[Federal Register Volume 73, Number 67 (Monday, April 7, 2008)]
[Proposed Rules]
[Pages 18721-18722]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-7153]
[[Page 18721]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-0402; Directorate Identifier 2007-NM-165-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Airplanes and Model
767 Airplanes Equipped With General Electric CF6-80C2 and CF6-80A
Series 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 certain Boeing Model 747 airplanes and Model 767 airplanes. This
proposed AD would require revising the airplane flight manual to advise
the flightcrew to use certain procedures during descent in certain
icing conditions. This proposed AD results from reports of several in-
flight engine flameouts, including multiple dual engine flameout events
and one total power loss event, in ice-crystal icing conditions. We are
proposing this AD to ensure that the flightcrew has the proper
procedures to follow in certain icing conditions. These certain icing
conditions could cause a multiple engine flameout during flight without
the ability of the engines to be relit, and consequent forced landing
of the airplane.
DATES: We must receive comments on this proposed AD by May 22, 2008.
ADDRESSES: You may send comments 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: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
For service information identified in this AD, contact Boeing
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.
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 (telephone 800-647-5527) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.
FOR FURTHER INFORMATION CONTACT: Margaret Langsted, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6500; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2008-0402;
Directorate Identifier 2007-NM-165-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.
Discussion
We have received reports indicating that there have been several
in-flight engine flameout events, including one dual event, on Model
767 airplanes and four dual events on Model 747 airplanes, in ice-
crystal icing conditions at altitudes between 13,000 and 36,000 feet
during descent. These airplanes were equipped with General Electric
(GE) CF6-80C2 series engines. Each flameout event was in or near
convective weather with ice-crystal icing; this type of icing does not
appear on radar due to its low reflectivity, and neither the airplane
ice detector nor visual indications indicate the presence of icing
conditions. Therefore, it is often undetected by the flightcrew. These
conditions can cause ice crystals to accumulate in the core flow path
of the engine during low-power conditions, such as idle or idle
descent. The accumulated ice sheds during throttle increase and is
ingested into the engine, causing the combustor to flameout resulting
in an in-flight flameout and potential damage to the high pressure
compressor due to ice impact. The GE CF6-80C2 and CF6-80A series
engines models have similar compressor designs.
Activating the engine anti-ice increases the flameout margin and
reduces the potential for multiple engine flameouts by increasing bleed
flow and idle speed. Engine anti-ice also assists with relighting the
engines by turning on the igniters on airplanes that are not equipped
with autorelight. However, in several of the subject engine flameout
events, the engine anti-ice was already on when the engines flamed out.
In each flameout event, the engines relit and continued to operate
normally for the remainder of the flight.
The requirement to activate the engine anti-ice prior to descent in
visible moisture with total air temperature less than 10 [deg]Celsius
(C) and greater than -40 [deg]C already exists for airplanes that are
not equipped with a primary in-flight ice detection system, which is
designed to automatically activate wing anti-ice and engine anti-ice
when the airplane is in icing conditions. However, the primary in-
flight ice detection system does not detect ice-crystal icing;
therefore, the engine anti-ice would not be activated during these
icing encounters. There is no requirement to activate engine anti-ice
at temperatures below -40 [deg]C, and this proposed AD would require
activation of engine anti-ice at temperatures below -40 [deg]C.
This condition, if not corrected, could result in a multiple engine
flameout during flight without the ability of the engines to be relit,
and consequent forced landing of the airplane.
FAA's Determination and Requirements of This Proposed AD
We are proposing this AD because we evaluated all relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the(se) same type
design(s). This proposed AD would require revising the airplane flight
manual (AFM) to advise the flightcrew to use certain procedures during
descent in certain icing conditions.
Interim Action
We consider this proposed AD interim action. If final action is
later
[[Page 18722]]
identified, we might consider further rulemaking then.
Costs of Compliance
There are about 1,064 airplanes of the affected design in the
worldwide fleet. The following table provides the estimated costs for
U.S. operators to comply with this proposed AD.
Estimated Costs
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Number of U.S.-
Action Work hours Average labor Parts Cost per registered Fleet cost
rate per hour airplane airplanes
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AFM revision...................................... 1 $80 $0 $80 340 $27,200
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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
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. 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.
We prepared a regulatory evaluation of the estimated costs to
comply with this proposed AD and placed it in the AD docket. 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
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
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 Federal Aviation Administration (FAA) amends Sec. 39.13 by
adding the following new airworthiness directive (AD):
Boeing: Docket No. FAA-2008-0402; Directorate Identifier 2007-NM-
165-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by May 22,
2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 747 airplanes and Model 767
airplanes, certified in any category, equipped with General Electric
CF6-80C2 or CF6-80A series engines.
Unsafe Condition
(d) This AD results from reports of several in-flight engine
flameouts, including multiple dual engine flameout events and one
total power loss event, in ice-crystal icing conditions. We are
issuing this AD to ensure that the flightcrew has the proper
procedures to follow in certain icing conditions. These certain
icing conditions could cause a multiple engine flameout during
flight without the ability of the engines to be relit, and
consequent forced landing of 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.
Airplane Flight Manual (AFM) Revision
(f) Within 14 days after the effective date of this AD, revise
the Limitations Section of the Boeing 747 or 767 AFM, as applicable,
to include the following statement. This may be done by inserting a
copy of this AD into the AFM.
``Prior to descent in visible moisture and TAT less than 10
[deg]C, including SAT less than -40 [deg]C, nacelle anti-ice switch
must be in the ON position.''
Note 1:
When a statement identical to that in paragraph (f) of this AD
has been included in the general revisions of the AFM, the general
revisions may be inserted into the AFM, and the copy of this AD may
be removed from the AFM.
Alternative Methods of Compliance (AMOCs)
(g)(1) The Manager, Seattle Aircraft Certification Office, FAA,
has the authority to approve AMOCs for this AD, if requested in
accordance with the procedures found in 14 CFR 39.19.
(2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
Before using any approved AMOC on any airplane to which the AMOC
applies, notify your appropriate principal inspector (PI) in the FAA
Flight Standards District Office (FSDO), or lacking a PI, your local
FSDO.
Issued in Renton, Washington, on March 27, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-7153 Filed 4-4-08; 8:45 am]
BILLING CODE 4910-13-P