Proposed Rule2023-07743
Airworthiness Directives; Various Helicopters
Primary source
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Published
April 12, 2023
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive 2021-23- 13, which applies to all helicopters equipped with a radio (also known as radar) altimeter. AD 2021-23-13 requires revising the limitations section of the existing rotorcraft flight manual (RFM) for your helicopter to incorporate limitations prohibiting certain operations requiring radio altimeter data when in the presence of 5G C-Band interference in areas as identified by Notices to Air Missions (NOTAMs). Since the FAA issued AD 2021-23-13, the FAA determined that additional limitations are needed due to the continued deployment of new 5G C-Band base stations whose signals are expected to cover most of the contiguous United States at transmission frequencies between 3.7- 3.98 GHz. This proposed AD would require revising the limitations section of the existing RFM to incorporate limitations prohibiting certain operations requiring radio altimeter data, due to the presence of 5G C-Band interference. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 88 Issue 70 (Wednesday, April 12, 2023)</title>
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[Federal Register Volume 88, Number 70 (Wednesday, April 12, 2023)]
[Proposed Rules]
[Pages 21931-21938]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-07743]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2023-0668; Project Identifier AD-2023-00199-R]
RIN 2120-AA64
Airworthiness Directives; Various Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede Airworthiness Directive 2021-23-
13, which applies to all helicopters equipped with a radio (also known
as radar) altimeter. AD 2021-23-13 requires revising the limitations
section of the existing rotorcraft flight manual (RFM) for your
helicopter to incorporate limitations prohibiting certain operations
requiring radio altimeter data when in the presence of 5G C-Band
interference in areas as identified by Notices to Air Missions
(NOTAMs). Since the FAA issued AD 2021-23-13, the FAA determined that
additional limitations are needed due to the continued deployment of
new 5G C-Band base stations whose signals are expected to cover most of
the contiguous United States at transmission frequencies between 3.7-
3.98 GHz. This proposed AD would require revising the limitations
section of the existing RFM to incorporate limitations prohibiting
certain operations requiring radio altimeter data, due to the presence
of 5G C-Band interference. The FAA is proposing this AD to address the
unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by May 12,
2023.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
<bullet> Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2023-0668; or in person at Docket Operations between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD
docket contains this NPRM, any comments received, and other
information. The street address for Docket Operations is listed above.
FOR FURTHER INFORMATION CONTACT: David Swartz, Continued Operational
Safety Technical Advisor, COS Program Management Section, Operational
Safety Branch, FAA, 222 W. 7th Ave, M/S #14 Anchorage, AK 99513; phone:
817-222-5390; email: <a href="/cdn-cgi/l/email-protection#e28d92879083968b8d8c838e91838487969ba2848383cc858d94"><span class="__cf_email__" data-cfemail="076877627566736e6869666b74666162737e4761666629606871">[email protected]</span></a>.
[[Page 21932]]
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include ``Docket No. FAA-2023-0668; Project Identifier
AD-2023-00199-R'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
the proposal because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
<a href="http://regulations.gov">regulations.gov</a>, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this proposed AD.
Confidential Business Information
CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as ``PROPIN.'' The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to David
Swartz, Continued Operational Safety Technical Advisor, COS Program
Management Section, Operational Safety Branch, FAA, 222 W. 7th Ave, M/S
#14 Anchorage, AK 99513; phone: 817-222-5390; email:
<a href="/cdn-cgi/l/email-protection#670817021506130e0809060b14060102131e2701060649000811"><span class="__cf_email__" data-cfemail="771807120516031e1819161b04161112030e3711161659101801">[email protected]</span></a>. Any commentary that the FAA receives that is
not specifically designated as CBI will be placed in the public docket
for this rulemaking.
Background
The FAA issued Airworthiness Directive (AD) 2021-23-13, Amendment
39-21811 (86 FR 69992, December 9, 2021) (AD 2021-23-13), for all
helicopters equipped with a radio altimeter. AD 2021-23-13 was prompted
by a determination that radio altimeters cannot be relied upon to
perform their intended function if they experience interference from
wireless broadband operations in the 3.7-3.98 GHz frequency band (5G C-
Band). AD 2021-23-13 requires revising the limitations section of the
existing RFM to incorporate limitations prohibiting certain operations
requiring radio altimeter data when in the presence of 5G C-Band
interference as identified by NOTAMs. The agency issued AD 2021-23-13
because radio altimeter anomalies that are undetected by the automation
or pilot, particularly close to the ground, could lead to loss of
continued safe flight and landing.
