[Federal Register Volume 63, Number 27 (Tuesday, February 10, 1998)]
[Proposed Rules]
[Pages 6826-6827]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-3344]
[[Page 6825]]
_______________________________________________________________________
Part VI
Department of Transportation
_______________________________________________________________________
Federal Aviation Administration
_______________________________________________________________________
14 CFR Part 135
Commercial Passenger-Carrying Operations in Single-Engine Aircraft
Under Instrument Flight Rules; Proposed Rule
Federal Register / Vol. 63, No. 27 / Tuesday, February 10, 1998 /
Proposed Rules
[[Page 6826]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 135
[Docket No. 28743; Notice No. 98-11]
RIN 2120-AG55
Commercial Passenger-Carrying Operations in Single-Engine
Aircraft Under Instrument Flight Rules
AGENCY: Federal Aviation Administration, DOT.
AGENCY: Notice of proposed rulemaking.
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SUMMARY: The Federal Aviation Administration (FAA) is proposing to
revise and clarify certain conditions and limitations in Part 135 for
instrument flight rule (IFR), passenger-carrying operations in single-
engine aircraft. The clarification is necessary to resolve ambiguity in
the current rule over the requirement for redundant power for
gyroscopic instrumentation. The intended effect of this action is to
remove any ambiguity concerning the required power sources for the
gyroscopic instruments required for flight under IFR for single engine
aircraft involved in commercial, passenger carrying operations.
DATES: Comments must be received by March 12, 1998.
ADDRESSES: Comments on this notice should be submitted in triplicate
to: Federal Aviation Administration, Office of the Chief Counsel, Attn:
Rules Docket (AGC-200), Room 915-G, Docket No. 28743, 800 Independence
Ave., SW, Washington, DC 20591.
Comments must be marked Docket No. 28743. Comments also may be
submitted electronically to the following Internet address: cmts@faa.dot.gov. Comments may be examined in room 915G weekdays
between 8:30 a.m. and 5 p.m. except on Federal holidays.
FOR FURTHER INFORMATION CONTACT: Mr. Dan Meier, Flight Standards
Service, Federal Aviation Administration, 800 Independence Ave., SW,
Washington, DC, 20591 (202) 267-8166.
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,
federal, or economic impact that might result from adopting the
proposals in this notice are also invited. Substantive comments should
be accompanied by cost estimates, if appropriate. 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 specified closing date for comments 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 dates for comments, in the Rules
Docket for examination by interested persons. A report summarizing each
substantive contact with 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 pre-addressed, stamped postcard on which the following
statement is made: ``Comments to Docket No. 28743.'' The postcard will
be date stamped and returned to the commenter.
Availability of NPRMs
An electronic copy of this document may be downloaded, using a
modem and suitable communications software, from the FAA regulations
section of the Fedworld electronic bulletin board service (703) 321-
3339), the Federal Register's electronic bulletin board service ((202)
512-1661), or the FAA's Aviation Rulemaking Advisory Committee Bulletin
Board service ((800) 322-2722 or (202) 267-5948).
Internet users may reach the FAA's web page at http://www.faa.gov
or the Federal Register web page at http://www.access.gpo.gov/su__ docs for access to recently published rulemaking documents.
Any person may obtain a copy of this NPRM by submitting a request
to the Federal Aviation Administration, Office of Rulemaking, ARM-1,
800 Independence Ave, SW, Washington, DC 20591, or by calling (202)
267-9677. Communications must identify the notice number or docket
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
On August 6, 1997, the FAA published Amendment 135-70 (62 FR 42364)
that allowed commercial, passenger-carrying operations under IFR in
single-engine aircraft under certain conditions and limitations, and
eliminates the limited IFR provision of the current rule. The effective
date for the new rule is May 4, 1998 (62 FR 45014) to allow operators
to obtain the necessary parts and approvals, to modify their operations
manuals and specifications, and to retrofit their aircraft. The FAA
also established Special Federal Aviation Regulations (SFAR) 81 to
accommodate those operators who may be ready to meet the requirements
of the rule sooner than the effective date.
Discussion of the Proposed Rule
Current SFAR 81, paragraph 2(b) and 14 CFR 135.163(h) require
single-engine, passenger-carrying aircraft flying IFR to have two
independent sources of energy (with means of selecting either), of
which at least one is an engine-driven pump or generator, each of which
is able to drive all gyroscopic instruments and installed so that
failure of one instrument or source does not interfere with the energy
supply to the remaining instruments or the other energy source.
A question was raised as to whether this requirement would allow
the use of a ``split panel,'' in which gyroscopic instruments could be
driven by different energy sources, including vacuum, bleed air, or
electrical sources. This question was also raised when the original
requirement for dual sources of energy for gyroscopic instruments was
promulgated. In the October 10, 1978 (43 FR 46769) preamble discussion
regarding Sec. 135.163(h), the Agency stated that:
Other commenters state that Sec. 135.163 prohibits ``splitting''
gyro instruments between electrical and vacuum sources and that
defeats safety. For instrument panels with both electric and vacuum
instruments, a pump or generator is unable to drive all gyroscopic
instruments. The pilot must be able to select an energy source which
will drive all gyros if the other source fails. Anything less under
IFR conditions would derogate safety. Where a split panel is
desired, each engine must have both a generator and a vacuum pump.
(emphasis added)
Thus, in October 1978, the Agency clearly contemplated that split
panels would be used and that failure of one energy source must not
impact the operation of the gyroscopic instruments. This requirement
can readily be met by multi-engine aircraft because 14 CFR parts 23 and
135 require each independent source of energy to be on separate engines
and that the means of selecting the energy source be either automatic
or manual. For single-engine aircraft, however, the issue centers on
[[Page 6827]]
whether one energy source must be able to drive all gyroscopic
instruments. While a single engine airplane does not provide engine
redundancy, system redundancy is still required for each gyroscopic
instrument.
