[Federal Register Volume 62, Number 151 (Wednesday, August 6, 1997)]
[Rules and Regulations]
[Pages 42364-42374]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-20641]



[[Page 42363]]

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Part IV





Department of Transportation





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Federal Aviation Administration



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14 CFR Part 135



Commercial Passenger-Carrying Operations in Single-Engine Aircraft 
Under Instrument Flight Rules; Final Rule

Federal Register / Vol. 62, No. 151 / Wednesday, August 6, 1997 / 
Rules and Regulations

[[Page 42364]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 135

[Docket No. 28743; Amendment No. 135-70]
RIN 2120-AG22


Commercial Passenger-Carrying Operations in Single-Engine 
Aircraft Under Instrument Flight Rules

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

SUMMARY: The Federal Aviation Administration (FAA) is amending the 
conditions and limitations in part 135 for instrument flight rule 
(IFR), passenger-carrying operations in single-engine aircraft. The 
rule will expand the passenger-carrying provisions of the current rule, 
add equipment requirements, as well as maintenance requirements to 
monitor engine reliability, and remove the limited IFR provisions of 
the existing rule for both single and multi-engine aircraft. Visual 
flight rules (VFR) flight into instrument meteorological conditions 
(IMC) is the most significant cause of fatal accidents in Alaska and is 
a serious problem for single-engine aircraft nationally. This action 
will increase the safety of single-engine, passenger-carrying 
operations by allowing planned instrument flight in the IFR system and 
by imposing certain other conditions and limitations.

DATEs: The rule is effective May 3, 1998, except for SFAR No. 81. 
Pending OMB clearance on the paperwork requirements, SFAR No. 81 is not 
effective until the FAA publishes in the Federal Register a document 
specifying the effective date. Comments on the clarification of 
Secs. 135.163(f)(2), 135.411(c), and/or 135.421 (c) and (d), including 
the paperwork requirements, must be received on or before September 5, 
1997.

ADDRESSES: Comments on the clarification of sections 135.163(f)(2), 
135.411(c), and/or 135.421 (c) and (d), including the paperwork 
requirements, should be submitted 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.

FOR FURTHER INFORMATION CONTACT: Ms. Katherine Hakala, Flight Standards 
Service, Federal Aviation Administration, 800 Independence Ave., SW, 
Washington, DC 20591, (202) 267-8166/3760.

SUPPLEMENTARY INFORMATION: 

Availability of Final Rule

    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's web page a http://www.access.gpo.gov/su__docs for access to 
recently published rulemaking documents.
    Any person may obtain a copy of this final rule 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 amendment number or 
docket number of this final rule.
    Persons interested in being placed on the mailing list for future 
rules 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.

I. Background

    Prior to October 10, 1978, passenger-carrying, single-engine 
instrument flight rule (SEIFR) operations were permitted if an aircraft 
could descend to visual flight rules (VFR) conditions in the event of 
an engine failure. This provision allowed operations in instrument 
meteorological conditions (IMC) or over-the-top of a ceiling, as long 
as VFR conditions existed below that ceiling (i.e., a buffer zone). In 
1978, part 135 was substantially revised for passenger-carrying 
operations over the top or in IFR conditions to require an aircraft to 
be able to descend under VFR if its engine fails (43 FR 46742; October 
10, 1978). This revision also provided for ``limited IFR'' operations 
which, if VFR conditions were forecast within 15 minutes flying time, 
allowed flight in IMC for the first 15 minutes of flight, and 
thereafter only if those IFR conditions were unforecast. Under the 
current regulation, a pilot can operate in IFR conditions if unforecast 
weather conditions are encountered while en route on a flight planned 
to be conducted under VFR. The pilot can make an IFR approach at the 
destination airport if unforecast weather conditions are encountered 
that do not allow an approach under VFR. This rule had the effect of 
eliminating the buffer zone provisions, restricting planned flights 
under IFR in IMC, and restricting VFR over-the-top flights to scattered 
or broken sky conditions. An exception to the two pilot requirement, or 
autopilot requirement, is provided for limited IFR operations in 
Sec. 135.103. Currently, limited IFR can be conducted as a single-pilot 
operation in aircraft with nine or fewer passenger seats. Cargo-only, 
single-engine aircraft can operate under IFR over the top without these 
restrictions.
    Since 1978, the FAA has received 12 petitions for exemptions from, 
or amendments to Sec. 135.181 to allow the use of all or specific 
models of single-engine aircraft in passenger-carrying IFR operations. 
Internationally, commercial operators in several countries have sought 
permission to conduct passenger operations in IMC with single-engine 
aircraft. Canada, following a cooperative effort with the engine 
manufacturers, aircraft manufacturers, and users that produced a well-
documented case, has allowed SEIFR passenger-carrying operations in 
turbine-powered airplanes since February 1993, with a number of 
specific requirements for equipment and training. Other countries are 
also considering permitting SEIFR passenger-carrying operations.
    In response to the petitions, the Canadian action, and changes in 
technology that have resulted in increasingly reliable engines and 
aircraft systems, the FAA asked its Office of Integrated Safety 
Analysis to conduct a study to determine if demonstrable differences 
exist between single- and multi-engine aircraft in visual 
meteorological conditions (VMC) and IMC. The study, Part 135 Single-
Engine Instrument Flight Rules Operations in instrument Meteorological 
Conditions, February 24, 1994, (available in the docket) reviewed the 
basis for the Canadian action and available data from a number of 
sources on powerplant/systems reliability and activity exposure data.
    In September 1994, the FAA asked the Aviation Rulemaking Advisory 
Committee (ARAC) to review the Canadian policy on SEIFR, re-examine FAA 
policies for commercial IMC and night operations by single-engine 
aircraft, determine conditions or limitations that such operations 
should meet, and recommend any changes. The ARAC formed a working group 
that included representatives of the FAA, Transport Canada-Aviation, 
the European Joint Aviation Authority (JAA), Australian Civil Aviation, 
several European national aviation authorities,

[[Page 42365]]

