This section of the FEDERAL REGISTER

contains notices to the public of the proposed

issuance of rules and regulations. The

purpose of these notices is to give interested

persons an opportunity to participate in the

rule making prior to the adoption of the final

rules.

Proposed Rules Federal Register

1298

Vol. 62, No. 6

Thursday, January 9, 1997

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–ANE–32]

RIN 2120–AA64

Airworthiness Directives; Pratt &

Whitney JT8D Series Turbofan Engines

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to Pratt

& Whitney JT8D–1, –1A, –1B, –7, –7A,

–7B, –9, –9A, –11, –15, – 17, and –17R

series turbofan engines. This proposal

would require initial and repetitive

fluorescent penetrant and eddy current

inspections of 4th stage low pressure

turbine (LPT) hubs for cracks, and, if

necessary, replacement with serviceable

parts. This proposal is prompted by a

report of an uncontained 4th stage LPT

blade release. The actions specified by

the proposed AD are intended to

prevent a 4th stage LPT blade release

due to hub cracking, which can result in

an uncontained engine failure and

damage to the aircraft.

DATES: Comments must be received by

March 10, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), New England

Region, Office of the Assistant Chief

Counsel, Attention: Rules Docket No.

96–ANE–32, 12 New England Executive

Park, Burlington, MA 01803–5299.

Comments may be inspected at this

location between 8:00 a.m. and 4:30

p.m., Monday through Friday, except

Federal holidays.

The service information referenced in

the proposed rule may be obtained from

Pratt & Whitney, Publication

Department, Supervisor Technical

Publications Distribution, M/S 132–30,

400 Main St., East Hartford, CT 06108;

telephone (860) 565–7700, fax (860)

565–4503. This information may be

examined at the FAA, New England

Region, Office of the Assistant Chief

Counsel, 12 New England Executive

Park, Burlington, MA.

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:

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 96–ANE–32.’’ 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

Assistant Chief Counsel, Attention:

Rules Docket No. 96–ANE–32, 12 New

England Executive Park, Burlington, MA

01803–5299.

Discussion

The Federal Aviation Administration

(FAA) has received a report of an

uncontained engine failure on a Pratt &

Whitney (PW) JT8D–15 turbofan engine.

On January 30, 1996, this engine,

installed on a Boeing Model 727–200

aircraft, experienced an uncontained 4th

stage low pressure turbine (LPT) blade

release during takeoff roll. The aircraft

sustained damage to the vertical

stabilizer and the engine cowling.

Inspection of the engine revealed that

the LPT blade release resulted from a

radial fracture of the 4th stage LPT hub.

The investigation determined that the

failure was due to a crack which

initiated in and propagated in low cycle

fatigue from an inclusion located in the

hub bore. This condition, if not

corrected, could result in a 4th stage

LPT blade release due to hub cracking,

which can result in an uncontained

engine failure and damage to the

aircraft.

Further investigation revealed that a

certain population of PW JT8D 4th stage

LPT hubs may contain inclusions of

aluminum/titanium carbonitrides rich

in cerium and lanthanum in the hub

bore that may initiate a crack in the

bore, and if undetected, may propagate,

resulting in a hub fracture and LPT

blade release. The cause of the inclusion

occurred during the material melting

process where a small amount of slag

created during the desulfurization/

deoxidization process of the vacuum

induction melt survived a subsequent

melt and was not detected by the

required nondestructive test inspections

for this material/part. The FAA has

determined that material produced prior

to April 31, 1983, has more

susceptibility to inclusions, whereas

subsequent to that date process

improvements have been implemented

to produce material that is less

susceptible to inclusions. Due to these

process improvements, the FAA has

identified certain 4th stage LPT hubs

produced prior to April 1983 that have

a greater potential for contamination.

Prior to the uncontained engine failure

on January 30, 1996, the FAA received

reports of two previous incidents of

cracks in the 4th stage LPT hub due to

inclusions that were discovered during

routine shop visits.

The FAA has reviewed and approved

the technical contents of PW Alert

Service Bulletin (ASB) No. A6274,
Federal Register / Vol. 62, No. 6 / Thursday, January 9, 1997 / Proposed Rules 1299

Revision 1, dated December 9, 1996,

that identifies by serial number (S/N)

affected 4th stage LPT hubs, and

describes procedures for fluorescent

penetrant inspection (FPI) and eddy

current inspection (ECI) of 4th stage LPT

hubs for cracks.

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

require initial and repetitive FPI and

ECI of affected 4th stage LPT hubs for

cracks, and, if necessary, replacement

with serviceable parts. The actions

would be required to be accomplished

in accordance with the ASB described

previously.

The FAA estimates that 381 engines

installed on aircraft of U.S. registry

would be affected by this proposed AD,

that it would take approximately 6 work

hours per engine to accomplish the

proposed actions, and that the average

labor rate is $60 per work hour. Based

on these figures, the total cost impact of

the proposed AD on U.S. operators is

estimated to be $137,160.

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 USC 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Pratt & Whitney: Docket No. 96–ANE–32.

Applicability: Pratt & Whitney (PW)

Models JT8D–1, –1A, –1B, –7, –7A, –7B, 9,

–9A, –11, –15, –17, and –17R turbofan

engines, with 4th stage low pressure turbine

(LPT) hubs identified by serial number (S/N)

in Table A of PW Alert Service Bulletin

(ASB) No. A6274, Revision 1, dated

December 97, 1996. These engines are

installed on but not limited to Boeing 727

and 737 series, and McDonnell Douglas DC–

9 series aircraft.

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 (b)

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 4th stage LPT blade failure due

to hub cracking, which can result in an

uncontained engine failure and damage to

the aircraft, accomplish the following:

(a) Perform fluorescent penetrant

inspection (FPI) and eddy current inspection

(ECI) of affected 4th stage LPT hubs for

cracks, in accordance with Paragraph 2A of

PW ASB No. A6274, Revision 1, dated

December 9, 1996, as follows:

(1) Inspect at the next time after the

effective date of this AD that the hub is

removed from the module and has been

debladed.

(2) Thereafter, inspect each time the hub is

removed from the module and has been

debladed.

(3) Remove from service any cracked 4th

stage LPT hub and replace with a serviceable

part.

(b) 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.

Issued in Burlington, Massachusetts, on

January 2, 1997.

Jay J. Pardee,

Manager, Engine and Propeller Directorate,

Aircraft Certification Service.

[FR Doc. 97–469 Filed 1–8–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 96–ANE–35]

RIN 2120–AA64

Airworthiness Directives; Pratt &

Whitney JT8D–200 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) JT8D–200 series turbofan

engines, that currently requires

installation and periodic inspection of

temperature indicators installed on the

No. 4 and 5 bearing compartment

scavenge oil tube and performance of

any necessary corrective action. This

action would require the installation

and periodic inspection of temperature

indicators to all PW JT8D–200 series

engines, including those incorporating

the containment hardware specified in

with AD 93–23–10. This proposal is

prompted by report of an uncontained

turbine failure due to a high pressure

turbine (HPT) shaft fracture on an

engine that had the containment

hardware installed. The actions

specified by the proposed AD are

intended to prevent fracture of the HPT

shaft, which can result in uncontained

release of engine fragments, engine fire,

inflight engine shutdown, or possible

aircraft damage.

DATE: Comments must be received by

March 10, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), New England

Region, Office of the Assistant Chief

Counsel, Attention: Rules Docket No.

96–ANE–35, 12 New England Executive

Park, Burlington, MA 01803–5299.

Comments may be inspected at this

location between 8:00 a.m. and 4:30

p.m., Monday through Friday, except

Federal holidays.