[Federal Register Volume 59, Number 248 (Wednesday, December 28, 1994)]
[Unknown Section]
[Page ]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31913]
[Federal Register: December 28, 1994]
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Part VII
Department of Transportation
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Federal Aviation Administration
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14 CFR Part 23
Powerplant Instruments; Fuel Pressure Indication; Proposed Rule
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. 28011; Notice No. 94-37]
RIN 2120-AF41
Powerplant Instruments; Fuel Pressure Indication
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes to amend the certification requirement
for fuel pressure indicators on pump fed engines of small airplanes to
permit regulatory alternatives to warn pilots of fuel system problems.
A fuel pressure indicator is not the only means available to the pilot
of indicating a fuel system problem. The proposed change would allow
airplanes to be certificated with means that indicate fuel flow, or
that monitor the fuel system and warn the pilot of a trend that could
lead to engine failure. New technology that would be incorporated as
means of compliance with the revised rule could improve engine
operation and reduce airplane operating costs.
DATES: Comments must be received on or before February 27, 1995.
ADDRESSES: Comments on this document should be mailed in triplicate to:
Federal Aviation Administration, Office of the Chief Counsel,
Attention: Rules Docket (AGC-10), Docket No. 28011, 800 Independence
Avenue SW., Washington, DC 20591. Comments delivered must be marked
Docket No. 28011. Comments may be inspected in room 915G weekdays
between 8:30 a.m. and 5 p.m., except on Federal holidays.
In addition, the FAA is maintaining an information docket of
comments in the Office of the Assistant Chief Counsel, ACE-7, Federal
Aviation Administration, Central Region, 601 East 12th Street, Kansas
City, Missouri 64106. Comments in the information docket may be
inspected in the Office of the Assistant Chief Counsel weekdays, except
Federal holidays, between the hours of 7:30 a.m. and 4 p.m.
FOR FURTHER INFORMATION CONTACT:
J. Lowell Foster, Standards Office, Small Airplane Directorate,
Aircraft Certification Service, Federal Aviation Administration, 601
East 12th Street, Kansas City, Missouri 64106; telephone (816) 426-
5688.
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
they may desire. Comments relating to the environmental, energy, or
economic impact that might result from adopting the proposals in this
notice are also invited. Substantive comments should be accompanied by
cost estimates. Comments should identify the regulatory docket or
notice number and should be submitted in triplicate to the Rules Docket
address specified above. All comments received on or before the closing
date for comments specified will be considered by the Administrator
before taking action on this proposed rulemaking. The proposals
contained in this notice may be changed in light of comments received.
All comments received 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 substantive public
contact with Federal Aviation Administration (FAA) personnel concerned
with this rulemaking will be filed in the docket. Commenters wishing
the FAA to acknowledge receipt of their comments submitted in response
to this notice must include a preaddressed, stamped postcard on which
the following statement is made: ``Comments to Docket No. 28011.'' The
postcard will be date stamped and mailed to the commenter.
Availability of NPRM
Any person may obtain a copy of this NPRM by submitting a request
to the Federal Aviation Administration, Office of Public Affairs,
Attention: Public Inquiry Center, APA-200, 800 Independence Avenue,
SW., Washington, DC 20591, or by calling (202) 267-3484. Communications
must identify the notice number of this NPRM.
Persons interested in being placed on the mailing list for future
NPRMs should request, from the above office, a copy of Advisory
Circular No. 11-2A, Notice of Proposed Rulemaking Distribution System,
which describes the application procedure.
Background
Statement of the Problem
The FAA proposes to amend Title 14 of the Code of Federal
Regulations (CFR), Sec. 23.1305(b)(4), which currently requires a fuel
pressure indicator for each pump fed engine. The pressure indicator
gives continuous fuel pressure readings to the pilot. This information
provides an advance warning of engine failure only when a pilot notices
that the pressure reading has deviated from the norm, and the pilot can
diagnose what those deviations mean in terms of potential engine
failure. This proposal would allow the options of a fuel pressure
indicator, a fuel flow indicator, or a means that continuously monitors
the fuel system and warns the pilot of any engine trend that could
cause engine failure. A fuel flow indicator would give continuous fuel
flow readings to the pilot; fuel flow information can be more
meaningful to the pilot during critical phases of flight. The proposed
continuous fuel system monitoring would alert the pilot to any trend
that could lead to engine failure.
