[Federal Register Volume 88, Number 115 (Thursday, June 15, 2023)]
[Rules and Regulations]
[Pages 39152-39161]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-12454]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No.: FAA-2019-0218; Amdt. No. 25-148]
RIN 2120-AL15
High Elevation Airport Operations
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Final rule.
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SUMMARY: This final rule amends certain airworthiness regulations
applicable to cabin pressurization systems and oxygen dispensing
equipment on transport category airplanes, to facilitate certification
of those airplanes, systems, and equipment for operation at high
elevation airports. This rule eliminates the need for certain
equivalent level of safety findings and exemptions.
DATES: Effective July 17, 2023.
ADDRESSES: For information on where to obtain copies of rulemaking
documents and other information related to this final rule, see ``How
To Obtain Additional Information'' in the SUPPLEMENTARY INFORMATION
section of this document.
FOR FURTHER INFORMATION CONTACT: Robert Hettman, Aircraft Systems
Section, AIR-623, Technical Innovation Policy Branch, Policy and
Innovation Division, Aircraft Certification Service, Federal Aviation
Administration, 2200 S 216th Street, Des Moines, Washington, 98198;
telephone and facsimile 206-231-3171; email [email protected].
SUPPLEMENTARY INFORMATION:
Authority for This Rulemaking
The FAA's authority to issue rules on aviation safety is found in
Title 49 of the United States Code. Subtitle I, section 106 describes
the authority of the FAA Administrator. Subtitle VII, Aviation
Programs, describes in more detail the scope of the agency's authority.
This rulemaking is promulgated under the authority described in
Subtitle VII, part A, subpart III, section 44701, ``General
Requirements.'' Under that section, the FAA is charged with promoting
safe flight of civil aircraft in air commerce by prescribing
regulations and minimum standards for the design and performance of
aircraft that the Administrator finds necessary for safety in air
commerce. This regulation is within the scope of that authority. It
prescribes new safety standards for the design and operation of
transport category airplanes.
I. Overview of Final Rule
This final rule amends two sections of title 14, Code of Federal
Regulations (14 CFR), part 25.
First, the rule amends Sec. 25.841, ``Pressurized cabins,'' for
airplanes equipped with cabin pressurization systems intended for
operations at airports with elevations at or above 8,000 feet. The FAA
considers airports with elevations greater than 8,000 feet as ``high
elevation airports.'' Section 25.841(a) still requires that cabin
pressure altitudes do not exceed 8,000 feet under normal operating
conditions, while the revisions allow cabin pressure altitudes to
exceed 8,000 feet during takeoff and landing at high elevation
airports. In addition, changes to Sec. 25.841(b)(6) allow applicants
to increase the threshold for activation of cabin pressure altitude
warnings to altitudes above 10,000 feet, to prevent nuisance warnings
to the flightcrew during takeoff and landing at high elevation
airports.
Second, this rule amends Sec. 25.1447, ``Equipment standards for
oxygen dispensing units,'' for airplanes equipped with passenger oxygen
systems intended for operations into or out of airports with elevations
above 13,000 feet. The revisions to Sec. 25.1447(c)(5) allow
applicants to raise the automatic presentation altitude for oxygen
masks located throughout the passenger cabin to altitudes above 15,000
feet while operating out of or into airports with elevations exceeding
13,000 feet.
This final rule affects manufacturers, modifiers, and operators of
transport category airplanes. The amendments to Sec. Sec. 25.841 and
25.1447 eliminate the burden on applicants and the FAA that results
from the processing of project-specific equivalent level of safety
(ELOS) findings and grants of exemption that are currently necessary
for the FAA to approve the designs of cabin pressurization systems and
oxygen dispensing units on airplanes intended to be used for operations
into or out of high elevation airports.
II. Background
A. Summary of the Problem
Current FAA regulations require that the cabin pressure altitude on
transport category airplanes remain at or below 8,000 feet in normal
operating conditions, and that supplemental oxygen be automatically
presented to passengers before the cabin pressure altitude reaches
15,000 feet. While these standards provide an acceptable level of
safety for normal operating conditions, they can hinder or conflict
with operations at high elevation airports.
To enable such operations, applicants develop specialized design
modifications that often cannot comply with cabin pressurization and
supplemental oxygen requirements in FAA regulations. In order to
approve such modifications and enable operation into high elevation
airports, the FAA typically must make and document an ELOS finding. The
FAA must typically also grant an exemption from the automatic oxygen
mask presentation requirements for operations into or out of airports
with elevations at or above 13,000 feet.
Transport airplane operators currently utilize seven airports in
the United States that have an elevation between 8,000 and 10,000 feet.
While no airports in the U.S. supporting transport airplane operations
are at an elevation higher than 10,000 feet, the FAA is aware of at
least five airports in other parts of the world that support transport
airplane operations and are at elevations that exceed 13,000 feet.
Therefore, it is for operations at these airports that applicants seek
either an ELOS or an exemption in order to obtain certification of
cabin pressurization and oxygen systems.
B. Discussion of Current Regulatory Requirements
Current regulatory requirements for cabin pressurization systems of
transport category airplanes are contained in Sec. 25.841(a) and (b).
Section 25.841(a) requires cabin pressurization systems to maintain the
interior cabin pressure so that the maximum cabin
[[Page 39153]]
pressure altitude does not exceed 8,000 feet. While an airplane is
operating on the ground before takeoff or after landing, however, the
interior cabin pressure must be equal to the outside ambient air
pressure, or airport pressure altitude. Otherwise, should the need for
an emergency evacuation arise, the pressure differential between
interior cabin and airport pressure altitude may be too high to allow
cabin attendants to open the doors. For airports above 8,000 feet, the
regulatory requirement of Sec. 25.841(a) to equip the airplane to keep
its cabin pressure altitude from exceeding 8,000 feet, and the
practical requirement for cabin pressure altitude to equal the airport
pressure altitude for takeoff and landing, are in direct conflict. This
creates a need for specialized design modifications and certification
approaches to accommodate these operations.
When a transport category airplane takes off from an airport with
an elevation below 8,000 feet, its cabin pressure altitude does not
normally exceed 8,000 feet. The cabin pressure nominally starts at the
ambient pressure altitude of the airport, and gradually increases as
the airplane climbs until the cabin pressure altitude stabilizes at an
altitude not exceeding 8,000 feet.
However, when a transport category airplane takes off from an
airport with an elevation at or above 8,000 feet, the cabin pressure
altitude necessarily exceeds 8,000 feet. The cabin pressure starts at
the airport's ambient pressure altitude at 8,000 feet or greater, and
then, if it is equipped with a system that complies with Sec.
25.841(a), decreases until it is not more than 8,000 feet. During the
time between takeoff and the point when cabin pressure altitude reaches
8,000 feet, the airplane's pressurization system is not in compliance
with the regulation. Similarly, when a transport category airplane is
landing at a high elevation airport, the interior cabin pressure
altitude will initially be at or below 8,000 feet, as required by Sec.
25.841(a), and then rise as the airplane descends, until the interior
cabin pressure altitude is the same as the ambient pressure altitude at
the airport. Since the maximum cabin pressure altitude of 8,000 feet is
exceeded to accommodate the operation into a high elevation airport,
the cabin pressurization system would again briefly not comply with the
8,000 foot limit in Sec. 25.841(a).