On the same day, the FAA also issued AD 2022-23-12, Amendment 39-
21810 (86 FR 69984, December 9, 2021) (AD 2021-23-12), to correct the
same unsafe condition on, and require similar operating limitations
for, all transport and commuter category airplanes equipped with a
radio altimeter.
Actions Since AD 2021-23-13
Rotorcraft Capability and Alterations: Since issuing AD 2021-23-13
and AD 2021-23-12, the FAA has reviewed data from alternative method of
compliance (AMOC) requests, demonstrating that these radio altimeters
can be relied upon to perform their intended function when operating
beyond a certain protection radius around 5G C-Band transmitters. The
iterative AMOC process allowed the FAA to gain insight into 5G C-Band
transmission impacts in a progressively more sophisticated manner. At
first, the FAA made conservative assumptions about the potential for
impact on radio altimeters from 5G C-Band transmissions and applied
them to all airspace. During the FAA's initial analyses of AMOC
requests, the FAA looked to protect against 5G C-Band interference
during critical operations that rely on radio altimeters, by
prohibiting these operations within the vicinity of known 5G C-Band
emitters. After some time and an improved understanding of the 5G C-
Band signals and their effects on specific radio altimeters, the FAA
was able to reduce the protected area around the 5G C-band emitters to
protect rotorcraft.
The FAA received and reviewed many more AMOC proposals from
transport category airplane operators for AD 2021-23-12 than from
helicopter operators for AD 2021-23-13. Some of the radio altimeters
used on rotorcraft are the same model as, or similar to, the radio
altimeters installed on transport category airplanes. As a result, the
AMOC process for AD 2021-23-12 and AD 2021-23-13 also provided data
about the varying levels of interference tolerance for a majority of
radio altimeters on the market, allowing the FAA to understand the
overall susceptibility to interference of the existing fleet of
rotorcraft. In addition, the FAA learned about the aircraft alterations
that can be accomplished quickly to improve a radio altimeter's
tolerance to transmissions in adjacent or nearby spectrum bands. Now
that the FAA better understands the performance of specific radio
altimeters and the means to make them more tolerant of transmissions in
adjacent or nearby spectrum bands, the FAA is proposing to retain the
existing prohibitions in AD 2021-23-13 with an option to upgrade to a
radio altimeter tolerant rotorcraft to avoid the prohibitions.
5G Compatibility: AMOCs allowing operations otherwise prohibited by
AD 2021-23-13 were based on voluntary operational mitigations
undertaken by AT&T and Verizon, 5G C-Band licensees. The FAA, AT&T, and
Verizon have collaborated extensively to ensure 5G C-Band radio
frequency transmissions and rotorcraft operations can safely co-exist.
In early January 2022, the FAA progressively tailored runway safety
zones around airports to envelop only the airspace areas where critical
phases of flight occur. Although these tailored runway safety zones
around airports primarily benefited transport and commuter airplane
operations, they also benefited rotorcraft operating at those airports.
This collaborative work has allowed safe rotorcraft operations to
continue in the short term.
Update to Safety Determination: The FAA's initial determination
that radio altimeters cannot be relied upon to perform their intended
function if they experience interference from wireless broadband
operations in the 5G C-Band remains unchanged. Unlike the Terrain
Awareness and Warnings Systems (TAWS) in transport airplanes, most
Helicopter Terrain Avoidance Warning Systems (HTAWS) do not rely on
radio altimeter inputs, but rather use radar altimeter data for
vertical situational awareness in low visibility conditions (i.e., snow
and dust blown up by rotor down wash) and as an input into several
procedures and automated system. This means that a 5G C-Band
interference event in most helicopters does not result in an erroneous
HTAWS alert.