History
The first requirement for a fuel pressure indicator was found in
Civil Air Regulation (CAR) 4b, the predecessor to part 25 of Title 14
for transport airplanes. That requirement applied to all reciprocating
engine airplanes. CAR 3, applicable to small airplanes, followed CAR 4b
and was the predecessor to part 23 of Title 14. Amendment 1 to CAR 3,
adopted December 15, 1946, required fuel pressure indicators on
airplanes with pump-fed engines. Many small airplanes of that era used
gravity-fed fuel systems, which made a fuel pressure indication
unnecessary. Also, a fuel pressure indication was not required if the
fuel pump was certificated as part of the engine. Since early fuel
pumps were less reliable, the intent of the CAR requirements was to
provide the pilot with advance warning of a fuel pump failure. This
allowed the pilot to diagnose the problem and prevent engine failure or
determine the cause after the engine quit.
Engines of the CAR 3 era were designed with carburetors.
Carburetors were replaced by fuel injection. At the same time, radial
engines were being replaced with horizontally opposed engines, the
configurations currently used in the majority of light airplanes.
As horizontally opposed engines gained popularity and grew in
displacement, two different types of fuel injection systems emerged.
One consisted of a fuel injector or fuel metering unit that relied on a
separate constant pressure pump to supply fuel to the injector. Since
the metering (regulating) was done at the injector, the fuel pressure
required was not critical as long as the pump could provide a specific
range of pressures. For example, if the injector had a 20 psi
requirement, 23-30 psi pump pressure was acceptable because the fuel
pressure on the outlet side of the injector was 20 psi. But, if the
pressure out of the pump fell below 20 psi, the injector would fail to
provide adequate fuel to the engine.
The second type of fuel injection system used a fuel pump in which
pressure was proportional to engine RPM. This pump is still referred to
as a speed-sensing integral fuel pump. Any change in pump pressure
resulted in a change in engine operation.
Regulatory interpretation resulted in confusion over what was
acceptable for fuel pressure monitoring, including the requirements for
the content of indicated information and the pressure pick-up location.
Some installations utilizing the constant pressure pump were required
to have a pressure indicator measuring unmetered fuel pressure at the
fuel pump output. On the other hand, installations using the speed-
sensing integral pump system were approved with a fuel pressure
indicator measuring metered fuel pressure at the fuel distribution
valve. Airplanes utilizing this system have a fuel pressure indicator
labeled in fuel used per hour or fuel flow. Agency policy, briefing
paper from Central Region dated October 7, 1981, accepted these fuel
pressure indicators as an equivalent means of compliance if the engine
was certificated with an integral speed-sensing pressure pump.
The Aircraft Owners and Pilots Association (AOPA) petitioned the
FAA for new standards that would allow, on all pump-fed engines, a fuel
flow system employing a differential pressure transducer to be accepted
as an equivalent means of compliance to the current fuel pressure
indicator requirements (55 FR 39299; September 26, 1990). The AOPA
believes that adopting its petition would open the door for the
development of new and valuable engine monitoring equipment, while
potentially reducing the instrument panel clutter.
In its petition, the AOPA states that one of the reasons for
current Sec. 23.1305(b)(4) is to give the pilots sufficient warning of
any decreasing trend that could lead to partial or total engine
failure. The AOPA also states that differential pressure indicators
should be accepted as a means of compliance with Sec. 23.1305(b)(4),
not that direct sensing systems should be removed from part 23.
Following receipt of the AOPA's petition for rulemaking, the FAA
requested that the Aviation Rulemaking Advisory Committee (ARAC) review
the petition and recommended a course of action to the FAA. The ARAC
was chartered in February 1991, under the Federal Advisory Committee
Act, to provide recommendations to the FAA Administrator on FAA
rulemaking activity relating to aviation safety issues.
