[Federal Register Volume 76, Number 135 (Thursday, July 14, 2011)]
[Rules and Regulations]
[Pages 41395-41397]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-17621]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2010-1024; Directorate Identifier 2010-NE-34-AD;
Amendment 39-16753; AD 2011-15-06]
RIN 2120-AA64
Airworthiness Directives; General Electric Company GE90-76B;
GE90-77B; GE90-85B; GE90-90B; and GE90-94B Turbofan Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: We are adopting a new airworthiness directive (AD) for the
products listed above. This AD requires initial and repetitive
fluorescent penetrant inspections (FPIs) and eddy current inspections
(ECIs) of the high-pressure compressor rotor (HPCR) 8-10 stage spool,
part numbers (P/Ns) 1844M90G01 and 1844M90G02, for cracks between the
9-10 stages at each piece-part exposure. This AD was prompted by cracks
discovered on one HPCR 8-10 spool between the 9-10 stages in the weld
joint. We are issuing this AD to prevent failure of the HPCR 8-10 stage
spool, uncontained engine failure, and damage to the airplane.
DATES: This AD is effective August 18, 2011.
ADDRESSES: For service information identified in this AD, contact GE-
Aviation M/D Rm. 285, One Neumann Way, Cincinnati, OH 45215, phone:
513-552-3272; e-mail: geae.aoc@ge.com. You may review copies of the
referenced service information at the FAA, Engine & Propeller
Directorate, 12 New England Executive Park, Burlington, MA. For
information on the availability of this material at the FAA, call 781-
238-7125.
Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (phone: 800-647-5527) is Document Management Facility,
U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE.,
Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: Jason Yang, Aerospace Engineer, Engine
Certification Office, FAA, 12 New England Executive Park, Burlington,
MA 01803; phone: 781-238-7747; fax: 781-238-7199; e-mail:
jason.yang@faa.gov.
SUPPLEMENTARY INFORMATION:
Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an airworthiness directive (AD) that would apply to
the specified products. That NPRM published in the Federal Register on
December 22, 2010 (75 FR 80370). That NPRM proposed to require initial
and repetitive FPIs and ECIs of the HPCR 8-10 stage spool, P/Ns
1844M90G01 and 1844M90G02, for cracks between the 9-10 stages, at each
piece-part exposure.
Comments
We gave the public the opportunity to participate in developing
this AD. The following presents the comments received on the proposal
and the FAA's response to each comment.
Request
Two commenters, General Electric Company and The Boeing Company,
requested that we remove the ``Unsafe
[[Page 41396]]
Condition'' paragraph from the AD, and reword the Summary section to
resemble the Summary section of AD 2002-04-11. The commenters stated
that, by their analyses, cracks in the weld joint would not develop
into an uncontained failure. The commenters stated that HPCR 8-10 stage
spools, P/Ns 1844M90G01 and 1844M90G02, be inspected by an enhanced
inspection, similar to those parts covered in AD 2002-04-11.
Answer
We do not agree. AD 2002-04-11 was issued because of additional
focused inspection procedures that had been developed by the
manufacturer. Because cracks were discovered on one HPCR 8-10 spool
between the 9-10 stages in the weld joint, this unsafe condition is
likely to exist or develop in other products of the same type design.
The unsafe condition could result in failure of the HPCR 8-10 stage
spool, uncontained engine failure, and damage to the airplane. We
determined that this unsafe condition requires mandatory repetitive
inspections for cracks. We did not change the AD.
Request
China Southern Airlines requested that we specify any terminating
actions to the repetitive inspections of the affected part numbers of
HPCR 8-10 spools.
Answer
We disagree. Unless the part is replaced with a part not subject to
this AD, no terminating actions to the repetitive inspections exist.
Question
China Southern Airlines asked if the initial and repetitive FPIs
and ECIs of the HPCR 8-10 stage spool at each piece-part exposure in
the shop effectively prevent failure during normal engine operation,
since the high-pressure module overhaul interval is 48,000 hours or
6,000 cycles when the spool can have piece-part exposure per current
GE90 Workscope Planning Guide.
