[Federal Register Volume 60, Number 100 (Wednesday, May 24, 1995)]
[Proposed Rules]
[Pages 27446-27448]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12710]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 94-NM-140-AD]
Airworthiness Directives; Boeing Model 747-400, 757, and 767
Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to Boeing Model 747-400, 757, and 767
series airplanes. This proposal would require a revision to the
Airplane Flight Manual that would advise flight crews to monitor the
engine indication and crew alerting system (EICAS) for ``status'' level
messages pertaining to impending engine fuel filter bypass. This
proposal also would require the installation of upgraded EICAS
computers that provide ``advisory'' level messages to indicate such
bypass conditions. This proposal is prompted by a finding that EICAS
computers currently installed on these airplanes do not provide an
appropriate indication to the flight crew of an impending engine fuel
filter bypass condition. The actions specified by the proposed AD are
intended to ensure that the flight crew is appropriately aware of
conditions involving a severely contaminated airplane fuel system and
the associated increased potential for engine power loss.
DATES: Comments must be received by July 19, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-140-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9 a.m. and 3 p.m., Monday through Friday, except
Federal holidays.
FOR FURTHER INFORMATION CONTACT: Jeff Duven, Aerospace Engineer,
Propulsion Branch, ANM-140S, Seattle Aircraft Certification Office,
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (206) 227-2688; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
[[Page 27447]] they may desire. Communications shall identify the Rules
Docket number and be submitted in triplicate to the address specified
above. All communications received on or before the closing date for
comments, specified above, will be considered before taking action on
the proposed rule. The proposals contained in this notice may be
changed in light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 94-NM-140-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules
Docket No. 94-NM-140-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA recently has learned that appropriate indication to the
flight crew of an impending engine fuel filter bypass condition is not
provided on Boeing Models 747-400 and 757 series airplanes, and on
Model 767 series airplanes powered by General Electric CF6-80A and CF6-
80C2 engines, Pratt & Whitney PW 4000 engines, and Rolls-Royce RB211-
524 engines. Such indication to the flight crew is required by part 25
of the Federal Aviation Regulations (14 CFR part 25), which establishes
the certification requirements for all transport category airplanes,
including the Models 747-400, 757, and 767.
Service experience has demonstrated that severe fuel contamination
can lead to fuel filter bypass, engine power loss, engine flameout, and
consequent airplane diversions. Fuel contaminants have been known to
adversely affect entire fuel systems on airplanes and, therefore, pose
a threat of complete loss of power on all engines. Clear indication to
the flight crew of an impending fuel filter bypass condition is
necessary in order to ensure that the flight crew is warned promptly of
conditions that could lead to a loss of power from one or more engines.
The engine indication and crew alerting system (EICAS) computers
installed on Model 747-400, 757, and 767 series airplanes use a multi-
level message system to provide indications of various conditions to
the flight crew. The levels of messages, in increasing order of
importance to the flight crew, are indicated as ``status,''
``advisory,'' ``caution,'' and ``warning.'' In general, ``status''
messages are used to ensure an acceptable airplane condition prior to
dispatch of the airplane. A ``status'' level message on the EICAS
computer is not considered to be an item that flight crews need to be
aware of during flight, or an item that would have any effect on the
flight planning considerations made by the flight crew.
The EICAS computers currently installed on all Model 747-400 and
757 series airplanes, and on certain Model 767 series airplanes, use a
``status'' level message to indicate impending engine fuel filter
bypass conditions. The FAA considers that this use of a ``status''
level message to indicate these conditions is an unsafe condition,
since such messages do not provide information to the flight crew at an
appropriate awareness level. Using a ``status'' level message to
indicate an impending engine fuel filter bypass condition could result
in the flight crew being unaware of a severely contaminated airplane
fuel system and the associated increased potential for engine power
loss. This condition, if not corrected, could result in the airplane
landing with reduced engine power, or the total loss of engine power
before the airplane is able to reach a suitable landing site.
It should be noted that the addressed unsafe condition pertains
only to situations involving gross fuel contaminants. Such contaminants
exceed the particulate size or concentration capabilities of what the
engine fuel filters are certified to handle. Additionally, the type of
gross fuel contaminants that are of concern do not include ice, which
can be eliminated by fuel heating. Contamination of airplane fuel
systems has occurred in the past and will likely occur in the future,
despite the many industry standards intended to maintain cleanliness of
the airplane fuel supply. Examples of such contamination found in
service include microbial growth, sealant, lint, metal particles, fuel
tank cleaning chemicals, and liquid fertilizer. There also have been
data indicating the existence of other contaminants in the fuel system
that, although unidentified, were severe enough to cause engine power
loss.
Since an unsafe condition has been identified that is likely to
exist on other products of this same type design, the proposed AD would
require, initially, a revision to the Limitations Section of the FAA-
approved Airplane Flight Manual (AFM) of affected airplanes that would
require the flight crew to respond to EICAS ``status'' level messages
that indicate impending engine fuel filter bypass conditions.
Information addressing the presence of multiple engine fuel filter
bypass messages would be contained in this AFM revision.
This proposed AD also would require the installation, on certain
airplanes, of upgraded EICAS computers that display an ``advisory''
level message to the flight crew to indicate that an impending engine
fuel filter bypass condition exists for each engine. Following
installation of the upgraded EICAS computers, the AFM information would
be required to be revised to be consistent with the displayed
information.
The upgraded EICAS installation would not be required for Model 767
airplanes powered by Pratt & Whitney JT9D engines, since those
airplanes are currently equipped with EICAS computers that provide the
level of indications that are otherwise proposed in this notice.
