Rule2022-09936
Statement of Policy on Performance Requirements for Operators of Aircraft That Are Equipped With Automatic Dependent Surveillance-Broadcast (ADS-B) Out
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
May 10, 2022
Effective
May 10, 2022
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
This action announces revisions to the FAA's policy on performance requirements for aircraft with Automatic Dependent Surveillance-Broadcast (ADS-B) Out equipment using the Selective Availability (SA)-Aware receivers in ADS-B rule airspace. The FAA will no longer expect aircraft with this equipment to perform a preflight availability prediction before operating in ADS-B rule airspace.
Full Text
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<title>Federal Register, Volume 87 Issue 90 (Tuesday, May 10, 2022)</title>
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[Federal Register Volume 87, Number 90 (Tuesday, May 10, 2022)]
[Rules and Regulations]
[Pages 27928-27931]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-09936]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 91
[Docket No. FAA-2022-0619]
Statement of Policy on Performance Requirements for Operators of
Aircraft That Are Equipped With Automatic Dependent Surveillance-
Broadcast (ADS-B) Out
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Policy statement.
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SUMMARY: This action announces revisions to the FAA's policy on
performance requirements for aircraft with Automatic Dependent
Surveillance-Broadcast (ADS-B) Out equipment using the Selective
Availability (SA)-Aware receivers in ADS-B rule airspace. The FAA will
no longer expect aircraft with this equipment to perform a preflight
availability prediction before operating in ADS-B rule airspace.
DATES: The policy described herein is effective May 10, 2022.
FOR FURTHER INFORMATION CONTACT: For technical information concerning
this action, contact James Marks, Flight Technologies and Procedures
Division, Aviation Safety, at (202) 267-8790.
SUPPLEMENTARY INFORMATION:
Authority for This Action
The FAA's authority to issue rules on aviation safety is found in
Title 49 of the United States Code (49 U.S.C.). 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 ADS-B Out equipage and performance requirements in Sec. Sec.
91.225 (Automatic Dependent Surveillance-Broadcast (ADS-B) Out
equipment and use) and 91.227 (Automatic Dependent Surveillance-
Broadcast (ADS-B) Out equipment performance requirements) of title 14
of the Code of Federal Regulations (14 CFR) were promulgated under the
authority described in Subtitle VII, Part A, Subpart I, Section 40103
(Sovereignty and Use of Airspace) and in Subpart III, Section 44701
(General Requirements). Under Section 40103, the FAA is charged with
prescribing regulations on the flight of aircraft (including
regulations on safe altitudes) for navigating, protecting, and
identifying aircraft and the efficient use of the navigable airspace.
Under section 44701, the FAA is charged 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.
In Sec. 91.227, the FAA set forth the ADS-B Out equipment
performance requirements including accuracy and integrity performance
standards. This policy statement is within the scope of the FAA's
authority and informs operators equipped with Selective Availability
(SA)-Aware receivers about a change to the FAA policy requiring they
perform preflight availability predictions to ensure their avionics
broadcast elements required by Sec. 91.227 as part of their Sec.
91.103 (Preflight Action) obligations.
I. Background
In 2010, the FAA issued a final rule prescribing equipage
requirements and performance standards for ADS-B Out avionics on
aircraft operating in certain airspace after January 1, 2020.\1\ ADS-B
Out is an advanced surveillance technology that combines an aircraft's
position source, other aircraft avionics, and a ground receiver
infrastructure to create an accurate and shared surveillance picture
between aircraft and air traffic control (ATC). ADS-B Out provides air
traffic controllers with real-time position information that is, in
most cases, more accurate than the information available with current
radar-based systems. With more accurate information, ATC will be able
to position and separate aircraft with improved precision and timing so
that efficiency and capacity will increase beyond current levels to
meet the predicted demand for ATC services while maintaining or
improving safety.
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\1\ Final Rule, Automatic Dependent Surveillance-Broadcast (ADS-
B) Out Performance Requirements to Support Air Traffic Control
(ATC), 75 FR 30160 (May 28, 2010).
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ADS-B Position Sources
Aircraft with ADS-B Out equipment continually broadcast
information, such as identification, position, altitude, and velocity,
through an onboard transmitter, which can be received by ADS-B ground
stations (or satellite receivers) and by other aircraft appropriately
equipped to receive this information. The ADS-B Out rule specifies the
aircraft's ADS-B Out equipment performance requirements for each flight
in rule airspace rather than requiring any particular type of position
source. All currently approved position sources rely on a Global
Positioning System (GPS) receiver.\2\ The quality of each type of
receiver can be described by its ``rule performance'' availability,
which means the GPS receiver's ability to achieve the performance
requirements of Sec. 91.227(c)(1)(i) and (iii) for navigation accuracy
category for position (NACp) and navigation integrity category (NIC).
