[Federal Register Volume 64, Number 194 (Thursday, October 7, 1999)]
[Proposed Rules]
[Pages 54582-54584]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-26136]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-66-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to Pratt & Whitney 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 action would add additional critical 
life-limited parts for enhanced inspection. This proposal is prompted 
by additional focused inspection procedures for other critical life-
limited rotating engine parts that have been developed by the 
manufacturer. 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 6, 1999.

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: ``[email protected]''. Comments sent 
via the Internet must contain the docket number in the subject line. 
Comments may be inspected at this location between 8:00 a.m. and 4:30 
p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Peter White, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7128, fax (781) 238-7199.

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 April 2, 1999, the Federal Aviation Administration (FAA) issued 
airworthiness directive (AD) 99-08-15, Amendment 39-311121 (64 FR 
17947, April 13, 1999), 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 Procedures and Parts

    Since the issuance of that AD, additional focused inspection 
procedures for other critical life-limited rotating engine parts have 
been developed. The new parts are the:

 High Pressure Compressor (HPC) 5th stage disk
 HPC front drum rotor
 HPC rear drum rotor
 HPC 15th stage disk
 High Pressure Turbine (HPT) 1st stage airseal--on certain 
models
 HPT 2nd stage airsealuon certain models
 HPT 1st stage (front) hub
 HPT 2nd stage (rear) hub

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 99-08-15 to require the additional 
critical life-limited rotating engine parts to be subject to focused 
inspection at each piece-part opportunity.

Changes From AD 99-08-15

    The FAA has revised the piece-part definition to make it clearer at 
which assembly level (assembly or detail) inspection of the part is 
acceptable.
    Also, the FAA has added additional part numbers (P/Ns) to the LPC 
Hub Assembly section of the AD to include the PW4098 models. While the 
inspections required for these parts were included in the 
manufacturer's service documentation upon entry into service and 
therefore do not need to be included in this AD, the FAA has included 
these P/Ns to make this AD an all-inclusive inspection requirement for 
all PW4000 series engine models.
    Finally, the FAA has corrected an error in the LPC hub assembly, 
which was discovered in the original AD. The detail P/N for the LPC hub 
assembly 
P/N 51B631 was changed from ``50B601'' to ``51B601.''

Economic Analysis

    The FAA estimates that 450 engines installed on airplanes of US 
registry would be affected by this proposed AD, that it would take 
approximately 8 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

[[Page 54583]]

figures and assuming that on average 5 components per visit will 
require an inspection, the total cost impact of the proposed AD on US 
operators is estimated to be $337,000 per year, or approximately $750 
per engine per year.

Regulatory Impact

    The regulations proposed herein would not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-11121 (64 FR 
17947, April 13, 1999), and by adding a new airworthiness directive, to 
read as follows:

Pratt & Whitney: Docket No. 98-ANE-66-AD. Supersedes AD 99-08-15, 
Amendment 39-11121.

    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, 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 accomplished 
previously.
    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, 
revise the Time Limits Section of the manufacturer's Engine Manual 
(EM), Part Numbers (P/Ns) 50A605, 50A443, 51A342, 50A822, 51A751, 
and 51A345, as applicable, for 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, PW4090D, and PW4098 
turbofan engines, and for air carrier operations revise the approved 
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 
applicable PW4000 series Engine Cleaning, Inspection, and Repair 
(CIR) Manuals:

----------------------------------------------------------------------------------------------------------------
                                                            CIR manual
   Nomenclature (description)            Part No.             section     CIR manual  inspection    CIR manual
----------------------------------------------------------------------------------------------------------------
Hub, LPC Assembly..............  50B221 (50B201 Detail);        72-31-07  Insp/Check-02.........          51A357
                                  50B321 (50B301
                                  Detail); 51B321
                                  (51B301 Detail);
                                  52B021 (52B001 Detail).
                                 51B631 (51B601 Detail);        72-31-07  Insp/check-02.........          51A750
                                  51B821 (51B801
                                  Detail); 52B521
                                  (52B501 Detail);
                                  52B421 (52B401
                                  Detail); 52B321
                                  (52B101 Detail);
                                  51B721 (52B101 Detail).
HPC 5th stage disk.............  51H005; 51H905; 54H405;        72-35-06  Insp/Check-02.........          51A357
                                  54H705; 54H705-001;
                                  56H605; 56H705.
                                 54H705; 55H805; 56H505.        72-35-06  Insp/Check-02.........          51A750
HPC front drum rotor...........  50H859; 50H859-001;            72-35-07  Insp/Check-02.........          51A357
                                  51H426-01; 52H559-01;
                                  52H926-01; 53H676-01;
                                  53H976-01; 54H626-01;
                                  54H816-01; 55H106-01;.
                                 53H406-01; 55H206-01;          72-35-07  Insp/Check-02.........          51A750
                                  56H306-01.
HPC rear drum rotor............  50H936; 50H936-002;            72-35-08  Insp/Check-02.........          51A357
                                  53H923-01; 53H923-001.
                                 53H973-01; 53H973-001;         72-35-10  Insp/Check-02.........          51A357
                                  54H803-01; 54H803-001;
                                  56H013-01.
                                 55H722-01; 55H410-01;          72-35-10  Insp/Check-02.........          51A750
                                  57H010-01; 57H210-01;
                                  57H610-01.
HPC 15th disk..................  55H615; 56H015; 57H715.        72-35-92  Insp/Check-02.........          51A750
HPT 1st stage airseal..........  50L663; 50L959; 53L003.        72-52-19  Insp/Check-02.........          51A750
HPT first stage hub............  50L501; 51L601; 51L201;        72-52-05  Insp/Check-02.........          51A357
                                  52L401; 52L301 (51L901
                                  Detail); 51L201-021
                                  (51L201 Detail);
                                  50L761 (52L201 Detail).
                                 52L901 (53L001 Detail);        72-52-05  Insp/Check-02.........          51A750
                                  52L701 (52L601
                                  Detail); 53L121
                                  (53L601 Detail);
                                  53L021 (53L101 Detail).