Furthermore, Sec. 25.841(b)(6) requires a warning indication at
the pilot or flight engineer station to indicate when the safe or
preset pressure differential and cabin pressure altitude limits are
exceeded. As described in Sec. 25.841(b)(6), appropriate warning
markings on the cabin pressure differential indicator meet the warning
requirement for pressure differential limits, and an aural or visual
signal (in addition to cabin altitude indicating means) meets the
warning requirement for cabin pressure altitude limits, if they warn
the flightcrew when the cabin pressure altitude exceeds 10,000 feet. To
support high elevation airport operations and avoid nuisance alerts,
airplane designers incorporate modifications to raise the cabin
pressure altitude at which the cabin pressure high altitude warning
indication occurs.
Currently, when an airplane designer applies to the FAA for
certification of an airplane with a cabin pressurization system
intended for operations at high elevation airports, the cabin
pressurization and cabin pressure altitude warning systems cannot meet
the design standards in Sec. 25.841(a) and (b)(6). To obtain FAA
approval of such designs, the airplane designer will typically include
compensating elements that provide an equivalent level of safety to
that intended by the regulations.\1\ For the design standards provided
by Sec. 25.841(a) and (b)(6), the FAA has found that compensating
factors such as the flightcrew's use of oxygen and minimizing the time
that the cabin pressure altitude may be above 8,000 feet can provide an
ELOS during high elevation airport operations. The FAA documents its
finding in a memorandum that communicates the agency's rationale to the
public.\2\ Processing an ELOS finding (i.e., evaluating the request,
analyzing the design, making the determination, and creating the
memorandum) creates an administrative burden on both the applicant and
the FAA during the certification process.
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\1\ The authority for the agency to make an ELOS finding is
provided in 14 CFR 21.21(b). Paragraph (b) of Sec. 21.21 specifies
that the FAA must find the proposed design meets the applicable
airworthiness requirements of subchapter C of chapter I of title 14
of the Code of Federal Regulations or that any airworthiness
provisions not complied with are compensated for by factors that
provide an equivalent level of safety.
\2\ ELOS memorandums are available electronically to the public
in the FAA's Dynamic Regulatory System (DRS) at https://drs.faa.gov/browse.
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Section 25.1447(c)(1) requires airplanes certified for operations
above 30,000 feet to include oxygen dispensing equipment that is
automatically presented to each of the airplane's occupants in the
event of depressurization, before the cabin pressure altitude reaches
15,000 feet. To avoid unnecessary presentations of the supplemental
oxygen equipment and the maintenance costs of servicing the system
afterward, applicants typically incorporate design features to
temporarily raise the automatic presentation altitude for oxygen masks
during high elevation airport operations. Currently, applicants whose
designs incorporate these features must submit a petition for an
exemption from Sec. 25.1447(c)(1).\3\ This creates an administrative
burden for both applicants who develop the petition and the FAA in the
evaluation and analysis of each petition.
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\3\ The Administrator's exemption authority is provided by 49
U.S.C. 44701(f) and implemented in accordance with 14 CFR part 11.
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C. Summary of the Notice of Proposed Rulemaking (NPRM)
The FAA published an NPRM (84 FR 13565) on April 5, 2019, that
proposed to amend Sec. Sec. 25.841, ``Pressurized cabins,'' and
25.1447, ``Equipment standards for oxygen dispensing units.'' The FAA
proposed these revisions to provide design standards for cabin
pressurization systems and oxygen dispensing equipment on transport
category airplanes intended for operation at airports with elevations
at or above 8,000 feet, also referred to in this preamble as ``high
elevation airports.''
In the NPRM, the FAA proposed adding new Sec. 25.841(c), as an
exception to Sec. 25.841(a), for systems designed to support
operations at high elevation airports. Proposed Sec. 25.841(c) would
have allowed the airplane's cabin pressure altitude to be equal to or
less than the airport elevation while the airplane is at or below
25,000 feet, provided the cabin pressurization system is designed to
minimize the time that passenger cabin occupants would be exposed to
cabin pressure altitudes exceeding 8,000 feet in flight.
The FAA also proposed adding new Sec. 25.841(d) as an exception to
Sec. 25.841(b)(6). This would have allowed an applicant to change the
threshold for the cabin pressure altitude warning indication from
10,000 feet to either 15,000 feet or 2,000 feet above the airport
elevation, whichever is greater, when operating into or out of a high
elevation airport and the airplane is at or below 25,000 feet. The FAA
proposed 2,000 feet above the airport elevation in order to allow for
system flexibility while maintaining a level of safety consistent with
previously issued ELOS determinations.
In the NPRM, the FAA also proposed to add new Sec. 25.1447(c)(5)
as an exception to Sec. 25.1447(c)(1) to allow approval of passenger
cabin oxygen dispensing units that automatically
[[Page 39154]]
deploy at 15,000 feet, or 2,000 feet above the airport elevation,
whichever is greater, during operations into or out of high elevation
airports. Similarly, the FAA proposed a variation of 2,000 feet above
the airport elevation to allow for system flexibility while maintaining
a level of safety consistent with previously-issued exemptions and to
harmonize with European Union Aviation Safety Agency (EASA) guidance.
The revisions proposed in the NPRM intended to eliminate
administrative tasks and analyses associated with the preparation and
processing of ELOS determinations and exemptions to accommodate
transport category airplane operations at high elevation airports,
without compromising safety. The FAA invited comments to the proposal,
and the comment period closed on June 4, 2019.
D. General Overview of Comments
The FAA received ten sets of comments. Three commenters were
airplane manufacturers: Boeing, Bombardier, and Embraer. The Aerospace
Industries Association and the General Aviation Manufacturers
Association (AIA/GAMA) commented collectively. One civil aviation
authority, the Transport Canada Civil Aviation Authority (TCCA),
provided comment. Three individuals commented, and three Health
Sciences majors submitted a collective comment.
The majority of the comments from industry were requests to revise
regulatory text for clarification and consistency. An individual also
described the need to make clear distinctions and utilize consistent
terminology. Another individual supported the economic cost savings,
but requested further information on new airplane designs. The three
Health Sciences majors opposed the proposed regulation because they
stated that the health risks of flying into high elevation airports
outweigh the economic benefits. Another commenter recommended not
approving high elevation operations and proposed the removal of
airports located at elevations greater than 7,500 feet for safety and
environmental reasons. A detailed discussion of the comments and
resulting regulatory changes is provided in section III.
E. Advisory Material
AIA/GAMA and Boeing suggested that the FAA develop and publish an
Advisory Circular (AC) on high elevation airport operations to provide
specific guidance on how to design cabin pressurization systems to
minimize the amount of time that passenger cabin occupants are exposed
to higher cabin pressure altitudes, to reduce the risk of hypoxia. The
FAA is providing additional discussion of this topic in this final rule
and does not consider it necessary to publish separate guidance.
