[Federal Register Volume 66, Number 116 (Friday, June 15, 2001)]
[Rules and Regulations]
[Pages 32533-32535]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-14824]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-22-AD; Amendment 39-12261; AD 2001-12-06]
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: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), that 
is applicable to GE CF34-1A, -3A, -3A1, -3A2, -3B, and -3B1 turbofan 
engines with No. 5 bearing rotating air seal part number (P/N) 
4019T60G01 installed. This amendment requires 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 
amendment 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 actions specified by this AD are intended to 
prevent No.5 bearing rotating air seal failures and possible 
uncontained engine failures.

DATES: Effective date July 20, 2001.

ADDRESSES: Information regarding this action may be examined at the 
Federal Aviation Administration (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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an AD that is 
applicable to GE CF34-1A, -3A, -3A1, -3A2, -3B, and -3B1 engines was 
published in the Federal Register on February 27, 2001 (66 FR 12443). 
That action proposed to 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, and installation of a new modified 
design No. 5 bearing rotating air seal, P/N 4019T60G03, as terminating 
action for the repetitive inspection requirements of this AD.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Requests To Eliminate Repetitive Inspection Requirements

    Three commenters request that the repetitive inspection 
requirements be eliminated from the AD. The commenters state that they 
are already performing the inspections based upon recommendations from 
the manufacturer. The FAA does not agree. Although these individual 
commenters may already be complying with the proposed requirements, the 
FAA has determined that an unsafe condition exists that warrants 
requiring all operators to conduct mandatory repetitive inspections, 
until the terminating actions are accomplished. Therefore, the FAA must 
issue an AD to require repetitive inspections, regardless of the 
manufacturer's recommendations.

Requests To Change Compliance Time for Initial Inspections

    Two commenters request that the time to comply with the initial 
inspection requirements be increased from 30 hours after the effective 
date of the proposed AD to 100 hours after the effective date, for 
CF34-1A, -3A, and -3A2 engines. The commenters feel that a 100-hour 
initial inspection provides an acceptable level of safety based on risk 
analysis conducted by the type certificate holder, and will reduce the 
economic burden on operators. The FAA agrees. Further review of risk 
analysis data supports that an acceptable level of safety would result 
with a 100-hour initial inspection threshold rather than a 30-hour 
initial inspection threshold. Therefore, the FAA has changed the 
initial inspection compliance time for CF34-1A, -3A, and -3A2 engines 
to ``100 flight hours from the effective date of this AD.''

Requests To Change Compliance Time for CF34-3B Repetitive 
Inspections

    One commenter requests that the time to comply with the repetitive 
inspection requirements be increased from an interval of 30 hours to an 
interval of 100 hours for CF34-3B engines. The commenter states that 
the extended time will reduce the economic impact on the commenter due 
to additional maintenance requirements, and make the CF34-3B inspection 
requirements the same as the CF34-3A inspection requirements. The FAA 
does not agree. Risk analysis data used by the FAA to establish the AD 
requirements shows that an unacceptable level of safety would result 
from increasing the inspection interval from 30 flight hours to 100 
flight hours for the CF34-3B engine fleet.

Requests To Clarify Who May Perform Maintenance Actions

    One commenter requests that the wording of the AD be revised to 
reflect that the pilot may do the check, but a maintenance technician 
must do any required maintenance actions. Additionally, the same 
commenter and another commenter, request that the AD be revised to 
clarify that on CF34-1A, -3A, and -3A2 turbofan engines, chip detector 
checks are maintenance actions and are not to be performed by flight 
crew. CF34-1A, -3A, and -3A2 turbofan engine models have individual 
chip detectors. Those chip detectors are checked with an ohmmeter, 
unlike the CF34-3A1, -3B, and -3B1 engine models, which have a single 
master chip detector with a white triangle or illuminated indicator. 
The FAA agrees. The intent of the AD is to allow chip detector 
indicator checks to be done by the pilot for engine models with the 
master chip detector installation. Although the proposed AD would not 
have authorized the pilot to do any task beyond a visual check of the 
indicator, the FAA agrees that additional clarity is needed. Therefore, 
the FAA has revised

[[Page 32534]]

paragraph (b) to clarify the requirements.

Requests To Allow Pilot to ``Sign-off'' 30 Flight Hour Magnetic 
Chip Detector Check

    Two commenters request that the pilot be allowed to sign-off the 
30-flight hour magnetic chip detector check. The commenters feel that 
the check is a very simple task on the CF34-3A1, -3B, and -3B1 engine 
installations. The chip detector panel location is accessed by aircrews 
on a daily basis in the normal course of their duties of determining 
and monitoring engine oil levels. The chip detector check that is 
required by paragraph (b) of the proposed AD is a simple go/no-go check 
and could be performed by an aircrew. The FAA agrees, but no revisions 
to the AD are needed as this is explicitly provided for in paragraph 
(b) of the proposed AD.

