[Federal Register Volume 66, Number 39 (Tuesday, February 27, 2001)]
[Proposed Rules]
[Pages 12443-12444]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-4763]



[[Page 12443]]

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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).

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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: ``[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 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 fleet-wide 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

[[Page 12444]]

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
------------------------------------------------------------------------
                                     Initial check
          Engine model                  within        Then within every:
------------------------------------------------------------------------
(1) CF34-3A1, -3B1, and 3B......  30 flight hours or  30 flight hours
                                   3 calendar days,    time-since-last-
                                   whichever is        inspected (TSLI)
                                   greater, from       or 3 calendar
                                   effective date of   days TSLI,
                                   this AD.            whichever is
                                                       greater.
------------------------------------------------------------------------
(2) CF34-1A, -3A, and -3A2......  30 flight hours,    100 flight hours
                                   from the            TSLI.
                                   effective date of
                                   this AD.
------------------------------------------------------------------------

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 cycles-in-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-in-
                                             service 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]
BILLING CODE 4910-13-P