[Federal Register Volume 62, Number 113 (Thursday, June 12, 1997)]
[Rules and Regulations]
[Pages 32023-32025]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-14955]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-ANE-22-AD; Amendment 39-10046; AD 97-12-04]
RIN 2120-AA64
Airworthiness Directives; General Electric Company GE90 Series
Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to General Electric Company (GE) GE90 series turbofan
engines. This action requires initial and repetitive borescope
inspections of compressor discharge pressure (CDP) manifolds for
cracks, and replacement, if necessary, with an improved design CDP
manifold. In addition, this AD requires, as terminating action to the
inspections, replacement with an improved design CDP manifold. This
amendment is prompted by reports of CDP manifold cracking that has
resulted in liberated material causing high pressure compressor (HPC)
blade damage. The actions specified in this AD are intended to prevent
inflight engine power loss or shutdown due to HPC blade damage caused
by liberated material from the CDP manifold.
DATES: Effective June 27, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of June 27, 1997.
Comments for inclusion in the Rules Docket must be received on or
before August 11, 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-22-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be sent
via the Internet using the following address: ``engineprop@faa.dot.gov''. 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
General Electric Technical Services, Attention: Leader for
distribution/microfilm, 10525 Chester Road, Cincinnati, OH 45215;
telephone (513) 672-8400 Ext. 114, fax (513) 672-8422. This information
may be examined at the FAA, New England Region, Office of the Assistant
Chief 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.
FOR FURTHER INFORMATION CONTACT: John E. Golinski, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (617)
238-7135, fax (617) 238-7199.
SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA)
has received reports of cracked compressor discharge pressure (CDP)
manifolds, Part Number (P/N) 1686M48G11, installed on General Electric
Company (GE) GE90 series turbofan engines. In two reports, the cracked
CDP manifold liberated material that resulted in high pressure
compressor (HPC) blade damage beyond serviceable limits. The failure
investigation has determined that the cause of the crack initiation and
propagation is attributed to excessive stresses in the manifold. The
cracks may initiate in a localized area around any one of the six outer
diameter bolts that attach the CDP manifold to the combustor case.
Multiple cracks that initiate can propagate in a direction that allow
CDP manifold material to become liberated. This material can enter the
HPC and result in hard body impact damage to the HPC blades. The FAA
has determined that an earlier configuration CDP manifold, P/N
1686M48G10, is also susceptible to cracking, which could result in
liberated CDP manifold material. This condition, if not corrected,
could result in inflight engine power loss or shutdown due to HPC blade
damage caused by liberated material from the CDP manifold.
The FAA has reviewed and approved the technical contents of GE
Aircraft Engines GE90 Service Bulletin (SB) No. 72-263, dated February
5, 1997, that describes procedures for initial and repetitive borescope
inspections for cracks in the CDP manifold, P/Ns 1686M48G10,
1686M48G11, and 1686M48G12. This AD, however, only requires inspection
of CDP manifolds, P/Ns 1686M48G10 and 1686M48G11. The FAA has also
reviewed and approved the technical contents of GE Aircraft Engines
GE90 SB No. 72-126, Revision 1, dated April 29, 1997, that describes
procedures for installation of improved design CDP manifolds.
Since an unsafe condition has been identified that is likely to
exist or develop on other engines of the same type design, this AD is
being issued to prevent liberation of CDP manifold material. This AD
requires initial and repetitive borescope inspections for cracks in CDP
manifolds, P/Ns 1686M48G10 and 1686M48G11. The repetitive inspection
intervals, or possible removal and replacement prior to further flight,
are defined by the condition of the CDP manifold based on the borescope
inspections. In addition, this AD requires, at the next shop visit
after the effective date of this AD, installing the improved design CDP
manifold, P/N 1686M48G12. Installation of the improved design CDP
manifold constitutes terminating action to the inspection requirements
of this AD. The actions are required to be accomplished in accordance
with the SBs described previously.
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.