aircraft and engine manufacturers, trade associations, pilot unions, 
and commercial operators. The committee recommended that Sec. 135.181 
be revised to permit SEIFR passenger-carrying operations provided 
certain requirements for equipment and training were met. The ARAC 
proposal, although not technically limited to a particular type of 
aircraft, proposed certain conditions that are met at present only by 
turbine-powered aircraft. The ARAC also recommended approval of the 
Alaska Air Carrier Association's (AACA) petition for exemption, which 
covers both turbine-powered and reciprocating engine aircraft. Both the 
ARAC and the FAA study focused on the issue of engine reliability.
    In 1995, the National Transportation Safety Board (NTSB) completed 
a study of operations in Alaska, Aviation Safety in Alaska, (Safety 
Study NTSB/SS-95/03, PB95-917006, November, 1995). The NTSB noted that, 
unlike the rest of the U.S., commuter airline service in Alaska is 
``dominated by single-engine airplanes powered by a reciprocating 
engine operating under VFR and crewed by one pilot.'' After reviewing 
Alaska aviation accidents from 1988 to 1993 (which include single and 
multi-engine aircraft), the NTSB concluded that ``VFR flight into IMC 
that result in fatal accidents continues to be the most significant 
safety problem in Alaskan aviation.'' VFR flight in IMC in Alaska 
accounted for 67 percent (6 of 9) fatal commuter airline accidents and 
47 percent (7 of 15) of the fatal air taxi accidents. Overall, in 
Alaska, VFR flight into IMC accounted for only 15 percent of the total 
accidents, but 54 percent of the fatal accidents. The NTSB recommended 
that the FAA proceed with rulemaking to allow SEIFR passenger-carrying 
operations in turbine-powered aircraft and evaluate whether extending 
the rule to all single-engine aircraft would provide a positive effect 
on safety.
    Prior to the Alaska aviation study, the NTSB conducted a study of 
emergency medical service (EMS) helicopters because their accident rate 
was twice the rate experienced by part 135 on demand helicopter 
operations and one and one-half times the rate for all turbine-powered 
helicopters. For the report, Safety Study--Commercial Emergency Medical 
Service Helicopter Operations (NTSB 1988), the NTSB investigated and 
evaluated 59 helicopter accidents in the rapidly growing commercial EMS 
helicopter industry. The Board determined that marginal weather 
conditions and inadvertent flight into IMC remain the most serious 
hazard that VFR helicopters encounter. ``The Board believes that 
although the IFR system is not designed optimally for IFR helicopters 
and that the nature of the EMS helicopter mission further complicates 
this problem, the safety advantages offered by IFR helicopters flown by 
current and proficient pilots are great enough that EMS programs should 
seriously consider obtaining this capability.''
    The Alaska Air Carriers Association in its petition for exemption 
has stated, and the NTSB study confirmed, that in many areas, only 
single-engine aircraft can be operated because of the limitations of 
the landing strips, which severely restrict the availability of air 
transport in these areas. The petitioners further stated that under the 
current rule, unless clear weather is forecast over the entire route 
from 15 minutes from the departure airport to the destination, 
passenger-carrying, single-engine commercial operations are not 
permitted. In many areas, aircraft are the only means of 
transportation; weather forecasts, when available, rarely predict 
continuing VFR conditions. Alaska, they stated, was particularly 
disadvantaged by the current rule.
    The FAA reviewed accident data from 1983 to 1996 on both 
reciprocating and turbine engines. Data indicated that there were 67 
accidents in on-demand operations that involved VFR flight into IFR 
conditions; single-engine aircraft were involved in 75 percent of these 
accidents. Although the number of such accidents is known, the rate of 
such accidents cannot be determined because the FAA does not collect 
data on the number of flights or flight hours for on-demand operations 
under part 135.
    Based on its analyses, the FAA, on December 3, 1996 (61 FR 64230), 
issued a notice of proposed rulemaking (NPRM) to amend part 135 to 
allow passenger-carrying SEIFR operations subject to the following 
conditions:
    <bullet> Each certificate holder should incorporate into their 
manufacturer's recommended maintenance program or FAA-approved 
maintenance program an engine trend monitoring program including an oil 
analysis at each 100 hours interval and a record of the findings; and
    <bullet> Each aircraft should have two independent electrical power 
generating sources or a standby battery that can maintain 150 percent 
of the minimum electrical load for at least one hour to operate 
navigation and communication equipment.
    The FAA proposed to eliminate the limited IFR provisions, permitted 
under the previous rule, for both single and multi-engine aircraft. In 
addition, the FAA sought comments on the need for redundant power 
sources for gyroscopic instruments. As the NPRM noted, allowing SEIFR 
operations also imposed on such operations all of the existing 
requirements for IFR operations, including additional equipment, an 
autopilot or second pilot, increased pilot experience, and more pilot 
training.
    In response to the NPRM, the FAA received over 200 comments from 
government entities, trade associations, pilots, air carriers, 
manufacturers, and individuals. Seven comments opposed all or part of 
the proposed rule. Today's final rule reflects a consideration of the 
comments received, which are discussed in Section III.

II. Overview of the Final Rule

    The rule promulgated today allows SEIFR operations in both turbine-
powered and reciprocating engines subject to the following conditions:
    <bullet> The certificate holder must incorporate into its 
maintenance program either the manufacturer's recommended engine trend 
monitoring program, which includes oil analysis, if appropriate, or an 
FAA approved engine trend monitoring program that includes an oil 
analysis at each 100 hour interval or at the manufacturer's suggested 
interval, whichever is more frequent; the certificate holder must 
maintain a record of the results from these trend monitoring programs 
in the engine maintenance records.
    <bullet> Each aircraft must have two independent electrical power 
generating sources each of which is able to supply all probable 
combinations of continuous inflight electrical loads for required 
instruments and equipment; or in addition to the primary electrical 
power generating source, a standby battery or an alternate source of 
electric power that is capable of supplying 150% of the electrical 
loads of all required instruments and equipment necessary for safe 
emergency operation of the aircraft for at least one hour.
    <bullet> Each aircraft must 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 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.

[[Page 42366]]

    Allowing SEIFR operations means that any certificate holder 
conducting such operations must meet all existing requirements for IFR 
operations, including those for equipment (e.g., vertical speed 
indicator, free-air temperature indicator, heated pilot tube, marker 
beacon receiver), crew (a second pilot or autopilot), pilot training 
and testing (proficiency check every six months), and pilot experience 
(1,200 hours). The new requirements will ensure that operators have an 
engine trend monitoring program, as well as written maintenance 
instructions. In addition, the rule requires that aircraft have 
redundant systems to provide needed power to maintain critical flight 
instruments as well as the necessary navigation and communications 
capability.
    Because the FAA is deleting the limited IFR provision, this rule 
will not take effect until May 3, 1998. This will allow operators the 
time to obtain the required equipment, retrofit aircraft, and revise 
their operations authority and manuals. Limited IFR provisions will 
remain in effect until that time. The FAA is also adopting a Special 
Federal Aviation Regulation (SFAR) No. 81 that will allow operators who 
can meet the requirements of the rule to begin SEIFR operations prior 
to the effective date of the rule, provided an information collection 
is approved and an OMB control number is assigned. Therefore, the SFAR 
will not take effect until the FAA has published a notice in the 
Federal Register specifying the effective date. It is anticipated that 
this notice will be published within 60 days.
    As explained in the NPRM, in the past, the rationale against SEIFR 
passenger-carrying operations centered on the hazards of losing an 
engine. Analysis indicates, however, a far more significant accident 
category: Flight under VFR into IMC. As discussed above, a recent NTSB 
study of aviation in Alaska indicated that VFR flight into IMC caused a 
disproportionate number of fatal accidents in part 135 operations in 
that state. Multi-engine airplanes are able to file and fly with 
passengers under IFR, while single-engine airplanes are only able (with 
few exceptions) to carry passengers under VFR. Thus, multi-engine 
airplanes have the advantage of contact with ATC, position following, 
en route and terminal weather information, and the higher altitude 
ensuring obstacle clearance and radio reception in the IFR system. 
Further, for IFR operations, part 135 requires additional fuel to be 
carried, and more stringent weather reporting requirements.
    The FAA Administrator, in a November 18, 1994 letter to pilots 
(``Winter Operations Emphasis Program 1994,'' available in the docket), 
expressed his concern about the number of accidents that occur when 
pilots are flying just below a low ceiling and collide with the 
terrain. He stated that one of the safest steps available was to take 
advantage of the IFR system. Aircraft flying at a published cruising 
altitude that guarantees obstacle clearance and radio reception have 
considerably more time to glide to a landing and maneuver to a safe 
landing area, whether VMC or IMC, than those flying below the ceiling.
    The number of accidents involving VFR flight into IMC is 
substantial. It is concern with this safety hazard that prompted the 
FAA to reconsider its limitations on single-engine IFR flight with 
passengers under part 135. Additionally, the FAA has considered the 
action of Canada that allowed single-engine passenger-carrying IFR 
under certain conditions, and the petitions for exemption of the Alaska 
Air Carrier Association and individual operators. The FAA concluded 
that this rule will reduce the number of accidents by allowing 
operators to take advantage of the IFR system and the significant 
safety benefits it provides.
    The FAA is aware that other nations have either not allowed SEIFR 
or have limited it to turbine-powered aircraft. In the U.S., however, 
single-engine aircraft are already allowed to conduct passenger-
carrying operations under VFR in both day and night, and in IFR 
conditions under the limited IFR provisions, if they meet existing 
requirements for IFR operations. Also, single engine cargo operations 
are presently authorized under IFR. The limited IFR rules have created 
a situation where pilots who encounter IMC must either file an IFR 
flight plan while en route or attempt to maintain VFR by flying below 
the ceiling. The FAA determined that safety would be improved if 
operators could complete adequate preflight planning and a file a 
flight plan in advance, take advantage of the IFR system while en 
route, and maintain the obstacle clearance provided by flying at higher 
altitudes.
    Paragraph 5.1.2 of Annex 6, Part 1 of the ICAO standard states, 
``Single engine aeroplanes shall only be operated in conditions of 
weather and light, and over such routes and diversions therefrom, that 
permit a safe forced landing to be executed in the event of engine 
failure.'' The ability to make such a safe landing will be enhanced if 
the aircraft is in the IFR system because it will be flying at a higher 
altitude, which provides more time to select a location and glide to a 
landing. In addition, the aircraft would be on an established route, 
with guaranteed communications, with ATC assistance readily available 
to select an appropriate landing area, or advise/direct search and 
rescue.