Therefore, the FAA has determined that a ``split panel,'' i.e.,
instruments driven by separate and independent sources, is an
acceptable configuration for single-engine aircraft provided that each
required gyroscopic instrument has a redundant energy source. This
means that if any one energy source fails, all gyroscopic instruments
must remain operable. This does not mean, however, that each source
must drive all of the instruments, but rather that the failure of any
one source would not result in the loss of energy to any gyroscopic
instrument powered by that energy source.
For example, an acceptable configuration would be a gyroscopic
direction indicator powered by redundant electrical sources, and a
gyroscopic pitch and bank indicator (with artificial horizon) powered
by bleed air and vacuum sources. Failure of any one energy source would
not affect operation of all of the gyroscopic instruments. Thus, in
this example, if one electrical source fails there is a redundant
electrical system to power the direction indicator, and the artificial
horizon indicator continues to be powered by the vacuum or bleed air
system.
Therefore, to clarify that although each independent source of
energy need not drive all gyroscopic instruments, and that each
gyroscopic instrument must be powered by redundant sources, the Agency
has deleted the phrase ``all gyroscopic instruments,'' and has replaced
it with the phrase ``all gyroscopic instruments powered by, or to be
powered by, that particular source.''
The FAA also wishes to clarify that where single-engine, passenger-
carrying IFR operations are flown with a single pilot and an autopilot,
only the gyroscopic instruments on the pilot's panel need be operable
and powered by redundant energy sources. However, where such operation
is to be flown with both a pilot and a co-pilot, the gyroscopic
instruments on both panels must be operable and powered by redundant
energy sources.
Another question was raised as to the meaning of the phrase ``means
of selecting either,'' as it pertains to energy source redundancy. As
discussed above, Sec. 23.1331(c) requires that the means of selecting
energy sources be either automatic or manual. In the example cited
above, Sec. 23.1331 would be met because when the direction indicator
failed, the redundant electrical source powering that instrument
automatically allowed for its continued operation.
Regulatory Analyses
The FAA is proposing this change because some commenters to the
final rule on Commercial Passenger-Carrying Operations in Single-Engine
Aircraft under Instrument Flight Rules had questions on the redundant
sources of power to the gyroscopic flight instruments. This propose
change will alleviate any ambiguity and clarify the regulatory
requirements. Therefore, the FAA has determined that this regulation
imposes no additional burden on any entity. Accordingly, it has been
determined that the action (1) is not significant under Executive Order
12866 and (2) is not a significant rule under the Department of
Transportation Regulatory Policies and Procedures (44 FR 11034;
February 26, 1979). Also, because this proposed amendment is editorial
in nature, no impact is expected to result and a full regulatory
evaluation is not required. In addition, the FAA certifies that this
proposal will not have a significant economic impact, either positive
or negative, on a substantial number of small entities under the
criteria of the Regulatory Flexibility Act.
International Trade Impact
The proposed amendment would not impose any costs on either U.S. or
foreign operators. Therefore, a competitive trade disadvantage would
not be incurred by either U.S. operators abroad or foreign operators in
the United States.
Paperwork Reduction Act
This proposed rule contains no information collection requests
requiring approval of the Office of Management and Budget pursuant to
the Paperwork Reduction Act (44 U.S.C. 3507 et seq.).
List of Subjects in 14 CFR Part 135
Air taxis, Aircraft, Aviation safety, Safety, Single-engine
aircraft.
For the reasons set out in the preamble, 14 CFR part 135 is
proposed to be amended as set forth below:
PART 135--OPERATING REQUIREMENTS: COMMUTER AND ON-DEMAND OPERATIONS
1. The authority citation for part 135 continues to read as
follows:
Authority: 49 U.S.C. 106(g), 40113, 44701-44702, 44705, 44709,
44711-44713, 44715-44717, 44722.
SFAR No. 81 [Amended]
2. Paragraph 2(b) of Special Federal Aviation Regulation No. 81 is
revised to read as follows:
SFAR No. 81--Passenger-Carrying Single-Engine IFR Operations
2. * * *
(a) * * *
(b) Two independent sources of energy (with means of selecting
either) of which at least one is an engine-driven pump or generator,
each of which is able to drive all gyroscopic instruments powered by,
or to be powered by, that particular source and installed so that
failure of one instrument or source does not interfere with the energy
supply to the remaining instruments or the other energy source, unless,
for single-engine aircraft in all cargo operations only, the rate of
turn indicator has a source of energy separate from the bank and pitch
and direction indicators. For the purpose of this paragraph, for multi-
engine aircraft, each engine-driven source of energy must be on a
different engine.
* * * * *
3. Section 135.163 is amended by revising paragraph (h) to read as
follows:
Sec. 135.163 Equipment requirements: Aircraft carrying passengers
under IFR.
* * * * *
(h) Two independent sources of energy (with means of selecting
either) of which at least one is an engine-driven pump or generator,
each of which is able to drive all gyroscopic instruments powered by,
or to be powered by, that particular source and installed so that
failure of one instrument or source, does not interfere with the energy
supply to the remaining instruments or the other energy source unless,
for single-engine aircraft in all cargo operations only, the rate of
turn indicator has a source of energy separate from the bank and pitch
and direction indicators. For the purpose of this paragraph, for multi-
engine aircraft, each engine-driven source of energy must be on a
different engine.
* * * * *
Issued in Washington, D.C. on February 4, 1998.
Thomas E. Stuckey,
Director, Flight Standards Service.
[FR Doc. 98-3344 Filed 2-9-98; 8:45 am]
BILLING CODE 4910-13-M
