[Federal Register Volume 71, Number 205 (Tuesday, October 24, 2006)]
[Proposed Rules]
[Pages 62215-62217]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-17742]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-25738; Directorate Identifier 2006-NE-27-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company (GE) CF6-80C2B 
Series 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 CF6-80C2B series turbofan engines with electronic control units 
(ECUs), installed on Boeing 747 and 767 airplanes. This proposed AD 
would require installing software version 8.2.Q1 to the engine ECU, 
which increases the margin to engine 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. We are proposing this AD to provide increased 
margin to flameout and to minimize the potential of an all-engine 
flameout event, due to ice accretion and shedding during flight.

DATES: We must receive any comments on this proposed AD by December 26, 
2006.

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.

[[Page 62216]]

     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    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.
    You may examine the comments on this proposed AD in the AD docket 
on the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: John Golinski, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; 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-2006-25738; 
Directorate Identifier 2006-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://
http://dms.dot.gov">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 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 docket that contains the proposal, any comments 
received and, any final disposition in person at the DOT Docket Office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Office (telephone (800) 647-5227) is located on 
the plaza level of the Department of Transportation Nassif Building at 
the street address stated in ADDRESSES. Comments will be available in 
the AD docket shortly after the Docket Management Facility receives 
them.

Discussion

    GE CF6-80C2 and CF6-80E1 series turbofan engines continue to 
experience flameout events that are due to ice accretion and shedding 
during flight. Though the investigation is not yet complete, exposure 
to ice crystals during flight is believed to be associated with these 
flameout events. We have received reports of 32 airplane events, 
including reports of multi-engine events where all engines on the 
airplane simultaneously experienced a flameout or other adverse 
operation. 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.
    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 proposed AD addresses only the CF6-80C2B series turbofan 
engines with ECUs, installed on Boeing 747 and 767 airplanes. The 
remaining CF6-80C2 and CF6-80E1 series engines are being studied by GE, 
and we may have future AD actions when studies are finished.
    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 73-0339, dated November 17, 2005. That 
SB describes procedures for installing software version 8.2.Q1 to the 
ECU. Software version 8.2.Q1 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.

Differences Between the Proposed AD and the Manufacturer's Service 
Information

    Although GE SB No. CF6-80C2 S/B 73-0339, dated November 17, 2005, 
recommends the incorporation of software version 8.2.Q1 at the next 
shop visit of the ECU, this proposed AD would:
     Require a more aggressive compliance schedule for 
incorporating the software; and
     Add a compliance requirement for affected engines 
installed on Boeing 767 airplanes, which the SB does not require.

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:
     For Boeing 767 airplanes, within 24 months after the 
effective date of this AD, installing software version 8.2.Q1 to the 
ECU on at least one of airplane's affected turbofan engines, and
     For all other affected turbofan engines, installing 
software version 8.2.Q1 to the ECU at the next shop visit of the ECU or 
engine, whichever occurs first, not to exceed five years after the 
effective date of this proposed AD.
    This software change will provide increased margin to flameout and 
reduce the rate of flameout occurrences due to ice accretion and 
shedding during flight. The proposed AD would require you to use the GE 
service bulletin described previously to perform these actions.

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 293 CF6-80C2B series 
turbofan engines with ECUs installed on Boeing 747 and 767 airplanes of 
U.S. registry. We estimate that 73 engines would have the software 
installed at

[[Page 62217]]

ECU overhaul, 147 engines would have the software installed during ECU 
repair, and 73 engines would have the software installed, not due to 
ECU overhaul or repair. It would take about six work-hours per engine 
to perform the proposed actions (ECU overhauls not included) and the 
average labor rate is $80 per work-hour. Based on these figures, we 
estimate the total cost of the proposed AD to U.S. operators to be 
$283,740. GE may provide the software at no cost to the operators, and 
reimburse the six work-hours labor cost until December 31, 2010.

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 engines 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 
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); 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. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

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-2006-25738; Directorate 
Identifier 2006-NE-27-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by December 26, 
2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) CF6-
80C2B1F, -80C2B2F, -80C2B4F, -80C2B5F, -80C2B6F, -80C2B6FA, -
80C2B7F, and -80C2B8F turbofan engines with electronic control units 
(ECUs), installed on Boeing 747 and 767 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 provide increased margin to flameout and 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.

Engine ECU Software Installation

    (f) For Boeing 767 airplanes, within 24 months after the 
effective date of this AD, install software version 8.2.Q1 to the 
engine ECU on at least one of the airplane's affected turbofan 
engines.
    (g) For all other affected turbofan engines, install software 
version 8.2.Q1 to the engine ECU at the next shop visit of the ECU 
or engine, whichever occurs first, not to exceed five years after 
the effective date of this AD.
    (h) Use paragraphs 3.A. through 3.B.(3)(f)4. of the 
Accomplishment Instructions of GE Service Bulletin No. CF6-80C2 S/B 
73-0339, dated November 17, 2005, to do the installation.

Definitions

    (i) For the purposes of this AD:
    (1) Next shop visit of the engine ECU is when the ECU is removed 
from the engine for overhaul or for maintenance.
    (2) Next shop visit of the engine is when the engine is removed 
from the airplane for maintenance in which a major engine 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 engine shop visit:
    (i) Removal of the upper high pressure compressor (HPC) stator 
case solely for airfoil maintenance.
    (ii) Module-level inspection of the HPC rotor 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 Teflon seal.

Alternative Methods of Compliance

    (j) 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.
    (k) Installation of later FAA-approved ECU software versions 
that follow version 8.2.Q1, are acceptable alternative methods of 
compliance to this AD.

Special Flight Permits

    (l) Under 14 CFR part 39.23, special flight permits are 
prohibited.

    Issued in Burlington, Massachusetts, on October 18, 2006.
Thomas A. Boudreau,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E6-17742 Filed 10-23-06; 8:45 am]
BILLING CODE 4910-13-P