Safety Recommendation A-20-038

-From Bryan Bedofrd, Administrator: The scope of the Federal Aviation Administration (FAA) Part 25 Auto-Ground Collision Avoidance System (GCAS) Panel was expanded to more broadly cover criteria for all GCAS variations for 14 CFR part 25 and part 23 aircraft. Part 23 aircraft will benefit significantly from these systems due to a higher rate of controlled flight into terrain accidents. Various avionics suppliers, system integrators/testers, and academia/research centers supporting part 23 technology and part 23 aircraft manufacturers are panel participants, inviting additional industry personnel to join the panel as part of this expansion.

The panel’s scope change also means that non-automatic GCAS and pilot-activated recovery systems (PARS) are now addressed in addition to auto-GCAS. It is important to note that an auto-GCAS will provide awareness to the flightcrew during an automatic collision avoidance maneuver, while a GCAS will not provide guidance to the flightcrew to perform the collision avoidance maneuver. PARS allows a pilot to manually initiate recovery for situations such as wake turbulence, unusual attitudes, and abnormal speeds, and provides mode and status indication.

The panel will continue to develop the requirements for part 25 and

On May 30, 2025, Acting FAA Administrator Christopher J. Rocheleau informed us that the agency is continuing the work described in its previous letter regarding Safety Recommendation A-20-38. We look forward to receiving your next update.

-From Christopher J. Rocheleau, Acting Administrator: The Federal Aviation Administration (FAA) and the Part 25 Airworthiness Standards: Transport Category Airplanes, Auto-Ground Collision Avoidance System (Auto-GCAS) Panel continues to develop the Part 25 Auto-GCAS Requirements Guide, using similar high-level objectives as the military and NASA GCAS systems, but making adaptations to criteria in consideration of the Auto-GCAS algorithms, autoflight system, support avionics, integrity monitoring, and a system safety evaluation for civil aircraft.

The panel has also considered relevant Part 23 research and testing experience and continues to discuss some of the more challenging implementation areas, including testing criteria; the pilot awareness interface and override capability; availability and suitability of terrain, obstacle, and airport database products; and validation of algorithm parameters. Additional research, analysis, simulation, and testing are necessary to develop mature policy and guidance to assess current and future proposed implementations of Auto-GCAS for Part 25 airplanes. The Part 25 Auto-GCAS Panel’s next steps include the following activities:

• Testing Criteria. We anticipate completing the development of testing criteria in fiscal year (FY) 2025.

• Pilot Awareness Interface and Override Capability. All requirements and variations based on existing implementations (i.e., US military and general aviation designs) are currently part of the

We note that the panel of experts that was formed in response to this recommendation has been expanded to include specialists from the FAA, National Transportation Safety Board, Department of Defense, National Aeronautics and Space Administration, foreign transport certification authorities, airplane manufactures, avionics suppliers, system integrators/testers, academia/research centers, and avionics associations. The panel has evaluated current Part 25 applicants who are interested in Auto-GCAS and accidents involving Part 25 airplanes that Auto-GCAS could have prevented.

We are encouraged to learn that the panel determined the benefits of implementing this technology warranted further discussion and evaluation. We also note that, in September 2023, the panel presented its work to RTCA Special Committee 231, which is considering updated or new minimum operational performance standards for Auto-GCAS, coupled or uncoupled to the autoflight system.

We continue to believe the panel’s work is responsive to this recommendation. Pending our review of the published report with the panel’s findings, Safety Recommendation A-20-38 remains classified OPEN-- ACCEPTABLE RESPONSE.

-From Michael G. Whitaker, Administrator: The Federal Aviation Administration (FAA) continues to work with Part 25 Airworthiness Standards: Transport Category Airplanes, Auto-Ground Collision Avoidance System (Auto-GCAS) Panel, with the support from the Department of Defense and National Aeronautics and Space Administration (NASA), to discuss the benefits and risks of adapting military and NASA Auto-GCAS technology for use in transport category airplanes. Since our last response, the Auto-GCAS panel evaluated current Part 25 applicants interested in this technology and who are actively working on these types of systems.

The panel also performed an accident analysis to look at controlled flight into terrain, loss of control in flight, and approach and landing accidents on Part 25 airplanes that may have been prevented if equipped with an Auto-GCAS. The panel subsequently determined the benefits of implementing Auto-GCAS warranted further discussion and evaluation.

The Auto-GCAS panel continues to meet regularly and has expanded to include specialists from the FAA, National Transportation Safety Board, DOD, NASA, foreign transport certification authorities, airplane manufactures, avionics suppliers, system integrators/testers, academia/research centers, and avionics associations. With this expanded panel, additional work is anticipated to determine the policy and guidance to assess implementations of Auto-GCAS in Part 25 airplanes.

