ADS-B Out Performance

FAR 91.227 ADS-B Out Performance

FAR 91.227 sets ADS-B Out performance standards: equipment class, accuracy, integrity, latency, and the data your aircraft must broadcast to ATC.

In Plain English

FAR 91.227 sets the performance standards your ADS-B Out equipment must meet whenever you operate in airspace where ADS-B is required under § 91.225. It tells you what the box must do, not where you need it.

Key points:

  • Equipment class: In Class A airspace, you must use 1090ES (TSO-C166b/c). Below Class A, either 1090ES or UAT (TSO-C154c/d) is acceptable.
  • Accuracy & integrity minimums: NACp < 0.05 NM, NACv < 10 m/s, NIC < 0.2 NM, SDA ≤ 10⁻⁵/hr, SIL ≤ 10⁻⁷/hr or sample.
  • Broadcast data (auto and pilot-entered) includes position, barometric and geometric altitude, velocity, squawk code, flight ID, IDENT, ICAO 24-bit address, emergency status, TCAS/RA status, and the quality metrics above.
  • Latency: Position must be transmitted within 2.0 seconds of measurement, with no more than 0.6 seconds uncompensated. Broadcast at least once per second airborne or moving, and once every 5 seconds when stationary on the surface.

Why it matters: ATC and other ADS-B In aircraft rely on this data for separation and traffic awareness. Bad accuracy or stale position data triggers a NON-COMPLIANT report and can prevent operations in rule airspace.