Technical Standard Order (TSO)-C166b and TSO-C154c contain the avionics
standards for outputting NACp and NIC.
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\2\ GPS is a specific type of Global Navigation Satellite System
(GNSS).
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FAA ADS-B Service Availability Prediction Tool (SAPT)
The ADS-B Service Availability Prediction Tool (SAPT) is a
preflight resource developed by the FAA, that predicts the ability of
standard GPS receivers to meet the requirements of Sec.
91.227(c)(1)(i) and (iii) along a given route of flight. This
prediction is based on the ability of the aircraft's position source
(e.g., GPS receiver) to meet ADS-B performance requirements based on
the type of GPS receiver (FAA TSOs C129, C129a, C145c/C146c, and C196)
and the predicted status of the GPS constellation. The SAPT also
evaluates if backup surveillance is available where position source
performance is predicted to fall below requirements.\3\ The ADS-B SAPT
is primarily intended for pilots, dispatchers, and commercial operators
to verify their predicted position source performance before flight and
ensure compliance with the ADS-B Out rule.\4\
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\3\ FAA plans to begin divesture of some radar infrastructure as
part of the transition to a satellite-based navigation and
surveillance system. During the period from 2020 to 2025, FAA's
planned radar divestures will focus primarily on eliminating
redundant/overlapping radars.
\4\ For more information on the SAPT, the FAA has developed the
ADS-B SAPT/Receiver Autonomous Integrity Monitoring (RAIM) User
Guide, which is available at: <a href="https://sapt.faa.gov/adsb-start.php">https://sapt.faa.gov/adsb-start.php</a>.
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Exemption No. 12555
In April 2015, Airlines for America (A4A) petitioned the FAA, on
behalf of
[[Page 27929]]
A4A member airlines, for an exemption from the Navigation Accuracy
Category for Position (NACp) and Navigation Integrity Category (NIC)
requirements of the rule. A key premise of the exemption was an
understanding that certain position sources were more likely than
others to not perform at the required level established by the ADS-B
Out rule. In August 2015, the Administrator issued Exemption No.
12555,\5\ a time-limited grant of exemption from Sec. 91.227(c)(1)(i)
and (iii) for the period from January 1, 2020, through December 31,
2024. Exemption 12555 permits operation of aircraft equipped with TSO-
C129 (SA-On) and TSO-C196 (SA-Aware) in ADS-B Out rule airspace during
periods when the GPS position provided to the installed ADS-B Out
equipment does not achieve the required accuracy or integrity
performance, provided certain conditions and limitations are met.
Additionally, Exemption 12555 does not require aircraft equipped with
SA-Aware GPS receivers to use a preflight availability prediction tool.
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\5\ Regulatory Docket Number FAA-2015-0971 (FAA Exemption No.
12555) at <a href="https://www.regulations.gov/docket/FAA-2015-0971">https://www.regulations.gov/docket/FAA-2015-0971</a>.
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2019 Policy Statement
On July 3, 2019, the FAA published a Federal Register document with
its policy on performance requirements for operators equipped with ADS-
B Out, including those equipped with a SA-Aware position source.\6\ The
FAA found that Wide Area Augmentation System (WAAS) \7\ was the only
GPS position source that consistently provided the equivalent
availability to radar at 99.9 percent availability.\8\ The FAA also
believed that SA-Aware receivers could meet a similar 99.9 percent
availability as long as there was no significant reduction in the GPS
satellite constellation. Given since the data at the time of
publication of the 2019 policy was limited, the FAA determined that
aircraft equipped with GPS position sources such as Selective Ability-
On (SA-On or SA-Aware were more likely to experience performance
outages that limited their access to the airspace defined in the ADS-B
rule.
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\6\ Statement of Policy on Performance Requirements for
Operators of Aircraft That are Equipped with ADS-B Out, 84 FR 31713
(July 3, 2019).
\7\ WAAS is a regional a space-based augmentation system (SBAS)
operated by the FAA.
\8\ FAA also determined that certain GPS tightly integrated with
inertial navigation systems would also provide 99.9 percent
availability.
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The 2019 policy statement reiterated Sec. 91.103's requirement
that pilots become familiar with all available information concerning a
flight. The FAA explained that given the previously identified
limitations of SA-On and SA-Aware receivers, the use of a preflight
prediction tool is a reliable way of satisfying due diligence
requirements under Sec. 91.103. Therefore, these operators were
required to confirm that a planned route of flight would comply with
the ADS-B performance requirements in Sec. 91.227(c)(1)(i) and (iii).
