01-25055. Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to Pratt & Whitney (PW) PW4000 series turbofan engines, that currently requires revisions to the Time Limits Section of the manufacturer's Engine Manuals (EMs) to include required enhanced inspection of selected critical life-limited parts at each piece-part exposure. This proposal would modify the airworthiness limitations section of the manufacturer's manual and an air carrier's approved continuous airworthiness maintenance program to incorporate additional inspection requirements. An FAA study of in-service events involving uncontained failures of critical rotating engine parts has indicated the need for mandatory inspections. The mandatory inspections are needed to identify those critical rotating parts with conditions, which if allowed to continue in service, could result in uncontained failures. The actions specified by this proposed AD are intended to prevent critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.

DATES:

Comments must be received by December 4, 2001.

ADDRESSES:

Submit comments to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 98-ANE-66-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via the Internet must contain the docket number in the subject line. Comments may be inspected at this location by appointment between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Robert McCabe, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 98-ANE-66-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 98-ANE-66-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

On June 5, 2000, the Federal Aviation Administration (FAA) issued airworthiness directive (AD) 2000-12-02, Amendment 39-11780 (65 FR 37473, June 15, 2000), to require revisions to the Time Limits Section in the Engine Manuals (EMs) for certain Pratt & Whitney (PW) PW4000 series turbofan engines to include required enhanced inspection of selected critical life-limited rotating components in the fan rotor at each piece-part exposure.

New Inspection Procedures

Since the issuance of that AD, an FAA study of in-service events involving uncontained failures of critical rotating engine parts has indicated the need for additional mandatory inspections. The mandatory inspections are needed to identify those critical rotating parts with conditions, which if allowed to continue in service, could result in uncontained failures. This proposal would modify the time limitations section of the manufacturer's manual and an air carrier's approved continuous airworthiness maintenance program to incorporate additional inspection requirements.

Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would supersede AD 2000-12-02 to require the additional critical life-limited rotating engine parts to be subject to focused inspection at each piece-part opportunity.

Economic Analysis

The FAA estimates that 500 engines installed on airplanes of US registry would be affected by this proposed AD, and that it would take approximately 10 work hours per engine to accomplish the proposed actions. The average labor rate is $60 per work hour, the average Shop Visit Rate is .097, and the average usage is 3,250hrs/year/engine. Based on these figures, the total cost impact of the proposed AD on US operators is estimated to be about $94,000 per year.

Regulatory Analysis

This proposed rule does not have federalism implications, as defined in Executive Order 13132, because it would not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Accordingly, the FAA has not consulted with state authorities prior to publication of this proposed rule.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. Section 39.13 is amended by removing Amendment 39-11780 (65 FR 37473, June 15, 2000), and by adding a new airworthiness directive, to read as follows:

Pratt & Whitney: Docket No. 98-ANE-66-AD. Supersedes AD 2000-12-02, Amendment 39-11780.

Applicability: Pratt & Whitney (PW) Model PW4050, PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, PW4152, PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, PW4168, PW4168A, PW4164, PW4074, PW4074D, PW4077, PW4077D, PW4084, PW4084D, PW4090, PW4090-3, PW4090D, and PW4098 turbofan engines, installed on but not limited to Airbus A300, A310, and A330 series, Boeing 747, 767, and 777 series, and McDonnell Douglas MD-11 series airplanes.

Note 1:

This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless already done.