[[Page 54584]]

 
HPT 2nd stage airseal..........  50L926 (50L925                 72-52-22  Insp/Check-02.........          51A750
                                  Detail)*; 50L976
                                  (50L925 Detail)*;
                                  50L960 (50L961
                                  Detail)*; 50L993
                                  (50L994 Detail)*.
HPT second stage hub...........  50L602-021 (50L602             72-52-06  Insp/Check-02.........          51A357
                                  Detail); 50L602-022
                                  (50L602 Detail);
                                  50L602-023 (50L602
                                  Detail); 50L602-024
                                  (50L602 Detail);
                                  50L602-001; 50L902-021
                                  (50L902 Detail);
                                  50L902-022 (50L902
                                  Detail); 52L002-021
                                  (52L002 Detail);
                                  52L402 (52L002
                                  Detail); 52L802
                                  (52L002 Detail);
                                  53L602 (52L002 Detail).
                                 52L702 (52L102 Detail);        72-52-06  Insp/Check-02.........          51A750
                                  53L232 (53L202
                                  Detail); 53L332
                                  (53L402 Detail);
                                  53L042 (53L702 Detail).
----------------------------------------------------------------------------------------------------------------
* These parts must be inspected at the Detail level (metering plugs and Dampers must be removed). Assembly P/N
  is listed only for reference and consistency with PW Manuals.

    Except as noted, all parts may be inspected at any part number 
level of disassembly listed in the Table above.
    (2) For the purposes of these mandatory inspections, piece-part 
opportunity means:
    (i) The part is considered completely disassembled when 
accomplished in accordance with the disassembly instructions in the 
manufacturer's engine manuals to either the detail or assembly level 
part numbers listed in the Table above (except as noted); 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 (c) of this AD, and 
notwithstanding contrary provisions in section 43.16 of the Federal 
Aviation Regulations (14 CFR 43.16), these mandatory inspections 
shall be performed only in accordance with the Time Limits Section 
of the manufacturer's EMs.

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

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Ferry Flights

    (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) FAA-certificated air carriers that have an approved 
continuous airworthiness maintenance program in accordance with the 
record keeping requirement of Sec. 121.369(c) of the Federal 
Aviation Regulations (14 CFR 121.369(c)) of this chapter must 
maintain records of the mandatory inspections that result from 
revising the Time Limits Section of the EMs and the air carrier's 
continuous airworthiness program. Alternately, certificated air 
carriers may establish an approved system of record retention that 
provides a method for preservation and retrieval of the maintenance 
records that include the inspections resulting from this AD, and 
include the policy and procedures for implementing this alternate 
method in the air carrier's maintenance manual required by 
Sec. 121.369(c) of the Federal Aviation Regulations (14 CFR 
121.369(c)); however, the alternate system must be accepted by the 
appropriate PMI and require the maintenance records be maintained 
either indefinitely or until the work is repeated. Records of the 
piece-part inspections are not required under Sec. 121.380(a)(2)(vi) 
of the Federal Aviation Regulations (14 CFR 121.380(a)(2)(vi)). All 
other operators must maintain the records of mandatory inspections 
required by the applicable regulations governing their operations.

    Note 3: The requirements of this AD have been met when the 
engine manual changes are made and air carriers have modified their 
continuous airworthiness maintenance plans to reflect the 
requirements in the EMs.

    Issued in Burlington, Massachusetts, on September 30, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-26136 Filed 10-6-99; 8:45 am]
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