[Federal Register Volume 65, Number 33 (Thursday, February 17, 2000)]
[Rules and Regulations]
[Pages 8039-8043]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-3336]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-19-AD; Amendment 39-11566; AD 99-23-26 R1]


Airworthiness Directives; General Electric Aircraft Engines CF34 
Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment revises an existing airworthiness directive 
(AD), that is applicable to General Electric Aircraft Engines (GE) CF34 
series turbofan engines. That AD currently requires:
    (1) Replacement of Buna-N O-rings with Viton O-rings; or
    (2) A new location of the vent groove on the MFC mounting flange; 
or
    (3) Installation of an MFC with improved overspeed protection.

This amendment requires the installation of an MFC with improved 
overspeed protection. If this action can not be completed within 30 
days of the effective date of this AD, then either:
    (1) Replace Buna-N O-rings with Viton O-rings, followed by 
replacement with an MFC with improved overspeed protection within a 
specified time; or

[[Page 8040]]

    (2) Replace with an MFC with a relocated vent groove on the MFC 
mounting flange and improved overspeed protection.

This amendment is prompted by nonsubstantive revisions to the 
manufacturer's service bulletins and comments from the manufacturer 
regarding various typographical errors in the AD. 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 February 17, 2000.
    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's No. CF34AL 73-A0025, 
dated July 7, 1999; CF34BJ 73-A0040, dated July 7, 1999; GE service 
bulletin (SB) CF34AL S/B 73-0026, dated August 12, 1999; and GE SB 
CF34BJ S/B 73-0041, dated August 12, 1999, was approved by the Director 
of the Federal Register as of December 6, 1999.
    The incorporation by reference of GE ASB No. A73-19, Revision 2, 
dated March 9, 1999; CF34-AL 73 A0019, Revision 3, dated September 9, 
1999; A73-33, Revision 2, dated March 9, 1999; CF34-BJ 73-A0033, 
Revision 3, dated September 9, 1999; CF34-BJ 73-A0033, Revision 4, 
dated November 1, 1999; and CF34-BJ 73-0041, Revision 1, dated November 
1, 1999 is approved by the Director of the Federal Register as of March 
20, 2000.

ADDRESSES: The service information referenced in this AD may be 
obtained from GEAE Technical Publications, Attention: H. Decker 
MZ340M2, 1000 Western Avenue, Lynn, MA 01910; telephone (781) 594-6323, 
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:

Events Leading to Original AD; AD No. 99-11-08

    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 required 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 
occurred 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 occurred first. That action was prompted by reports 
of rapid uncommanded engine acceleration events. That condition, if not 
corrected, could have resulted in uncommanded engine accelerations, 
which could have resulted in an engine overspeed, uncontained engine 
failure, and damage to the airplane.

Events Leading to Current AD; AD No. 99-23-26

    After the FAA issued AD 99-11-08, the engine manufacturer 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 would achieve a similar level of safety as the installation of an 
MFC with a correctly located flange vent groove. On the basis of that 
information, the FAA issued AD 99-23-26 on November 5, 1999 (64 FR 
63171, November 19, 1999) to supersede AD 99-11-08.

Events Leading to This AD Revision

    AD 99-23-26 was issued as a Final Rule; request for comments, and 
interested persons were given an opportunity to comment. Due 
consideration has been given to the comments received.

Request To Remove Certain MFC P/N's From Paragraphs (a) and (a)(2)

    One commenter, the manufacturer, states that paragraphs (a) and 
(a)(2) incorrectly require that MFC part numbers (P/N's) 6078T55P12, 
6078T55P13, 6078T55P14, 6078T55P15, and 6078T55P16 be replaced with 
MFC's with the relocated vent groove. The manufacturer points out that 
those MFC's incorporate overspeed protection and are not subject to the 
requirements of this AD. The Federal Aviation Administration (FAA) 
agrees. Paragraphs (a) and (a)(2) have been changed to delete MFC P/N's 
6078T55P12, 6078T55P13, 6078T55P14, 6078T55P15, and 6078T55P16 from 
this AD.

