Federal Register / Vol. 66, No. 39 / Tuesday, February 27, 2001 / Proposed Rules 12443

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–NE–22–AD]

RIN 2120–AA64

Airworthiness Directives; General

Electric Company (GE) CF34–1A, –3A,

–3A1, –3A2, –3B, and –3B1 Turbofan

Engines

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: The FAA proposes to adopt a

new airworthiness directive (AD) that

applies to GE CF34–1 and –3 series

turbofan engines with No. 5 bearing

rotating air seal part number (P/N)

4019T60G01 installed. This proposal

would require initial and repetitive

checks of the magnetic chip detector

indicators, which are located in the

lubrication system for the engine

bearings, and installation of an

improved No. 5 bearing rotating air seal

as a terminating action. This proposal is

prompted by a report of the failure of a

No. 5 bearing rotating air seal that led

to a fire in the cavity of the low pressure

turbine (LPT), overtemperature of the

LPT turbine disk, and excessive turbine

disk growth. The FAA is proposing this

AD to prevent No.5 bearing rotating air

seal failures and possible uncontained

engine failures.

DATES: The FAA must receive comments

on this proposal by March 29, 2001.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), New England

Region, Office of the Regional Counsel,

Attention: Rules Docket No. 2000–NE–

22–AD, 12 New England Executive Park,

Burlington, MA 01803–5299. Comments

may also be sent via the Internet using

the following address: ‘‘9-aneadcomment@faa.gov’’. 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. The service information

referenced in the proposed rule may be

obtained from GEAE Technical

Publications, Attention N. Hanna

MZ340M2, 1000 Western Avenue, Lynn,

MA 01910; telephone: 781 594–2906;

fax: 781 594–0600. This information

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:

Eugene Triozzi, Aerospace Engineer,

Engine Certification Office, FAA, Engine

and Propeller Directorate, 12 New

England Executive Park, Burlington MA

01803–5299; telephone: 781 238–7148,

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 to the address

specified above. All communications

received on or before the closing date

for comments, specified above, will be

considered before we take action on the

proposed rule. The proposals contained

in this action 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 sent

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 action

must send a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 2000–NE–22–AD.’’ The

postcard will be date stamped and

returned to the commenter.

Availability of NPRM’s

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. 2000–NE–22–AD, 12 New

England Executive Park, Burlington, MA

01803–5299.

Discussion

The FAA was recently made aware of

a CF34–3A1 turbofan engine that

experienced an in-flight failure of the

No. 5 bearing rotating air seal. The

manufacturer’s investigation revealed

that the engine experienced spalling and

wear of the No. 5 bearing roller bearing

outer race. This caused the No. 5

bearing rotating air seal to rub and

separate at the seal braze joint. The air

seal failure resulted in a fire in the low

pressure turbine cavity which caused

the stage 3 low pressure turbine disk to

overheat and grow excessively, resulting

in an in-flight shutdown. The FAA has

concluded that this failure sequence,

under certain conditions, could progress

further and result in a disk rupture and

uncontained engine failure. This

proposal would require initial and

repetitive checks of magnetic chip

detector indicators, which are located in

the lubrication system for the engine

bearings, in order to detect No. 5 bearing

roller distress before air seal failure.

Risk analyses of a potential disk rupture

were conducted separately for CF34–

3A1, –3B, and –3B1 engines, and for

CF34–1A, –3A, and –3A2 engines, in

consideration of differences in engine

maintenance programs for different

engine models. The FAA has

determined that the repetitive check

intervals in this proposed rule would

result in acceptable levels of safety for

each type of operation, provided that

terminating actions are completed fleetwide in accordance with the

requirements of this AD. The

installation of the modified design No.

5 bearing rotating air seal, P/N

4019T60G03, constitutes terminating

action for the inspection requirements

of this AD. This proposal is prompted

by reports of one No. 5 bearing rotating

air seal failure, and seven No. 5 bearing

failures, that had the potential to lead to

air seal failures. The actions specified

by the proposed AD are intended to

prevent No. 5 bearing rotating air seal

failures and possible uncontained

engine failures.

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

require initial and repetitive checks of

magnetic chip detector indicators, and

installation of an improved No. 5

bearing rotating air seal as terminating

action, to prevent No. 5 bearing rotating

air seal failures and possible

uncontained engine failures.

Economic Impact

There are about 1650 engines of the

affected design in the worldwide fleet.

