Document ID: FAA-2013-0186-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2013-04-02T04:00Z

[Federal Register Volume 78, Number 63 (Tuesday, April 2, 2013)]
[Proposed Rules]
[Pages 19628-19630]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-07546]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0186; Directorate Identifier 2013-NE-11-AD]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain General Electric Company (GE) GE90-76B, -85B, -90B, -94B, -
110B1, and -115B turbofan engines. This proposed AD was prompted by 
multiple reports of failure of certain stage 1 high-pressure turbine 
(HPT) stator shrouds due to accelerated corrosion and oxidation. This 
proposed AD would require initial and repetitive on-wing borescope 
inspections (BSIs) for corrosion and oxidation, of the affected stage 1 
HPT stator shrouds, and removal from service before further flight, if 
the parts fail the inspection. We are proposing this AD to prevent 
failure of the stage 1 HPT stator shrouds, resulting in in-flight 
shutdown of one or more engines, loss of thrust control, and damage to 
the airplane.

DATES: We must receive comments on this proposed AD by June 3, 2013.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
General Electric Company, One Neumann Way, MD Y-75, Cincinnati, OH; 
phone: 513-552-2913; email: geae.aoc@ge.com; and Web site: www.GE.com. 
You may view 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 proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES 
section. Comments will be available in the AD docket shortly after 
receipt.

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; email: 
jason.yang@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2013-0186; 
Directorate Identifier 2013-NE-11-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

[[Page 19629]]

Discussion

    We received one report of an aborted takeoff, and multiple reports 
of stage 1 HPT stator shroud distress resulting in engine removals on 
airplanes with GE90 turbofan engines. Investigation revealed that the 
stage 1 HPT stator shrouds failed due to accelerated corrosion and 
oxidation. GE is still investigating the cause of the accelerated 
corrosion and oxidation. This condition, if not corrected, could result 
in failure of the stage 1 HPT stator shrouds, resulting in in-flight 
shutdown of one or more engines, loss of thrust control, and damage to 
the airplane.

Relevant Service Information

    We reviewed GE Service Bulletin (SB) No. GE90 S/B 72-1076, dated 
November 19, 2012, and SB No. GE90-100 S/B 72-0528, dated November 15, 
2012. The SBs describe procedures for performing BSIs of the stage 1 
HPT stator shrouds for accelerated corrosion and oxidation.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would require initial and repetitive on-wing BSIs 
of stage 1 HPT stator shrouds, part number (P/N) 1847M52P14, and P/N 
1847M52P16, for corrosion and oxidation, and removal from service 
before further flight if the parts fail the inspection.

Differences Between the Proposed AD and the Service Information

    The SBs require completing and sending to GE the Inspection 
Findings Report Form after each inspection. This proposed AD does not.

Costs of Compliance

    We estimate that this proposed AD would affect about 100 GE90 
engines installed on airplanes of U.S. registry. We also estimate that 
it would take about four hours per engine to perform one inspection. 
The average labor rate is $85 per hour. Based on these figures, we 
estimate the cost of the proposed AD on U.S. operators for one 
inspection to be $34,000.

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 >We determined that this proposed AD would not have 
federalism implications under Executive Order 13132. This proposed AD 
would 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 this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska to the extent 
that it justifies making a regulatory distinction, 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.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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):

General Electric Company: Docket No. FAA-2013-0186; Directorate 
Identifier 2013-NE-11-AD.

(a) Comments Due Date

    We must receive comments by June 3, 2013.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE):
    (1) GE90-76B, -85B, -90B, and -94B turbofan engines with stage 1 
high-pressure turbine (HPT) stator shrouds, part number (P/N) 
1847M52P14, installed.
    (2) GE90-110B1 and -115B turbofan engines with stage 1 HPT 
stator shrouds, P/N 1847M52P16, installed.

(d) Unsafe Condition

    This AD was prompted by multiple reports of failure of certain 
stage 1 HPT stator shrouds due to accelerated corrosion and 
oxidation. We are issuing this AD to prevent failure of the stage 1 
HPT stator shrouds, resulting in in-flight shutdown of one or more 
engines, loss of thrust control, and damage to the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(f) Borescope Inspections of the Stage 1 HPT Stator Shrouds

    (1) Perform an initial on-wing borescope inspection (BSI) of the 
stage 1 HPT stator shrouds for corrosion and oxidation before 
accumulating 2,100 cycles since new (CSN), or within 100 cycles in 
service (CIS) after the effective date of this AD, whichever occurs 
later.
    (2) Thereafter, repeat the BSI of the stage 1 HPT stator shrouds 
every 250 cycles since last inspection (CSLI) or fewer, depending on 
the results of the inspection.
    (3) For engines listed in paragraph (c)(1) of this AD:
    (i) Perform the inspections using Section 3.A of the 
Accomplishment Instructions of GE Service Bulletin (SB) No. GE90 S/B 
72-1076, dated November 19, 2012; and
    (ii) Use Section 3.B of the Accomplishment Instructions of SB 
No. GE90 S/B 72-1076, dated November 19, 2012, to determine the next 
inspection interval.
    (4) For engines listed in paragraph (c)(2) of this AD:
    (i) Perform the inspections using Section 3.A of the 
Accomplishment Instructions of GE SB No. GE90-100 S/B 72-0528, dated 
November 15, 2012; and
    (ii) Use Section 3.B of the Accomplishment Instructions of SB 
No. GE90-100 S/B 72-0528, dated November 15, 2012, to determine the 
next inspection interval.
    (5) Remove from service before further flight, any stage 1 HPT 
stator shrouds found with any hole further than 0.35-inch from the 
shroud leading edge and hole size more than 0.25-inch diameter, or 
more than 0.049 square inch area.
    (6) The inspection findings reporting specified in Section 3.A 
of the

[[Page 19630]]

Accomplishment Instructions of GE SB No. GE90 S/B 72-1076, dated 
November 19, 2012, and in Section 3.A of the Accomplishment 
Instructions of GE SB No. GE90-100 S/B 72-0528, dated November 15, 
2012, are not required by this AD.

(g) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, FAA, may approve AMOCs 
for this AD. Use the procedures in 14 CFR 39.19 to make your 
request.

(h) Related Information

    (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; email: jason.yang@faa.gov.
    (2) For service information identified in this AD, contact 
General Electric Company, One Neumann Way, MD Y-75, Cincinnati, OH; 
phone: 513-552-2913; email: geae.aoc@ge.com; and Web site: 
www.GE.com. You may view 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.

    Issued in Burlington, Massachusetts, on March 26, 2013.
Thomas A. Boudreau,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-07546 Filed 4-1-13; 8:45 am]
BILLING CODE 4910-13-P