III. Discussion of Public Comments and Final Rule
The FAA has made changes to this final rule in response to comments
made by the public. Some of the changes are to terminology to improve
clarity, while other changes are in response to technical comments
related to design of cabin pressurization systems. Summaries of the
comments and the FAA's responses are grouped by category in the
following subsections.
A. Clarification of Terminology
Six commenters recommended that the FAA use the term ``cabin
pressure altitude'' in the regulatory language and preamble, in lieu of
the term ``cabin pressure'' as used in the NPRM including proposed
changes to Sec. 25.841. ``Cabin pressure'' is a measurement of
pressure, typically pounds per square inch, while ``cabin pressure
altitude'' is an equivalent measurement expressed in height above sea
level, typically feet. The FAA agrees that the suggested change would
promote clarity and consistency, and in this final rule uses ``cabin
pressure altitude'' instead of ``cabin pressure'' when referring to the
condition in the airplane cabin.
B. Cabin Pressure Altitude at the Maximum Operating Altitude
Section 25.841(a) limits the cabin pressure altitude to not more
than 8,000 feet at the maximum operating altitude of the airplane under
normal operating conditions. In the NPRM, the FAA proposed revising
Sec. 25.841(a) to remove the phrase ``at the maximum operating
altitude of the airplane.'' As discussed in the NPRM, the FAA did not
intend Sec. 25.841(a) to imply that the cabin pressure altitude could
exceed 8,000 feet under normal operating conditions provided the
airplane was below the maximum operating altitude.
In response to the NPRM, TCCA asked if the FAA would update any
advisory materials to clarify the intent of the term ``under normal
operating conditions.'' The FAA does not intend to update or add any
advisory materials for this rulemaking and notes that the term ``normal
operating conditions'' currently in Sec. 25.841(a) is not being
changed by this rule. As the term relates to Sec. 25.841(a), the FAA
considers normal operating conditions to mean that the cabin
pressurization system is operating normally, rather than under some
alternative mode due to system failure. The FAA considers operating at
the maximum operating altitude of the airplane a normal operating
condition. In the context of this rulemaking, the FAA also considers
operations into or out of a high elevation airport a normal operating
condition.
C. Cabin Pressurization Limits
In the NPRM, the FAA proposed changes to Sec. 25.841(a) related to
operations at airports with elevations exceeding 8,000 feet. When
issuing the NPRM, the FAA did not consider airports that may be planned
or under construction which would exceed an elevation of 15,000 feet.
AIA/GAMA and Boeing requested that the FAA add an exception to Sec.
25.841(a) to account for probable pressurization failures that could
occur while operating at airports with elevations exceeding 15,000
feet. When operating at such airports, a probable pressurization system
failure could occur while the cabin pressure altitude is above 15,000
feet, and the airplane pressurization system would not comply with
current Sec. 25.841(a). The commenters suggested that the FAA should
also consider the effects of probable failures of a cabin
pressurization system during operations into or out of airports with
elevations that exceed 15,000 feet.
The FAA agrees with the commenters. Under normal operating
conditions into or out of airports with elevations near 15,000 feet,
the cabin pressure altitude is likely to be near or above 15,000 feet
for short durations. The FAA still considers any probable failure of
the cabin pressurization system during this timeframe to be a system
failure, even if the airplane's cabin pressure altitude is already
above 15,000 feet due to operation at the airport. The closer the
airplane is to the airport, the closer the cabin pressure altitude will
be to the airport pressure altitude. If the cabin pressure altitude
were already above 13,000 feet while the airplane is near the high
elevation airport, a probable cabin pressurization failure would not
result in significant changes in cabin pressure altitude that would
increase passenger risk of hypoxia. The FAA is therefore adding in this
final rule an exception to Sec. 25.841(a)(1) to allow certification of
systems despite probable cabin pressurization system failures \4\
resulting in cabin pressure altitudes which exceed 15,000 feet. In the
event
[[Page 39155]]
of such failures, new Sec. 25.841(c)(1) specifies that the cabin
pressure altitude cannot exceed either 15,000 feet or 2,000 feet above
the airport elevation, whichever is higher. These exceptions
accommodate operations into or out of airports with elevations near
15,000 feet.
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\4\ A probable failure condition is a failure condition having
an average probability per flight hour greater than the order of
1x10E-5.
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D. Cabin Pressure Altitudes Exceeding 8,000 Feet
In the NPRM, the FAA proposed new Sec. 25.841(c)(1) to allow cabin
pressure altitude during operations at high elevation airports to be
equal to or less than the airport elevation provided the airplane is at
or below 25,000 feet.
AIA/GAMA, Boeing, Bombardier, and TCCA suggested removing the
proposed restriction of this allowance to altitudes at or below 25,000
feet, due to concerns over passenger discomfort that may result from
the rapid changes in cabin pressure altitude that might occur with
systems designed to meet this restriction. They noted that the
restriction would limit design options and could inadvertently result
in designs that employ rapid increases in cabin pressure altitude in
excess of those typically necessary to accommodate operations into high
elevation airports.
The commenters cited a scenario that assumed an average airplane
descent rate of 2,500 ft/min, which results in a descent time of
approximately four minutes from 25,000 feet to an airport with an
elevation of 15,000 feet. Assuming an initial cabin pressure altitude
of 8,000 feet when the airplane descends through 25,000 feet, the
pressurization systems would begin commanding the cabin pressure
altitude to increase to reach the airport elevation of 15,000 feet in
this timeframe. This results in a cabin pressure altitude ascent rate
in excess of 1,000 ft/min. A similar cabin pressure altitude descent
rate would be required during the climb phase after takeoff from a
15,000-foot elevation airport.
While this rate of cabin pressure altitude change would meet the
FAA's objective to minimize the time the cabin pressure altitude is
above 8,000 feet, the FAA acknowledges that rapid changes in pressure
could cause passenger discomfort, and injury to the eardrum, if the
pressure difference between the middle and outer ear continues to
rapidly increase. As discussed by the commenters, typical operations
utilize a change in cabin pressure altitude on average around 500 ft/
min. Although using a slower airplane descent or ascent rate may be a
viable option for some high elevation airport operations, it is not
always possible at some high elevation airports due to surrounding
terrain, and may cause issues for air traffic control and flight
planning.
For these reasons, the FAA agrees with the commenters, and in this
final rule has revised proposed Sec. 25.841(c)(1) to eliminate the
restriction that the cabin pressure altitude may only be above 8,000
feet while the airplane is at or below 25,000 feet, when undertaking
operations at high elevation airports. This decision is consistent with
ELOS determinations made by the FAA in which the proposed design
required the flightcrew to configure the cabin pressurization system
for high elevation airport operations while the airplane was at the top
of descent, rather than at or below 25,000 feet.
Conversely, three Health Sciences majors collectively expressed
concern with increased health risks to passengers at cabin pressure
altitudes above 8,000 feet. Another individual recommended not
approving high elevation airport operations, and removal of airports
over 7,500 feet for safety and to ``reduce development in these fragile
zones.'' The group of three individuals suggested that the potential
health risks outweigh the economic benefits to the airline industry
from the proposed regulations. They noted that the flying public might
not be aware of potential health issues associated with low cabin air
pressure, and under this new rule may be less able to make fully
informed choices about the potential risks posed to them by flying.