In January 1992, the Fuel Indicators Working Group of the ARAC on
General Aviation and Business Airplane Issues began review of the
AOPA's petition. Subsequently, the ARAC, recommended that the FAA
revise the certification standards for fuel pressure indicators. The
ARAC agreed with the AOPA's petition to allow a pressure-based fuel
flow system, but felt that there may be other options in the future,
and that the AOPA's language regarding a differential pressure
transducer would be too restrictive. Technical advances in the
automobile industry with engine systems and controls may offer
improvements over the current warning systems. The ARAC did not want
the proposed rule to be limited to a fuel pressure or pressure-based
fuel flow gauge.
General Discussion of the Proposals
Section 23.1305
The intent of the fuel pressure indicator requirement for pump-fed
engines is to advise the pilot of a fuel pressure deficiency before
total engine failure. The term ``indicator'' in Sec. 23.1305(b)(4)
implies that the fuel pressure be constantly displayed.
This proposal would change the current requirements in that a fuel
pressure indicator or a fuel flow indicator would be acceptable. The
fuel flow indicator would constantly display information that the pilot
could use to evaluate engine power, fuel mixture, and other engine
performance factors. Furthermore, it is technologically possible to
have a microprocessor that monitors engine operation and triggers a
warning if the fuel system operation does not match the other monitored
engine trends. Therefore, this proposal would also change the rule to
accept a means that monitors the fuel system and warns the pilot of any
trend that could lead to engine failure.
Accordingly, this proposal would adopt a performance standard,
instead of a requirement for specific equipment. In this way, the
designer could show compliance with paragraph (b) of the proposal by
developing any design that monitors the fuel system and warns the pilot
of any trend that could lead to engine failure. The ARAC did not
believe this would reduce the level of safety originally intended by
the requirement. A warning light system could possibly alert the pilot
sooner than if the pilot relied on an instrument panel scan to notice a
trend in the fuel pressure indication.
Microprocessing units that monitor engine operation and warn of
fuel system problems have already been incorporated in transport
aircraft and automobiles. Furthermore, pilots are not monitoring gauges
like they use to; instead, they are increasingly relying on warnings to
alert them. Late model automobiles, computers and other equipment are
designed to protect the operators from mistakes by using built-in
warnings. It is important to note that this NPRM does not propose to
allow ``idiot lights'' to replace fuel pressure gauges. A light that
comes on at the same time that the engine quits is useless. A warning
light system that would comply with this proposal would be
sophisticated enough to read transients and trends, and would give a
useful warning to the pilot. The FAA expects this proposal to result in
fuel systems that provide the pilot with useful engine operating
information; thereby, it would offer more value to the operator.
Today, fuel pumps are more reliable than those built in the 1940's
and 50's. Consequently, airplane operators are more concerned about
reducing engine operating costs than they are about the probability of
a fuel pump failure.
A fuel flow indicator offers additional value compared to a fuel
pressure indicator. It enables the operator to monitor the engine's
fuel consumption and compare it to fuel consumption listed in the
airplane flight manual. If a fuel monitoring system is installed that
automatically controls the engine or helps the pilot to properly lean
the fuel mixture, then engine operation would be optimized and the
direct operating costs would go down through reduced fuel consumption.
Reciprocating engines run better if the fuel to air mixture is leaned
out according to the optimum (manufacturer's) specified setting.
Furthermore, fuel flow also relates to power, and pilots can use fuel
flow readings to quickly assess the health of their engine during
critical phases of flight, such as takeoff.
Comprehensive engine monitors and redesigned electronic engine
instrument displays are also being used in experimental aircraft. The
FAA should encourage airplane manufacturers to utilize new technology
to improve operation and reduce operating costs. New engine monitoring
systems may improve reliability and engine life, resulting in increased
safety.
The proposal would achieve the same safety objective as the current
rule; the crew would have sufficient warning of any negative trend that
could lead to partial or total engine failure. However, the proposal
recognizes that this objective can be achieved by measuring fuel
pressure, fuel flow, or with a ``smart'' fuel monitoring system.
International Compatibility
The agency has reviewed corresponding International Civil Aviation
Organization international standards and recommended practices and
Joint Aviation Authorities requirements for compatibility.
Paperwork Reduction Act
In accordance with the Paperwork Reduction Act of 1990 (44 U.S.C.
3501 et seq.), there are no reporting or recordkeeping requirements
associated with this proposed rule.