The FAA is concerned that 5G C-Band interference events will occur
more frequently as telecommunication companies continue to deploy 5G C-
[[Page 21933]]
Band services throughout the country and the safety benefit from the
use of radio altimeters in helicopters will be lost. On January 11,
2023, the FAA published an NPRM that would supersede AD 2021-23-12 for
transport and commuter category airplanes equipped with a radio
altimeter (88 FR 1520) (``transport NPRM''). The transport NPRM
proposed, in part, to require that after February 1, 2024, operations
under part 121 must be conducted with a radio altimeter tolerant
airplane. This proposed requirement was prompted by the FAA's
determination that erroneous system warnings due to a malfunctioning
radio altimeter will lead to flightcrew desensitization to system
warnings. The FAA has assessed the cumulative effects of increasing
numbers of erroneous warnings for rotorcraft, such as the display of
erroneous vertical position input to the pilot, and determined that it
has not yet risen to the level of an unsafe condition. For this reason,
the FAA is not proposing to mandate equipage of radio altimeters
meeting certain tolerance requirements for all helicopters, as proposed
in the transport NPRM for airplanes.
Why New Corrective Action is Needed: The FAA expects an increase in
the number of 5G C-Band base stations around airports in the national
airspace system (NAS) and expects these stations to transmit in the
entire 5G C-Band frequency band (from 3.7 to 3.98 GHz). Since the FAA
issued AD 2021-23-13, which focused solely on a limited airspace
environment, 5G C-Band base stations have increasingly begun
transmission in other areas of the country. Whereas 5G C-Band
transmissions were initially limited to 3.7 to 3.8 GHz, these
transmissions have also begun to expand to 3.8 to 3.98 GHz, and the FAA
expects deployment at the higher end of the frequency range to expand
after July 1, 2023.\1\ These higher frequencies are nearer to the
spectrum allocation where radio altimeters operate (4.2 to 4.4 GHz),
which means that the potential for interference to radio altimeters
from in-band and spurious \2\ emissions may be more likely. In
addition, the FAA expects approximately 19 additional telecommunication
companies in addition to AT&T and Verizon will begin transmitting in
the C-Band at some point after June 2023.\3\ As the 21
telecommunication companies authorized to transmit 5G C-Band continue
to expand transmissions throughout the country, using NOTAMs to
identify affected areas and assessing proposed AMOCs will become
untenable. NOTAMs are temporary means of disseminating information
until the information can be publicized by other means. Given 5G C-Band
signals are not expected to be temporary and that 5G C-Band signals
will cover the contiguous U.S., NOTAMs are no longer the best means of
communicating the location of the 5G C-Band environment. In addition,
given the information gleaned over the past year, the FAA is now able
to identify the conditions under which radio altimeters can be relied
on to perform their intended function in the presence of a 5G C-Band
environment. Therefore, case-by-case AMOC approvals that allow
performing certain operations otherwise prohibited by an AD are no
longer the most efficient way for helicopter operators to show that
their radio altimeters perform their intended function in the 5G C-Band
environment.
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\1\ FCC licenses authorized 5G transmissions from 3.7 to 3.98
GHz.
\2\ The tolerance to 5G spurious emissions is the level of
aggregate interference in the radio altimeter band below which the
installed radio altimeter system will meet its performance standards
and perform its intended function.
\3\ The additional 19 telecommunications companies will have
access to the FCC-licensed spectrum after current users vacate use
of the frequencies.
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Determination of Rotorcraft Radio Altimeter Tolerance Requirements:
The FAA is proposing interference tolerance requirements for radio
altimeters that can be used across the affected fleet. Rotorcraft
meeting these proposed minimum performance levels would be allowed to
perform the prohibited operations in the contiguous U.S. airspace and
would no longer be required to include the RFM limitations specified in
AD 2021-23-12. After July 1, 2023, rotorcraft that do not meet the
proposed minimum performance levels would be subject to the prohibited
operations.
The FAA determined the proposed interference tolerance requirements
by using the fuller understanding of specific radio altimeter
capabilities the FAA gained during the AMOC process for AD 2021-23-12
and AD 2021-23-13. This process revealed the radio altimeter
modifications that would not require a substantial system redesign,
allowing aircraft operators to readily replace radio altimeters or
install filters that allowed the aircraft to operate safely in a
mitigated 5G environment.