They filed information concerning the health risks of high cabin
pressure altitudes and the effects of hypoxia on primarily elderly and
infants.
The FAA acknowledges the possibility of increased health risks to
some passengers exposed to cabin pressure altitudes above 8,000 feet
for extended periods of time. However, this rulemaking is only
applicable to airplane designs and systems seeking approval for
operations at high elevation airports, not all airplane designs. For
some passengers, there may be increased health risks with flight in
general because their blood oxygen saturation may reach levels
considered hypoxic during exposure to typical cabin pressure altitudes
experienced during flight. The FAA has sponsored research on this
subject \5\ to enhance the awareness of the public and medical
communities of these risks. The FAA expects that passengers travelling
to high elevation airports do so intentionally and accept the potential
health risks of visiting or living at high altitude. Areas surrounding
these high elevation airports are sufficiently inhabited that the need
for airplane service has arisen. High elevation airports allow
transportation to areas that may otherwise be difficult to reach. Air
travel to these areas allows for easier transportation of not only
people, but also supplies such as medical equipment and other cargo.
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\5\ National Air Transportation Center of Excellence for
Research in the Intermodal Transport Environment (RITE)/Airliner
Cabin Environment Research (ACER) Program, Report No. RITE-ACER-CoE-
2011-1, Health Effects of Aircraft Cabin Pressure for Older and
Vulnerable Passengers, dated November 2011, Final Report. https://www.faa.gov/data_research/research/med_humanfacs/cer/media/HealthEffectsVulnerablePassengers.pdf.
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Since travel to these areas is necessary, the FAA is adopting, as
proposed, the condition in Sec. 25.841(c)(2) that the system minimize
the time that the cabin pressure altitude is above 8,000 feet. The FAA
expects that the cabin pressurization system design will automatically
control the cabin pressure altitude once descent into the high
elevation airport is initiated, to ensure that the cabin pressure
altitude is equal to the pressure altitude at the airport when the
airplane lands. As such, the FAA expects the cabin pressure altitude to
be above 8,000 feet for no more than 15 to 20 minutes during most high
elevation airport operations. For example, assuming a constant airplane
descent rate of 2,500 ft/min, a descent from 40,000 feet to an airport
elevation of 15,000 feet would take approximately 10 minutes. Assuming
a constant change in cabin pressure altitude of 500 ft/min, a change in
cabin pressure altitude from 8,000 feet to 15,000 feet would take
approximately 14 minutes. The FAA recognizes that many variables are
associated with flights into or out of specific high elevation
airports, so descent rates and cabin pressure altitude changes will
vary. However, in accordance with Sec. 25.841(c)(2), the design must
minimize the time that the cabin pressure altitude may be above 8,000
feet during high elevation airport operations. The FAA's intent is that
manufacturers optimize the airplane flight manual procedures and cabin
pressurization system to minimize the time that the cabin pressure
altitude is above 8,000 feet to safely support high elevation airport
operations.
E. Cabin Pressure High Altitude Warning System
Section 25.841(b)(6) requires a warning indication at the pilot or
flight engineer station to indicate when the safe or preset pressure
differential and cabin pressure altitude limits are exceeded. The FAA
did not propose any changes to this section, but TCCA recommended
clarifying it by replacing
[[Page 39156]]
``warning indication at the pilot or flight engineer station'' with
``warning indication at the flightcrew station.'' The purpose of that
requirement is to provide warning to the flightcrew at the appropriate
time, not to prescribe a location within the flight deck to receive
such a warning. Therefore in this final rule the FAA has revised Sec.
25.841(b)(6) to require a warning indication for the flightcrew when
the safe or preset pressure differential or cabin pressure altitude
limit is exceeded.
The NPRM proposed adding new Sec. 25.841(d) as an exception to
Sec. 25.841(b)(6) to allow for changes to the threshold for activation
of the cabin pressure high altitude warning alert from 10,000 feet, so
that it is provided at either 15,000 feet or 2,000 feet above the
airport elevation, whichever is greater, when the airplane is operating
at a high elevation airport and at or below 25,000 feet. Because of
multiple comments, the FAA has revised the structure of Sec. 25.841(d)
from what was proposed in the NPRM. The FAA revised the introductory
paragraph of Sec. 25.841(d), as detailed below, to accommodate the
varied nature of the designs of cabin pressure altitude warning
systems. The NPRM proposed in Sec. 25.841(d)(1), that if the threshold
for activation of the cabin pressure high altitude warning is shifted
above 10,000 feet, an alert is provided to the flightcrew. This final
rule moved the requirement to Sec. 25.841(d)(2) and, as explained in
more detail below, revised it to refer to an indication rather than an
alert. In this context, the cabin pressure high altitude warning alert
is referring to the system that provides warning to the flight crew
that the safe or pre-set cabin pressure altitude has been exceeded.
Section 25.841(d)(2) in this final rule requires that indication is
provided to the flight crew when the cabin pressure high altitude
warning alert is shifted above 10,000 feet.
The FAA received multiple requests that the FAA not adopt the
proposed condition that the activation altitude for the cabin pressure
high altitude warning alert could only be raised above 10,000 feet once
the airplane was at or below 25,000 feet. In response, the FAA has
revised Sec. 25.841(d)(1) to include the following alternative
conditions for when the activation altitude for the cabin pressure high
altitude warning alert can be raised.
As previously discussed, the NPRM proposed adding new Sec.
25.841(d) as an exception to Sec. 25.841(b)(6). This would have
allowed for adjustment to the cabin pressure high altitude warning
alert to be provided at 15,000 feet, or 2,000 feet above the airport
elevation, whichever is greater, when the airplane is operating into or
out of a high elevation airport and at or below 25,000 feet. AIA/GAMA,
Boeing, and TCCA requested that the FAA clarify Sec. 25.841(d) to
explain that the cabin pressure high altitude warning alert should be
provided at cabin pressure altitudes ``up to'' 15,000 feet or 2,000
feet above the airport elevation. The exception proposed in the NPRM
would have allowed for certification of a system that raised the
activation threshold for the cabin pressure high altitude warning alert
from the 10,000 feet in the current rule, to 15,000 feet. However, that
proposal would not have accommodated designs where the cabin pressure
high altitude warning alert could vary as a function of airport
elevation and activate at some point between 10,000 and 15,000 feet. As
described by the commenters, some cabin pressure high altitude warning
systems are a function of the pressure altitude data entered into the
flight computer and not an analog pressure switch. For these types of
systems, the cabin pressure high altitude warning system may have a
unique setting that varies as a function of pressure altitude rather
than a simple step up from 10,000 feet to 15,000 feet. The FAA does not
intend for applicants to change the cabin pressure high altitude
warning system unless it is necessary to prevent nuisance warnings
during operations into or out of high elevation airports. As a result,
in this final rule Sec. 25.841(d) allows the cabin pressure high
altitude warning alert to be triggered at elevations ``up to'' 15,000
feet or 2,000 feet above the airplane's maximum takeoff and landing
altitude, whichever is greater, when operating into or out of a high
elevation airport.
AIA/GAMA and Boeing also requested that the FAA revise Sec.
