[Federal Register Volume 64, Number 223 (Friday, November 19, 1999)]
[Rules and Regulations]
[Pages 63171-63174]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-29740]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-19-AD; Amendment 39-11422; AD 99-23-26]
RIN 2120-AA64


Airworthiness Directives; General Electric Aircraft Engines CF34 
Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to General Electric Aircraft Engines (GE) CF34 series 
turbofan engines, that currently requires installation of a main fuel 
control (MFC) that incorporates a flange vent groove and installation 
of an MFC with improved overspeed protection. This amendment requires 
replacement of Buna-N O-rings with Viton O-rings or a new location of 
the vent groove on the MFC mounting flange, or installation of an MFC 
with improved overspeed protection. This amendment is prompted by the 
determination that the location of the reworked vent groove was 
ineffective, and that replacement of Buna-N preformed packings with 
Viton preformed packings will alleviate the unsafe condition. The 
actions specified by this AD are intended to prevent uncommanded engine 
accelerations, which could result in an engine overspeed, uncontained 
engine failure, and damage to the airplane.

DATES: Effective December 6, 1999.
    The incorporation by reference of GE Alert Service Bulletins 
(ASB's) No. A73-33, dated November 21, 1997; A73-33, Revision 1, dated 
May 29.1998; and A73-19, Revision 1, dated February 20, 1998, was 
approved by the Director of the Federal Register as of July 27, 1999.
    The incorporation by reference of GE ASB No. CF34AL 73-A0025, dated 
July 7, 1999; CF34BJ 73-A0040, dated July 7, 1999; CF34AL S/B 73-0026, 
dated August 12, 1999; and CF34BJ S/B 73-0041, dated August 12,1999, is 
approved by the Director of the Federal Register as of December 6, 
1999.

[[Page 63172]]

    Comments for inclusion in the Rules Docket must be received on or 
before January 18, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 98-ANE-19-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ane-
[email protected].'' Comments sent via the Internet must contain the 
docket number in the subject line.
    The service information referenced in this AD 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, Burlington, MA; or at the Office of the 
Federal Register, 800 North Capitol Street, NW, suite 700, Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Norman Brown, Controls Specialist, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7181, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: On May 17, 1999, the Federal Aviation 
Administration (FAA) issued airworthiness directive (AD) 99-11-08, 
Amendment 39-11179 (64 FR 28905, May 28, 1999), to require, within 800 
hours time in service (TIS) or 120 days after the effective date of 
that AD, whichever occurs first, installation of an MFC incorporating a 
flange vent groove. In addition, that AD requires installation of an 
MFC with improved overspeed protection for: CF34-3A1 and -3B1 series 
engines, installed on Canadair Regional Jet airplanes, within 4,000 
hours TIS after the effective date of that AD, or 24 months after the 
effective date of that AD, whichever occurs first; and for CF34-1A, -
3A, -3A1, -3A2, and -3B series engines, installed on Canadair 
Challenger airplanes, at the next hot section inspection, or within 60 
months after the effective date of that AD, whichever occurs first. 
That action was prompted by reports of rapid uncommanded engine 
acceleration events. That condition, if not corrected, could result in 
uncommanded engine accelerations, which could result in an engine 
overspeed, uncontained engine failure, and damage to the airplane.

Events Leading to this AD

    Since the issuance of that AD, the engine manufacturer has informed 
the FAA that GE CF34 Alert Service Bulletin (ASB) No. A73-18, Revision 
1, dated September 24, 1997, and CF34 ASB No. A73-32, Revision 1, dated 
September 24, 1997, that describe procedures for reworking MFC's by 
adding a flange vent groove were in error and had incorrectly located 
the flange vent groove. Also, the manufacturer has determined that 
replacement of the Buna-N preformed packings (O-rings) with Viton O-
rings will achieve a similar level of safety as the installation of an 
MFC with a correctly located flange vent groove.