The interference tolerance requirements are represented by a power
spectral density (PSD) curve. The PSD curve, as depicted in figure 1 to
paragraph (g)(1) of this proposed AD, represents the height over the
ground and received power from a 5G C-Band emitter, at or below which
the radio altimeter is expected to function reliably, measured in
decibel-milliwatts (dBm) per megahertz (MHz). For purposes of this
proposed AD, a ``radio altimeter tolerant rotorcraft'' is one for which
the radio altimeter, as installed, demonstrates tolerance to radio
altimeter interference at or above PSD curve threshold specified in
figure 1 to paragraph (g)(1) of this proposed AD. A radio altimeter
tolerant rotorcraft also demonstrates tolerance to an aggregate
spurious emission level of -42 dBm/MHz in the 4200-4400 MHz radio
altimeter band. For purposes of this proposed AD, a ``non-radio
altimeter tolerant rotorcraft'' is one for which the radio altimeter,
as installed, does not demonstrate those tolerances. Operators will
have the option to upgrade to a radio altimeter tolerant rotorcraft if
they wish to avoid the prohibitions in this proposed AD. Some operators
may need to install filters between the radio altimeter and antenna to
increase a radio altimeter's tolerance. For others, the addition of a
filter will not be sufficient to address interference susceptibility;
therefore, the radio altimeter will need to be replaced with an
upgraded radio altimeter. The FAA has determined that radio altimeter
tolerant rotorcraft are not expected to experience interference during
a critical phase of flight in the contiguous U.S. airspace.
Areas of Operation: Over the past year, the FAA and the aviation
industry, using data voluntarily provided by AT&T and Verizon, have
identified maximum power levels for 5G C-Band transmissions that would
permit safe aircraft operations. This data includes 5G C-Band tower or
antenna locations, fundamental transmission power levels, and antenna
height. The FAA has found that rotorcraft meeting the proposed
standards as represented by the PSD curve can safely perform the
prohibited operations specified in this proposed AD. These operations
are safe for radio altimeter tolerant rotorcraft to perform within the
contiguous U.S. airspace as long as telecommunication companies
transmit at parameters under the current voluntary agreements with the
FAA and FCC.
Compatibility with 5G C-Band Providers: The FAA has determined that
any U.S. 5G C-Band provider that maintains the mitigated actions will
not have an effect on the safety of rotorcraft with radio altimeters
that meet the interference tolerance requirements. The FAA will assess
the effects of any changes to transmission parameters in
[[Page 21934]]
the contiguous U.S. airspace to determine whether they would result in
a hazard to air navigation. If the transmission changes negatively
affect the safe operation of a radio altimeter tolerant rotorcraft, the
FAA will re-evaluate the risks and determine if further rulemaking is
warranted.
Therefore, the FAA has determined that an unsafe condition exists
when performing certain operations in the presence of 5G C-Band
transmissions affecting the proper function of radio altimeters. For
that reason, operators would be required to revise their existing RFM
to prohibit these operations unless operating a radio altimeter
tolerant rotorcraft. This proposed requirement would take effect on
July 1, 2023.
FAA's Determination
The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.
Proposed AD Requirements in This NPRM
For rotorcraft with radio altimeters that meet the proposed
interference tolerance requirements, this proposed AD would terminate
the operational limitations imposed by AD 2021-23-13 with no further
action.
For rotorcraft with radio altimeters that do not meet the proposed
interference tolerance requirements, this proposed AD would retain the
requirement in AD 2021-23-13 to revise the existing RFM to incorporate
limitations prohibiting the following operations in the presence of 5G
C-Band wireless broadband interference as identified by NOTAM (NOTAMs
will be issued to state the specific airports where the radio altimeter
is unreliable due to the presence of 5G C-Band wireless broadband
interference) until June 30, 2023. On or before June 30, 2023, this
proposed AD would also require, for non-radio altimeter tolerant
rotorcraft, revising the existing RFM to incorporate limitations
prohibiting these same operations in the contiguous U.S. airspace.
Interim Action
The FAA considers that this AD, if adopted as proposed, would be an
interim action. Once the Technical Standard Order (TSO) standard for
radio altimeters is established, which will follow the existing
international technical consensus on the establishment of the minimum
operational performance standards (MOPS), the FAA anticipates that the
MOPS will be incorporated into the TSO. The FAA also anticipates that
rotorcraft incorporating equipment approved under the new Radio
Altimeter TSO will be able to operate in the contiguous U.S. airspace
with no 5G C-Band-related RFM limitations. Once a new radio altimeter
TSO is developed, approved, and available, the FAA might consider
additional rulemaking.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 1,128 helicopters of U.S. registry. The FAA estimates the
following costs to comply with this proposed AD.