25.841(d) to allow the cabin pressure high altitude warning alert to
activate at up to 15,000 feet or within 2,000 feet of the airplane's
maximum takeoff and landing altitude during high elevation airport
operations, rather than 2,000 feet above the airport elevation. For
example, high elevation airports in Tibet have a maximum pressure
altitude of approximately 15,400 feet; therefore, an airplane operating
into this area would need to have a cabin pressure high altitude
warning alert activated before the cabin pressure altitude reaches
17,400 feet to avoid a nuisance warning. If the same airplane were used
for operations into an airport with an elevation of 14,000 feet, the
cabin pressure high altitude warning alert would need to be provided
before the cabin pressure altitude reached 16,000 feet. As such, the
rule proposed in the NPRM would require either a system specifically
designed for each airport, or a system that could change the cabin
pressure high altitude warning alert as a function of the pressure
altitude at the airport. The commenters also noted that there is still
a large portion of the airplane fleet which utilizes an analog pressure
switch to activate the cabin pressure altitude warning alert, and
therefore implementing a variable system is either not possible or
would be extremely costly to implement for derivative airplane models.
The FAA agrees with the commenters and revised Sec. 25.841(d) to
state that when operating into or out of airports with elevations
exceeding 8,000 feet, the cabin pressure altitude warning alert may be
provided up to 15,000 feet, or 2,000 feet above the airplane's maximum
takeoff and landing altitude, whichever is greater. For reference, the
maximum takeoff and landing altitude is defined in the applicable
flight manual as an operational limitation of the airplane. This change
to the final rule will accommodate various designs of the cabin
pressure altitude warning system and prevent unnecessary warning alerts
while still including provisions intended to maintain an acceptable
level of safety during operations into and out of high altitude
airports. The provision in Sec. 25.841(d)(1) is intended to minimize
the time that the cabin pressure altitude is above 8,000 feet as well
as minimize the time that the cabin altitude warning alert for the
flight crew is shifted above 10,000 feet. Section 25.841(d)(2) requires
indication to the flight crew that the altitude for the cabin pressure
altitude warning system alert has been changed for high altitude
operations. Section 25.841(d)(3) requires one of two different methods
intended to protect the flight crew from the effects of hypoxia during
high altitude airport operations. The first option requires an
additional alert to notify the flight crew when to don oxygen in
accordance with their applicable operating regulations. Such a system,
if installed, provides the same intended function as the cabin altitude
warning alert. The second option is to have approved procedures in the
airplane flight manual that would require at least one pilot to don
oxygen when the cabin pressure altitude warning alert is shifted for
high altitude operations. Such provisions are consistent with
previously issued ELOS determinations depending on the specific
aircraft design that was being considered.
[[Page 39157]]
As previously discussed, the FAA is not adopting the condition,
originally proposed for Sec. 25.841(c)(1), that the cabin pressure
altitude of the airplane may only be above 8,000 feet during operations
into or out of high elevation airports while the airplane is at or
below 25,000 feet. In the NPRM, the FAA also proposed Sec. 25.841(d),
which would have allowed the cabin pressure high altitude warning alert
to be activated at cabin pressure altitudes above 10,000 feet during
high elevation airport operations provided the airplane was at or below
25,000 feet. AIA/GAMA, Boeing, and TCCA suggested raising or
eliminating the 25,000 foot operating condition on the increased
activation altitude for the cabin pressure high altitude warning alert
when the cabin pressurization system is configured either automatically
or by the flightcrew for high elevation airport operations, to avoid
potential nuisance alerts during descent. The FAA agrees with the
commenters. When the cabin pressurization system is configured for high
elevation airport operations, either manually by the flightcrew or
automatically as dictated by the design, during descent the cabin
pressure altitude may reach 10,000 feet before the airplane passes
25,000 feet. Such a condition may unnecessarily activate the cabin
pressure high altitude warning alert certified to existing regulations.
In this final rule, the FAA has therefore revised Sec. 25.841(d) to
remove the condition that the activation altitude for the cabin
pressure high altitude warning alert could only exceed 10,000 feet
while the airplane was at or below 25,000 feet.
In addition, in this final rule, the FAA adds Sec. 25.841(d)(1) to
require that during landing, the activation altitude for the cabin
pressure high altitude warning alert may not be changed to exceed
10,000 feet before the start of descent into the high elevation
airport. Following takeoff from a high elevation airport, the cabin
pressure altitude warning must be reset to 10,000 feet, either
automatically or manually by the flightcrew, before beginning cruise
operation. Both requirements ensure that the cabin pressure high
altitude warning alert remains at 10,000 feet during cruise while
allowing operational flexibility during climb out of and descent into
high elevation airports. This is consistent with ELOS determinations
that the FAA has made, approving systems for which the cabin pressure
high altitude warning alert is changed to exceed 10,000 feet for high
elevation airport operations once the aircraft enters descent, rather
than below 25,000 feet.
AIA/GAMA and Boeing also requested that the FAA revise the
condition requiring a flightcrew alert that the activation altitude for
the cabin pressure high altitude warning has shifted to above 10,000
feet in proposed Sec. 25.841(d)(1) to refer to an ``indication''
system instead of an ``alert'' system. As described in the preamble for
Sec. 25.1322, amendment 25-131 (75 FR 67209, November 2, 2010) (Sec.
25.1322), the word ``alert'' describes a flight deck indication meant
to attract the attention of the flightcrew and identify a non-normal
operational or airplane system condition. For high elevation airport
operations, the alert originally proposed in Sec. 25.841(d)(1) was for
a normal operating condition, not for a non-normal condition. Thus,
requiring that an alert be provided for a normal operating condition is
not appropriate.
The FAA agrees with the commenters, and this final rule revises
Sec. 25.841(d) to refer to an indication system rather than an alert
system. Revised Sec. 25.841(d)(2) requires an indication to be
provided to the flightcrew that the activation altitude for the cabin
pressure high altitude warning alert has shifted above 10,000 feet
cabin pressure altitude. The FAA considers the required indication to
be in support of normal operations and flightcrew action may not
necessarily be required. However, depending on which certification
method in Sec. 25.841(d)(3) the applicant follows, flight procedures
may still require the pilot to don oxygen when the indication denotes
that the cabin pressure high altitude warning has shifted above 10,000
feet cabin pressure altitude.
In the NPRM, the FAA proposed that Sec. 25.841(d)(2) require that
if the system shifts the cabin pressure high altitude warning above
10,000 feet automatically, it must also alert the flightcrew to take
action should the automatic shift function fail. AIA/GAMA, Boeing, and
Bombardier suggested removal of this additional alert. The commenters
suggested that such an alert is unnecessary and the need to provide
crew alerts is already addressed through compliance with Sec. Sec.
25.1309(c) and 25.1322.
The FAA agrees with the commenters. For any system that an
applicant proposes to reconfigure for high elevation airport
operations, Sec. 25.1309 would be applicable and require the applicant
to conduct a hazard analysis that includes system failure. The FAA is
not adopting the proposal that Sec. 25.841(d)(2) require an additional
alert to the flightcrew. An additional alert may or may not be
necessary depending on the hazard analysis that must still be conducted
in accordance with Sec. 25.1309.
