Airworthiness Directives; Pratt & Whitney JT8D-200 Series Turbofan Engines

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 96-ANE-33; Amendment 39-9896; AD 97-02-11]

RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney JT8D-200 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) JT8D-200 series turbofan engines,

that requires, for front compressor front hubs (fan hubs), cleaning;

initial and repetitive eddy current (ECI) and fluorescent penetrant

inspections (FPI) of tierod and counterweight holes for cracks; removal

of bushings; the cleaning and ECI and FPI of bushed holes for cracks;

and, if necessary, replacement with serviceable parts. In addition,

this AD requires reporting the findings of cracked fan hubs. This

amendment is prompted by a report of an uncontained failure of a fan

hub. The actions specified by this AD are intended to prevent fan hub

failure due to tierod, counterweight, or bushed hole cracking, which

could result in an uncontained engine failure and damage to the

aircraft.

DATES: Effective March 5, 1997.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of March 5, 1997.

ADDRESSES: The service information referenced in this AD may be

obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108;

telephone (860) 565-6600, fax (860) 565-4503. This information may be

examined at the Federal Aviation Administration (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.

FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine

Certification Office, FAA, Engine and Propeller Directorate, 12 New

England Executive Park, Burlington, MA 01803-5299; telephone (617) 238-

7134, fax (617) 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 Pratt & Whitney (PW) JT8D-200

series turbofan engines was published in the Federal Register on

October 4, 1996 (61 FR 51847). That action proposed to require

cleaning, initial and repetitive eddy current inspections (ECI) and

fluorescent penetrant inspections (FPI) for cracks of tierod and

counterweight holes; removing bushings; initial and repetitive ECI and

FPI of bushed holes for cracks; and, if necessary, replacing with

serviceable parts. The compliance requirements allow selection of

inspection schedules depending on fan hub S/Ns listed in PW Alert

Service Bulletin (ASB) No. A6272, dated September 24, 1996, and

includes an inspection schedule for those fan hubs whose S/Ns are not

listed in the ASB. In addition, the proposed AD requires reporting the

number of initial inspections and the findings of cracked fan hubs.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

One commenter states that the Notice of Proposed Rulemaking (NPRM)

as written was confusing and subject to interpretation, and offered a

number of editorial suggestions. The FAA reviewed the suggestions and

concurs in part with the changes.

The commenter states that the applicability should be expressed to

the lowest practical level by including the phrase ``front compressor

front hub (fan hub)'' and its corresponding part number in the

applicability statement. The FAA concurs. The applicability section in

this final has been revised to read ``* * * engines with front

compressor front hub (fan hub) Part Number 5000501-01 installed''.

The commenter states that a stronger statement regarding the

initial inspections for fan hubs with less than 4,000 cycles since new

(CSN) was

[[Page 4903]]

needed. The commenter suggests adding the intent of the first note on

page 8 of PW ASB No. A6272, dated September 24, 1996, which requires

inspection after the fan hub has accumulated more than 4,000 cycles in

service. This change would eliminate the need for paragraph (a) of the

proposed rule. The FAA concurs. The structure of the compliance section

in this final rule has been modified to include the initial 4,000 CSN

inspection requirement in the beginning of each of two compliance

paragraphs. Paragraph (a) of this final rule will cover coolant channel

drilled (CCD) fan hubs identified by S/N in the SB, and paragraph (b)

for inspection of all other affected fan hubs. For each population of

hubs, the initial inspection must not be completed until the fan hub

has accumulated more than 4,000 CSN.

The commenter states that paragraph (c) of the NPRM is vague and

should specify what is to be reported. The FAA concurs and has added

the requirement of reporting in accordance with Accomplishment

Instructions, Paragraph F, of Attachment 1 to PW ASB No. A6272, dated

September 24, 1996, to this final rule.

The commenter states that paragraph (a) and Table 1 of the NPRM do

not clearly indicate that the operator is to choose one of the three

options in Table 1 and stick with the corresponding reinspection

interval. The commenter suggests adding ``or'' after options 1 and 2 in

Table 1 and adding a note to require that the operator follow the

initial and repetitive requirements of the option chosen. The FAA

concurs in part. The ``or'' has been added as suggested. The original

proposal contained such a requirement in proposed paragraph (b)(1)(i),

which has been carried over into new paragraph (a)(2). Operators must

follow the repetitive inspection interval corresponding to the selected

initial inspection time.

The commenter states that the time limit for reporting in paragraph

(c) of the NPRM is unreasonable because its administrative personnel do

not work on weekends and during holiday periods. The commenter

recommends a 10 day limit for reporting. The FAA does not concur. A 48

hour period should be adequate and is a standard reporting requirement

time limit in ADs. The AD does not require that only administrative

personnel submit the report to the FAA.

Two commenters, including the National Transportation Safety Board,

state that they agree with the NPRM's proposed initial and repetitive

inspection program on the population of hubs that were produced using

the CCD procedure, based on the investigation that indicates that these

hubs may have a higher risk of abusive machining damage. However, since

the commenters do not agree that CCD hubs are the only suspect fan

hubs, the commenters do not agree with the proposed inspection program

for the remaining hub population. The NPRM proposed to inspect the

remaining population (those hubs not CCD) when the hub assembly is

stripped to the piece part level. The commenters are concerned that

this proposal may allow hubs to be initially inspected as late as

10,000 cycles in service (CIS) after the effective date of this AD. The

commenters believe that these hubs are of nearly equal concern as the

fan hubs produced by CCD and the proposed interval is too long to

detect all potential cracks before they may be expected to propagate to

failure. The commenters propose that inspection/reinspection occur at

the next shop visit for all of those hubs that have between 10,000 and

15,000 CIS since new regardless of the type of drill used during

manufacture.

