[Federal Register Volume 65, Number 87 (Thursday, May 4, 2000)]
[Proposed Rules]
[Pages 25892-25893]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-11178]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 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.
 
 ========================================================================
 

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

[[Page 25892]]



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).

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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: ``[email protected]''. 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 in-flight 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

[[Page 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.


Sec. 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 in-flight 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 time-in-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]
BILLING CODE 4910-13-P