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

25892

Vol. 65, No. 87

Thursday, May 4, 2000

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99–NE–48–AD]

RIN 2120–AA64

Airworthiness Directives; General

Electric Aircraft Engines CT7 Series

Turboprop 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

certain General Electric Aircraft Engines

(GEAE) CT7 series turboprop engines.

This proposal would require initial and

repetitive inspections of the propeller

gearbox (PGB) oil filter impending

bypass button (IBB) for extension

(popping). This proposal would also

require follow-on inspections,

maintenance, and replacement actions if

the PGB oil filter IBB is popped; and if

necessary, replacement of the PGB with

a serviceable PGB. In addition, this

proposal would require a one-time

removal of possibly improperly

hardened PGB input pinions and

replacement with PGB input pinions

that were manufactured using the

proper hardening process as terminating

action to the repetitive inspections. This

proposal is prompted by reports of

improperly hardened PGB input

pinions. The actions specified by the

proposed AD are intended to prevent

PGB input pinion failure, which could

result in PGB failure and an in-flight

engine shutdown.

DATES: Comments must be received by

July 3, 2000.

ADDRESSES: Submit comments to the

Federal Aviation Administration (FAA),

New England Region, Office of the

Regional Counsel, Attention: Rules

Docket No. 99–NE–48–AD, 12 New

England Executive Park, Burlington, MA

01803–5299. Comments may also be

sent via the Internet using the following

address: ‘‘9-ane-adcomment@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

General Electric Aircraft Engines, 1000

Western Ave, Lynn, MA 01910;

telephone (781) 594–3140, fax (781)

594–4805. 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:

Barbara Caufield, Aerospace Engineer,

Engine Certification Office, FAA, Engine

and Propeller Directorate, 12 New

England Executive Park, Burlington, MA

01803–5299; telephone (781) 238–7173,

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 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 99–NE–48–AD.’’ 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

Regional Counsel, Attention: Rules

Docket No. 99–NE–48–AD, 12 New

England Executive Park, Burlington, MA

01803–5299.

Discussion

The Federal Aviation Administration

(FAA) has received reports of

improperly hardened propeller gearbox

(PGB) input pinions installed on

General Electric Aircraft Engines

(GEAE) CT7 series turboprop engines.

The investigation revealed that the

manufacturing process for PGB input

pinions changed in September 1996.

Two PGB input pinions have been

found with nonconforming material

hardness and case depth, which led to

premature pinion wear. Premature

pinion wear may be detected by daily

IBB inspections and follow-on

inspections if the IBB is popped. The

requirement to inspect the IBB for

extension daily ensures early detection

of premature pinion wear. This

condition, if not corrected, could result

in PGB input pinion failure, which

could result in PGB failure and an inflight engine shutdown.

Service Bulletins (SB’s)

The FAA has reviewed and approved

the technical contents of GEAE (CT7–TP

Series) SB 72–422, Revision 2, dated

November 3, 1999, that describes

procedures for inspections of the PGB

oil filter impending bypass button (IBB)

for extension (popping), and if the PGB

oil filter IBB is popped, follow-on

inspections, maintenance, and

replacement actions. This SB also

describes rejection criteria for replacing

the PGB, if necessary. Finally, this SB

identifies PGB’s by serial number (SN)

that require inspection.

The FAA has also has reviewed and

approved the technical contents of

GEAE (CT7–TP Series) SB 72–423,

dated June 1, 1999, that describes

procedures for replacing possibly

improperly hardened PGB input pinions

with PGB input pinions manufactured

using the proper hardening process. In

addition, this SB identifies the PGB

input pinions by SN and the SN of the

Federal Register / Vol. 65, No. 87 / Thursday, May 4, 2000 / Proposed Rules 25893

last known PGB in which those input

pinions were installed.

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 an initial inspection of the PGB

oil filter IBB for popping within 50

hours time-in-service (TIS) after the

effective date of this AD. If the PGB oil

filter IBB is popped, this proposed AD

would require follow-on inspections,

maintenance, and replacement actions,

and if necessary, replacement of the

PGB with a serviceable PGB. Following

the initial inspection of the PGB oil

filter IBB, the inspections would take

place each operational day.

Terminating Action

In addition, this AD would require, at

the next return of the PGB to a CT7

turboprop overhaul facility after the

effective date of this AD, replacing

possibly improperly hardened PGB

input pinions with PGB input pinions

manufactured the proper hardening

process. Installation of a PGB input

pinion manufactured using the proper

hardening process constitutes

terminating action to the repetitive

inspections. The actions would be

required to be accomplished in

accordance with the SB’s described

previously.

Economic Analysis

There are approximately 170 engines

of the affected design installed on

aircraft of US registry that would be

affected by this proposed AD. The FAA

estimates that each IBB inspection

would take approximately 0.25 work

hours per engine, and the average labor

rate is $60 per work hour. Follow-on

borescope inspections would take

approximately 4 work hours per engine;

unscheduled PGB removal and

replacement would take 60 work hours

per engine. Therefore, the total cost

impact on US operators would be

approximately $663,000.

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 Aircraft Engines: Docket

No. 99–NE–48–AD.

Applicability: General Electric Aircraft

Engines (GEAE) CT7 series turboprop

engines, with propeller gearboxes (PGB’s)

and PGB input pinions identified by serial

number (SN) in Table 1 of GEAE (CT7–TP

Series) Service Bulletin (SB) 72–422,

Revision 2, dated November 3, 1999, and in

Table 1 of GEAE (CT7–TP Series) SB 72–423,

dated June 1, 1999. These engines are

installed on but not limited to SAAB 340

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 (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 PGB input pinion failure,

which could result in PGB failure and an inflight engine shutdown, accomplish the

following:

Inspections

(a) Inspect the PGB oil filter impending

bypass button (IBB) for extension (popping)

in accordance with the following schedule:

(1) Initially inspect within 50 hours timein-service (TIS) after the effective date of this

AD.

(2) Thereafter, inspect each operational

day.

(b) If the PGB oil filter IBB is popped,

replace the oil filter and perform follow-on

inspections immediately. Perform PGB

maintenance, or replace the PGB with a

serviceable PGB, if necessary; in accordance

with the Accomplishment Instructions of

GEAE (CT7–TP Series) SB 72–422, Revision

2, dated November 3, 1999. Then comply

with (a) or (c).

(c) At the next return of the PGB to a CT7

turboprop overhaul facility after the effective

date of this AD, but no later than one year

after the effective date of this AD, remove

from service improperly hardened PGB input

pinions and replace with airworthy PGB

input pinions manufactured using the proper

hardening process, in accordance with the

Accomplishment Instructions of GEAE (CT7–

TP Series) SB 72–423, dated June 1, 1999.

Terminating Action

(d) Installation of a PGB input pinion in

accordance with paragraph (c) of this AD

constitutes terminating action to the

repetitive inspections required by paragraph

(a) of this AD.

Alternative Methods of Compliance

(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 (ECO). Operators shall

submit their request through an appropriate

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.

Ferry Flights

(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.

Issued in Burlington, Massachusetts, on

April 27, 2000.

David A. Downey,

Assistant Manager, Engine and Propeller

Directorate, Aircraft Certification Service.

[FR Doc. 00–11178 Filed 5–3–00; 8:45 am]

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