F. Automatic Presentation of Oxygen Masks
The NPRM proposed adding Sec. 25.1447(c)(5) as an exception to
Sec. 25.1447(c)(1) to allow approval of passenger cabin oxygen
dispensing units that are automatically presented at 15,000 feet or
within 2,000 feet of the airport elevation, whichever is higher,
provided the airplane is being operated at altitudes at or below 25,000
feet. This change was meant to relieve applicants and the FAA from the
burden of preparing and processing exemptions from the passenger oxygen
mask automatic presentation altitude requirement in Sec.
25.1447(c)(1). During operations into some high elevation airports,
increasing the cabin pressure altitude at which passenger cabin oxygen
dispensing units are automatically presented is required in order to
avoid unnecessary presentations.
AIA/GAMA and Boeing requested that new Sec. 25.1447(c)(5) allow
automatic oxygen mask presentations at up to 15,000 feet or within
2,000 feet of the airplane's maximum takeoff and landing altitude,
rather than within 2,000 feet of the airport elevation. They noted that
many in-production airplanes, which an applicant may seek to certify
for operation at high elevation airports, utilize an analog pressure
switch to automatically deploy the oxygen masks. Implementing a
variable system is either not possible or would be extremely costly to
implement on airplanes with this type of design, according to the
commenters. AIA/GAMA, Boeing, and Bombardier commented that the
proposed rule would have required either an automatic oxygen mask
presentation system unique for each airport, or a system that would
automatically change the oxygen mask presentation altitude as a
function of the airport elevation. In addition, landing at a high
elevation airport, which is below the airplane's maximum certified
takeoff and landing altitude, will have a negligible difference between
when masks might be automatically presented due to a sudden loss of
cabin pressure, and when the airplane lands. The FAA agrees with the
commenters, and Sec. 25.1447(c)(5) allows automatic oxygen mask
presentations at up to 15,000 feet or within 2,000 feet of the
airplane's maximum takeoff and landing altitude, to accommodate the
variation in design and potential unnecessary presentation of the
oxygen masks.
[[Page 39158]]
In addition, AIA/GAMA and Boeing suggested that the FAA not adopt
the requirement proposed in the NPRM that the passenger oxygen mask
presentation altitude could only be reset during high elevation
operations when the airplane is below 25,000 feet. As discussed by the
commenters, not allowing the flightcrew to reset the oxygen mask
presentation altitude until the airplane is below 25,000 feet creates
additional crew workload, which could be avoided if the airplane is
allowed to be configured at the top of descent. Reduction in crew
workload during the critical descent phase allows the crew to focus on
other tasks. The FAA agrees with the commenters and Sec. 25.1447(c)(5)
omits the condition proposed in the NPRM that the oxygen mask
presentation altitude only be revised when the airplane is at or below
25,000 feet.
In the discussion of Sec. 25.1447(c)(5) in the NPRM, the FAA
proposed raising the automatic presentation altitude for passenger
oxygen masks during operations into all airports above 8,000 feet.
However, the intent of this rulemaking, in part, is to eliminate the
need for processing exemptions to Sec. 25.1447(c)(1) to avoid nuisance
oxygen mask presentations while operating at airports with elevations
that would otherwise cause oxygen mask presentations. When operating
into airports with elevations at or below 13,000 feet, the automatic
presentation altitude for the oxygen masks could still be below 15,000
feet, the required presentation altitude in Sec. 25.1447(c)(1), and
avoid inadvertent oxygen mask presentations. As a result, the FAA has
not granted exemptions to the automatic oxygen mask presentation
requirements in Sec. 25.1447(c)(1) for airplanes proposed to be
approved for operations at airports with elevations at or below 13,000
feet. As a result of all related comments, Sec. 25.1447(c)(5), as
adopted in this final rule, states that when operating into or out of
airports with elevations above 13,000 feet, the dispensing units
providing the required oxygen flow must be automatically presented to
the occupants within 2,000 feet of the airplane's maximum takeoff and
landing altitude.
In addition, an individual commenter described various operational
considerations that should be made by operators when operating into
high elevation airports, such as the potential need to provide oxygen
to passengers that may need it while the airplane is on the ground or
when cabin pressure altitudes are above 8,000 feet. The FAA agrees that
there are many operational issues to consider when operating into and
out of high elevation airports. However, this rulemaking is limited to
approval of new airplane type designs with cabin pressurization systems
and oxygen systems intended for operations into and out of high
elevation airports. Operational considerations are outside the scope of
this rulemaking activity.
The FAA also received comments to revise specific preamble text of
the NPRM. The specific preamble text from the NPRM is not restated in
this final rule, so specific editorial suggestions to the preamble text
of the NPRM are not applicable. No changes were made to this final rule
in this regard.
IV. Regulatory Notices and Analyses
A. Regulatory Evaluation
Changes to Federal regulations must undergo several economic
analyses. First, Executive Order 12866 and Executive Order 13563, as
amended by Executive Order 14094 (``Modernizing Regulatory Review''),
direct that each Federal agency shall adopt a regulation only upon a
reasoned determination that the benefits of the intended regulation
justify its costs. Second, the Regulatory Flexibility Act of 1980 (Pub.
L. 96-354) requires agencies to analyze the economic impact of
regulatory changes on small entities. Third, the Trade Agreements Act
(Pub. L. 96-39) prohibits agencies from setting standards that create
unnecessary obstacles to the foreign commerce of the United States. In
developing U.S. standards, the Trade Act requires agencies to consider
international standards and, where appropriate, that they be the basis
of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995
(Pub. L. 104-4) requires agencies to prepare a written assessment of
the costs, benefits, and other effects of proposed or final rules that
include a Federal mandate 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. The current threshold after adjustment for inflation is
$177 million using the most current (2022) Implicit Price Deflator for
the Gross Domestic Product. This portion of the preamble summarizes the
FAA's analysis of the economic impacts of this final rule.
In conducting these analyses, FAA has determined that this final
rule (1) has benefits that justify its costs; (2) is not an
economically ``significant regulatory action'' as defined in section
3(f) of Executive Order 12866, as amended; (3) will not have a
significant economic impact on a substantial number of small entities;
(4) will not create unnecessary obstacles to the foreign commerce of
the United States; and (5) will not impose an unfunded mandate on
state, local, or tribal governments, or on the private sector by
exceeding the threshold identified previously. These analyses are
summarized below.
Currently, the FAA processes ELOS memorandums to document ELOS
findings when an airplane manufacturer or modifier requests
certification of airplane cabin pressurization systems used for
operations into or out of airports with elevations at or above 8,000
feet. The FAA also processes exemptions to the automatic oxygen mask
presentation requirements for operations into or out of airports with
elevations at or above 13,000 feet. The final rule will eliminate the
need to continue performing the administrative tasks and analyses
associated with the processing of an ELOS or exemption to accommodate
operations at high elevation airports for transport category airplanes
without compromising safety.
This final rule will result in small quantifiable cost savings. The
FAA issues on average four ELOS findings and two exemptions per year
related to high elevation airports, devoting between 20 to 100
engineering hours for each ELOS or exemption processed. The FAA
estimates industry organizations seeking certification expend the same
range of engineering hours for each ELOS and exemption processed. Using
the loaded wage rate of $83.86 for aerospace engineer,\6\ the FAA
estimates the total annual cost savings of this final rule could range
from $20,126 to $100,632 for both industry and FAA.