III. Discussion of Comments

    The FAA received over 200 comments on the SEIFR proposed rule. 
Seven of the commenters oppose the rule; all of these commenters 
propose changes to the rule. The remaining commenters state their 
support for the rule based on the reasons given in the NPRM for the 
proposal. A number of rule supporters suggest changes to the rule, or 
requested clarification of the technical requirements.

A. General Opposition

    The Air Line Pilots' Association (ALPA) and Raytheon Aircraft 
Corporation both oppose the rule as a whole on the grounds that VFR 
flight into IMC is illegal and could be prevented by other means. They 
state that the FAA's solution is inherently unsafe. The commenters 
state that VFR flight into IMC could be prevented by increasing weather 
minimums or imposing penalties for illegal operations. They state that 
single-engine aircraft will never be as safe as multi-engine aircraft 
in the same operating conditions. They further state that the rule 
would increase the accident rate and that FAA data indicate the 
accident rate from propulsion system failure is eight times higher for 
single-engine than for multi-engine aircraft. A commenter states that 
more than 18 percent of single-engine propulsion failures occur in IMC.
    The FAA notes that the current VFR standards represent a level of 
safety which experience has shown to be acceptable. Increasing VFR 
minimums would not address the problem of VFR flight into IMC. An 
increase in the current VFR minimums could, unnecessarily, restrict 
part 135 operators who are limited only to VFR operations. Adequate 
penalties already exist for violations of these regulations.
    VFR flight into IMC is generally the result of inaccurate weather 
reports or unavailable forecasts. In deteriorating conditions, pilots 
are forced to fly at lower altitude to maintain VMC (or VFR 
conditions). The FAA determined that this rule will improve this 
situation by requiring additional fuel reserves and weather reporting 
necessary for IFR operations; by providing immediate assistance by ATC 
to the affected crew; by guaranteeing radio communication

[[Page 42367]]

from a minimum enroute altitude; by providing quicker notification of 
search and rescue assistance, all the while having additional 
assistance in the cockpit of another crewmember or autopilot. 
Therefore, the FAA has determined that this amendment will create a 
safer flying environment than the environment provided for in the 
current rules.
    The number of engines is only one factor of many that leads to a 
successful flight. The FAA is improving the total operating environment 
with this amendment. The single engine IFR passenger-carrying operation 
will be a planned operation (IFR preflight planning of routes, weather, 
fuel, and alternates), conducted in an ATC controlled environment, with 
better trained and qualified pilots, with additional equipment 
(autopilot if not two pilots, backup electrical and pneumatic sources), 
and backed by an improved maintenance program that includes engine 
health monitoring. It also is important to note that single-engine 
aircraft are already permitted under the current regulations to carry 
passengers during both day and night in VFR conditions, and under 
limited IFR conditions. Also, single engine cargo operations are 
presently authorized without having to meet the limited IFR provisions. 
Thus, the FAA has already endorsed the use of single-engine aircraft in 
air transportation. This amendment will make the total operating 
environment for these aircraft safer for the traveling public.

B. Turbine Versus Reciprocating Engines

    Although many commenters support the extension of this rule to all 
single-engine aircraft, several commenters state that the rule should 
be limited to turbine-powered aircraft. These commenters state that 
adequate data on engine reliability exist only for turbine-powered 
aircraft. Transport Canada states that the NPRM is ``almost totally 
lacking in the safeguards we included in our rule to mitigate the risks 
inherent in SEIFR.''
    Further, Transport Canada states that it is not convinced that 
opening SEIFR to all single-engine aircraft without restriction will 
achieve the FAA's safety goals. Transport Canada also is not convinced 
that trend monitoring for reciprocating engines can provide the same 
reliable information and warnings that similar programs for turbine 
engines provide. It states the belief that only turbine-powered engines 
offer sufficient reliability.
    The Joint Aviation Authority of Europe (JAA) states that it has no 
intention of including reciprocating-powered engines in its proposal to 
allow limited commercial travel and IMC flight for single-engine 
aircraft. JAA's proposal will be limited to turbine-powered engines and 
require a flight proficiency test, an area navigation system, autopilot 
or two pilots, specific approval on the air operator certificate, a 
radio altimeter, airborne weather equipment, a continuous ignition 
system, a shoulder harness for passengers, and supplemental oxygen for 
pressurized aircraft. In addition, terrain onto which a forced landing 
can be made should be available at all phases of flight. JAA states 
that ``the absence of any consideration of the ability to carry out a 
forced landing in the event of an engine failure seems to the JAA not 
to accord with the Standard in ICAO Annex 6, Chapter 5, Paragraph 
5.1.2.''
    In response, the FAA understands the concerns expressed by these 
commenters, but upon consideration, has determined that this amendment 
should apply to both reciprocating and turbine-powered aircraft. In 
examining the types of accidents that were occurring, the FAA 
determined that there would be a positive benefit to extending the rule 
to all properly certificated airplanes. The amendment addresses a 
number of factors, i.e., improved maintenance programs, more detailed 
preflight planning, operations in the IFR system, immediate assistance 
from ATC, second pilot or autopilot, and improved pilot training and 
qualifications. When combined, the FAA expects these improvements to 
save lives. Additionally, in their comment to the proposed rule change, 
the NTSB supported the proposal stating that the ``Board accepts the 
FAA's conclusion that a positive effect on safety would be obtained by 
approving commercial, passenger-carrying IFR operations in single-
engine airplanes powered by both turbine and reciprocating engines, 
subject to the additional equipment and operating limitations.''
    SEIFR operations under part 135 are not without restrictions. 
Operators who choose to use single-engine aircraft in part 135 
passenger-carrying operations must comply with all the additional 
equipment and training requirements that apply to IFR operations.
    In response to JAA's concerns regarding harmonization, the FAA 
fully supports harmonization efforts with JAA and Transport Canada, 
where appropriate. JAA's proposal is concerned largely with a European 
aeronautical and geographical environment. The FAA has required in this 
rulemaking many of the items proposed by JAA; however, the FAA believes 
that JAA's full proposal would have the effect of deterring 
participation of operators of single-engine part 135 aircraft in the 
IFR system and by so doing, contribute to the type of safety situation 
that this rule seeks to improve.
    Additionally, the FAA recognizes that Transport Canada has taken 
the lead with allowing operations with single engine turbine aircraft. 
In fact, the FAA considered Transport Canada's work as it developed its 
proposal. The FAA will continue to support harmonization efforts to the 
maximum extent practicable; however, because of its large aircraft 
population operating under part 135 and its extensive IFR system, the 
FAA will continue to address aviation safety issues in the United 
States in light of its unique situation. The FAA notes, however, that 
to the extent that Canada's aviation rules preclude the use of single-
engine aircraft powered by reciprocating engines in IFR operations, 
then such U.S. certificated single-engine operations may not be able to 
conduct single engine, passenger-carrying operations in Canadian 
airspace.
    Therefore, the FAA intends to file a difference to the single-
engine operational standard of Annex 6, Chapter 5, Paragraph 5.1.2. to 
become effective upon the effective date of the SFAR.

C. Equipment Requirements

Independent Generators/Second Battery Requirement
    A number of commenters state that it would be too costly for 
electrical systems to provide a second battery capable of supplying 150 
percent of the minimum electrical load for a least one hour, as 
proposed. One commenter says that such a battery would weigh 30 pounds 
and result in a more complex electrical system increasing the 
probability of electrical failure. Another commenter writes that he 
does not know of such a system that is widely available, reliable, and 
reasonable in cost. Instead of requiring a standby battery system, the 
commenter proposed requiring an ``easily noticeable warning light,'' 
which indicates immediately that the power generating source is 
failing. Several commenters suggest a requirement to carry a handheld 
transceiver, perhaps with an alkaline battery pack, to address concerns 
about the loss of the airplane battery or alternator/generator. In 
general, commenters who disagree with the requirement for a backup 
power supply argue that there is enough redundancy currently required.

