Airworthiness Directives; Pratt & Whitney PW2000 Series Turbofan Engines

[Federal Register Volume 64, Number 70 (Tuesday, April 13, 1999)]
[Rules and Regulations]
[Pages 17949-17951]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-8864]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-61-AD; Amendment 39-11120; AD 99-08-14]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney PW2000 Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Pratt & Whitney (PW) PW2000 series turbofan engines, that 
requires revisions to the engine manufacturers time limits section 
(TLS) to include enhanced inspection of selected critical life-limited 
parts at each piece-part exposure. This amendment will also require an 
air carrier's approved continuous airworthiness maintenance program to 
incorporate these inspection procedures. This amendment is prompted by 
a Federal Aviation Administration (FAA) study of in-service events 
involving uncontained failures of critical rotating engine parts that 
indicated the need for improved inspections. The improved inspections 
are needed to identify those critical rotating parts with conditions 
that if allowed to continue in service, could result in uncontained 
failures. The actions specified by this 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: Effective May 13, 1999.

ADDRESSES: The information contained in this AD may be examined at the 
FAA, New England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to PW PW2000 series turbofan engines 
was published in the Federal Register on August 31, 1998 (63 FR 46202). 
That action proposed to require within the next 30 days after the 
effective date of this AD, revisions to the Time Limits Section (TLS) 
of the Engine Manuals, and, for air carriers, the approved continuous 
airworthiness maintenance program. The manufacturer of PW2000 series 
turbofan engines has provided the FAA with a detailed proposal that 
identifies and prioritizes the critical life-limited rotating engine 
parts with the highest potential to hazard the airplane in the event of 
failure, along with instructions for enhanced, focused inspection 
methods. The enhanced inspections resulting from this AD will be 
conducted at piece-part opportunity, as defined in this AD, rather than 
specific inspection intervals.
    Interested persons have been afforded an opportunity to participate 
in the

[[Page 17950]]

making of this amendment. Due consideration has been given to the 
comments received.
    One commenter supports the measures outlined in the proposed rule.
    One commenter states that the manual references are not specific 
enough and requests that the manual references include the specific 
task or subtask that is to be performed. The FAA partially concurs. The 
reference method in this ad will not be changed. The FAA agrees that 
there is a benefit to using the tasks and subtasks. However, in the 
case of this AD, the FAA believes that the manner of referencing is 
arbitrary since either the reference method employed within this AD, or 
the task and subtask codes method will direct the reader to the desired 
inspection in the engine manual.
    One commenter states that paragraph (a)(2)(ii) is confusing as to 
inspection requirements for damaged parts and wants the piece part 
language used to trigger inspections modified. The FAA does not concur. 
Standardized language to define the piece-part condition and trigger 
focused inspection is required for uniform application of these new 
requirements across all operators. The language contained in the 
proposed rule has been developed by and agreed to by a broad group of 
FAA and Industry members. Therefore, the piece-part definition will not 
be changed.
    One commenter asks that each referenced manual section for the 
required inspections should also clearly state whether miscellaneous 
parts are to be removed or left in place. The FAA concurs. This AD has 
been reviewed relative to this suggestion. There are two areas on the 
PW2000 disks that are not typically disassembled, and after review, are 
not required to be disassembled to meet the intent of the proposed 
inspection. One of these areas is the tie-rod bolthole that, in some 
cases, has a repair bushing installed. The removal of these bushings 
would likely introduce more problems than they would solve, and a crack 
or failure in this region, at the disk outside diameter (OD), would not 
result in an uncontained failure. The other area is the spinner flange 
flared nuts. These are captive nuts and must be drilled or machined to 
be removed. Again, their removal or replacement would likely introduce 
more problems than would be solved, and cracking or failure in this 
region would also not result in an uncontained failure.
    One commenter believes that the FAA should urge the original 
equipment manufacturers (OEM's) to agree on universal precleaning and 
fluorescent penetrant inspection (FPI) procedures and to call them out 
in their service documents. The commenter believes that there is a lack 
of uniform cleaning procedures that are employed by the industry before 
conducting FPI inspections. The FAA partially concurs. The FAA 
recognizes the need for, and is currently engaged in, several other 
initiatives that will provide standardized guidance on precleaning and 
several other procedural aspects of FPI. The FAA will take action on 
standardized procedures when standardized procedures are developed and 
consensus is reached in the industry. No changes will be made to this 
AD.
    Several commenters ask that the FAA clarify the record keeping 
aspects of the mandatory inspections resulting from the required 
changes to the Original Equipment Manufacturer's manual and operator's 
continuous airworthiness maintenance program. One commenter believes 
that paragraph (e) of the proposed rule is unclear and suggests that it 
be revised by eliminating the word ``or'' from the first sentence and 
beginning a second sentence with ``In lieu of the record * * *.'' Two 
commenters state that the AD should be revised to clearly specify which 
types of maintenance records must be retained (i.e., inspection 
results, defect reporting requirements, date of performed maintenance, 
signature of the person performing the maintenance). These commenters 
believe that these revisions are necessary in order to avoid potential 
differences in interpretation between the air carriers and the FAA. 
And, one commenter states that the AD should clarify that there is no 
need for a special form to comply with the AD record keeping 
requirements. The FAA concurs in part. Generally, record keeping 
requirements are addressed in other regulations and this AD does not 
change those requirements. In order to allow flexibility from operator 
to operator, the FAA does not concur that the AD itself specify the 
precise nature of the records that will result from the required 
changes to the manufacturer's manual and operator's maintenance 
program. The FAA has, however, revised Paragraph (e) of this AD to 
clarify record keeping aspects of the new mandatory inspections.
    Two commenters point out that inspection 06 referred to in the NPRM 
does not exist in the present manual. Inspection 06 is the inspection 
that is being mandated by this proposed AD. The FAA concurs. PW will 
include inspection 06 in the next manual revision.
    Several commenters ask that the disks be identified by using the 
term ``all'' instead of identifying the disks by specific part numbers. 
The commenters believe that using the term ``all'' to identify the 
disks will eliminate the need for issuing a future AD every time a new 
P/N is added. The FAA partially concurs. Using the reference ``all'' 
instead of specific P/N's is preferable in some aspects. Using ``all'' 
eliminates the possibility of omitting parts that exists whenever using 
specific P/N's. However, P&W has initiated the manual changes, they are 
accurate, and will not be changed at this time. Future parts will be 
addressed by introduction into the service documentation instead of 
future AD's. These inspections will be incorporated into the 
maintenance plan and documentation for new parts from the beginning. 
This AD deals only with parts that are already in service. This 
proposed AD will not be changed to use ``all.''
    No comments were received on the economic analysis contained in the 
proposed rules. Based on that analysis, the FAA has determined that the 
annual per engine cost of $223 does not create a significant economic 
impact on small entities.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