Request To Remove Certain MFC P/N's Paragraph (e)

    The same commenter asks that MFC P/N's 6078T55P12, 6078T55P13, 
6078T55P14, 6078T55P15, and 6078T55P16 be deleted from paragraph (e) 
where they are listed as MFC P/N's that are not serviceable. The 
commenter also asks that MFC P/N's 6047T74P07, 6047T74P09, and 
6091T07P01 be added to the listing of MFC P/N's that are not 
serviceable. The commenter points out that those MFC P/N's 6078T55P12, 
6078T55P13, 6078T55P14, 6078T55P15, and 6078T55P16 incorporate 
overspeed protection and are serviceable parts. The Federal Aviation 
Administration (FAA) agrees. Paragraph (e) has been changed to delete 
MFC P/N's 6078T55P12, 6078T55P13, 6078T55P14, 6078T55P15, and 
6078T55P16 from this AD. MFC P/N's 6047T74P07, 6047T74P09, and 
6091T07P01 have been added to the listing of unserviceable MFC P/N's.

Request for a Correction to an SB Reference

    The same commenter states that the reference to SB CF34AL S/B 73-
0026, dated August 12, 1999, in paragraph (b) is incorrect and should 
be SB CF34-BJ 73-0041, dated August 12, 1999. The commenter asks that 
Revision 1, dated November 1, 1999, to SB CF34-BJ 73-0041 be listed in 
paragraph (b). Revision 1, dated November 1, 1999, was issued by the 
manufacturer after AD 99-23-26 was issued. The FAA agrees. The 
reference to ``SB CF34AL S/B 73-0026'' in paragraph (b) has been 
changed to ``SB CF34-BJ 73-0041'' and ``or Revision 1, dated November 
1, 1999,'' has been added to paragraph (b).

Request To Add Certain Later SB Revisions to This AD

    The same commenter also asks that references to following SB's be 
added to

[[Page 8041]]

the applicable paragraphs in the compliance section of this AD:
     A73-19, Revision 2, dated March 9, 1999; and
     CF34-AL 73-A0019, Revision 3, dated September 9, 1999; and
     73-33, Revision 2, dated March 9, 1999; and
     CF34-BJ 73-A0033, Revision 3, dated September 9, 1999; and
     CF34-BJ 73-A0033, Revision 4, dated November 1, 1999; and
     CF34-BJ 73-0041, Revision 1, dated November 1, 1999.
    The issuance of the SB revisions was not communicated to the FAA. 
The FAA agrees. References to the above SB's have been added to the 
applicable paragraphs in the compliance section of this AD.

Request To Allow Future Revisions of the SB's To Be Referenced

    The same commenter asks that the AD refer to the ``latest 
revisions'' of the SB's rather than specific revisions to the 
manufacturer's SB's. The FAA does not agree. The Administrative 
Procedures Act requires that all SB's incorporated by reference in AD's 
be approved and a copy retained by the Office of the Federal Register. 
A reference to the ``latest revision''of a SB necessarily implies a 
reference to a document that does not yet exist, and, therefore, to a 
document for which the FAA cannot obtain the approval for incorporation 
by reference. The FAA may approve later revisions to the referenced 
SB's as alternate methods of compliance under the provisions of 
paragraph (f) of the AD.

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, CF34BJ S/B 73-0041, dated August 12,1999, and 
CF34BJ S/B 73-0041, Revision 1, dated November 1, 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, A73-19, Revision 2, dated March 9, 1999; or CF34 ASB No. CF34-AL 
73-A0019, Revision 3, dated September 9, 1999, and CF34 ASB No. A73-33, 
dated November 21, 1997; A73-33, Revision 1, dated May 29, 1998; A73-
33, Revision 2, dated March 9, 1999; or CF34 ASB No. CF34-BJ 73-A0033, 
Revision 3, dated September 9, 1999, or Revision 4, dated November 1, 
1999, that describe procedures for installation of a reworked MFC with 
improved overspeed protection.
    When an MFC is returned to the manufacturer for drilling a 
relocated vent groove, the overspeed protection upgrades will be 
accomplished at the same time.