Requests To Increase the Compliance Time for Mandatory Terminating 
Action

    One commenter requests that the compliance time for the mandatory 
terminating action for the CF34-3A1, -3B, and -3B1 be increased from 
15,000 cycles-in-service (CIS) after the effective date of the proposed 
AD, to 18,000 CIS after the effective date of the proposed AD. The 
commenter requests the change in anticipation of future rotating part 
life limit increases, and to coincide with scheduled shop visits in the 
future if life limits are increased. The FAA does not agree. The level 
of safety provided by the requirements of the proposed AD were 
established based upon compliance within 15,000 CIS after the effective 
date to the AD, and no additional data was provided by the commenter to 
show that an acceptable level of safety would be provided if the 
terminating action deadline were extended. In addition, further review 
with the type certificate holder indicated that future life limit 
increases are not anticipated for all affected engine models.

Request for Clarification of the Mandatory Terminating Action 
Compliance Time

    The same commenter requests that the compliance time for the 
mandatory terminating action be revised to indicate terminating actions 
are not required upon reaching 15,000 cycles-since-new (CSN), but 
instead that terminating actions are required after accumulating 15,000 
additional CIS after the effective date of this AD. The commenter 
states that one operator has misinterpreted the existing wording as a 
hard limit of 15,000 CSN. The FAA agrees. The intent of the proposed AD 
was to require terminating action within 15,000 CIS accumulated after 
the effective date of the AD, and was not intended to impose a 15,000 
CSN limit. The FAA has changed the wording in Table 2 accordingly.

Request To Incorporate Chip Detector Check as Part of the Flight 
Checklist

    One commenter requests that the chip detector check be done as part 
of the aircrew normal acceptance of terminating flight checklist. The 
commenter feels that precedence for aircrews performing simple go/no-go 
checks as part of an approved checklist can be found in AD 92-16-51 for 
the EMB120. The FAA partially agrees. The FAA agrees that the engine 
chip detector check can be performed by the aircrew, which is provided 
for in paragraph (b) of the AD. However, as further stated in paragraph 
(b), 91.417(a)(2)(v) of the Federal Aviation Regulations [14 CFR 
91.417(a)(2)(v)] requires that for AD actions involving recurring 
inspections, records must be maintained, including the time and date 
when the next action is required. Accordingly, although the chip 
detector checks may be included in the aircrew daily checklist, this 
would not obviate the need for the operator to record each AD 
accomplishment, and no changes to the proposed rule are required.

Request for a New Paragraph To Require a Maintenance Operational 
Check of the Engine Master Chip Detector

    One commenter requests that a new paragraph be added to the 
proposed AD to require a maintenance operational check (BITE) of the 
engine master chip detector. The check would be required to be done at 
the air carriers' first scheduled maintenance opportunity, but not to 
exceed seven calendar days. The commenter feels that this check would 
provide an equivalent of better level of safety than that proposed in 
the AD. The FAA does not agree. The FAA has no data that mandating 
operational checks of the engine master chip detector system would 
improve the level of safety provided by the proposed rule as currently 
written.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Economic Impact

    There are about 1,650 engines of the affected design in the 
worldwide fleet. The FAA estimates that 1,075 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 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:

[[Page 32535]]

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 a new airworthiness directive 
to read as follows:

2001-12-06  General Electric Company: Amendment 39-12261. 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 already 
done.
    To prevent No.5 bearing rotating air seal failures and possible 
uncontained engine failures, do the following:

Magnetic Chip Detector Indicator Check

    (a) Check magnetic chip detector indicators in accordance with 
the following Table 1:

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

    (b) For CF34-3A1, -3B, and -3B1 turbofan engine models, 
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. The operator of the airplane must record completion of 
the checks in the airplane records to show compliance with this AD, 
in accordance with sections 43.9 and 91.417(a)(2)(v) of the Federal 
Aviation Regulations 14 CFR part 43.9 and 14 CFR part 
91.417(a)(2)(v). The records must be maintained as required by the 
applicable Federal Aviation Regulation.

Detection of Chips

    (c) If a chip detection is indicated, 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 the 
following Table 2:

                             Table 2.--Compliance Times for Replacement of Air Seal
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                               Engine model                                              Replace at
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(1) CF34-3A1, -3B1, and -3B..............................................  Next shop visit when HPT is exposed,
                                                                            but do not exceed 15,000 cycles-in-
                                                                            service from 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
                                                                            from the effective date of this AD.
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Mandatory 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.

Special Flight Permits

    (g) Special flight permits may be issued in accordance 
Secs. 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.

Effective Date of This AD

    (h) This amendment becomes effective on July 20, 2001.

    Issued in Burlington, Massachusetts, on June 5, 2001.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-14824 Filed 6-14-01; 8:45 am]
BILLING CODE 4910-13-P