[Federal Register Volume 72, Number 136 (Tuesday, July 17, 2007)]
[Proposed Rules]
[Pages 39039-39041]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-13835]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28319; Directorate Identifier 2007-NE-27-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company (GE) CF6-
80C2D1F Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for GE CF6-80C2D1F turbofan engines, installed on McDonnell Douglas 
Corporation MD-11 series airplanes. This proposed AD would require 
removing previous software versions from the engine electronic control 
unit (ECU). Engines with new version software will have increased 
margin to flameout. This proposed AD results from reports of engine 
flameout events during flight, including reports of events where all 
engines simultaneously experienced a flameout or other adverse 
operation. Although the root cause investigation is not yet complete, 
we believe that exposure to ice crystals during flight is associated 
with these flameout events. We are proposing this AD to minimize the 
potential of an all-engine flameout event caused by ice accretion and 
shedding during flight.

DATES: We must receive any comments on this proposed AD by September 
17, 2007.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     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.
     Fax: (202) 493-2251.
    You can get the service information identified in this proposed AD 
from General Electric Company via Lockheed Martin Technology Services, 
10525 Chester Road, Suite C, Cincinnati, Ohio 45215, telephone (513) 
672-8400, fax (513) 672-8422.

FOR FURTHER INFORMATION CONTACT: John Golinski, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone: (781) 238-7135, 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-2007-28319; 
Directorate Identifier 2007-NE-27-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 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.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 
DOT Web site, anyone can find and read the

[[Page 39040]]

comments in any of our dockets, including 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) or you may visit http://dms.dot.gov.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://dms.dot.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

    GE CF6-80C2 and CF6-80E1 series turbofan engines continue to 
experience flameout events that are due to ice accretion and shedding 
into the engine during flight. Although the investigation is not yet 
complete, we believe that the ice accretion is caused by exposure to 
ice crystals during flight. Industry reports 35 airplane flameout 
events, including reports of multi-engine events where all engines on 
the airplane simultaneously experienced a flameout. Some of these 
events had high pressure compressor blade damage that may have been 
caused by impact with shedding ice. In all events, the engines 
restarted and continued to operate normally for the remainder of the 
flight.
    This proposed AD addresses only the CF6-80C2D1F turbofan engines, 
installed on McDonnell Douglas Corporation MD-11 series airplanes. We 
believe this model of CF6-80C2 engine is susceptible to flameouts 
caused by ice accretion and shedding into the engine during flight. 
Similar AD actions for other CF-80C2 and CF6-80E1 series engines may be 
forthcoming.
    We view an all-engine flameout event as an unsafe condition 
particularly for low-altitude events, or other factors that might 
result in the inability to restart the engines and regain control of 
the airplane. Since some aspects of this problem are not completely 
understood, this proposed AD is considered an interim action due to 
GE's on-going investigation. Future AD action might become necessary 
based on the results of the investigation and field experience. This 
condition of insufficient margin to engine flameout due to ice 
accretion and shedding during flight, if not addressed, could result in 
an all-engine flameout event during flight.

Relevant Service Information

    We have reviewed and approved the technical contents of GE Service 
Bulletin (SB) No. CF6-80C2 S/B 73-0351, dated April 11, 2007. That SB 
describes procedures for removing certain software versions from the 
ECU, and installing a software version that is FAA-approved. The new 
FAA-approved software version described in the SB modifies the variable 
bleed valve schedule, which will provide an increased margin to 
flameout. This increased margin is expected to reduce the rate of 
flameout occurrences due to ice accretion and shedding during flight.

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 
removing certain software versions from the engine ECU.

Interim Action

    These actions are interim actions due to the on-going 
investigation. We may take further rulemaking actions in the future, 
based on the results of the investigation and field experience.

Costs of Compliance

    We estimate that this proposed AD would affect 175 CF6-80C2D1F 
turbofan engines installed on McDonnell Douglas Corporation MD-11 
series airplanes of U.S. registry. We estimate it would take about 3 
work-hours per ECU to perform the proposed actions if done at ECU shop 
visit, and 6 work-hours per ECU if done at engine shop visit. We 
estimate that 50% of the ECUs would be worked at ECU shop visit and the 
remaining 50% worked at engine shop visit. The average labor rate is 
$80 per work-hour. Based on these figures, we estimate the cost to U.S. 
operators to be $63,120. Our cost estimate is exclusive of warranty 
coverage.