The FAA does not concur at this time. The FAA's analysis of this

problem indicates that hubs manufactured using coolant-channel drills

are more susceptible to work hardened areas in the tierod and

counterweight holes that could serve as a crack origin. The FAA

concludes, therefore, that it is logical to treat these two distinct

populations of compressor hubs differently in terms of when operators

must perform the required inspections. Requiring all hubs to be

inspected according to the CCD schedule is not supported by the

available data. The investigation, however, continues and should any

additional data become available, the FAA may initiate further

rulemaking as required.

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.

There are approximately 2,624 engines of the affected design in the

worldwide fleet. The FAA estimates that 1,279 engines installed on

aircraft of U.S. registry will be affected by this AD, that it will

take approximately 20 work hours per engine for 360 engines to

disassemble, remove, inspect, and reassemble engines, and 4 work hours

per engine for 919 engines to inspect at piece-part exposure, and that

the average labor rate is $60 per work hour. Based on these figures,

the total cost impact of the AD on U.S. operators is estimated to be

$862,560.

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.

List of Subjects in 14 CFR Part 39

Air Transportation, Aircraft, Aviation safety, Incorporation by

reference, 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:

97-02-11 Pratt & Whitney: Amendment 39-9896. Docket 96-ANE-33.

Applicability: Pratt & Whitney JT8D-209, -217, -217C, and -219

series turbofan engines with front compressor front hub (fan hub),

Part Number (P/N) 5000501-01, installed. These engines are installed

on but not limited to McDonnell Douglas MD-80 series aircraft.

[[Page 4904]]

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 (e) 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 front compressor front hub (fan hub) failure due to

tierod, counterweight, or bushed hole cracking, which could result

in an uncontained engine failure and damage to the aircraft,

accomplish the following:

(a) For fan hubs identified by serial numbers (S/Ns) in Appendix

A of PW Alert Service Bulletin (ASB) No. A6272, dated September 24,

1996, after the fan hub has accumulated more than 4,000 cycles in

service since new (CSN), accomplish the following:

(1) Select an initial inspection interval from Table 1 of this

AD and inspect for cracks in accordance with the Accomplishment

Instructions, Paragraph A, Part 1, and, if applicable, Paragraph B,

of PW ASB No. A6272, dated September 24, 1996.

(2) Reinspect at the interval in Table 1 of this AD that

corresponds to the selected initial inspection interval, and in

accordance with the Accomplishment Instructions, Paragraph A, Part

1, and, if applicable, Paragraph B, of PW ASB No. A6272, dated

September 24, 1996.

Table 1

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Initial inspection Reinspection

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1. Within 1,050 cycles in service (CIS) After accumulating 2,500 CIS

after the effective date of this AD, or since last inspection, but

prior to accumulating 5,050 CSN, not to exceed 6,000 CIS

whichever occurs later. since last inspection.

OR

2. Within 990 CIS after the effective date After accumulating 2,500 CIS

of this AD, or prior to accumulating since last inspection, but

4,990 CSN, whichever occurs later. not to exceed 8,000 CIS

since last inspection.

OR

3. Within 965 CIS after the effective date After accumulating 2,500 CIS

of this AD, or prior to accumulating since last inspection, but

4,965 CSN, whichever occurs later. not to exceed 10,000 CIS

since last inspection.

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(b) For fan hubs with S/Ns not listed in Appendix A of PW ASB

No. A6272, dated September 24, 1996, after the fan hub has

accumulated more than 4,000 CSN, inspect at the next time the fan

hub is in the shop at piece-part level, but not to exceed 10,000 CIS

after effective date of this AD in accordance with the

Accomplishment Instructions, Paragraph A, Part 2, and, if

applicable, Paragraph B, of PW ASB No. A6272, dated September 24,

1996.

(c) Remove from service fan hubs found cracked or fan hubs that

exceed the bushed hole acceptance criteria in accordance with PW ASB

No. A6272, dated September 24, 1996, and replace with serviceable

parts.

(d) Report findings of cracked fan hubs in accordance with

Accomplishment Instructions, Paragraph F, of Attachment 1 to PW ASB

No. A6272, dated September 24, 1996, within 48 hours after

inspection to Robert Guyotte, Manager, Engine Certification Branch,

Engine Certification Office, FAA, Engine and Propeller Directorate,

12 New England Executive Park, Burlington, MA 01803-5299; telephone

(617) 238-7142, fax (617) 238-7199; Internet:

Robert.G[email protected]. Reporting requirements have been

approved by the Office of Management and Budget and assigned OMB

control number 2120-0056.

(e) 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 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.

(f) 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 aircraft to a location where

the requirements of this AD can be accomplished.

(g) The actions required by this AD shall be done in accordance

with the following PW ASB:

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Document No. Pages Revision Date

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A6272.......................... 1-21 Original September 24,

1996.

NDIP-892....................... 1-30 A September 15,

1996.

Attachment I................... AI-1- .................

AI-4 A September 15,

1996.

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Total pages: 55.

This incorporation by reference was approved by the Director of

the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR

part 51. Copies may be obtained from Pratt & Whitney, 400 Main St.,

East Hartford, CT 06108; telephone (860) 565-6600, fax (860) 565-

4503. 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.

(h) This amendment becomes effective on March 5, 1997.

Issued in Burlington, Massachusetts, on January 13, 1997.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification

Service.

[FR Doc. 97-1703 Filed 1-31-97; 8:45 am]

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