The FAA estimates that 1075 engines

installed on aircraft of U.S. registry

would be affected by this proposed AD,

that it would take about 0.5 work hours

per engine to do the proposed checks,

and that the average labor rate is $60 per

work hour. Based on these figures, the

total proposed AD cost impact on U.S.

operators, for the initial check is

estimated to be $32,250. In addition, the

replacement air seal cost is

approximately $2,400 per unit, so the

total proposed material cost impact on

12444 Federal Register / Vol. 66, No. 39 / Tuesday, February 27, 2001 / Proposed Rules

U.S. operators is estimated to be

$2,580,000. No additional labor is

required for air seal replacement, as this

will occur during normal exposure at

shop visit. Based on these figures, the

total proposed AD cost impact on U.S.

operators, is estimated to be $2,612,250.

Regulatory Impact

This proposal does not have

federalism implications, as defined in

Executive Order 13132, because it

would not have a substantial direct

effect 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.

Accordingly, the FAA has not consulted

with state authorities prior to

publication of this proposal.

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.

39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

General Electric Company: Docket No. 2000–

NE–22–AD.

Applicability: This airworthiness directive

(AD) is applicable to CF34–1A, –3A, –3A1,

–3A2, –3B, and –3B1 turbofan engines with

No. 5 bearing rotating air seal, part number

(P/N) 4019T60G01 installed. These engines

are installed on but not limited to

Bombardier Inc. (Canadair) Model CL–600–

2A12, Model CL–600–2B16, and Model CL–

600–2B19, airplanes.

Note 1: This 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 (f) 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: Compliance with this AD is

required as indicated, unless accomplished

previously.

To prevent No. 5 bearing rotating air seal

failures and possible uncontained engine

failures, accomplish the following:

Magnetic Chip Detector Indicator Check

(a) Check magnetic chip detector indicators

in accordance with Table 1 as follows:

TABLE 1.—INITIAL AND REPETITIVE CHECKS

Engine model Initial check within Then within every:

(1) CF34–3A1, –3B1, and 3B ......... 30 flight hours or 3 calendar days, whichever is

greater, from effective date of this AD.

30 flight hours time-since-last-inspected (TSLI) or 3

calendar days TSLI, whichever is greater.

(2) CF34–1A, –3A, and –3A2 ......... 30 flight hours, from the effective date of this AD .... 100 flight hours TSLI.

Chip Detector Indicator Check,

Authorization

(b) Notwithstanding section 43.3 of the

Federal Aviation Regulations (14 CFR 43.3),

the checks required by paragraph (a) of this

AD may be performed by an aircrew member

holding at least a private pilot certificate.

Completion of the checks must be entered

into the airplane records showing

compliance with this AD, in accordance with

sections 43.9 and 91.417(a)(2)(v) of the

Federal Aviation Regulations (14 CFR 43.9

and 14 CFR 91.417(a)(2)(v)). The records

must be maintained as required by the

applicable Federal Aviation Regulation.

Detection of Chips

(c) If the magnetic chip detector indicator

shows a white triangle or is illuminated,

either condition indicates a chip detection.

Remove the chip detector and disposition the

chip, and the engine, using the engine

maintenance manual procedures.

Replacement of Air Seal

(d) Remove No. 5 bearing rotating air seal

P/N 4019T60G01, and replace with air seal

P/N 4019T60G03, in accordance with Table

2 as follows:

TABLE 2.—COMPLIANCE TIMES FOR

REPLACEMENT OF AIR SEAL

Engine model Replace At

(1) CF34–3A1,

–3B1, and –3B.

Next shop visit when HPT

is exposed, but do not

exceed 15,000 cyclesin-service after the effective date of this AD.

(2) CF34–1A,

–3A, and –3A2.

Next 3000-hour hot section inspection or at

next 6,000-hour overhaul, whichever occurs

first, but not to exceed

3,000 hours time-inservice after the effective date of this AD.

Terminating Action

(e) Replacement of air seal P/N

4019T60G01 with air seal P/N 4019T60G03

constitutes terminating action for the

repetitive inspection requirements specified

in paragraph (a) of this AD.

Alternative Methods of Compliance

(f) 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 (ECO). Operators shall

submit their request through an appropriate

Federal Aviation Administration (FAA)

Principal Maintenance Inspector, who may

add comments and then send it to the

Manager, 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.

Issued in Burlington, Massachusetts, on

February 20, 2001.

Jay J. Pardee,

Manager, Engine and Propeller Directorate,

Aircraft Certification Service.

[FR Doc. 01–4763 Filed 2–26–01; 8:45 am]

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