[[Page 42368]]

    In response to comments, the FAA, in the final rule, requires 
either two independent electrical generating sources, or a standby 
battery or an alternate electrical source to serve as a second power 
source (as opposed to specifying only a battery) if that source can 
supply 150% of the electrical loads necessary for emergency operations 
of the aircraft for at least one hour. This requirement introduces 
redundancy for the generator and alternator and ensures that, if a 
generator or alternator fails, the aircraft will still be able to use 
certain equipment for a period of time in which to make a safe approach 
and landing.
    A handheld transceiver is not on the aircraft equipment list; 
because such equipment is not permanently installed, its presence on an 
aircraft could not be assured and, therefore, it would not meet the 
regulatory requirement. In reference to the comment recommending a 
warning light system, the FAA has determined that such a system 
provides no redundancy and would only identify a failure as it is 
happening rather than providing the aircraft with electrical power for 
needed equipment for at least one more additional hour after the 
failure of the primary system has occurred.
    Further, the FAA believes that an alternate electrical source, such 
as a standby battery, that would be approved for use in a single-engine 
IFR will be a cost effective means of providing a level of safety 
equivalent to an aircraft with a dual electrical system. The FAA has 
used the phrase ``alternate source of electric power'' in this 
amendment. Although the FAA envisions that alternate source to be a 
battery or an electrical storage unit, the wording provides for future 
technology that may replace a simple battery.
    The NPRM proposed, as an alternative to having two independent 
electrical generating sources installed on the aircraft, a single 
generating source and a standby battery capable of supplying 150% of 
the minimum electrical load for at least one hour to operate navigation 
and communication equipment. Commenters raised questions as to what was 
meant by the term ``minimum electrical load'' as it pertains to the 
capacity of the standby battery. Upon further review, the Agency 
recognizes that the proposed Sec. 135.163(f)(2) regulatory language did 
not comport with its intent regarding the electrical loads that the 
standby battery must be capable of providing.
    Therefore, in this final rule, the Agency is clarifying its intent 
that the standby battery be capable of supplying 150% of the electrical 
loads for all required instruments and equipment necessary for the safe 
emergency operation of the aircraft for one hour. This is consistent 
with the redundancy requirements specified for multiengine aircraft in 
Sec. 135.163(g). The FAA further recognizes that in an actual emergency 
situation, the pilot will shed electrical loads to the minimum required 
for safe operation. Required instruments and equipment could include 
single navigation and communication equipment, but could also include 
other equipment necessary for the safe operation of the aircraft in the 
actual environment, such as pilot heat or instrument lighting. The FAA 
is therefore deleting both the phrase ``minimum'' and ``to operate 
navigation and communication equipment'' from the regulatory language 
to clarify that the battery capacity is not limited solely to the 
capacity needed to operate navigation and communication equipment, but 
other necessary equipment as well. Thus, should an operator choose not 
to install two independent electrical power generating sources on the 
aircraft, this alternate minimum electrical power source will provide 
the necessary system redundancy for safe emergency operation of the 
flight.
    The FAA further finds that although it did not propose this precise 
language in the NPRM, it is unnecessary and not in the public interest 
to delay the entire single-engine IFR rulemaking on this minor 
technical issue. Nevertheless, the FAA invites comment on the final 
regulatory language in Sec. 135.163(f)(2).
Redundant Power Source for Gyroscopic Instruments
    The FAA specifically sought comments on whether a redundant power 
source for gyroscopic instruments is needed. One commenter responds 
that requiring dual engine-driven, pneumatic pumps would go a long way 
to precluding loss of air-driven gryos. If both pumps were lost because 
the engine stopped, the battery should last long enough to allow the 
aircraft to glide to a landing. One commenter states that French IFR 
rules achieve redundant gyroscopic instruments with one attitude 
indicator and a second attitude indicator or a turn indicator and a 
slip indicator powered by a source independent of the first attitude 
power source. Another commenter states that a third attitude indicator 
should be installed with at least 3-minute self-contained electrical 
source independent of the aircraft's main electrical system. The NTSB 
recommended a requirement for a redundant source of power for attitude 
gyroscopic instrumentation. The Board stated that despite requirements 
for partial panel training, the fatal accident record indicates that 
many pilots have experienced difficulty maintaining aircraft control 
during actual partial panel situations. Another commenter, however, 
states that because there are so few system failures in IFR flight, 
redundant systems for gyroscopes are unnecessary.
    By this amendment, the FAA has adopted the proposed requirement for 
redundant power sources for gyroscopic instruments to the final rule. 
Although the NPRM did not contain the regulatory language, the Agency 
proposed the redundant power source requirement in the preamble. The 
FAA recognized that the failure of the vacuum/pressure pump of the 
pneumatic system during IFR in IMC can lead to spatial disorientation 
of the pilot and loss of aircraft control. The redundancy or the 
pneumatic system will put single-engine aircraft systems on parity with 
existing twin-engine aircraft. Because the FAA proposed redundancy for 
passenger-carrying operations, but not for all-cargo operations, the 
final rule requirement for redundancy of power source for gyroscopic 
instruments is limited to passenger-carrying operations.
Autopilot/Co-pilot Requirement
    Several commenters state that the proposed rule does not 
substantiate the need for two pilots or a single pilot with autopilot. 
There are concerns because the vast majority of single engine aircraft 
do not have an autopilot installed that meets the requirements of 
Sec. 135.105, and retrofitting such aircraft may cost up to $20,000 and 
add up to 30 pounds to the empty weight of an aircraft. In addition, 
according to the commenter, if another crewmember is added to comply 
with the regulation, one less seat would be available on the small 
planes, which would be a ``severe economic burden.'' Another commenter 
states that the FAA should allow two-axis autopilots; a requirement for 
a three-axis autopilot would eliminate most single-engine aircraft 
currently equipped with autopilots.
    In response, the FAA disagrees that an autopilot or second pilot is 
not needed. The complexity and workload in IMC is such that a three-
axis autopilot as opposed to a two-axis autopilot, or second pilot is 
necessary for safety in air transportation. Section 135.105 currently 
establishes a standard for an autopilot capable of operating the 
aircraft controls about three axes.
    Concerning the comment on weight penalty and the cost issue, the 
FAA has determined that these requirements, as well as the other 
requirements for

[[Page 42369]]

equipment, training and checking, operations, maintenance, etc., are 
based on experience and are considered necessary for safety. The FAA 
has determined that they remain valid for any air carrier involved in 
commercial passenger-carrying operations. Therefore, the FAA is 
adopting the autopilot or second pilot as proposed.
Other Equipment
    Commenters suggest other equipment that should be required for 
SEIFR operations. One commenter states that a radar altimeter should be 
required because it shows actual height above the terrain. Another 
commenter states that for planes with six or more passengers, the FAA 
should mandate an emergency cockpit checklist, a cockpit voice 
recorder, and weather radar. For turbine-powered airplanes, TCAS and 
GPWS should be required when carrying six or more passengers. Area 
navigation systems provide an additional margin of safety where radar 
coverage is minimal. A third commenter states that the NPRM does not 
adequately address pitot system anti-icing. Any flight where flight 
temperatures will be below 40 deg. F should require dual heated pitot 
systems to ensure that the pilot will have airspeed and static system 
operation in IMC. Fuel tank vents and stall warning systems need to be 
ice protected. Windshield de-ice is needed for winter operations in 
Alaska. The commenter also suggests self-powered attitude indicators 
should be added to single-engine aircraft used for SEIFR operations.
    To respond, the FAA notes that radar altimeters are only required 
for Category II and III operations. As for the emergency cockpit 
checklist, a cockpit voice recorder, weather radar, TCAS, GPWS, and 
area navigation systems, the FAA has decided that this equipment is not 
necessary for the planned operations affected by this rule.
    Regarding the comment on icing, flight into icing conditions is 
already prohibited by Sec. 135.227 unless the aircraft is adequately 
equipped. This rule does not change the equipment requirements for 
flight into icing conditions. Also, this rule does not relieve an 
operator from having an aircraft certified for flight into icing 
conditions, if those operations are anticipated.