To prevent critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane, accomplish the following:

Inspections

(a) Within the next 30 days after the effective date of this AD, (1) revise the Time Limits section of the manufacturer's Engine Manual, Part Numbers 50A342, 50A345, 50A443, 50A605, 50A751, 51A342, 50A822, 51A751 and 51A345, as appropriate for the Pratt & Whitney PW4050, PW4052, PW4056, PW4060, PW4060A, PW4062, PW4060C, PW4152, PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, PW4164, PW4168, PW4168A, PW4074, PW4074D, PW4077, PW4077D, PW4084, PW4084D, PW4090, PW4090-3, PW4090D, and PW4098 series turbofan engines, and (2) for air carrier's, revise the approved mandatory inspections section of the continuous airworthiness maintenance program, by adding the following: “MANDATORY INSPECTIONS

(1) Perform inspections of the following parts at each piece-part opportunity in accordance with the instructions provided in the PW4000 series Engine Cleaning, Inspection and Repair (CIR) Manuals:

For Engine Manuals 50A443, 50A605, and 50A822, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
Hub, Front Compressor	All	72-31-07	Insp/Check-02	51A357
Hub, Turbine Front Assy (Stage 1)	All	72-52-05	Insp/Check-02	51A357
Hub, Turbine Intermediate Rear (Stage 2)	All	72-52-06	Insp/Check-02	51A357

For Engine Manual 50A342, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
Hub, LPC Assembly	All	72-31-07	Insp/Check-02	51A357
Hub, Turbine Front Assembly (Stage 1)	All	72-52-05	Insp/Check-02	51A357
Seal—Air, HPT 2nd Stage	All	72-52-22	Insp/Check-02	51A357
Hub, Turbine Rear (Stage 2)	All	72-52-06	Insp/Check-02	51A357

For Engine Manuals 50A345 and 50A751, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
Hub, LPC Assembly	All	72-31-07	Insp/Check-02	51A750
Seal—Air, HPT 1st Stage	All	72-52-19	Insp/Check-02	51A750
Hub, Turbine Front Assembly (1st Stage)	All	72-52-05	Insp/Check-02	51A750
Seal—Air, HPT 2nd Stage Assembly	All	72-52-22	Insp/Check-02	51A750
Hub, Turbine rear Assembly (2nd Stage)	All	72-52-06	Insp/Check-02	51A750

For Engine Manuals 50A443, 50A605, and 50A882, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
HPC 5th Stage Disk	All	(1) 72-35-06	Insp/Check-02	51A357
HPC Front Drum Rotor	All	(1) 72-35-07	Insp/Check-02	51A357
HPC Rear Drum Rotor	All	(2) 72-35-08	Insp/Check-02	51A357
HPC Rear Drum Rotor	All	(3) 72-35-10	Insp/Check-02	51A357
(1) For PW4000-94” Phase I & III ONLY.
(2) For PW4000-94” Phase I ONLY.
(3) For PW4000-94” Phase III ONLY.

For Engine Manuals 51A342, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
HPC 5th Stage Disk	All	72-35-06	Insp/Check-02	51A357
HPC Front Drum Rotor	All	72-35-07	Insp/Check-02	51A357
HPC Rear Drum Rotor	All	72-35-10	Insp/Check-02	51A357

For Engine Manuals 51A345 and 51A751, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
HPC 5th Stage Disk	All	72-35-06	Insp/Check-02	51A750
HPC Front Drum Rotor	All	72-35-07	Insp/Check-02	51A750
HPC Rear Drum Rotor	All	72-35-10	Insp/Check-02	51A750
HPC 15th Stage Disk	All	72-35-92	Insp/Check-02	51A750
HPT 1st Stage Airseal	All	72-52-19	Insp/Check-02	51A750
HPT Front Hub	All	72-52-05	Insp/Check-02	51A750
HPT 2nd Stage Airseal	All	72-52-22	Insp/Check-02	51A750
HPT Rear Hub	All	72-52-06	Insp/Check-02	51A750

For Engine Manuals 50A443, 50A605, and 50A882, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
Stage 3 LPT Disk	All	72-53-13	Insp/Check-02	51A357
Stage 4 LPT Disk	All	72-53-14	Insp/Check-02	51A357
Stage 5 LPT Disk	All	72-53-15	Insp/Check-02	51A357
Stage 6 LPT Disk	All	72-53-16	Insp/Check-02	51A357