Operators could use any reliable preflight prediction tool, with the
SAPT providing a comprehensive and reliable preflight prediction for
operators. The policy statement explained that for operators who had
been notified by the FAA of consistent and repeated ADS-B Out
performance issues, conducting an operation in accordance with the
policy without first redressing the identified non-performance issue
would be considered a continuation of the non-compliance with the
performance requirements. Also, if an operator failed to conduct a
preflight availability prediction for the operator's intended operation
and subsequently encountered degradation of GPS performance that
resulted in the aircraft falling below the performance requirements of
Sec. 91.227(c)(1)(i) and (iii), that operator would be deemed to have
violated the ADS-B rule--even if the operator's flight were to be
rerouted due to unforeseen circumstances.
Performance Based Operations Aviation Rulemaking Committee (PARC)
Exemption 12555 Action Team
In August 2020, the FAA tasked the PARC to form an action team
comprised of industry stakeholders and FAA subject matter experts to
report on the following:
1. Identify barriers and appropriate mitigations to air carrier
Exemption 12555 equipage plans that lead to full compliance with Sec.
91.227; and
2. Describe status of applicable equipment availability relative to
achievement of operator equipage plans toward end state of Exemption
12555 on December 31, 2024.
The PARC provided a forum for the U.S. aviation community to
discuss, prioritize, and resolve issues, provide direction for U.S.
flight operations criteria and produce U.S. consensus positions for
global harmonization on performance-based airspace operations. The PARC
action team requested that the FAA provide a report on ADS-B Out
equipped aircraft with approved position sources and their ability to
meet the equivalent operational availability of radar (99.9% or greater
availability requirement). In addition to the 4 years of data used to
support the 2019 policy document, an additional 3 years of position
source performance data was given to the PARC action team to analyze.
FAA analysis and prior modeling in support of the ADS-B Aviation
Rulemaking Committee indicated that the critical ADS-B quality
parameter was the NIC parameter defined in Sec. 91.227(c)(1)(iii). FAA
data indicated a historical operational availability with regard to
required NIC rule performance for the following ADS-B position source
types:
--SA-On GPS receivers achieved between 98-99% operational availability;
--SA-Aware GPS receivers achieved 99.9%, or greater, operational
availability; and
--Satellite-Based-Augmentation System (SBAS) receivers achieved 99.9%,
or greater, operational availability
In consideration of these findings, the PARC Exemption 12555 action
team recommended removing the requirement for aircraft equipped with
SA-Aware GPS receivers to use a preflight availability prediction tool
(e.g., the Service Availability Prediction Tool (SAPT)).
The FAA agrees that the demonstrated performance of SA-Aware GPS
receivers has been equivalent to, or better than, a single radar since
the FAA began monitoring ADS-B performance in 2015. Years of additional
data and assurances that the GPS constellation will remain at current
levels have given the FAA confidence that SA-Aware GPS receivers will
consistently provide the availability required by the ADS-B regulation.
The FAA accepts any residual risk associated with SA-Aware GPS receiver
performance falling below the regulatory requirement. As such, the FAA
is adopting the subject PARC Exemption 12555 action team recommendation
and is revising preflight policy issued in 2019 for aircraft equipped
with SA-Aware GPS receivers in this document.
II. Discussion of the Policy
Preflight Availability Prediction Policy
Given the demonstrated performance of SA-Aware (TSO-C196) GPS
receivers over a seven-year monitoring period and the expectation that
the GPS constellation will provide coverage at current levels for the
foreseeable future, the FAA now finds that such GPS receivers
consistently provide an equivalent availability to that of a single
radar at 99.9 percent operational availability. Aircraft equipped with
SA-Aware GPS receivers during periods of GPS constellation degradation
that negatively impact the ability of ADS-B
[[Page 27930]]
Out equipment to meet performance requirements associated with the rule
will be deemed compliant with the ADS-B Out rule requirements.
Therefore, the operators of aircraft equipped with position sources
that meet the performance requirements of TSO-C196 (SA-Aware) is not
required to perform a preflight availability prediction to fulfill
their Sec. 91.103 due diligence obligation. For aircraft equipped with
GPS receivers that do not meet the performance requirements of TSO-196
or TSO-C145/146, the operator must run a preflight prediction.