Answer
Yes, the FAA has determined that the actions required by the AD
will effectively prevent failure of the HPCR 8-10 stage spool by
removing cracked parts from service.
Conclusion
We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
the AD as proposed.
Costs of Compliance
We estimate that this AD will affect 33 GE90-76B; GE90-77B; GE90-
85B; GE90-90B; and GE90-94B engines, installed on airplanes of U.S.
registry. We also estimate that it will take about 2 work-hours per
engine to perform the inspection, and that the average labor rate is
$85 per work-hour. Based on these figures, we estimate the total cost
of the AD to U.S. operators to be $5,610 for one inspection cycle.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII: Aviation Programs,
describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701: ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.
Regulatory Findings
This AD will not have federalism implications under Executive Order
13132. This AD 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.
For the reasons discussed above, I certify that this AD:
(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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):
2011-15-06 General Electric Company: Amendment 39-16753; Docket No.
FAA-2010-1024; Directorate Identifier 2010-NE-34-AD.
Effective Date
(a) This AD is effective August 18, 2011.
Affected ADs
(b) None.
Applicability
(c) This AD applies to General Electric Company GE90-76B; GE90-
77B; GE90-85B; GE90-90B; and GE90-94B turbofan engines with a high-
pressure compressor rotor (HPCR) 8-10 stage spool, part number (P/N)
1844M90G01 or 1844M90G02, installed.
Unsafe Condition
(d) This AD was prompted by cracks discovered on one HPCR 8-10
spool between the 9-10 stages in the weld joint. We are issuing this
AD to prevent failure of the HPCR 8-10 stage spool, uncontained
engine failure, and damage to the airplane.
Compliance
(e) Comply with this AD within the compliance times specified,
unless already done.
Inspections of the HPCR 8-10 Stage Spool
(f)(1) At the next piece-part exposure of the HPCR 8-10 stage
spool after the effective date of this AD, perform a fluorescent
penetrant inspection (FPI) and eddy current inspection (ECI) of the
weld joint between the 9-10 stages of the HPCR 8-10 stage spool for
cracks.
(2) Thereafter, perform repetitive FPIs and ECIs of the weld
joint between the 9-10 stages of the HPCR 8-10 stage spool for
cracks at every piece-part exposure of the HPCR 8-10 stage spool.
(3) Remove from service any HPCR 8-10 stage spool found cracked.
(4) Guidance on performing the FPI can be found in GE90
(GEK100700) Engine Manual, Chapter 72-31-08, Inspection 001.
[[Page 41397]]
(5) Guidance on performing the ECI can be found in GE90
(GEK100700) Engine Manual, Chapter 72-31-08, Special Procedures 001.
Definition
(g) For the purpose of this AD, piece-part exposure is when the
HPCR stage 8-10 spool is removed from the engine and completely
disassembled.
Alternative Methods of Compliance (AMOCs)
(h) The Manager, Engine Certification Office, FAA, has the
authority to approve AMOCs for this AD, if requested using the
procedures found in 14 CFR 39.19.
Related Information
(i)(1) For more information about this AD, contact Jason Yang,
Aerospace Engineer, Engine Certification Office, FAA, 12 New England
Executive Park, Burlington, MA 01803; phone: 781-238-7747; fax: 781-
238-7199; e-mail: jason.yang@faa.gov.
(2) For service information identified in this AD, contact
General Electric Company, GE-Aviation, Room 285, 1 Neumann Way,
Cincinnati, OH 45215, phone: 513-552-3272; fax: 513-552-3329; e-
mail: geae.aoc@ge.com. For information on the availability of this
material at the FAA, call 781-238-7125.
Material Incorporated by Reference
(j) None.
Issued in Burlington, Massachusetts, on July 7, 2011.
Peter A. White,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 2011-17621 Filed 7-13-11; 8:45 am]
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