Airworthiness Directives; Pratt & Whitney PW2000 Series Turbofan Engines

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

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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]

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