Regulatory Evaluation Summary
Proposed changes to federal regulations must undergo several
economic analyses. First, Executive Order 12866 directs Federal
agencies to promulgate new regulations or modify existing regulations
only if the potential benefits to society outweigh the potential costs.
Second, the Regulatory Flexibility Act of 1980 requires agencies to
analyze the economic impact of regulatory change son small entities.
Finally, the Office of Management and Budget directs agencies to assess
the effects of regulatory change son international trade. In conducting
these analyses, the FAA has determined that this rule: (1) Would
generate benefits exceeding its costs and is not significant as defined
in Executive Order 12866; (2) is not significant as defined in DOT's
Policies and Procedures; (3) would not have a significant economic
impact on small entities; and (4) would not affect international trade.
These analyses, available in the docket, are summarized below.
Cost-Benefit Analysis
Since the proposed rule would permit but not require alternative
means of warning pilots of fuel system problems, it is inherently cost-
beneficial. To the extent that it would encourage the development and
utilization of comprehensive engine control, monitoring and diagnostic
systems in the future, it would contribute benefits in the form of
enhanced safety, improved fuel efficiency, power output, and engine
life.
Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (RFA) was enacted by
Congress to ensure that small entities are not unnecessarily and
disproportionately burdened by government regulations. The RFA requires
a Regulatory Flexibility Analysis if a rule would have a significant
economic impact, either detrimental or beneficial, on a substantial
number of small entities. Based on criteria in FAA Order 2100.14A,
Regulatory Flexibility Criteria and guidance, the FAA has determined
that the proposed rule would not have a significant economic impact on
a substantial number of small manufacturers or operators.
International Trade Impact Assessment
The proposed rule would not constitute a barrier to international
trade, including the export of U.S. airplanes to foreign markets or the
import of foreign airplanes into the United States.
Federalism Implications
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 12866, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
Conclusion
The FAA proposes to amend the airworthiness standards to allow
airplane manufacturers to utilize new technology for fuel system
monitoring to improve the operation and economy of part 23 airplanes
powered by pump-fed engines. The current requirements provide for a
fuel pressure indication; it, thus, limits the means of compliance. The
advances in automobile engine monitoring systems and electronics offer
technology that should be utilized by the aviation community. By
broadening this airworthiness standard, fuel flow indicators or new
fuel system monitors may be utilized that will provide more useful
information to the pilot.
For the reasons discussed in the preamble, and based on the
findings in the Regulatory Flexibility Determination and the
International Trade Impact Analysis, the FAA has determined that this
proposed regulation is not significant under Executive Order 12866. In
addition, the FAA certifies that this proposal, if adopted, 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. This proposal is not considered significant
under DOT Regulatory Policies and Procedures (44 FR 11034; February 26,
1979). An initial regulatory evaluation of the proposal, including a
Regulatory Flexibility Determination and Trade Impact Analysis, has
been placed in the docket. A copy may be obtained by contacting the
person identified under FOR FURTHER INFORMATION CONTACT.
List of Subjects in 14 CFR Part 23
Aircraft, Air transportation, Aviation safety, Safety.
The Proposed Amendment
In consideration of the foregoing, the Federal Aviation
Administration proposes to amend part 23 of the Federal Aviation
Regulations (14 CFR part 23) as follows:
PART 23--AIRWORTHINESS STANDARDS; NORMAL, UTILITY, ACROBATIC, AND
COMMUTER CATEGORY AIRPLANES
1. The authority citation for part 23 continues to read as follows:
Authority: 49 U.S.C. 1344, 1354(a), 1355, 1421, 1423, 1425,
1428, 1429, 1430; 49 U.S.C. 106(g).
2. Section 23.1305 is amended by revising paragraph (b)(4) to read
as follows:
Sec. 23.1305 Powerplant instruments.
* * * * *
(b) * * *
(4) For each pump-fed engine, a means:
(i) That continuously indicates, to the pilot, the fuel pressure or
fuel flow; or
(ii) That continuously monitors the fuel system and warns the pilot
of any trend that could lead to engine failure.
* * * * *
Issued in Washington D.C. on December 21, 1994.
Elizabeth Yoest,
Acting Director, Aircraft Certification Service.
[FR Doc. 94-31913 Filed 12-27-94; 8:45 am]
BILLING CODE 4910-13-M