[[Page 17951]]

List of Subjects in 14 CFR Part 39

    Air Transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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 adding the following new 
airworthiness directive:

99-08-14  Pratt & Whitney: Amendment 39-11120. Docket 98-ANE-61-AD.

    Applicability: Pratt & Whitney (PW) PW2037, PW2040, PW2037M, 
PW2240, PW2337, PW2043, PW2643, and PW2143, series turbofan engines, 
installed on but not limited to Boeing 757 series and Ilyushin IL-
96T 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:
    (a) Within the next 30 days after the effective date of this AD, 
revise the manufacturer's Time Limits section (TLS) of the 
manufacturer's engine manual, Part Numbers (P/N's) 1A6231 and 
1B2412, as appropriate for the PW PW2037, PW2040, PW2037M, PW2240, 
PW2337, PW2043, PW2643, and PW2143 series turbofan engines, and for 
air carriers 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 
PW2000 series Engine Manuals:

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                                                                  Manual
         Part nomenclature                Part No. (P/N)         section                 Inspection
----------------------------------------------------------------------------------------------------------------
Hub, 1st Stg Comp.................  1A9001 (Assy P/N 1A9021)..   72-31-04  Inspection--06.
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    (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 manufacturer's 
engine manual to either part number level listed in the table above, 
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 Sec. 43.16 of Federal 
Aviation Regulations (14 CFR 43.16), these enhanced inspections 
shall be performed only in accordance with the TLS of the 
appropriate PW2000 series engine manuals.
    (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. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector (PMI), who may add comments and then 
send it to the Manager, 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.

    (d) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the aircraft to a location where the 
requirements of this AD can be accomplished.
    (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 Instructions for Continuous 
Airworthiness (ICA) 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 engine manuals.

    (f) This amendment becomes effective on May 13, 1999.

    Issued in Burlington, Massachusetts, on April 2, 1999.
Jay J. Pardee,
Manager, Engine and Propeller Directorate,
Aircraft Certification Service.
[FR Doc. 99-8864 Filed 4-12-99; 8:45 am]
BILLING CODE 4910-13-P