Due to the reduced performance of SA-On receivers relative to ADS-B
rule requirements, operators of aircraft with these receivers are
expected to use a preflight availability prediction tool to predict the
ability of an aircraft position source to meet the performance
requirements of Sec. 91.227(c)(1)(i) and (iii) along a given route of
flight. For non-exemption holders with SA-On receivers and exemption
holders after expiration of Exemption 12555, a preflight availability
prediction tool should be used to comply with Sec. 91.103 due
diligence requirements for a planned route of flight in ADS-B rule
airspace. If the predicted SA-On receiver performance does not support
compliance with Sec. 91.227 for the proposed flight, the FAA expects
operators to adjust the flight plan (e.g., departure time, route) as
needed to avoid any areas or time periods predicted with degraded GPS
performance. Holders of Exemption 12555 are expected to follow the
conditions of that exemption until it expires on December 31, 2024.
After an operator receives a satisfactory preflight availability
prediction for an intended operation, there may be certain conditions
that warrant a subsequent prediction. For example, a change in
departure time or a change in the satellite constellation as indicated
by a Notice to Air Missions (NOTAM) may have an effect on the predicted
GPS performance for the intended operation. If an operator becomes
aware of a change that could result in degraded GPS performance prior
to receiving an initial ATC clearance for the intended route of flight,
the operator should--consistent with preflight action required by Sec.
91.103--conduct a subsequent preflight availability prediction for the
planned flight to ensure that GPS performance is still predicted to
comply with the performance requirements of Sec. 91.227(c)(1)(i) and
(iii).
The duty under Sec. 91.103 to conduct a subsequent preflight
availability prediction for an intended route of flight will cease once
an operator receives an ATC route clearance for the intended operation.
More specifically, if an operator receives a satisfactory preflight
availability prediction and an ATC route clearance for the intended
operation, the FAA will consider the operator as having exercised its
due diligence in ensuring the intended operation complies with the
performance requirements in Sec. 91.227. Therefore, upon receiving a
satisfactory preflight availability prediction and an ATC clearance for
an intended route of flight, the operator will be deemed to have
complied with the preflight availability prediction requirement and the
performance requirements of Sec. 91.227(c)(1)(i) and (iii).
The FAA recognizes that there are circumstances outside the
operator's control that may result in unanticipated changes to an
operator's planned route of flight, which may cause temporary degraded
GPS performance and technical noncompliance with Sec. 91.227(c)(1)(i)
and (iii). For example, ATC will continue to exercise its
responsibility for the safe and efficient movement of air traffic,
including changes to the routing of traffic to achieve those
objectives. In addition, a planned route of flight may be changed due
to environmental conditions, such as a thunderstorm, or an operator may
experience unexpected GPS degradations during flight. After an ATC
route clearance is obtained for the flight, the FAA does not expect an
operator to conduct a subsequent preflight availability prediction to
accommodate rerouting caused by ATC or environmental conditions.
The FAA notes that the policy described above applies only to those
operators who have exercised due diligence required in Sec. 91.103 by
performing a preflight availability prediction. For example, if an
operator fails to conduct a required preflight availability prediction
for the operator's intended operation and subsequently encounters
technical non-compliance with the performance requirements of Sec.
91.227(c)(1)(i) and (iii), that operator will be deemed to have
violated the ADS-B rule even if the operator's flight were rerouted due
to unforeseen circumstances.
When an operator performs a preflight availability prediction using
the FAA's SAPT tool, the SAPT retains a record of each transaction
enabling the FAA to confirm that an operator took preflight action. The
FAA recommends that operators using an alternate tool retain
documentation that verifies the completion of the satisfactory
preflight availability prediction for each intended route of flight.
The FAA recommends that the prediction should be done not more than 24
hours prior to the planned departure. Predictions using SAPT to
determine the availability of backup surveillance per Exemption 12555
should be done within the 3 hours prior to a planned departure.
GPS Interference
There may be times when the GPS position source cannot meet the
required technical performance due to planned GPS interference. In the
event of a scheduled interference outage of GPS, the FAA will issue a
NOTAM that identifies the airspace and time periods that may be
affected by the interference. The affected area will frequently
encompass a large radius of ADS-B Out rule airspace. The FAA finds that
requiring operators to avoid the affected area would cause significant
disruption to air traffic in that vicinity. Furthermore, there is no
guarantee that these operators would experience actual interference and
a degradation in GPS performance in the area. For these reasons, the
FAA has determined that it would be impractical and not in the public
interest to require operators to avoid the affected area based on the
chance that an otherwise compliant flight could experience GPS
interference.
