The modification shall be done in accordance with the following Boeing service documents:

Document No.	Pages	Revision	Date
ASB 747-73A2055	1-10	Original	June 8, 1990
Total pages: 10			
ASB 767-73A0033	1-12	Original	June 5, 1990
Total pages: 12			

This incorporation by reference was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of October 1, 1990 (55 FR 37316, September 11, 1990). Copies may be obtained from Boeing Commercial Airplanes, Post Office Box 3707, Seattle, WA 98124-2207. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment becomes effective on July 12, 1993.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_93-08-16.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
93-08-16
Document Type:
AD Final Rules
Docket Number:
92-ANE-06
Subject Heading:
PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines
Subject:
Fuel Pump
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
07/12/1993
Make:
Pratt & Whitney Division
Model:
PW4050 | PW4052 | PW4056 | PW4060 | PW4060A
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: 93-08-16
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   92-ANE-06

AMENDMENT:   39-8564

AD NUMBER:   93-08-16

SUBJECT HEADING:   PRATT & WHITNEY Models PW4050, PW4052, PW4056, PW4060, and PW4060A Engines

ACTION:  

SUMMARY:  

DATES:   Effective July 12, 1993.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   93-08-16 PRATT & WHITNEY: Amendment 39-8564. Docket 92-ANE-06. Supersedes AD 90-20-11, Amendment 39-6682.
Applicability: Pratt & Whitney PW4050, PW4052, PW4056, PW4060, and PW4060A model turbofan engines equipped with electronic engine control (EEC) Part Numbers 50D437, 50D821, 50D823, 51D011, and 51D012, installed on but not limited to Boeing 747 and 767 aircraft.
Compliance: Required within 30 calendar days after the effective date of this airworthiness directive (AD), unless accomplished previously.
To prevent a high pressure compressor (HPC) failure caused by excessive blade tip to airseal interference, which can result in total loss of engine thrust, accomplish the following:
(a) Incorporate the requirements of Boeing Commercial Airplanes Alert Service Bulletin (ASB) 747-73A2055, dated June 8, 1990, on PW4000 powered Boeing 747-400 aircraft, so that the minimum inflight rotational speed (rpm) of the low pressure rotor is limited to Approach Idle rpm.
(b) Incorporate the requirements of Boeing Commercial Airplanes ASB 767-73A0033, dated June 5, 1990, on PW4000 powered Boeing 767-200/-300 aircraft, so that the minimum inflight rotational speed of the low pressure rotor inflight is limited to Approach Idle rpm.
(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(d) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.
(e) The modification shall be done in accordance with the following Boeing service documents:

Document No.	Pages	Revision	Date
ASB 747-73A2055	1-10	Original	June 8, 1990
Total pages: 10			
ASB 767-73A0033	1-12	Original	June 5, 1990
Total pages: 12			

This incorporation by reference was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of October 1, 1990 (55 FR 37316, September 11, 1990). Copies may be obtained from Boeing Commercial Airplanes, Post Office Box 3707, Seattle, WA 98124-2207. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment becomes effective on July 12, 1993.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

This site is not affiliated with or endorsed by the FAA. Always verify with official sources.