However, the AFM for those airplanes does not contain appropriate
information addressing these messages. Therefore, this proposed AD
would require revising the Limitations Section of that AFM to include
information addressing the situation where multiple advisory level
messages are present, indicating that multiple engine fuel filters are
in an impending bypass condition.
There are approximately 1,378 Model 747-400, 757, and 767 series
airplanes of the affected design in the worldwide fleet. The FAA
estimates that 588 airplanes of U.S. registry would be affected by this
proposed AD.
The proposed initial revision to the AFM would take approximately 1
work hour per airplane to accomplish, at an average labor rate of $60
per work hour. Based on these figures, the total cost impact of this
proposed action on U.S. operators is estimated to be $35,280, or $60
per airplane.
The FAA currently has no specific cost estimates associated with
the proposed installation of upgraded EICAS computers, since the
upgrade has not been developed yet. The FAA has been advised, however,
that the manufacturer is planning other changes to these EICAS
computers that are [[Page 27448]] necessary to provide for global
positioning system (GPS) navigation capability and other enhanced
features. The proposed compliance time of four years for the EICAS
installation requirements of this AD will allow a portion of the EICAS
computers installed on airplanes affected by this AD to have the
required EICAS message upgrade made coincidentally with those other
planned EICAS changes, thereby reducing the costs and scheduling impact
of such changes on operators. As indicated earlier in this preamble,
the FAA specifically invites the submission of comments and other data
regarding the economic aspect of this proposal.
The proposed revision to the AFM that would be required subsequent
to the installation of the upgraded EICAS computers would take
approximately 1 work hour per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the total cost
impact of this proposed action on U.S. operators is estimated to be
$35,280, or $60 per airplane.
The regulations proposed herein would not have substantial direct
effects 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. Therefore, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that 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);
and (3) if promulgated, 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. A copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
part 39 of the Federal Aviation Regulations (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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
Boeing: Docket 94-NM-140-AD.
Applicability: All Model 747-400, 757, and 767 series airplanes;
certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To ensure that the flight crew is appropriately aware of
conditions involving a severely contaminated airplane fuel system
and the associated increased potential for engine power loss,
accomplish the following:
(a) For all Model 747-400 series airplanes: Within 60 days after
the effective date of this AD, revise the Limitations Section of the
FAA-approved Airplane Flight Manual (AFM) to include the following
statement. This may be accomplished by inserting a copy of this AD
in the AFM.
``Respond to the EICAS STATUS CUE by checking for the following
status level messages(s):
ENG 1 FUEL FILT
ENG 2 FUEL FILT
ENG 3 FUEL FILT
ENG 4 FUEL FILT
If more than one of these impending fuel filter bypass messages
is displayed, airplane fuel system contamination may be present,
which can result in erratic engine operation and engine flameout.''
(b) For all Model 757 series airplanes, and Model 767 series
airplanes powered by General Electric CF6-80A and CF6-80C2 engines,
Pratt & Whitney PW 4000 engines, and Rolls-Royce RB211-524 engines:
Within 60 days after the effective date of this AD, revise the
Limitations Section of the FAA-approved Airplane Flight Manual (AFM)
to include the following statement. This may be accomplished by
inserting a copy of this AD in the AFM.
``Respond to the EICAS STATUS CUE by checking for the following
status level messages(s):
R ENG FUEL FILT
L ENG FUEL FILT
If more than one of these impending fuel filter bypass messages
is displayed, airplane fuel system contamination may be present,
which can result in erratic engine operation and engine flameout.''
(c) For Model 767 series airplanes powered by Pratt & Whitney
JT9D engines: Within 60 days after the effective date of this AD,
revise the Limitations Section of the FAA-approved Airplane Flight
Manual (AFM) to include the following statement. This may be
accomplished by inserting a copy of this AD in the AFM.
``If both of the following EICAS advisory level messages for
impending fuel filter bypass are displayed, and engine fuel icing is
not suspected (based on the fuel temperature being too high or
because engine fuel heat has been selected ``on''), airplane fuel
system contamination may be present, which can result in erratic
engine operation and engine flameout:
R ENG FUEL FILT
L ENG FUEL FILT''
(d) For all Model 747-400 series airplanes; all Model 757 series
airplanes; and Model 767 series airplanes powered by General
Electric CF6-80A and CF6-80C2 engines, Pratt & Whitney PW 4000
engines, and Rolls-Royce RB211-524 engines: Accomplish the
requirements of paragraph (d)(1) and (d)(2) of this AD:
(1) Within 4 years after the effective date of this AD, install
an upgraded engine indication and crew alerting system (EICAS)
computer that will provide ``advisory'' level messages to the flight
crew to indicate an impending engine fuel filter bypass condition
for each engine. The installation shall be accomplished in
accordance with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA, Transport Airplane Directorate.
(2) Coincidental with the installation required by paragraph
(d)(1) of this AD, remove the AFM revisions required by paragraphs
(a) and (b) of this AD, and revise the Limitations Section of the
AFM to advise the flight crew that impending engine fuel filter
bypass advisory level messages for multiple engines may indicate
contamination of the airplane fuel system, which can result in
erratic engine operation and engine flameout. The revision to the
Limitations Section must be approved by the Manager, Seattle ACO,
FAA, Transport Airplane Directorate.
(e) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Seattle ACO, FAA, Transport
Airplane Directorate. Operators shall submit their requests through
an appropriate FAA Principal Operations Inspector, who may add
comments and then send it to the Manager, Seattle ACO.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(f) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished. Issued in Renton,
Washington, on May 18, 1995. Original Signed By:
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-12710 Filed 5-23-95; 8:45 am]
BILLING CODE 4910-13-U