Differences Between the SB's and This AD

    The GE SB's allow the MFC on CF34-1A, -3A, 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 a 
serviceable MFC 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. Replacement of the Buna-N O-rings 
is not required on CF34-1A, -3A, and -3A2 models. The actions are 
required to be accomplished in accordance with the service bulletin 
described previously.
    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.

Regulatory Impact

    The regulations adopted herein will 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order (EO) 13132.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-11422 (64 FR 
63171, November 19, 1999) and by adding a new airworthiness directive, 
Amendment 39-11566, to read as follows:

99-23-26 R1  General Electric Aircraft Engines (GE): Amendment 39-
11566. Docket 98-ANE-19-AD. Revises AD 99-23-26, Amendment 39-11422.

    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

[[Page 8042]]

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, or 6078T55P10 is 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, or 6078T55P10 
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, or revision 1, dated 
November 1, 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 SB CF34-BJ S/B 73-0041, dated 
August 12, 1999, or Revision 1, dated November 1, 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; or Revision 2, dated March 9, 1999; 
or with step 3A(1) through step 3A(7) of the Accomplishment 
Instructions of CF34 ASB No. CF34-BJ 73-A0033, Revision 3, dated 
September 9, 1999, or Revision 4, dated November 1, 1999.
    (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; or Revision 2, dated March 9, 1999; 
or with step 3A(1) through step 3A(7) of the Accomplishment 
Instructions of CF34 ASB No. CF34-BJ 73-A0033, Revision 3, dated 
September 9, 1999, or Revision 4, dated November 1, 1999.
    (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; or Revision 2, dated March 9, 1999; or 
with step 3A(1) through step 3A(7) of the Accomplishment 
Instructions of CF34 ASB No. CF34-AL 73-A0019, Revision 3, dated 
September 9, 1999.

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, 6047T74P07, 6047T74P09, or 6091T07P01.

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 
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.

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
----------------------------------------------------------------------------------------------------------------
CF34AL 73-A0025..................  All......................  Original................  Jul. 7, 1999.
CF34AL 73-0026...................  All......................  Original................  Aug. 12, 1999.
CF34BJ 73-A0040..................  All......................  Original................  Jul. 7, 1999.
CF34BJ 73-0041...................  All......................  Original................  Aug. 12, 1999.
CF34-BJ 73-0041..................  All......................  1.......................  Nov. 1, 1999.
A73-19...........................  All......................  1.......................  Feb. 20, 1998.
A73-19...........................  1........................  2.......................  Mar. 9, 1999.
                                   3........................  2.......................  Mar. 9, 1999.
CF34-AL 73-A0019.................  All......................  3.......................  Sept. 9, 1999.
A73-33...........................  All......................  Original................  Nov. 21, 1997.
A73-33...........................  All......................  1.......................  May 29, 1998.
A73-33...........................  1........................  2.......................  Mar. 9, 1999.
                                   3........................  2.......................  Mar. 9, 1999.
CF34-BJ 73-A0033.................  All......................  3.......................  Sept. 9, 1999.
CF34-BJ 73-A0033.................  All......................  4.......................  Nov. 1, 1999.
----------------------------------------------------------------------------------------------------------------

    (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. The incorporation by reference of GE 
ASB's No. CF34AL 73-A0025, dated July 7, 1999; CF34BJ 73-A0040, 
dated July 7, 1999; GE service bulletin (SB) CF34AL S/B 73-0026, 
dated August 12, 1999; and GE SB CF34BJ S/B 73-0041, dated August 
12, 1999, 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 December 6, 
1999.

Address for Obtaining Referenced Service Bulletins

    (j) Copies may be obtained from GEAE Technical Publications, 
Attention: H. Decker MZ340M2, 1000 Western Avenue, Lynn, MA 01910; 
telephone (781) 594-6323, fax (781) 594-0600. Copies may be 
inspected at the

[[Page 8043]]

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 the date of publication.

    Issued in Burlington, Massachusetts, on February 8, 2000.
Thomas A. Boudreau,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-3336 Filed 2-16-00; 8:45 am]
BILLING CODE 4910-13-P