Regulation Text
14 CFR § 91.227
§ 91.227 Automatic Dependent Surveillance-Broadcast (ADS-B) Out equipment performance requirements. (a)For the purposes of this section: is a function of an aircraft's onboard avionics that periodically broadcasts the aircraft's state vector (3-dimensional position and 3-dimensional velocity) and other required information as described in this section. () specifies the accuracy of a reported aircraft's position. () specifies the accuracy of a reported aircraft's velocity. specifies an integrity containment radius around an aircraft's reported position. refers to the equipment installed onboard an aircraft used to process and provide aircraft position (for example, latitude, longitude, and velocity) information. indicates the probability of the reported horizontal position exceeding the containment radius defined by the NIC on a per sample or per hour basis. indicates the probability of an aircraft malfunction causing false or misleading information to be transmitted. is the total time between when the position is measured and when the position is transmitted by the aircraft. is the time for which the aircraft does not compensate for latency. (b)— (1) Aircraft operating in Class A airspace must have equipment installed that meets the antenna and power output requirements of Class A1S, A1, A2, A3, B1S, or B1 equipment as defined in TSO-C166b and Section 2 of RTCA DO-260B (as referenced in TSO-C166b), or TSO-C166c and Section 2 of RTCA DO-260C as modified by DO-260C—Change 1 (as referenced in TSO-C166c). (2) Aircraft operating in airspace designated for ADS-B Out, but outside of Class A airspace, must have equipment installed that meets the antenna and output power requirements of either: (i) Class A1S, A1, A2, A3, B1S, or B1 as defined in TSO-C166b and Section 2 of RTCA DO-260B (as referenced in TSO-C166b) or TSO-C166c and Section 2 of RTCA DO-260C as modified by DO-260C—Change 1 (as referenced in TSO-C166c); or (ii) Class A1S, A1H, A2, A3, B1S, or B1 equipment as defined in TSO-C154c and Section 2 of RTCA DO-282B (as referenced in TSO-C154c), or TSO-C154d and Section 2 of RTCA DO-282C (as referenced in TSO-C154d). (c),— (1) For aircraft broadcasting ADS-B Out as required under § 91.225 (a) and (b)— (i) The aircraft's NACmust be less than 0.05 nautical miles; (ii) The aircraft's NACmust be less than 10 meters per second; (iii) The aircraft's NIC must be less than 0.2 nautical miles; (iv) The aircraft's SDA must be less than or equal to 10per flight hour; and (v) The aircraft's SIL must be less than or equal to 10per flight hour or per sample. (2) Changes in NAC, NAC, SDA, and SIL must be broadcast within 10 seconds. (3) Changes in NIC must be broadcast within 12 seconds. (d)Each aircraft must broadcast the following information, as defined in TSO-C166b (including Section 2 of RTCA DO-260B, as referenced in TSO-C166b), TSO-C166c (including Section 2 of RTCA DO-260C as modified by DO-260C—Change 1, as referenced in TSO-C166c), TSO-C154c (including Section 2 of RTCA DO-282B, as referenced in TSO-C154c), or TSO-C154d (including Section 2 of RTCA DO-282C, as referenced in TSO-C154d). The pilot must enter information for message elements listed in paragraphs (d)(7) through (10) of this section during the appropriate phase of flight. (1) The length and width of the aircraft; (2) An indication of the aircraft's latitude and longitude; (3) An indication of the aircraft's barometric pressure altitude; (4) An indication of the aircraft's velocity; (5) An indication if a collision avoidance system is installed and operating in a mode that can generate resolution advisory alerts; (6) If an operable collision avoidance system is installed, an indication if a resolution advisory is in effect; (7) An indication of the Mode A transponder code specified by ATC; (8) An indication of the aircraft identification that is submitted on the flight plan or used for communicating with ATC, except when the pilot has not filed a flight plan, has not requested ATC services, and is using a TSO-C154c or TSO-C154d self-assigned temporary 24-bit address; (9) An indication if the flightcrew has identified an emergency, radio communication failure, or unlawful interference; (10) An indication of the aircraft's “IDENT” to ATC; (11) An indication of the aircraft assigned ICAO 24-bit address, except when the pilot has not filed a flight plan, has not requested ATC services, and is using a TSO-C154c or TSO-C154d self-assigned temporary 24-bit address; (12) An indication of the aircraft's emitter category; (13) An indication of whether an ADS-B In capability is available; (14) An indication of the aircraft's geometric altitude; (15) An indication of the Navigation Accuracy Category for Position (NAC); (16) An indication of the Navigation Accuracy Category for Velocity (NAC); (17) An indication of the Navigation Integrity Category (NIC); (18) An indication of the System Design Assurance (SDA); and (19) An indication of the Source Integrity Level (SIL). (e)— (1) The aircraft must transmit its geometric position no later than 2.0 seconds from the time of measurement of the position to the time of transmission. (2) Within the 2.0 total latency allocation, a maximum of 0.6 seconds can be uncompensated latency. The aircraft must compensate for any latency above 0.6 seconds up to the maximum 2.0 seconds total by extrapolating the geometric position to the time of message transmission. (3) The aircraft must transmit its position and velocity at least once per second while airborne or while moving on the airport surface. (4) The aircraft must transmit its position at least once every 5 seconds while stationary on the airport surface. (f)Operators with equipment installed with an approved deviation under § 21.618 of this chapter also are in compliance with this section. (g)The standards required in this section are incorporated by reference with the approval of the Director of the Office of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. This incorporation by reference (IBR) material is available for inspection at the FAA and the National Archives and Records Administration (NARA). Contact the FAA at: Office of Rulemaking (ARM-1), 800 Independence Avenue SW, Washington, DC 20590 (telephone 202-267-9677). For information on the availability of this material at NARA, visitor emailThis material is also available from the following sources indicated in this paragraph (g). (1) U.S. Department of Transportation, Subsequent Distribution Office, DOT Warehouse M30, Ardmore East Business Center, 3341 Q 75th Avenue, Landover, MD 20785; telephone (301) 322-5377; website:(select the link “Search Technical Standard Orders”). (i) TSO-C166b, Extended Squitter Automatic Dependent Surveillance-Broadcast (ADS-B) and Traffic Information Service-Broadcast (TIS-B) Equipment Operating on the Radio Frequency of 1090 Megahertz (MHz), December 2, 2009. (ii) TSO-C166c, Extended Squitter Automatic Dependent Surveillance-Broadcast (ADS-B) and Traffic Information Service-Broadcast (TIS-B) Equipment Operating on the Radio Frequency of 1090 Megahertz (MHz), March 10, 2023. (iii) TSO-C154c, Universal Access Transceiver (UAT) Automatic Dependent Surveillance-Broadcast (ADS-B) Equipment Operating on the Frequency of 978 MHz, December 2, 2009. (iv) TSO-C154d, Universal Access Transceiver (UAT) Automatic Dependent Surveillance-Broadcast (ADS-B) Equipment Operating on the Radio Frequency of 978 Megahertz (MHz), March 10, 2023. (2) RTCA, Inc., 1150 18th St. NW, Suite 910, Washington, DC 20036; telephone (202) 833-9339; website: (i) RTCA DO-260B, Minimum Operational Performance Standards for 1090 MHz Extended Squitter Automatic Dependent Surveillance-Broadcast (ADS-B) and Traffic Information Services-Broadcast (TIS-B), Section 2, Equipment Performance Requirements and Test Procedures, December 2, 2009. (ii) RTCA DO-260C, Minimum Operational Performance Standards for 1090 MHz Extended Squitter Automatic Dependent Surveillance-Broadcast (ADS-B) and Traffic Information Services-Broadcast (TIS-B), Section 2, Equipment Performance Requirements and Test Procedures, December 17, 2020. (iii) RTCA DO-260C, Minimum Operational Performance Standards for 1090 MHz Extended Squitter Automatic Dependent Surveillance-Broadcast (ADS-B) and Traffic Information Services-Broadcast (TIS-B), Change 1, January 25, 2022. (iv) RTCA DO-282B, Minimum Operational Performance Standards for Universal Access Transceiver (UAT) Automatic Dependent Surveillance-Broadcast (ADS-B), Section 2, Equipment Performance Requirements and Test Procedures, December 2, 2009. (v) RTCA DO-282C, Minimum Operational Performance Standards (MOPS) for Universal Access Transceiver (UAT) Automatic Dependent Surveillance-Broadcast (ADS-B), Section 2, Equipment Performance Requirements and Test Procedures, June 23, 2022. [Docket FAA-2007-29305, 75 FR 30194, May 28, 2010; Amdt. 91-314-A, 75 FR 37712, June 30, 2010, as amended by Amdt. 91-316, 75 FR 37712, June 30, 2010; Docket FAA-2023-1836, Amdt. 91-371, 88 FR 71477, Oct. 17, 2023]
Oral Exam Questions a DPE Might Ask
Q1What information must your ADS-B Out system broadcast, and which items do you as the pilot have to enter?
Per FAR 91.227(d), the system broadcasts position, altitude (baro and geometric), velocity, ICAO address, emitter category, NAC/NIC/SDA/SIL, and TCAS status. The pilot enters the assigned Mode A squawk, flight ID/call sign, emergency status, and IDENT during the appropriate phase of flight.
Q2What are the latency and update-rate requirements for ADS-B Out position broadcasts?
FAR 91.227(e) requires geometric position to be transmitted within 2.0 seconds of measurement, with no more than 0.6 seconds uncompensated. Position and velocity must broadcast at least once per second airborne or moving, and once every 5 seconds while stationary on the surface.
Q3What equipment class is required for ADS-B Out in Class A airspace versus below Class A?
Under FAR 91.227(b), Class A operations require 1090ES equipment meeting TSO-C166b or C166c. Below Class A, you may use either that 1090ES equipment or UAT equipment meeting TSO-C154c or C154d.
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FAR 91.227 — ADS-B Out Equipment Performance Rules