Comments Invited
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
[[Page 32024]]
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 97-ANE-22-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 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 adding the following new
airworthiness directive:
97-12-04 General Electric Company: Amendment 39-10046. Docket 97-
ANE-22-AD.
Applicability: General Electric Company (GE) Models GE90-76B, -
77B, -85B, -90B, and -92B turbofan engines, with compressor
discharge pressure (CDP) manifolds, Part Numbers (P/Ns) 1686M48G10
or 1686M48G11, installed. These engines are installed on but not
limited to Boeing 777 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 (e) 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 inflight engine power loss or shutdown due to
liberated CDP manifold material, accomplish the following:
(a) Perform borescope inspections of the CDP manifold for cracks
in accordance with the Accomplishment Instructions of GE90 Service
Bulletin (SB) No. 72-263, dated February 5, 1997, as follows:
(1) For engines with greater than 500 total engine cycles (TEC)
on the effective date of this AD, inspect within 25 cycles in
service (CIS) after the effective date of this AD.
(2) For engines with 500 or less TEC on the effective date of
this AD, inspect within 125 CIS after the effective date of this AD,
or prior to accumulating 500 TEC, whichever occurs first.
(b) Based on inspections accomplished in paragraph (a) of this
AD, accomplish the following:
(1) Prior to further flight, remove those manifolds found with
liberated pieces or with cracks that meet or exceed the length or
orientation criteria in paragraph C(3)(c) or D(3)(c) of the
Accomplishment Instructions of GE90 SB No. 72-263, dated February 5,
1997, and replace with CDP manifolds, P/N 1686M48G12, in accordance
with GE90 SB No. 72-126, Revision 1, dated April 29, 1997.
(2) For manifolds found with axial cracks less than or equal to
0.5 inches, thereafter, perform borescope inspections of CDP
manifolds daily, remove, if necessary, and replace in accordance
with paragraph (b)(1) of this AD.
(3) For manifolds with no visible cracks, accomplish the
following:
(i) Perform borescope inspections of CDP manifolds at intervals
not to exceed 125 CIS since last inspection, remove, if necessary,
and replace in accordance with paragraph (b)(1) of this AD.
(ii) If manifolds are found with axial cracks less than or equal
to 0.5 inches, thereafter, perform borescope inspections of CDP
manifolds daily, remove, if necessary, and replace in accordance
with paragraph (b)(1) of this AD.
(c) At the next shop visit after the effective date of this AD,
install an improved CDP manifold, P/N 1686M48G12, in accordance with
GE90 SB No. 72-126, Revision 1, dated April 29, 1997. Installation
of this CDP manifold constitutes terminating action to the
inspection requirements of this AD.
(d) For the purpose of this AD, a shop visit is defined as an
engine removal for engine maintenance that cannot be performed while
installed on the aircraft and that entails separation of pairs of
mating engine flanges.
(e) 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.
Operators shall submit their request 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.
(f) 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 inspection requirements of this AD can be accomplished.
(g) The actions required by this AD shall be done in accordance
with the following GE90 SBs:
[[Page 32025]]
------------------------------------------------------------------------
Document No. Revision Pages Date
------------------------------------------------------------------------
72-263....................... Original.... 1-18 Feb. 5, 1997.
Total pages: 18.
72-126....................... 1........... 1-8 Apr. 29, 1997.
Total pages: 8.
------------------------------------------------------------------------
This incorporation by reference was approved by the Director of
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. Copies may be obtained from General Electric Technical
Services, Attention: Leader for distribution/microfilm, 10525
Chester Road, Cincinnati, OH 45215; telephone (513) 672-8400 Ext.
114, fax (513) 672-8422. Copies may be inspected at the FAA, New
England Region, Office of the Assistant Chief 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.
(h) This amendment becomes effective on June 27, 1997.
Issued in Burlington, Mass., on May 30, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 97-14955 Filed 6-11-97; 8:45 am]
BILLING CODE 4910-13-U
