[Federal Register Volume 62, Number 110 (Monday, June 9, 1997)]
[Proposed Rules]
[Pages 31370-31371]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-14957]


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

  Federal Register / Vol. 62, No. 110 / Monday, June 9, 1997 / Proposed 
Rules  

[[Page 31370]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-18-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CT58 Series 
Turboshaft 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 General Electric Company CT58 
series turboshaft engines. This proposal would require removal from 
service of certain stage 1 and 2 forward cooling plates, and stage 2 
aft cooling plates, and replacement with serviceable parts. This 
proposal is prompted by reports of certain cooling plates forged with 
contaminated alloy that could reduce the lives of the parts. The 
actions specified by the proposed AD are intended to prevent cooling 
plate fracture, which could result in a contained engine failure, and 
an inflight engine shutdown.

DATES: Comments must be received by August 8, 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. 97-ANE-18-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ad-
[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 Company (GE), 1000 Western Ave., Lynn, 
MA 01909; telephone (671) 594-9894, fax (617) 594-1527. 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 97-ANE-18-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 Assistant Chief Counsel, 
Attention: Rules Docket No. 97-ANE-18-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received reports of 
certain stage 1 and stage 2 forward cooling plates and stage 2 aft 
cooling plates, installed on General Electric Company (GE) Models CT58-
110-1, -110-2, -140-1, -140-2, and T58-GE-3/-5/-8F/-10/-100 turboshaft 
engines, forged with contaminated alloy that could reduce the lives of 
the parts. Iron-rich inclusions were found in forgings produced by a 
vendor using A286 material. These inclusions were first found on parts 
from two heat lots during the normal Vacuum Induction Melt (VIM) in-
process macroetch inspections. The parts from these two heat lots were 
then scrapped. Corrective actions to the VIM process were implemented 
to prevent the reoccurrence of iron-rich inclusions. Records of all 
heat lots produced from this vendor prior to the implementation of the 
corrective actions, totaling 56 heat lots, were reviewed. Twenty five 
out of the 56 heat lots were determined to be potentially contaminated. 
Approximately 300 GE CT58 cooling plates were produced from one 
potentially contaminated heat lot. A retired cooling plate from this 
suspected heat lot was macroetch inspected and was found with an 
inclusion. This condition, if not corrected, could result in cooling 
plate fracture, which could result in a contained engine failure, and 
an inflight engine shutdown.
    The FAA has reviewed and approved the technical contents of GE 
Aircraft Engines CT58 Service Bulletin (SB) No. 72-188 (CEB-293), dated 
March 25, 1997, that describes procedures for removal from service of 
certain stage 1 and 2 forward cooling plates, and stage 2 aft cooling 
plates, and replacement with serviceable parts.
    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 removal from service of certain stage 1 and 2 
forward cooling plates, and stage 2 aft cooling plates, and replacement 
with serviceable parts. The actions would be required to be 
accomplished in accordance with the SB described previously.

[[Page 31371]]

    There are approximately 400 engines of the affected design in the 
worldwide fleet. The FAA estimates that 126 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, and 
that it would not take any additional work hours per engine to 
accomplish the proposed actions at next part exposure. Required parts 
would cost approximately $2,730 per engine, based on the estimated 
current part cost. Based on these figures, the total cost impact of the 
proposed AD on U.S. operators is estimated to be $343,980. The 
manufacturer, however, has advised the FAA of a program to prorate the 
cost of required parts downward by a factor equal to the quotient of 
the difference between the original life limit of 4,000 hours time in 
service and the total cycles of life consumed at time of removal, 
divided by the original life limit. Therefore, the actual cost to 
operators may be less than the FAA's estimate.
    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 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 Company: Docket No. 97-ANE-18-AD.

    Applicability: General Electric Company (GE) Models CT58-110-1, 
-110-2, -140-1, and -140-2 , and T58-GE-3/-5/-8F/-10/-100 series 
turboshaft engines, with stage 1 forward cooling plate, Part Number 
(P/N) 37C300055P101, stage 2 forward cooling plate, P/N 3000T88P02, 
and stage 2 aft cooling plate, P/N 3002T27P01, installed. These 
engines are installed on but not limited to Boeing Vertol 107 
series, and Sikorsky S61 and S62 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 cooling plate fracture, which could result in a 
contained engine failure and an inflight engine shutdown, accomplish 
the following:
    (a) Remove from service affected cooling plates, listed by 
serial number in GE Aircraft Engines CT58 Service Bulletin (SB) No. 
72-188 (CEB-293), dated March 25, 1997, and replace with serviceable 
parts, at the next part exposure, or next light overhaul, whichever 
occurs first, but not to exceed 1,000 hours time in service (TIS) 
for engines installed on aircraft that have engaged in Repetitive 
Heavy Lift (RHL) operations, or 2,000 hours TIS for engines 
installed on aircraft that have never engaged in RHL operations, in 
accordance with that SB.
    (b) For the purpose of this AD, the following definitions apply:
    (1) RHL operation is defined as performing more than 10 lift-
carry-drop cycles per hour TIS without landing, or more than 10 
takeoffs and landings per hour TIS.
    (2) Light overhaul is defined as scheduled engine maintenance 
that allows the engine to continue in service until scheduled major 
overhaul time is reached.
    (c) 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 shall 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.

    (d) 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 May 27, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 97-14957 Filed 6-6-97; 8:45 am]
BILLING CODE 4910-13-U