---------------------------------------------------------------------------
\6\ $59.12 is the average wage salary cost for aerospace
engineer, which accounts 70.5% of employer costs; and $24.74 or
29.5% is the fringe benefits. https://www.bls.gov/news.release/pdf/ecec.pdf (accessed on 12/20/22).
---------------------------------------------------------------------------
As a result, this rulemaking will reduce the cost of airplane
certification without reducing the current level of safety. The
expected outcome will be a minimal economic impact resulting in a small
regulatory burden relief. The FAA requested comments with supporting
justification about the FAA determination of minimal economic impact.
No such comments were received. Therefore, the FAA has determined that
this final rule is not a ``significant regulatory action'' as defined
in section 3(f) of Executive Order 12866, as amended, and is not
``significant'' as defined in DOT's Regulatory Policies and Procedures.
B. Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA)
establishes ``as a
[[Page 39159]]
principle of regulatory issuance that agencies shall endeavor,
consistent with the objectives of the rule and of applicable statutes,
to fit regulatory and informational requirements to the scale of the
businesses, organizations, and governmental jurisdictions subject to
regulation.'' To achieve this principle, agencies are required to
solicit and consider flexible regulatory proposals and to explain the
rationale for their actions to assure that such proposals are given
serious consideration. The RFA covers a wide range of small entities,
including small businesses, and not-for-profit organizations.
Agencies must perform a review to determine whether a rule will
have a significant economic impact on a substantial number of small
entities. If the agency determines that it will, the agency must
prepare a regulatory flexibility analysis as described in the RFA.
However, if an agency determines that a rule is not expected to have a
significant economic impact on a substantial number of small entities,
section 605(b) of the RFA provides that the head of the agency may so
certify and a regulatory flexibility analysis is not required. The
certification must include a statement providing the factual basis for
this determination, and the reasoning should be clear.
The final rule relieves the industry from requesting that the FAA
make a determination that an ELOS exists for certification of airplane
cabin pressurization systems used for operations into or out of
airports with elevations at or above 8,000 feet above sea level. This
final rule also relieves industry from petitioning for exemptions to
the automatic oxygen mask presentation requirements for operations into
and out of airports with elevations above 13,000 feet above sea level.
This expected outcome will be a minimal economic impact with small
burden relief and savings for any small entity affected by this
rulemaking action.
If an agency determines that a rulemaking will not result in a
significant economic impact on a substantial number of small entities,
the head of the agency may so certify under section 605(b) of the RFA.
Therefore, as provided in section 605(b), the head of the FAA certifies
that this final rulemaking will not result in a significant economic
impact on a substantial number of small entities.
C. International Trade Impact Assessment
The Trade Agreements Act of 1979 (Pub. L. 96-39) prohibits Federal
agencies from establishing standards or engaging in related activities
that create unnecessary obstacles to the foreign commerce of the United
States. Pursuant to these Act, the establishment of standards is not
considered an unnecessary obstacle to the foreign commerce of the
United States, so long as the standard has a legitimate domestic
objective, such as the protection of safety, and does not operate in a
manner that excludes imports that meet this objective. The statute also
requires consideration of international standards and, where
appropriate, that they be the basis for U.S. standards. The FAA has
assessed the effect of this final rule and determined that its purpose
is to protect the safety of U.S. civil aviation. Therefore, the final
rule is in compliance with the Trade Agreements Act.
D. Unfunded Mandates Assessment
Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement
assessing the effects of any Federal mandate in a final agency rule
that may result in an expenditure of $100 million or more (adjusted
annually for inflation) in any one year. The current threshold after
adjustment for inflation is $177 million using the most current (2022)
Implicit Price Deflator for the Gross Domestic Product. This final rule
does not contain such a mandate; therefore, the requirements of Title
II of the Act do not apply.
E. Paperwork Reduction Act
The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires
that the FAA consider the impact of paperwork and other information
collection burdens imposed on the public. The FAA has determined that
there is no new requirement for information collection associated with
this final rule.
F. International Cooperation
(1) In keeping with U.S. obligations under the Convention on
International Civil Aviation, it is FAA's policy to conform to
International Civil Aviation Organization (ICAO) Standards and
Recommended Practices to the maximum extent practicable. The FAA has
reviewed the corresponding ICAO Standards and Recommended Practices and
has found no differences with these final regulations.
(2) European Union Aviation Safety Agency (EASA) certification
requirements related to oxygen dispensing units in CS 25.1447(c)(1) are
similar to those in Sec. 25.1447(c)(1). In amendment 18 of
Certification Specifications and Acceptable Means of Compliance for
Large Aeroplanes, CS-25,\7\ the EASA describes an acceptable means of
compliance (AMC) in AMC 25.1447(c)(1). Specifically, AMC 25.1447(c)(1)
states: ``The design of the automatic presentation system should take
into account that when the landing field altitude is less than 610 m
(2,000 feet) below the normal preset automatic presentation altitude,
the automatic presentation altitude may be reset to landing field
altitude plus 610 m (2,000 feet).'' Thus, the FAA's change to Sec.
25.1447 is consistent with guidance provided by EASA.
---------------------------------------------------------------------------
\7\ Amendment 18 of European Aviation Safety Agency,
``Certification Specifications and Acceptable Means of Compliance
for Large Aeroplanes,'' CS-25, dated June 22, 2016, can be found at
this web address: https://www.easa.europa.eu/document-library/certification-specifications/cs-25-amendment-18.
---------------------------------------------------------------------------
(3) EASA has not published advisory material to accommodate
operations into or out of high elevation airports in consideration of
the cabin pressure altitude and warning requirements in CS 25.841.
G. Environmental Analysis
FAA Order 1050.1F, ``Environmental Impacts: Policies and
Procedures,'' identifies FAA actions that are categorically excluded
from preparation of an environmental assessment or environmental impact
statement under the National Environmental Policy Act in the absence of
extraordinary circumstances. The FAA has determined this rulemaking
action qualifies for the categorical exclusion identified in paragraph
5-6.6 of Order 1050.1F and involves no extraordinary circumstances.
V. Executive Order Determinations
A. Executive Order 13132, Federalism
The FAA has analyzed this final rule under the principles and
criteria of Executive Order 13132, ``Federalism.'' The agency
determined that this action will not have a substantial direct effect
on the States, or the relationship between the Federal Government and
the States, or on the distribution of power and responsibilities among
the various levels of government, and, therefore, does not have
federalism implications.
B. Executive Order 13175, Consultation and Coordination With Indian
Tribal Governments
Consistent with Executive Order 13175, Consultation and
Coordination with Indian Tribal Governments,\8\ and
[[Page 39160]]
FAA Order 1210.20, American Indian and Alaska Native Tribal
Consultation Policy and Procedures,\9\ the FAA ensures that Federally
Recognized Tribes (Tribes) are given the opportunity to provide
meaningful and timely input regarding proposed Federal actions that
have the potential to affect uniquely or significantly their respective
Tribes. At this point, the FAA has not identified any unique or
significant effects, environmental or otherwise, on tribes resulting
from this proposed rule.