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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RFM revision for non-radio altimeter 1 work-hour x $85 per $0 $85 $95,880
tolerant rotorcraft (Retained action hour = $85.
from AD 2021-23-13).
New RFM revision for non-radio 1 work-hour x $85 per 0 85 95,880
altimeter tolerant rotorcraft. hour = $85.
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Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. 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.
The FAA is issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701: General requirements.
Under that section, Congress charges the FAA with promoting safe flight
of civil aircraft in air commerce by prescribing regulations for
practices, methods, and procedures the Administrator finds necessary
for safety in air commerce. This regulation is within the scope of that
authority because it addresses an unsafe condition that is likely to
exist or develop on products identified in this rulemaking action.
Regulatory Findings
The FAA has determined that this proposed AD would not have
federalism implications under Executive Order 13132. This proposed AD
would not have a substantial direct effect on the States, on the
relationship between the national Government and the States, or on the
distribution of power and responsibilities among the various levels of
government.
For the reasons discussed above, I certify that the proposed
regulation:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Would not affect intrastate aviation in Alaska, and
(3) Would not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 39.13 by:
0
a. Removing Airworthiness Directive (AD) 2021-23-13, Amendment 39-21811
(86 FR 69992, December 9, 2021), and
0
b. Adding the following new AD:
Various Helicopters: Docket No. FAA-2023-0668; Project Identifier
AD-2023-00199-R.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by May 12, 2023.
[[Page 21935]]
(b) Affected ADs
This AD replaces AD 2021-23-13, Amendment 39-21811 (86 FR 69992,
December 9, 2021) (AD 2021-23-13).
(c) Applicability
This AD applies to all helicopters, certificated in any
category, equipped with a radio (also known as radar) altimeter.
These radio altimeters are installed on various helicopter models
including, but not limited to, the helicopters for which the design
approval holder is identified in paragraphs (c)(1) through (20) of
this AD.
(1) Airbus Helicopters
(2) Airbus Helicopters Deutschland GmbH
(3) Air Space Design and Manufacturing, LLC
(4) Bell Textron Canada Limited
(5) Bell Textron Inc.
(6) Brantly International, Inc.
(7) Centerpointe Aerospace Inc.
(8) Columbia Helicopters, Inc.
(9) The Enstrom Helicopter Corporation
(10) Erickson Air-Crane Incorporated, DBA Erickson Air-Crane
(11) Helicopteres Guimbal
(12) Siam Hiller Holdings, Inc.
(13) Kaman Aerospace Corporation
(14) Leonardo S.p.a.
(15) MD Helicopters Inc.
(16) PZL Swidnik S.A.
(17) Robinson Helicopter Company
(18) Schweizer RSG LLC
(19) Scotts-Bell 47 Inc.
(20) Sikorsky Aircraft Corporation
(d) Subject
Air Transport Association (ATA) of America Code 3444, Ground
Proximity System.
(e) Unsafe Condition
This AD was prompted by determination that radio altimeters
cannot be relied upon to perform their intended function if they
experience interference from wireless broadband operations in the
3.7-3.98 GHz frequency band (5G C-Band). The FAA is issuing this AD
because radio altimeter anomalies that are undetected by the
automation or pilot, particularly close to the ground, could lead to
loss of continued safe flight and landing.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Definitions
(1) For purposes of this AD, a ``radio altimeter tolerant
rotorcraft'' is one for which the radio altimeter, as installed,
demonstrates the tolerances specified in paragraphs (g)(1)(i) and
(ii) of this AD, using a method approved by the FAA. No actions are
required by this AD for radio altimeter tolerant rotorcraft.
(i) Tolerance to radio altimeter interference at or above the
power spectral density (PSD) curve threshold specified in figure 1
to paragraph (g)(1) of this AD.
(ii) Tolerance to an aggregate base station conducted spurious
emission level of -42 dBm/MHz in the 4200-4400 MHz radio altimeter
band.