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, 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-2007-28319; Directorate 
Identifier 2007-NE-27-AD.

[[Page 39041]]

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by September 
17, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) CF6-80C2D1F 
turbofan engines, installed on McDonnell Douglas Corporation MD-11 
series airplanes.

Unsafe Condition

    (d) This AD results from reports of engine flameout events 
during flight, including reports of events where all engines 
simultaneously experienced a flameout or other adverse operation. We 
are issuing this AD to minimize the potential of an all-engine 
flameout event, due to ice accretion and shedding during flight. 
Exposure to ice crystals during flight is believed to be associated 
with these flameout events.

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.

Interim Action

    (f) These actions are interim actions due to the on-going 
investigation, and we may take further rulemaking actions in the 
future based on the results of the investigation and field 
experience.

Engine Electronic Control Unit (ECU) Software Removal

    (g) At the next shop visit of the engine or of the ECU, 
whichever occurs first, and not to exceed 60 months from the 
effective date of this AD, remove the following software versions 
from the ECUs:

               Table 1.--Removal of ECU Software Versions
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          Software version                 Installed in ECU part No.
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(1) 8.5.A...........................  1851M51P01, 1851M51P02,
                                       1851M52P01, 1851M52P02,
                                       1851M53P01, 1851M53P02
(2) 8.3.C...........................  1471M69P01, 1471M69P02, 1519M91P01
(3) 8.3.D...........................  1519M91P02
(4) 8.3.E...........................  1519M91P03, 1519M91P04
(5) 8.3.F...........................  1519M91P05
(6) 8.3.G...........................  1519M91P06, 1820M34P01
(7) 8.3.H...........................  1519M91P07, 1820M34P02
(8) 8.3.J...........................  1519M91P09, 1519M91P10,
                                       1820M34P04, 1820M34P05
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Previous Software Versions of ECU Software

    (h) For a period of 24 months after the effective date of this 
AD, once an ECU containing a software version not listed in Table 1 
of this AD is installed on an engine, that ECU can be replaced with 
an ECU containing a previous version of software listed in Table 1.
    (i) Once the software version listed in Table 1 of this AD has 
been removed and new FAA-approved software version is installed in 
an ECU, reverting to those older software versions in that ECU is 
prohibited.
    (j) After 60 months from the effective date of this AD, use of 
an ECU with a software version listed in Table 1 of this AD is 
prohibited.

Definitions

    (k) For the purposes of this AD:
    (1) Next shop visit of the ECU is when the ECU is removed from 
the engine for overhaul or maintenance after the effective date of 
this AD.
    (2) Next shop visit of the engine is when the engine is removed 
from the airplane for maintenance in which a major flange is 
disassembled after the effective date of this AD. The following 
engine maintenance actions, either separately or in combination with 
each other, are not considered a next shop visit of the engine:
    (i) Removal of the upper high pressure compressor (HPC) stator 
case solely for airfoil maintenance.
    (ii) Module-level inspection of the HPC rotor stages 3-9 spool.
    (iii) Replacement of stage 5 HPC variable stator vane bushings 
or lever arms.
    (iv) Removal of the accessory gearbox.
    (v) Replacement of the inlet gearbox polytetrafluoroethylene 
seal.

Alternative Methods of Compliance

    (l) 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.

Special Flight Permits

    (m) Special flight permits are not authorized.

Related Information

    (n) Information on removing ECU software and installing new 
software, which provides increased margin to flameout, can be found 
in GE Service Bulletin No. CF6-80C2 S/B 73-0351, dated April 11, 
2007.
    (o) Contact John Golinski, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone: (781) 238-7135, fax: (781) 238-
7199, for more information about this AD.

    Issued in Burlington, Massachusetts, on July 11, 2007.
Francis A. Favara,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-13835 Filed 7-16-07; 8:45 am]
BILLING CODE 4910-13-P