---------------------------------------------------------------------------
\8\ 65 FR 67249 (Nov. 6, 2000).
\9\ FAA Order No. 1210.20 (Jan. 28, 2004), available at https://www.faa.gov/documentLibrary/media/1210.pdf.
---------------------------------------------------------------------------
C. Executive Order 13211, Regulations That Significantly Affect Energy
Supply, Distribution, or Use
The FAA analyzed this final rule under Executive Order 13211,
Actions Concerning Regulations that Significantly Affect Energy Supply,
Distribution, or Use (May 18, 2001). The agency has determined that it
is not a ``significant energy action'' under the Executive order and it
is not likely to have a significant adverse effect on the supply,
distribution, or use of energy.
D. Executive Order 13609, International Cooperation
Executive Order 13609, Promoting International Regulatory
Cooperation, promotes international regulatory cooperation to meet
shared challenges involving health, safety, labor, security,
environmental, and other issues and to reduce, eliminate, or prevent
unnecessary differences in regulatory requirements. The FAA has
analyzed this action under the policies and agency responsibilities of
Executive Order 13609, and has determined that this action will not
effect on international regulatory cooperation.
VI. How To Obtain Additional Information
A. Rulemaking Documents
An electronic copy of a rulemaking document may be obtained by
using the internet--
1. Search the Federal eRulemaking Portal (www.regulations.gov);
2. Visit the FAA's Regulations and Policies web page at
www.faa.gov/regulations_policies/; or
3. Access the Government Printing Office's web page at
www.GovInfo.gov.
Copies may also be obtained by sending a request (identified by
notice, amendment, or docket number of this rulemaking) to the Federal
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence
Avenue SW, Washington, DC 20591, or by calling (202) 267-9680.
B. Comments Submitted to the Docket
Comments received may be viewed by going to https://www.regulations.gov and following the online instructions to search the
docket number for this action. Anyone is able to search the electronic
form of all comments received into any of the FAA's dockets by the name
of the individual submitting the comment (or signing the comment, if
submitted on behalf of an association, business, labor union, etc.).
C. Small Business Regulatory Enforcement Fairness Act
The Small Business Regulatory Enforcement Fairness Act (SBREFA) of
1996 requires FAA to comply with small entity requests for information
or advice about compliance with statutes and regulations within its
jurisdiction. A small entity with questions regarding this document,
may contact its local FAA official, or the person listed under the FOR
FURTHER INFORMATION CONTACT heading at the beginning of the preamble.
To find out more about SBREFA on the internet, visit https://www.faa.gov/regulations_policies/rulemaking/sbre_act/.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Navigation (air), Reporting and
recordkeeping requirements.
The Amendments
In consideration of the foregoing, the Federal Aviation
Administration amends 14 CFR part 25 as follows:
PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
0
1. The authority citation for part 25 continues to read as follows:
Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702 and
44704.
0
2. Amend Sec. 25.841 by revising paragraphs (a) introductory text,
(a)(1), and (b)(6) and adding paragraphs (c) and (d) to read as
follows:
Sec. 25.841 Pressurized cabins.
(a) Except as provided in paragraph (c) of this section,
pressurized cabins and compartments to be occupied must be equipped to
provide a cabin pressure altitude of not more than 8,000 feet under
normal operating conditions.
(1) If certification for operation above 25,000 feet is requested,
the airplane must be designed so that occupants will not be exposed to
cabin pressure altitudes in excess of 15,000 feet after any probable
failure condition in the pressurization system except as provided in
paragraph (c) of this section.
* * * * *
(b) * * *
(6) Warning indication to the flightcrew when the safe or preset
pressure differential or cabin pressure altitude limit is exceeded.
Appropriate warning markings on the cabin pressure differential
indicator meet the warning requirement for pressure differential
limits. An alert meets the warning requirement for cabin pressure
altitude limits if it warns the flightcrew when the cabin pressure
altitude exceeds 10,000 feet, except as provided in paragraph (d) of
this section.
* * * * *
(c) When operating into or out of airports with elevations at or
above 8,000 feet, the cabin pressure altitude in pressurized cabins and
occupied compartments may be up to, or greater than, the airport
elevation by 2,000 feet, provided--
(1) In the event of probable failure conditions of the cabin
pressurization system, the cabin pressure altitude must not exceed
15,000 feet, or 2,000 feet above the airport elevation, whichever is
higher; and
(2) The cabin pressurization system is designed to minimize the
time in flight that occupants may be exposed to cabin pressure
altitudes exceeding 8,000 feet.
(d) When operating into or out of airports with elevations at or
above 8,000 feet, the cabin pressure high altitude warning alert may be
provided at up to 15,000 feet, or 2,000 feet above the airplane's
maximum takeoff and landing altitude, whichever is greater, provided:
(1) During landing, the change in cabin pressure high altitude
warning alert may not occur before the start of descent into the high
elevation airport and, following takeoff, the cabin pressure high
altitude warning alert must be reset to 10,000 feet before beginning
cruise operation;
(2) Indication is provided to the flightcrew that the cabin
pressure high altitude warning alert has shifted above 10,000 feet
cabin pressure altitude; and
(3) Either an alerting system is installed that notifies the
flightcrew members on flight deck duty when to don oxygen in accordance
with the applicable operating regulations, or a limitation is provided
in the airplane flight manual that requires the pilot flying the
airplane to don oxygen when the cabin pressure altitude warning has
shifted above 10,000 feet, and requires other flightcrew members on
flight deck
[[Page 39161]]
duty to monitor the cabin pressure and utilize oxygen in accordance
with the applicable operating regulations.
0
3. Amend Sec. 25.1447 by revising paragraph (c)(1) and adding
paragraph (c)(5) to read as follows:
Sec. 25.1447 Equipment standards for oxygen dispensing units.
* * * * *
(c) * * *
(1) There must be an oxygen dispensing unit connected to oxygen
supply terminals immediately available to each occupant wherever
seated, and at least two oxygen dispensing units connected to oxygen
terminals in each lavatory. The total number of dispensing units and
outlets in the cabin must exceed the number of seats by at least 10
percent. The extra units must be as uniformly distributed throughout
the cabin as practicable. Except as provided in paragraph (c)(5) of
this section, if certification for operation above 30,000 feet is
requested, the dispensing units providing the required oxygen flow must
be automatically presented to the occupants before the cabin pressure
altitude exceeds 15,000 feet. The crewmembers must be provided with a
manual means of making the dispensing units immediately available in
the event of failure of the automatic system.
* * * * *
(5) When operating into or out of airports with elevations above
13,000 feet, the dispensing units providing the required oxygen flow
must be automatically presented to the occupants at cabin pressure
altitudes no higher than 2,000 feet above the airplane's maximum
takeoff and landing altitude.
Issued under authority provided by 49 U.S.C. 106(f), 44701(a),
and 44703 in Washington, DC.
Billy Nolen,
Acting Administrator.
[FR Doc. 2023-12454 Filed 6-14-23; 8:45 am]
BILLING CODE 4910-13-P