Manufacturer Service Information

    The FAA has reviewed and approved the technical contents of GE CF34 
Alert Service Bulletins (ASB's) No. CF34AL 73-A0025, dated July 7, 
1999, and CF34BJ 73-A0040, dated July 7, 1999, that describe procedures 
for replacement of the Buna-N preformed packings; CF34AL S/B 73-0026, 
dated August 12, 1999, and CF34BJ S/B 73-0041, dated August 12,1999, 
that describe procedures for installation of a reworked MFC with a 
relocated pressure relief groove; and CF34 ASB No. A73-19, Revision 1, 
dated February 20, 1998, and CF34 ASB No. A73-33, dated November 21, 
1997, that describe procedures for installation of a reworked MFC with 
improved overspeed protection.

Differences Between the ASB's and this AD

    The GE ASB's allow the MFC on CF34-1A, -3A1, and -3A2 engines to be 
used until the MFC is removed for cause and then replaced with an MFC 
with a relocated vent groove. Because of the possibility that an unsafe 
condition may develop, this AD requires that the MFC be replaced with 
an MFC with a relocated vent groove when the MFC is removed for any 
reason.

Requirements of this AD

    Since an unsafe condition has been identified that is likely to 
exist or develop on other General Electric (GE) CF34 turbofan engines 
of the same type design, this AD supersedes AD 99-11-08 to require 
either replacement of Buna-N O-rings with Viton O-rings or replacement 
of the MFC with an MFC with a relocated vent groove within 30 days 
after the effective date of this AD. The actions are required to be 
accomplished in accordance with the service bulletin described 
previously.

Immediate Action

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Request for Comments

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD 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 98-ANE-19-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation

[[Page 63173]]

that must be issued immediately to correct an unsafe condition in 
aircraft, and is not a ``significant regulatory action'' under 
Executive Order 12866. It has been determined further that this action 
involves an emergency regulation under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979). If it is determined that 
this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, may 
be obtained from the Rules Docket at the location provided under the 
caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety,
    Incorporation by reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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 removing Amendment 39-11179, (64 FR 
28905, May 28, 1999), and by adding a new airworthiness directive, 
Amendment 39-11422, to read as follows:

AD 99-23-26: Amendment 39-11422: Docket 98-ANE-19-AD. Supersedes AD 
99-11-08, Amendment 39-11179.

    Applicability: General Electric (GE) CF34-1A, CF34-3A, -3A1, -
3A2, and CF34-3B and -3B1 series turbofan engines, installed on but 
not limited to Bombardier, Inc. Canadair airplane models CL-600-
2A12, -2B16, and -2B19.

    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 (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: Required as indicated, unless accomplished 
previously.
    To prevent uncommanded engine accelerations, which could result 
in an engine overspeed, uncontained engine failure, and damage to 
the airplane, accomplish the following:

Replacement Requirements

    (a) If the main fuel control (MFC) part numbers (P/N's) 
6078T55P02, 6078T55P03, 6078T55P04, 6078T55P05, 6078T55P06, 
6078T55P07, 6078T55P08, 6078T55P09, 6078T55P10, 6078T55P12, 
6078T55P13, 6078T55P14, 6078T55P15, or 6078T55P16 installed, and if 
the MFC has Buna-N preformed packings (O-rings), P/N's R1307P020 and 
R1307P141, do one of the following:
    (1) Replace Buna-N O-rings with Viton O-rings, P/N's M83485-1-
020 (M83485/1-020) and 37B201714P130, within 30 days after the 
effective date of this AD, in accordance with the Accomplishment 
Instructions, paragraph 3.A., of alert service bulletin (ASB) CF34AL 
73-A0025, dated July 7, 1999 or ASB CF34BJ 73-A0040, dated July 7, 
1999. Or,
    (2) For all CF34-3A1 engines with serial numbers (SN's) 807001 
and up, CF34-3B engines with SN's 872001 and up, and CF34-3B1 
engines with SN's 872001 and up, with main fuel control (MFC) part 
numbers (P/N's) 6078T55P02, 6078T55P03, 6078T55P04, 6078T55P05, 
6078T55P06, 6078T55P07, 6078T55P08, 6078T55P09, 6078T55P10, 
6078T55P12, 6078T55P13, 6078T55P14, 6078T55P15, or 6078T55P16 
installed, within 30 days after the effective date of this AD, 
install an MFC with a flange vent groove that conforms to the 
requirements of CF34 ASB CF34AL S/B 73-0026, dated August 12,1999, 
or CF34BJ S/B 73-0041, dated August 12, 1999.