For Engine Manual 51A342, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
Stage 3 LPT Disk	All	72-53-13	Insp/Check-02	51A357
Stage 4 LPT Disk	All	72-53-14	Insp/Check-02	51A357
Stage 5 LPT Disk	All	72-53-15	Insp/Check-02	51A357
Stage 6 LPT Disk	All	72-53-16	Insp/Check-02	51A357
Stage 7 LPT Disk	All	72-53-61	Insp/Check-02	51A357

For Engine Manual 51A345, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
Stage 3 LPT Disk	All	72-53-13	Insp/Check-02, Config-1	51A750
Stage 4 LPT Disk	All	72-53-14	Insp/Check-02	51A750
Stage 5 LPT Disk	All	72-53-60	Insp/Check-02	51A750
Stage 6 LPT Disk	All	72-53-16	Insp/Check-02, Config-1	51A750
Stage 7 LPT Disk	All	72-53-72	Insp/Check-02	51A750
Stage 8 LPT Disk	All	72-53-62	Insp/Check-02, Config-1	51A750
Stage 9 LPT Disk	All	72-53-63	Insp/Check-02	51A750

For Engine Manual 51A751, add the following table data:

Part nomenclature	Part No.	CIR manual section	CIR manual inspection	CIR manual
Stage 3 LPT Disk	All	72-53-13	Insp/Check-02, Config-2. See Note (1)	51A750
Stage 4 LPT Disk	All	72-53-14	Insp/Check-02	51A750
Stage 5 LPT Disk	All	72-53-60	Insp/Check-02	51A750
Stage 6 LPT Disk	All	72-53-16	Insp/Check-02, Config-2. See Note (1)	51A750
Stage 7 LPT Disk	All	72-53-72	Insp/Check-02	51A750
Stage 8 LPT Disk	All	72-53-62	Insp/Check-02, Config-2. See Note (1)	51A750
Stage 9 LPT Disk	All	72-53-63	Insp/Check-02	51A750
(1) FPI method only.

(2) For the purposes of these mandatory inspections, piece-part opportunity means:

(i) The part is considered completely disassembled when done in accordance with the disassembly instructions in the manufacturers engine manual; and

(ii) The part has accumulated more than 100 cycles in service since the last piece-part opportunity inspection, provided that the part was not damaged or related to the cause for its removal from the engine.”

(b) Except as provided in paragraph (d) of this AD, and notwithstanding contrary provisions in section 43.16 of the Federal Aviation Regulations (14 CFR 43.16), these enhanced inspections shall be performed only in accordance with the TLS of the appropriate PW4000 series Engine Manuals.

Alternative Method of Compliance

(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 Engine Certification Office. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Engine Certification Office.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.

Special Flight Permits

(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Continuous Airworthiness Maintenance Program

(e) The record of the mandatory inspections required as a result of revising the Time Limits of the PW4000 series Engine Manuals as provided by paragraph (a) of this AD shall be maintained by FAA certificated air carriers who have an approved continuous airworthiness maintenance program in accordance with the record keeping system currently specified in their manual required by sections 121.369 of the Federal Aviation Regulations (14 CFR 121.369); or, in lieu of the record showing the current status of each mandatory inspection required by sections 121.380(a)(2)(vi) of the Federal Aviation Regulations (14 CFR 121.380(a)(2)(vi)), certificated air carriers may establish an alternate system of record retention that provides a method for preservation and retrieval of the maintenance record that includes the inspections resulting from this AD, and include the policy and procedures for implementing this alternate method in the manual required by sections 121.369 (c) of the Federal Aviation Regulations (14 CFR 121.369 (c)) provided the alternate system must require the maintenance record be maintained either indefinitely or until the work is repeated.

Note 3:

These record keeping requirements apply only to the records used to document the mandatory enhanced inspections required as a result of revising the Time Limits section of the PW4000 series Engine Manuals as provided in paragraph (a) of this AD, and do not alter 1 or amend the record keeping requirements for any other AD or regulatory requirement.

Issued in Burlington, Massachusetts, on October 1, 2001.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.