D. Oil Analysis/Maintenance/Trend Monitoring/Engine Health

    Several commenters are concerned about the oil analysis 
requirements. Several letters mention that while oil analysis as part 
of a maintenance program may be justified, expensive engine maintenance 
should not be required based solely on this one parameter. According to 
the commenter, one ``bad'' sample is not sufficient reason for 
maintenance until further analysis is performed. Oil samples may be 
misleading because it is possible to have sample contamination; as the 
commenter noted, a single operation on a dusty day with the carburetor 
heat left on accidentally allowing unfiltered air into the engine may 
create a contaminated sample. The commenter suggests that other tools, 
such as compression checks and borescopes, should be used in 
conjunction with oil analyses.
    Another commenter states that oil analysis has never enabled him to 
predict, and therefore avoid, engine problems. He gave an example of 
one instance where a turbocharger broke down, filling the engine's oil 
screen with metal. After contacting the oil lab to find out why the oil 
analysis tests had not predicted the failure, the lab indicated to him 
that the particles of metal in the oil were ``too big'' to be detected 
by regular analysis.
    One commenter says that those in the oil analysis business are 
concerned about their liability insurance if their opinion is mandated 
rather than advisory. Another commenter writes that oil analysis should 
not be required at each 100 hours of inspection, but rather at 100 
hours of operations because not all oil changes are made at 100-hour 
inspections. Other commenters suggest replacing ``oil analysis'' with 
``trend monitoring and/or oil analysis.'' Finally, two commenters 
suggest requiring ``oil analysis'' and an oil and filter change every 
50 hours rather than 100 hours. Another commenter states that 
spectrographic oil analysis is not a predictor of fatigue failures, 
which are the most common cause of piston-engine power loss.
    FAA has determined that engine health trend monitoring can play an 
important part in preventive maintenance by providing an early warning 
of potential problems. The final rule gives operators the option of 
adopting the manufacturer's trend monitoring program or an FAA-approved 
trend monitoring program that includes oil analysis. The FAA is 
currently updating its advisory materials on trend monitoring programs 
(AC 21-105A, ``Engine Power Loss Accident Prevention,'' dated 11/20/
80).
    While the FAA recognizes that the possibility exists for misleading 
oil analyses, each laboratory analysis report must be treated 
individually and in conjunction with previous reports. If the data 
indicate a possible problem exists, further inspection and/or 
maintenance is necessitated. This approach is consistent with the 
current practice of inspection if one of the engine's cylinders had a 
bad compression reading because carbon deposits were keeping a valve 
from properly seating.
    FAA has determined that a spectrographic oil analysis, properly 
performed, provides the owner/operator with a reliable, advance warning 
of a potential failure based on the amount of metal and bearing 
material in the oil sample. Although contamination can occur at any 
stage, in a comprehensive maintenance inspection program, oil analysis 
will provide useful trend information. The FAA agrees with the comment 
that oil analysis will not always give advance warning of fatigue 
failures, such as crankshaft separation, but neither do other 
inspection techniques, such as borescope inspections and compression 
tests.
    Regarding the recommendation to change the interval of oil sampling 
from 100 hours to 50 hours, the FAA notes that 100-hour interval is 
considered an ``industry standard.'' Under the final rule, operators 
must follow the manufacturer's monitoring program recommendations if 
they call for more frequent checks.
    The FAA also recognizes that oil analysis may not be applicable to 
certain engine types, e.g. Pratt and Whitney PT-6. Therefore, in the 
final rule, the operator is given the option to choose between the 
manufacturer's published trend monitoring program, which may or may not 
contain a provision for oil analysis based on the engine type and 
design, or the FAA-approved program that must include oil analysis. 
Published manufacturer's trend monitoring programs are available for 
turbine engines, however, the FAA is not aware of any published trend 
monitoring program for reciprocating aircraft.
    To clarify the recordkeeping requirements, the FAA has added a new 
Sec. 135.421(e) to require the recordation and maintenance of the 
results of each test, observation, or inspection required by the 
applicable engine monitoring program in the engine maintenance records. 
Although the FAA proposed a recordkeeping requirement for the engine 
trend monitoring, the FAA requests comment on the modification to the 
recordkeepng requirement to be codified in Sec. 135.421(e). The 
required recordation is subject to OMB approval, as required by the 
Paperwork Reduction Act. An information collection control number will 
be assigned for it if and when OMB approval is given; that

[[Page 42370]]

number would be listed in part 11, subpart F, of Title 14.

E. Training

    One commenter suggests that training should emphasize partial panel 
operations and systems failure recognition; such training could be 
included in part 135 training manuals. Another commenter states that an 
ATP certificate should be required for SEIFR operations. Commenters 
also suggest that simulator training and a six-month IFR check should 
be required.
    The FAA agrees with the commenter that additional emphasis and 
checking in partial panel and system failure recognition are necessary. 
Existing regulations require training in systems failures. The FAA will 
review and update its handbooks and training related material to ensure 
that partial panel operations are evaluated on the instrument 
competency checks for the affected operators and that proper attention 
is given when operators' training programs are approved and reviewed.
    In addition, the FAA notes that an ATP certificate is required for 
pilot-in-command positions on large airplanes usually operated under 
part 121. The experience and skill level required for single-engine air 
transportation under IFR are not equivalent to those required for large 
transport category airplanes. The FAA maintains that a commercial pilot 
certificate and appropriate ratings are sufficient qualification for 
operations conducted under this rule; part 135 requires 1,200 hours of 
flight time for IFR operations. On simulator training, the FAA notes 
that part 121 does not require simulator training. Simulators are not 
available for most of the types of aircraft that will operate under 
this rule. For those aircraft that have simulators available, operators 
are encouraged to use them. Also, some training may be accomplished in 
a training device (Sec. 135.347). The FAA does not believe that 
required simulator training is necessary for adequate safety for the 
anticipated operations. Last, a six-month instrument proficiency check 
is already required (Sec. 135.297) by the existing regulations.

F. Removal of Limited IFR

    Several commenters believe that the elimination of the present 
``limited IFR'' rules would not be in the best interest of safety. They 
believe that operations in limited IFR conditions allowed by 
Secs. 135.103 and 135.181 should still apply to single-engine airplanes 
without autopilots because the rules allow a qualified pilot to make an 
approach if, due to unforecast weather, the intended destination goes 
below VFR minimums. Another commenter does not favor eliminating these 
sections because pilots would lose the ability to climb out of the low 
level fog layer that often persists at some airports during the morning 
hours of the day. One commenter argues for maintaining the ``limited 
IFR'' rule because it is safer to offer the ability to operate under 
limited IFR rather than to force a pilot to scud run in and out of an 
uncontrolled field, or face delays at a tower controlled field, all the 
while watching the weather conditions worsen. Another commenter 
suggested amending Sec. 135.103 to exempt the autopilot for this 
section.
    Current data, as discussed in the NPRM, for on-demand Part 135 
accidents involving single-engine aircraft indicate that poor inflight 
planning and decision-making, and other weather-related errors 
resulting from attempts to maintain VFR flight are the major causes of 
accidents. While the possibility of a failure of the single engine 
exists, the FAA has, it believes, reduced that possibility further by 
additional maintenance requirements. The possibility of pilot 
mishandling has also been reduced, in the judgment of the FAA, by 
emphasizing training in partial panel emergency procedures and system 
failure recognition when combined with equipment redundancies.
    As mentioned above, the FAA is improving the total operating 
environment with this amendment. A single-engine passenger-carrying 
operation will be a planned operation (IFR preflight planning of 
routes, weather, fuel, and alternates), conducted in an ATC controlled 
environment, with better trained pilots, with additional equipment 
(autopilot if not two pilots, redundant electrical and vacuum systems), 
backed by an improved inspection program that includes engine trend 
monitoring. Therefore, the FAA has not retained the limited IFR rule 
because the FAA concluded, based on available data, that planned flight 
under IFR provides a higher standard of safety than unplanned flight 
under the limited IFR rule.

