[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]



=======================================================================
-----------------------------------------------------------------------

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).

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

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