Document ID: FAA-2010-1024-0006
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: General Electric Co. GE90-76B; GE90-77B; GE90-85B; GE90-90B; and GE90-94B Turbofan Engines
Posted Date: 2011-07-14T04:00Z

[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]
BILLING CODE 4910-13-P