
[Federal Register Volume 74, Number 120 (Wednesday, June 24, 2009)]
[Proposed Rules]
[Pages 30020-30022]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-14807]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0143; Directorate Identifier 2009-NE-05-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company GE90-110B1, 
GE90-113B, and GE90-115B Series Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for General Electric Company (GE) GE90-110B1, GE90-113B, and GE90-115B 
series turbofan engines with stage 6 low-pressure turbine (LPT) blades, 
part number (P/N) 1765M37P03 or P/N 1765M37P04, installed. This 
proposed AD would require initial and repetitive inspections for shroud 
interlock wear of the stage 6 LPT blades. This proposed AD would also 
require replacing those blades with stage 6 LPT blades eligible for 
installation at the next engine shop visit as terminating action to the 
repetitive blade inspections. This proposed AD results from eight 
reports of GE90-115B stage 6 LPT single-blade separation events. We are 
proposing this AD to prevent failure of stage 6 LPT blades, which could 
result in uncontained engine failure and damage to the airplane.

DATES: We must receive any comments on this proposed AD by August 24, 
2009.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.
    Contact General Electric Company via GE--Aviation, Attn: 
Distributions, 111 Merchant St., Room 230, Cincinnati, Ohio 45246; 
telephone (513) 552-3272; fax (513) 552-3329, for a copy of the service 
information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT: Barbara Caufield, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; e-mail: 
barbara.caufield@faa.gov; telephone (781) 238-7146; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2009-0143; Directorate 
Identifier 2009-NE-05-AD'' in the subject line of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of the proposed AD. We will consider 
all comments received by the closing date and may amend the

[[Page 30021]]

proposed AD in light 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 
with FAA personnel concerning this proposed AD. Using the search 
function of the Web site, anyone can find and read the comments in any 
of our dockets, including, if provided, the name of the individual who 
sent the comment (or signed the comment on behalf of an association, 
business, labor union, etc.). You may review the DOT's complete Privacy 
Act Statement in the Federal Register published on April 11, 2000 (65 
FR 19477-78).

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office 
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 Operations office (telephone (800) 647-5527) is 
the same as the Mail address provided in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

Discussion

    Since December of 2007, GE reported eight instances of stage 6 LPT 
single-blade failures in some GE90 series engines. GE's investigation 
indicated that excessive wear at the shroud interlock of stage 6 LPT 
blades, P/N 1765M37P03 or P/N 1765M37P04, caused the failures. The 
interlock surface wears during operation which results in a loss of 
axial preload (contact between two surfaces) between two adjacent stage 
6 LPT blades. This wear leads to increased tip deflection and blade 
stress. This condition, if not corrected, could result in failure of 
stage 6 LPT blades, which could result in uncontained engine failure 
and damage to the airplane.

Relevant Service Information

    We have reviewed and approved the technical contents of GE Service 
Bulletin No. GE90-100 SB 72-0260, Revision 6, dated May 1, 2009. That 
SB describes procedures for inspecting stage 6 LPT blades, P/N 
1765M37P03, and P/N 1765M37P04, for shroud interlock wear.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would require 
initial and repetitive inspections for shroud interlock wear of stage 6 
LPT blades, P/N 1765M37P03 and P/N 1765M37P04. This proposed AD would 
also require replacing those blades with stage 6 LPT blades eligible 
for installation, at the next engine shop visit, as terminating action 
to the repetitive blade inspections. The proposed AD would require you 
to use the service information described previously to perform these 
actions.

Costs of Compliance

    We estimate that this proposed AD would affect four GE GE90 series 
engines installed on airplanes of U.S. registry. We also estimate that 
it would take about 18 work-hours per engine to perform one inspection 
of the stage 6 LPT blades, and that the average labor rate is $80 per 
work-hour. Replacement stage 6 LPT blades would cost $258,280 per 
engine. We estimate that no additional labor costs would be incurred to 
perform the required blade replacements, because the replacements would 
be done at the time of the engine shop visit. Based on these figures, 
we estimate the total cost of the proposed AD for one inspection to 
U.S. operators to be $1,038,880.

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 have 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 that the proposed AD:
    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); and
    3. Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive:

General Electric Company: Docket No. FAA-2009-0143; Directorate 
Identifier 2009-NE-05-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by August 24, 
2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) GE90-110B1, 
GE90-113B, and GE90-115B series turbofan engines with stage 6 low-
pressure turbine (LPT) blades, part number (P/N) 1765M37P03 or P/N 
1765M37P04, installed. These engines are installed on, but not 
limited to, Boeing 777-200LR, 777-300ER, and 777 Freighter series 
airplanes.

[[Page 30022]]

Unsafe Condition

    (d) This AD results from eight reports of GE90-115B stage 6 LPT 
single-blade separation events. We are issuing this AD to prevent 
failure of stage 6 LPT blades, which could result in uncontained 
engine failure and damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.

Inspections

    (f) Before accumulating 3,000 engine operating hours time-since-
new, or 400 engine cycles-since-new, whichever occurs first, inspect 
the stage 6 LPT blades, P/N 1765M37P03 or P/N 1765M37P04 for shroud 
interlock wear. Thereafter, reinspect within every 1,000 engine 
operating hours, or within 125 engine cycles-since-last inspection, 
whichever occurs first. Use paragraphs 3.A. through 3.A.(3)(g)(12) 
of the Accomplishment Instructions of GE Service Bulletin (SB) No. 
GE90-100 SB 72-0260, Revision 6, dated May 1, 2009, to do the 
inspections.

Terminating Action

    (g) At the next engine shop visit, replace stage 6 LPT blades, 
P/N 1765M37P03 or P/N 1765M37P04, with stage 6 LPT blades eligible 
for installation as terminating action to the repetitive inspections 
required by this AD.

Installation Prohibition of Affected Stage 6 LPT Blades

    (h) After the effective date of this AD, do not install any 
stage 6 LPT blades, P/N 1765M37P03 or P/N 1765M37P04, onto any 
engine.

Previous Credit

    (i) An inspection performed before the effective date of this AD 
using GE SB No. GE90-100 SB 72-0260, Revision 4, dated October 8, 
2008, or Revision 5, dated November 7, 2008, satisfies the initial 
inspection requirement of this AD.

Definition

    (j) For the purpose of this AD, an engine shop visit is 
induction of the engine into the shop for any cause.

Alternative Methods of Compliance

    (k) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (l) Contact Barbara Caufield, Aerospace Engineer, Engine 
Certification Office, FAA, Engine & Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
barbara.caufield@faa.gov; telephone (781) 238-7146; fax (781) 238-
7199, for more information about this AD.
    (m) Guidance on stage 6 LPT blades that are eligible for 
installation can be found in GE Service Bulletin No. 72-0279, 
Revision 1, dated December 11, 2008, and GE Service Bulletin No. 72-
0313, dated March 18, 2009.
    (n) Contact General Electric Company via GE--Aviation, Attn: 
Distributions, 111 Merchant St., Room 230, Cincinnati, Ohio 45246; 
telephone (513) 552-3272; fax (513) 552-3329, for a copy of the 
service information identified in this AD.

    Issued in Burlington, Massachusetts, on June 17, 2009.
Carlos Pestana,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E9-14807 Filed 6-23-09; 8:45 am]
BILLING CODE 4910-13-P