Figure 1 to paragraph (g)(1)--Effective Power Spectral Density
BILLING CODE 4910-13-P
[[Page 21936]]
[GRAPHIC] [TIFF OMITTED] TP12AP23.030
(2) For purposes of this AD, a ``non-radio altimeter tolerant
rotorcraft'' is one for which the radio altimeter, as installed,
does not demonstrate the tolerances specified in paragraphs
(g)(1)(i) and (ii) of this AD.
(h) Retained Rotorcraft Flight Manual (RFM) Revision for Non-Radio
Altimeter Tolerant Rotorcraft
For non-radio altimeter tolerant rotorcraft: On or before
January 4, 2022, revise the Limitations Section of the existing RFM
for your helicopter by incorporating the limitations specified in
figure 2 to paragraph (h) of this AD. This may be done by inserting
a copy of this AD into the existing RFM for your helicopter. The
action required by this paragraph may be performed by the owner/
operator (pilot) holding at least a private pilot certificate and
must be entered into the aircraft records showing compliance with
this AD in accordance with 14 CFR 43.9(a)(1) through (4) and 14 CFR
91.417(a)(2)(v). The record must be maintained as required by 14 CFR
91.417 or 14 CFR 135.439.
Figure 2 to paragraph (h)--RFM Revision
[[Page 21937]]
[GRAPHIC] [TIFF OMITTED] TP12AP23.031
(i) RFM Revision for Non-Radio Altimeter Tolerant Rotorcraft
For non-radio altimeter tolerant rotorcraft, do the actions
specified in paragraphs (i)(1) and (2) of this AD.
(1) On or before June 30, 2023, revise the Limitations Section
of the existing RFM for your helicopter by including the information
specified in figure 3 to paragraph (i) of this AD. This may be done
by inserting a copy of this AD into the existing RFM for your
helicopter. The action required by this paragraph may be performed
by the owner/operator (pilot) holding at least a private pilot
certificate and must be entered into the aircraft records showing
compliance with this AD in accordance with 14 CFR 43.9(a)(1) through
(4) and 14 CFR 91.417(a)(2)(v). The record must be maintained as
required by 14 CFR 91.417 or 14 CFR 135.439. Incorporating the RFM
revision required by this paragraph terminates the RFM revision
required by paragraph (h) of this AD.
(2) Before further flight after incorporating the limitations
specified in figure 3 to paragraph (i) of this AD, remove the RFM
revision required by paragraph (h) of this AD.
Figure 3 to paragraph (i)--RFM Revision for Non-Radio Altimeter
Tolerant Rotorcraft
[GRAPHIC] [TIFF OMITTED] TP12AP23.032
(j) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Operational Safety Branch, FAA, has the
authority to approve AMOCs for this AD, if requested using the
procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19,
send your request to your principal inspector or responsible Flight
Standards Office, as appropriate. If sending information directly to
the manager of the Operational Safety Branch, send it to the
attention of the person identified in paragraph (k) of this AD.
Information may be emailed to: <a href="/cdn-cgi/l/email-protection#4b0a0604080b2d2a2a652c243d"><span class="__cf_email__" data-cfemail="a3e2eeece0e3c5c2c28dc4ccd5">[email protected]</span></a>.
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the responsible Flight Standards Office.
(3) AMOCs approved for AD 2021-23-13 are approved as AMOCs for
the requirements specified in paragraph (h) of this AD until June
30, 2023.
(k) Related Information
For more information about this AD, contact David Swartz,
Continued Operational Safety Technical Advisor, COS Program
Management Section, Operational Safety Branch, FAA, 222 W. 7th Ave,
M/S #14 Anchorage, AK 99513; phone: 817-222-5390; email:
<a href="/cdn-cgi/l/email-protection#2e415e4b5c4f5a4741404f425d4f484b5a576e484f4f00494158"><span class="__cf_email__" data-cfemail="7d120d180f1c091412131c110e1c1b1809043d1b1c1c531a120b">[email protected]</span></a>.
(l) Material Incorporated by Reference
None.
[[Page 21938]]
Issued on April 5, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2023-07743 Filed 4-10-23; 8:45 am]
BILLING CODE 4910-13-C
</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>Indexed from Federal Register on April 12, 2023.
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