Replacement of the MFC

    (b) For all CF34-1A, -3A, and -3A2 series engines with SN's 
350003 through 350525, install an MFC with a flange groove that 
conforms to the requirements of CF34 ASB CF34AL S/B 73-0026, dated 
August 12, 1999, the next time the engine is removed or the next 
time the MFC is removed.
    (c) Install a serviceable MFC with improved overspeed protection 
as follows:
    (1) For all CF34-1A, -3A, and -3A2 series engines, install a 
serviceable MFC at the next hot section inspection, or within 53 
months after the effective date of this AD, whichever occurs first, 
in accordance with step 2A through step 2G of the Accomplishment 
Instructions of CF34 ASB No. A73-33, dated November 21, 1997, or 
Revision 1, dated May 29, 1998.
    (2) For CF34-3A1, and -3B series engines installed on Canadair 
aircraft models CL601 or CL604 (Challenger airplanes), install a 
serviceable MFC at the next hot section inspection, or within 53 
months after the effective date of this AD, whichever occurs first, 
in accordance with step 2A through step 2G of the Accomplishment 
Instructions of CF34 ASB No. A73-33, dated November 21, 1997, or 
Revision 1, dated May 29, 1998.
    (3) For CF34-3A1 and -3B1 series engines installed on Canadair 
aircraft model CL601RJ (Regional Jet airplanes), install a 
serviceable MFC within 4,000 hours TIS after the effective date of 
this AD, or within 17 months after the effective date of this AD, 
whichever occurs first, in accordance with step 2A through step 2G 
of the Accomplishment Instructions of CF34 ASB No. A73-19, Revision 
1, dated February 20, 1998.

Terminating Action

    (d) Replacing an MFC with a serviceable MFC, as defined in 
paragraph (e) of this AD, constitutes terminating action for the 
requirements of this AD.

Definition of a Serviceable MFC

    (e) For the purposes of this AD, a serviceable MFC is defined as 
any MFC that incorporates the improved overspeed protection 
modifications, or an MFC that has been reworked to provide the 
improved overspeed protection as provided by the applicable GE ASB 
and is not one of the following P/N's 6078T55P02, 6078T55P03, 
6078T55P04, 6078T55P05, 6078T55P06, 6078T55P07, 6078T55P08, 
6078T55P09, 6078T55P10, 6078T55P12, 6078T55P13, 6078T55P14, 
6078T55P15, 6078T55P16, 6047T74P11, 6047T74P12, or 6091T07P02.

Alternative Method 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 requests 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.

Special Flight Permits

    (g) 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.

Manufacturer Service Bulletins

    (h) The inspection shall be done in accordance with the 
following GE service bulletins:

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           Document no.                    Pages               Revision                      Date
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CF34AL 73-A0025..................  All.................  Original...........  July 7, 1999.
CF34AL 73-0026...................  All.................  Original...........  August 12,1999.
CF34BJ 73-0040...................  All.................  Original...........  July 7,1999.

[[Page 63174]]

 
CF34BJ 73-0041...................  All.................  Original...........  August 12,1999.
A73-19...........................  All.................  1..................  February 20, 1998.
A73-33...........................  All.................  Original...........  November 21, 1997.
A73-33...........................  All.................  1..................  May 29, 1998.
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    Total pages: 27.
    (i) The incorporation by reference of GE ASB A73-19, dated February 
20, 1998; ASB A73-33, dated November 21, 1997; and ASB A73-33, revision 
1, dated May 29, 1998, was approved by the Director of the Federal 
Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of 
July 27, 1999.

Address for Obtaining Referenced Service Bulletins

    (j) Copies 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. Copies may be inspected 
at the FAA, New England Region, Office of the Regional Counsel, 12 New 
England Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

Effective Date of This AD

    (k) This amendment becomes effective on December 6, 1999.

    Issued in Burlington, Massachusetts, on November 5, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-29740 Filed 11-18-99; 8:45 am]
BILLING CODE 4910-13-P