G. Weather and Terrain Issues

    Transport Canada states that flight under IFR requires that the 
aircraft be certified for flight into known icing for at least the 
northern U.S.; few existing single-engine aircraft in commercial 
service are so certified. Another commenter states that icing is a 
greater problem than VFR flight into IMC. The greater number of 
accidents due to inadvertent encounters with icing will more than 
offset any improvements in the VFR to IMC accident rate. Reciprocating 
engine aircraft certification rules do not require a demonstration of 
any ability to continue to operate in icing conditions. In addition, a 
few commenters state the SEIFR over mountainous terrain should be 
barred.
    The FAA recognizes that authorizing an aircraft to operate in IFR 
conditions neither converts an aircraft to ``all-weather,'' nor allows 
it to do anything for which it is not certificated or equipped. Under 
Sec. 135.227, operators using aircraft not certified for known icing 
conditions may not operate in those conditions. An aircraft that does 
not meet the requirements for flying in icing conditions may not be 
operated in those conditions. Additionally, the FAA notes that part 135 
operators can already operate under IFR in U.S. airspace using aircraft 
that are not certified for known icing as long as the operations 
anticipated are outside of known icing conditions.
    Single-engine aircraft limited by service ceiling or lack of 
pressurization or oxygen will not be capable of using the IFR system 
over some mountainous terrain. In addition, the FAA notes that finding 
a suitable landing place in mountainous terrain, if a forced landing is 
necessary, may not be very much different from finding a suitable 
landing place in a wide, densely populated area. Single engine aircraft 
are not presently restricted from either area. Thus, single engine 
operations addressed in this amendment will not be so restricted 
either.

H. National Application of the Rule

    A commenter suggests that the FAA should limit all SEIFR operations 
to only Alaska (turbine or reciprocating engine) or, at least, limit 
SEIFR with reciprocating-engine aircraft to only Alaska. A commenter 
states that if specific operations in remote areas require exemptions, 
these should be handled on a case-by-case basis, not by adopting a 
national standard. Several commenters state that this rule will result 
in operators trading in multi-engine aircraft and replacing them with 
reciprocating engine, single-engine aircraft.
    The FAA considered the conditions of weather and terrain in Alaska 
to be a ``worst-case'' operating environment. Authorization in the 
regulations for use of single-engine air transportation under IFR in 
Alaska would justify single-engine air transportation under IFR in the 
contiguous U.S. where operating conditions are generally less severe. 
The FAA's regulatory evaluation indicates

[[Page 42371]]

that this rule will create a net safety benefit in the other 49 states 
as well as Alaska. Exemptions are handled on a case-by-case basis; 
however, the rationale that the FAA would use to justify an exemption 
would also apply to all similarly-situated operators.
    The FAA does not expect the operators currently flying multi-engine 
aircraft will switch to single-engine aircraft simply because of this 
rule change. Decisions about the type of aircraft to operate are 
complex. Operators must weigh numerous factors when selecting aircraft, 
for example, aircraft availability and age, customer base, and 
geographical location. Whatever choice operators make, the FAA remains 
convinced that the rule will increase safety of single-engine, 
passenger-carrying operations.

I. Other Comments

    Several comments support the ARAC proposals. One commenter states 
that the FAA received only 12 petitions for exemptions since 1978, 
which is not a significant number. Finally, one commenter states the 
proposal would result in slower, single-engine aircraft at metropolitan 
airports, taxing the ATC system, and in more inexperienced pilots 
flying in hazardous conditions. To overcome these problems, they 
suggest that any aircraft that cannot maintain 140 knots on final 
approach should be excluded from Class B airspace and that pilot 
qualifications should include 2,000 hours of flight time.
    The FAA commends the ARAC for its detailed work on the SEIFR 
proposal; as is evident, the ARAC proposal formed a basis for this 
action. In fact, the FAA notes that this final rule incorporates a 
number of the ARAC proposals. Other ARAC proposals are not needed 
because they duplicate existing requirements. The ARAC proposals, 
although not technically limited to a particular type of aircraft, 
cited conditions that are met at present by only turbine-powered 
aircraft. The ARAC also recommended that the FAA grant the Alaska Air 
Carriers Association's petition for exemption, which covers all single-
engine aircraft.
    FAA rulemaking is not contingent only upon public petition. In the 
case of this rule, the petitions for exemption, one of which was 
submitted by a trade association, were only part of an overall, growing 
awareness by industry and FAA that the limited IFR rule was no longer 
serving its original purpose and that the better safety alternative 
would be to allow all qualified part 135 operators to use the IFR 
system from departure to termination of the flight.
    Finally, the FAA is unaware of any evidence that this rule would 
place an excessive burden on the ATC system or result in delays in the 
terminal area.

IV. Maintenance of Required Equipment

    Section 135.411 requires an operator of an aircraft type 
certificated for 9 or fewer passengers to have that aircraft 
maintained, at a minimum, in accordance with parts 91 and 43 of Title 
14. The maintenance is performed on the basis of 100-hour and annual 
inspections, as those inspections are described in part 43, appendix D. 
For an aircraft type certificated for 9 or fewer passengers, 
Sec. 135.411 also accepts an approved aircraft inspection program 
(AAIP), as described in Sec. 135.419.
    Section Sec. 135.419(a) provides that, when the FAA finds that the 
aircraft inspections required under part 91 are not adequate to meet 
part 135, the FAA may amend the operator's operations specifications to 
require an AAIP. Section Sec. 135.419(f) provides that, when the FAA 
finds that revisions to an AAIP are necessary for the continued 
adequacy of the program, the operator must, after notification from the 
FAA, make the necessary revisions. Long-standing rules, therefore, 
enable the FAA to make even major adjustments to an operator's 
maintenance program that are necessary to maintain the level of safety 
appropriate for carrying passengers or cargo for compensation or hire.
    Section 135.421(a) describes additional maintenance requirements 
for each operator of an aircraft type certificated for 9 or fewer 
passengers; it requires the operator to comply with the manufacturer's 
recommended maintenance program, or with an AAIP, for each aircraft, 
engine, propeller, rotor, and item of emergency equipment. In Notice 
96-14, the FAA proposed to add paragraph (c) to Sec. 135.421 to require 
the single engine aircraft operator to incorporate into its 
manufacturer's recommended maintenance program or AAIP, an engine trend 
monitoring program that includes a 100-hour oil analysis and record of 
findings.
    The equipment required under Sec. 135.105 and new Sec. 135.163 (f) 
and (h) will frequently be installed in accordance with a supplemental 
type certificate (STC); the holder of that certificate may be required 
by 14 CFR Sec. 21.50 to furnish instructions for continued 
airworthiness (ICAW), in which case, it is important that the operator 
maintain the equipment in accordance with those instructions to 
maintain the level of safety appropriate for carrying passengers for 
compensation or hire. It is imperative for each part 135 operator, no 
matter what the method of approval of the installation, to have the 
equipment required by this rule maintained to the level of safety 
appropriate for carrying passengers for compensation or hire.
    Accordingly, the FAA has decided to adopt new Sec. 135.421(d). New 
Sec. 135.421(d) will require the operator to ensure that the equipment 
required by Sec. 135.105 and new Sec. 135.163 (f) and (h) is maintained 
in accordance with written maintenance instructions that will provide a 
level of safety equivalent to ICAW. If the manufacturer provides ICAW, 
the operator may use those; to deviate from the ICAW, the operator will 
be required to obtain FAA approval. New Sec. 135.421(d) applies to 
operators who have 100-hour and annual inspection based programs, and 
operators who have AAIPs. Therefore, if operator does not utilize the 
applicable manufacturer's maintenance manual or instructions for 
continued airworthiness prepared by the manufacturer, then it must have 
written maintenance instructions, acceptable to the Administrator, 
containing the methods, techniques, and practices to maintain the 
equipment required in Secs. 135.105 and 135.163 (f) and (h).
    Although this modification to the maintenance requirements was not 
explicitly stated in Notice 96-14, the FAA has decided to adopt it in 
this final rule. As explained above, long-standing rules enable the FAA 
to make necessary adjustments to an operator's maintenance program. 
Furthermore, operators should realistically expect to be required to 
properly maintain all equipment that is critical to SEIFR operations. 
The FAA has determined that many operators already have the items of 
equipment installed in their aircraft, and are maintaining those items 
in accordance with instructions that are not stated in the amount of 
detail necessary for the level of safety expected for SEIFR operations. 
New Sec. 135.421(d) will require those instructions to be written and 
acceptable to the Administrator.
    Because the FAA did not explicitly propose Sec. 135.421(d), the FAA 
invites comment on that section's final regulatory language. The 
required written maintenance instructions are subject to OMB approval, 
as required by the Paperwork Reduction Act. An information collection 
control number will be assigned for them if and when OMB approval is 
given; that number would be listed in part 11, subpart F, of Title 14.
    Section 135.411 requires an operator of an aircraft type 
certificated for 10 or

[[Page 42372]]

more passengers to have that aircraft maintained in accordance with a 
program that meets the requirements of Secs. 135.415, 135.417, and 
135.423 through 135.443. That program is referred to as a continuous 
airworthiness maintenance and inspection program (CAMP). Section 
135.425(c) requires that a CAMP ensure that each aircraft released to 
service has been properly maintained for operation under part 135. 
Section 135.427(b) requires the CAMP to include the programs required 
by Sec. 135.425 that must be followed in performing maintenance, 
preventive maintenance, and alteration of the operator's aircraft, 
including the airframe, engines, propellers, rotors, appliances, 
emergency equipment, and parts. Instructions for maintaining the 
equipment required by Secs. 135.105 and 135.163 (f) and (h) will be 
incorporated into operators' CAMPs.