Accordingly, operators should proceed with their intended operation
if the only anticipated ADS-B noncompliance would be due to the planned
GPS interference. Under this policy, an operator who is required to
perform a preflight availability prediction for the intended route of
flight is still required to obtain a satisfactory preflight
availability prediction. When a NOTAM identifies the airspace and time
periods that may be affected by GPS interference, an operator will not
be required to alter his or her route of flight to avoid the area based
solely on that NOTAM. As explained in the preamble to the final rule,
if an aircraft's avionics meet the performance requirements but
unexpected GPS degradations during flight inhibit the position source
from providing adequate accuracy and integrity, ATC will be alerted via
the aircraft's broadcasted data and services will be provided to that
aircraft using the backup strategy. If an operator encounters actual
GPS interference during their flight that results in a degradation of
ADS-B Out performance, the policy described above will apply provided
the operator has taken the appropriate preflight actions.
[[Page 27931]]
SAPT Outages
As noted, certain operators are required to use a preflight
availability prediction tool prior to a planned flight. Some operators
will use the FAA SAPT for this purpose. The FAA intends that SAPT will
be continuously available to operators. However, because unexpected
circumstances could lead to a SAPT outage, the inability to access the
tool could have an adverse impact on operators with SA-On receivers. As
previously noted in Advisory Circular (AC) 90-114, ADS-B Operations,
ATC will issue a NOTAM announcing when the SAPT is not available.
The FAA understands that a SAPT outage prevents those operators who
hold relief under Exemption No. 12555 from confirming the availability
of back-up surveillance as required under the exemption's conditions
and limitations.\9\ It also reduces the ability of non-exemption
holders without their own preflight availability prediction tool to
determine that a particular operation will meet the performance
requirements prior to conducting an operation. The unavailability of
the SAPT for brief periods would result in operators having to choose
between conducting flights that might result in non-compliance or not
conducting an operation that might have complied with ADS-B Out rule
performance. The FAA does not intend to inhibit operators from
conducting otherwise permissible operations when the SAPT is
unavailable. As such, when there is a SAPT outage, the policy described
above will apply to operators who rely on the SAPT if their operation
falls below the performance requirements.
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\9\ The FAA anticipates that any outage would be of short
duration and any potential risk would be minimal because, concurrent
with the outage, GPS performance would have to fall below rule
values on the route of flight and radar coverage would have to be
unavailable at the same time and location.
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III. Summary
Unless otherwise authorized by ATC, all aircraft operating in the
airspace identified in Sec. 91.225 must comply with the ADS-B Out
performance requirements in Sec. 91.227. Under the FAA's revised
policy, aircraft equipped with SA-Aware GPS receivers described in this
document are not required to perform a preflight service availability
prediction, including those aircraft not covered by Exemption 12555.
Aircraft equipped with SA-On receivers should continue performing
preflight availability predictions and can use the guidance contained
in AC 90-114, ADS-B Operations, when conducting preflight actions for
operations planned within airspace described in Sec. 91.225. Holders
of Exemption 12555 must continue to meet the conditions and limitations
associated with the exemption. Holders of Exemption 12555 should revise
applicable equipage plans to reflect any changes affected by policy
contained in this document and submit revised plans to the FAA per
conditions specified by the exemption.
As described in this document, there are circumstances outside of
an operator's control that may result in a temporary degradation of GPS
performance and an apparent violation of Sec. 91.227. An operator may
exercise due diligence in performing a preflight availability
prediction for its intended route of flight but experience rerouting by
ATC after obtaining an initial ATC route clearance, which may cause an
unanticipated degradation of performance. Additionally, an operator may
encounter actual GPS interference on its intended path of flight, which
would affect the ability of an aircraft to meet the performance
requirements of Sec. 91.227. Lastly, an operator may not be able to
complete a preflight availability prediction for its intended route of
flight due to the FAA's SAPT being out of service. As previously
explained, the FAA recognizes that these situations are outside of the
operator's control. Therefore, the FAA will not take legal enforcement
action for apparent noncompliance with Sec. 91.227 due to the
circumstances discussed in this document to the extent such an
application would impose a standard of conduct wholly outside the
operator's control.
IV. Effective Date
Policy in this document is effective immediately and supersedes
policy contained in FRN Docket No. FAA-2019-0539. Additional
information on the policy described in this document will be contained
in the next revision of AC 90-114, ADS-B Operations.
Issued in Washington, DC, on May 4, 2022.
Gregory E. Schwab,
Acting Chief of Staff, Air Traffic Organization.
[FR Doc. 2022-09936 Filed 5-9-22; 8:45 am]
BILLING CODE 4910-13-P
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