V. Section-by-Section Discussion of Changes

    Special Federal Aviation Regulation (SFAR) No. 81 is added to allow 
operators who can meet the requirements of this rule before the 
effective date to begin SEIFR operations. The SFAR is not effective 
until the FAA publishes a notice specifying the effective date in the 
Federal Register. The SFAR terminates on the effective date of the 
Commercial Passenger-Carrying Operations in Single-Engine Aircraft 
Under Instrument Flight Rules rule.
    As proposed, Sec. 135.101 is revised to eliminate the reference to 
Sec. 135.103, which is deleted, and to delete the word ``conditions'' 
after IFR. Deletion of the word ``conditions'' clarifies that any 
operation for which an IFR flight plan is filed must have a second 
pilot or an autopilot, even if the flight can be conducted in VFR 
conditions.
    As proposed, Sec. 135.103 is deleted because it is no longer 
needed.
    Section 135.163 is revised to add, for multi-engine aircraft, 
reference to alternators. For single-engine aircraft, a requirement is 
added for two independent electrical power generating sources or a 
standby battery or alternate source of electric power. A requirement is 
also added for a redundant energy system for gyroscopic instruments; 
the existing exception in paragraph (h) for single-engine aircraft is 
not limited to single-engine aircraft in all-cargo operations.
    As proposed, Sec. 135.181 is revised by dropping all of the limited 
IFR conditions. Only the performance requirements for multi-engine 
aircraft and over-the-top requirements remain.
    Section 135.411 is revised to add a reference to Sec. 135.421 as it 
pertains to the maintenance requirements for single engine passenger-
carrying aircraft under IFR.
    Section 135.421 is revised to add the requirement for engine trend 
monitoring for aircraft used in passenger-carrying SEIFR operations, 
and the requirement for written maintenance instructions, acceptable to 
the Administrator, for the equipment required in Secs. 135.105, and 
135.163 (f) and (h).

Regulatory Evaluation Summary

    The Federal Aviation Administration (FAA) is updating and revising 
the regulations to allow single-engine, passenger carrying aircraft to 
operate under the instrument flight rules. The rule will reduce the 
incentive for operators to conduct low altitude operations under 
marginal weather conditions. However, this rule will also require 
operators to meet the more stringent requirements for such flights 
including additional aircraft equipment.
    The cost of this final rule is estimated at $170.3 million ($127.6 
million, discounted). The most costly provision is on the requirement 
for an autopilot, which is estimated at $94.9 million discounted and 
represents about 74.3 percent of the total. The FAA concludes that the 
expected quantitative benefits will be $354.6 million or $249.1 
million, discounted. If the rule is 75 percent effective in reducing 
fatalities and injuries, then the expected quantitative benefits will 
be $284.3 million or $199.5 million discounted over ten years. The 
benefits estimate should be considered low because the added equipment, 
etc. required for single-engine aircraft should result in fewer overall 
fatalities. The benefits analysis does not take this into account.
    If fewer disruptions, cancellations, etc. were considered a cost-
savings instead of a benefit, then both the benefit estimate and the 
cost estimate should be reduced by $156.9 million ($110.2 million 
discounted). The cost of the rule, net of these costs savings, will be 
$13.4 million or $17.4 million, discounted, and the benefits of this 
rule, namely safety benefits (assuming 75 percent effectiveness), will 
be $127.7 million or $89.3 million discounted over ten years. While the 
discounted costs and benefits are lower than the undiscounted costs and 
benefits, respectively, the discounted net costs are higher than the 
undiscounted net costs.
    Under the guidelines presented in FAA Order 2100.14A, the FAA has 
determined that the final rule will not have a significant economic 
impact, positive or negative, on small operators.
    This final rule is not expected to have any impact on trade 
opportunities for U.S. firms doing business overseas or foreign firms 
doing business in the United States. The final rule will primarily 
affect U.S. operators of aircraft for hire that provide domestic 
service.
    This final rule does not contain any Federal intergovernmental or 
private sector mandate. Therefore, the requirements of Title II of the 
Unfunded Mandates Reform Act of 1995 do not apply.

Regulatory Flexibility Assessment

    The Regulatory Flexibility Act of 1980 (RFA) was enacted by 
Congress to ensure that small entities are not unnecessarily or 
disproportionately burdened by Federal Regulations. The RFA requires an 
analysis if a final rule will have ``a significant economic impact on a 
substantial number of small entities.'' The definitions of small 
entities and guidance material for making determinations required by 
the RFA are contained in the Federal Register (47 FR 32825, July 29, 
1982). Federal Aviation Administration (FAA) order 2100.14A outlines 
the agency's procedures and criteria for implementing the RFA.
    With respect to the final rule, a ``small entity'' is an operator 
of aircraft for hire with nine or fewer aircraft. A ``significant 
economic impact on a small entity'' is defined as an annualized net 
compliance cost for operators of aircraft for hire which in 1996 
dollars is $126,100 for scheduled operators whose aircraft have more 
than 60 seats. It is $70,490 for scheduled operators whose fleets have 
aircraft with seating capacities of 60 or fewer seats (other scheduled 
operators) and $4,960 for unscheduled operators. A substantial number 
of small entities is defined as a number that is 11 or more and which 
is more than one-third of small operators subject to the final rule.
    The FAA estimates that the annualized cost of the final rule is 
about $4,708 per aircraft and that the annualized cost savings to the 
operator is about $2,142 per aircraft. Therefore, the net annualized 
cost is about $2,566 per aircraft.
    The FAA has initially determined that if every operator were 
defined as unscheduled, then operators with two aircraft or more will 
incur a significant impact.
    The cost for an operator with two aircraft is slightly over the 
threshold of $4,960 by approximately three and a half percent. However, 
in the regulatory evaluation and the above regulatory

[[Page 42373]]

flexibility analysis, the FAA has made conservative assumptions that 
could result in costs per aircraft being overestimated. For example, 
the FAA has assumed that none of the aircraft are in partial compliance 
with any of the equipment requirements of this regulation. To the 
extent that some operators have aircraft that are in partial 
compliance, then costs per aircraft have been overestimated and the FAA 
believes that compliance costs per aircraft are overestimated by more 
than five percent. An example of this are the weight penalty costs. The 
FAA assumed that a battery and related hardware would add 30 pounds to 
the weight of the aircraft. A Gill 25 amp battery weighing 22 pounds 
plus hardware would be adequate and weighs about 25 pounds. Therefore, 
the difference in weight (5 pounds  x  15 gallons/pound  x  $2.32/
gallon=$174) would result in aircraft being under the threshold. 
Consequently, operators with two or fewer aircraft would not likely to 
be significantly impacted. The FAA has concluded that this is the case 
and, therefore, the rule will not affect a substantial number of small 
entities. In addition, many operators that the FAA considered as being 
potentially impacted may choose not to carry passengers under IFR. For 
these reasons, the FAA has determined that a substantial number of 
operators will not be positively or negatively impacted in a 
significant way.

International Trade Impact Statement

    This final rule is not expected to have any impact on trade 
opportunities for U.S. firms doing business overseas or foreign firms 
doing business in the United States. The final rule will primarily 
affect U.S. operators of aircraft for hire that provide domestic 
service.

Unfunded Mandates Reform Act Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (the Act), 
enacted as Pub. L. 104-4 on March 22, 1995, requires each Federal 
agency, to the extent permitted by law, to prepare a written assessment 
of the effects of any Federal mandate in a proposed or final agency 
rule that may result in the expenditure by State, local, and tribal 
governments, in the aggregate, or by the private sector, of $100 
million or more (adjusted annually for inflation) in any one year. 
Section 204(a) of the Act, 2 U.S.C. 1534(a), requires the Federal 
agency to develop an effective process to permit timely input by 
elected officers (or their designees) of State, local, and tribal 
governments on a proposed ``significant intergovernmental mandate.'' A 
``significant intergovernmental mandate'' under the Act is any 
provision in a Federal agency regulation that will impose an 
enforceable duty upon State, local, and tribal governments, in the 
aggregate, of $100 million (adjusted annually for inflation) in any one 
year. Section 203 of the Act, 2 U.S.C. 1533, which supplements section 
204(a), provides that before establishing any regulatory requirements 
that might significantly or uniquely affect small governments, the 
agency shall have developed a plan that, among other things, provides 
for notice to potentially affected small governments, if any, and for a 
meaningful and timely opportunity to provide input in the development 
of regulatory proposals.
    This final rule does not meet the cost thresholds described above. 
Furthermore, this final rule will not impose a significant cost on 
small governments and will not uniquely affect those small governments. 
Therefore, the requirements of Title II of the Unfunded Mandates Reform 
Act of 1995 do not apply.

Paperwork Reduction Act of 1995

    The proposed recordkeeping requirements for the engine trend 
monitoring (new Sec. 135.421(e)) and the written maintenance 
instructions (new Sec. 135.421(d)) are subject to OMB approval, as 
required by the Paperwork Reduction Act. Pending OMB clearance on the 
paperwork requirements, SFAR No. 81 is not effective until the FAA 
publishes in the Federal Register a notice specifying the effective 
date. An information collection control number will be assigned if and 
when OMB approval is given; that number would be listed in part 11, 
subpart F of Title 14.

Conclusion

    For the reasons discussed in the Preamble, and based on the 
findings in the Regulatory Flexibility Assessment and the International 
Trade Impact Analysis, the FAA has determined that this rule is not a 
``significant regulatory action'' under Executive Order 12866. In 
addition, the FAA certifies that this regulation does not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act of 1980. This amendment is not considered significant 
under Order DOT 2100.5, Policies and Procedures for Simplification, 
Analysis, and Review of Regulations. A regulatory evaluation of the 
regulation is available in the docket.

List of Subjects in 14 CFR Part 135

    Air carriers, Air taxis, Air transportation, Aircraft, Airmen, 
Airworthiness, Aviation safety, On-demand operations, Pilots, 
Rotorcraft, Safety, Single-engine aircraft, Single-engine airplane.
    For the reasons set out in the preamble, 14 CFR part 135 is 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.

    2. Special Federal Aviation Regulation No. 81 is added to read as 
follows:

SFAR No. 81--PASSENGER-CARRYING SINGLE-ENGINE IFR OPERATIONS.

    1. Purpose and Eligibility.
    (a) This Special Federal Aviation Regulation provides for the 
approval of single-engine passenger-carrying operations under 
instrument flight rules (IFR) during the month prior to the 
effective date of the Commercial Passenger-Carrying Operations in 
Single-Engine Aircraft Under Instrument Flight Rules rule.
    (b) This SFAR terminates on May 3, 1998.
    (c) Only those single-engine, passenger-carrying operations 
meeting all the applicable requirements of part 135 and those 
requirements set forth in paragraph 2 of this SFAR may operate under 
IFR.
    2. Contrary provisions of Secs. 135.103 and 135.181 
notwithstanding, a person may conduct passenger-carrying operations 
under IFR in single-engine aircraft if the following conditions are 
met:
    (a) The aircraft has two independent electrical power generating 
sources each of which is able to supply all probable combinations of 
continuous inflight electrical loads for required instruments and 
equipment; or in addition to the primary electrical power generating 
source, a standby battery or an alternate source of electric power 
that is capable of supplying 150% of the electrical loads of all 
required instruments and equipment necessary for safe emergency 
operation of the aircraft for at least one hour;
    (b) The aircraft has 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;
    (c) The aircraft meets the autopilot requirements of 
Sec. 135.105 or has a second in command;
    (d) The certificate holder's maintenance inspection program 
incorporates either the manufacturer's recommended engine trend

[[Page 42374]]

monitoring program, which includes an oil analysis, if appropriate, 
or an FAA approved engine trend monitoring program that includes an 
oil analysis at each 100 hour interval or at the manufacturer's 
suggested interval, whichever is more frequent.
    (e) The results of each test, observation, and inspection 
required by the applicable engine trend monitoring program are 
recorded and maintained in the engine maintenance records; and
    (f) Written maintenance instructions containing the methods, 
techniques, and practices necessary to maintain the equipment 
specified in paragraph 2 (a), (b), and (c) are prepared.

    3. Section 135.101 is revised to read as follows:


Sec. 135.101  Second in command required under IFR.

    Except as provided in Sec. 135.105, no person may operate an 
aircraft carrying passengers under IFR unless there is a second in 
command in the aircraft.


Sec. 135.103  [Removed and reserved]

    4. Section 135.103 is removed and reserved.
    5. Section 135.163 is amended by revising paragraphs (f), (g), and 
(h) to read as follows:


Sec. 135.163  Equipment requirements: Aircraft carrying passengers 
under IFR.

* * * * *
    (f) For a single-engine aircraft:
    (1) Two independent electrical power generating sources each of 
which is able to supply all probable combinations of continuous 
inflight electrical loads for required instruments and equipment; or
    (2) In addition to the primary electrical power generating source, 
a standby battery or an alternate source of electric power that is 
capable of supplying 150% of the electrical loads of all required 
instruments and equipment necessary for safe emergency operation of the 
aircraft for at least one hour;
    (g) For multi-engine aircraft, at least two generators or 
alternators each of which is on a separate engine, of which any 
combination of one-half of the total number are rated sufficiently to 
supply the electrical loads of all required instruments and equipment 
necessary for safe emergency operation of the aircraft except that for 
multi-engine helicopters, the two required generators may be mounted on 
the main rotor drive train; and
    (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 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.
* * * * *
    6. Section 135.181 is amended by revising paragraphs (a)(1) and (c) 
to read as follows:


Sec. 135.181  Performance requirements: Aircraft operated over-the-top 
or in IFR conditions.

    (a) * * *
    (1) Operate a single-engine aircraft carrying passengers over-the-
top; or
* * * * *
    (c) Without regard to paragraph (a) of this section, if the latest 
weather reports or forecasts, or any combination of them, indicate that 
the weather along the planned route (including takeoff and landing) 
allows flight under VFR under the ceiling (if a ceiling exists) and 
that the weather is forecast to remain so until at least 1 hour after 
the estimated time of arrival at the destination, a person may operate 
an aircraft over-the-top.
* * * * *


Sec. 135.411  [Amended]

    7. Section 135.411 is amended by adding paragraph (c) to read as 
follows:
* * * * *
    (c) Single engine aircraft used in passenger-carrying IFR 
operations shall also be maintained in accordance with Sec. 135.421 
(c), (d), and (e).
    8. Section 135.421 is amended by adding paragraph (c), (d), and (e) 
to read as follows:


Sec. 135.421  Additional maintenance requirements.

* * * * *
    (c) For each single engine aircraft to be used in passenger-
carrying IFR operations, each certificate holder must incorporate into 
its maintenance program either:
    (1) the manufacturer's recommended engine trend monitoring program, 
which includes an oil analysis, if appropriate, or
    (2) an FAA approved engine trend monitoring program that includes 
an oil analysis at each 100 hour interval or at the manufacturer's 
suggested interval, whichever is more frequent.
    (d) For single engine aircraft to be used in passenger-carrying IFR 
operations, written maintenance instructions containing the methods, 
techniques, and practices necessary to maintain the equipment specified 
in Secs. 135.105, and 135.163 (f) and (h) are required.
    (e) No certificate holder may operate a single engine aircraft 
under IFR, carrying passengers, unless the certificate holder records 
and maintains in the engine maintenance records the results of each 
test, observation, and inspection required by the applicable engine 
trend monitoring program specified in (c) (1) and (c) (2) of this 
section.

    Issued in Washington, DC on July 31, 1997.
Barry L. Valentine,
Acting Administrator.
[FR Doc. 97-20641 Filed 8-1-97; 11:49 am]
BILLING CODE 4910-13-M