On September 1, 2023, the Part 25 Auto-GCAS Panel’s work was presented to RTCA Special Committee 231, Terrain Awareness Warning System (TAWS), and the FAA is awaiting their consideration for an updated or new Minimum Operational Performance Standards for Auto-GCAS, coupled and/or uncoupled to the autoflight system.

We note that the panel of experts formed in response to this recommendation continues to meet regularly to discuss design, performance, and safety requirements, and recently developed a baseline auto-GCAS requirements guide.

We further note that you are planning to expand the panel to include other Part 25 certification authorities, airplane manufacturers, and avionics suppliers, and that these additional experts will provide recommendations for further developing the requirements guide to include topics such as pilot interface and override capability; sufficient terrain, obstacle, and airport database products; validation of algorithm parameters; and appropriate hazard classifications and failure conditions to consider.

We continue to believe the panel’s work is responsive to this recommendation. Pending our review of future updates and a published report with the panel’s findings, Safety Recommendation A-20-38 remains classified OPEN-- ACCEPTABLE RESPONSE.

-From Billy Nolen, Acting Administrator: The Federal Aviation Administration (FAA) continues to work with part 25, Airworthiness Standards: Transport Category Airplanes, Auto-Ground Collision Avoidance System (Auto-GCAS) Panel. As previously stated, this panel consists of subject matter experts from the FAA, Department of Defense, and National Aeronautics and Space Administration (NASA). The main objective of this panel is to discuss the risks and benefits of adapting military and NASA Auto-GCAS technology for use in civil transport category airplanes. The intended outcome is to identify additional airworthiness and operational requirements for transport category airplanes.

These requirements could be considered for use in future part 25 policy efforts, including support for reduced crew and unmanned cargo operations.

Since our last response, the Auto-GCAS Panel has met regularly to discuss design, performance, and safety requirements. The panel has used these discussions to develop a baseline (generic) Auto-GCAS Requirements Guide based on current implementations, research, and testing on multiple platforms, including performance-limited airplanes (i.e., low to medium, large, and heavy maneuverability). Additionally, the panel discussed the system aspects that can be adapted for detection and maneuvering, pilot alerting, integrity monitoring, and integration philosophy.

We are expanding the Auto-GCAS Panel to include other part 25 certification authorities, airplane manufacturers, and avionics suppliers. This expanded panel will develop additional guidance and recommendations for inclusion in the requirements guide in some of the more challenging implementation areas, including the pilot interface and override capability; sufficient terrain, obstacle, and airport database products; validation of algorithm parameters; and appropriate hazard classifications and failure conditions to consider.

We note that a panel of experts evaluated the benefits and risks of adapting military Auto-GCAS technology for use in civil transport category aircraft. We further note that you are now working with the National Aeronautics and Space Administration and the US Air Force to use their technical expertise and gather information about the current implementation of Auto-GCAS. Pending our review of future updates and a published report with the panel’s findings, Safety Recommendation A-20-38 remains classified OPEN-- ACCEPTABLE RESPONSE.

-From Steve Dickson, Administrator: The Federal Aviation Administration (FAA) convened a panel of experts to evaluate the benefits and risks of adapting military Automatic Ground Collision Avoidance System (Auto-GCAS) technology for use in civil transport category aircraft. We are currently working with the National Aeronautics and Space Administration (NASA) and the United States Air Force to gather information on the current implementation of Auto-GCAS and provide technical expertise and support for the panel discussions and recommendations. An example of this support occurred on September 22, 2021, when the FAA used NASA simulator facilities to experience current Auto-GCAS applications.

The first Auto-GCAS Panel Meeting was held on November 10, 2021. The panel discussed: • the benefits and risks of adapting military/NASA Auto-GCAS technology for use in civil transport category airplanes; • what could be adapted as far as the detection and maneuver, and annunciations/alerts provided to the pilot; • failure conditions to be considered and evaluated; and • unique civil transport airworthiness and operational items that need to be addressed.

Our next meeting is anticipated to occur in the first quarter of 2022. I will keep the Board informed of the FAA’s progress on this recommendation and anticipate providing an update by December 31, 2022.

We are pleased to learn that you are taking the initial steps to form a panel of subject matter experts to evaluate the benefits and risks of adapting military automatic ground collision avoidance system technology for use in civil transport-category aircraft. We look forward to receiving updates on the panel’s evaluation. Pending our review of the published report on the committee’s findings, Safety Recommendation A-20-38 is classified OPEN-- ACCEPTABLE RESPONSE.

-From Steve Dickson, Administrator: The FAA agrees with the Board that the benefits and risks of adapting military automatic ground collision avoidance system technology for use in civil transport-category aircraft should be evaluated. We are assessing the scope of work necessary, identifying the appropriate subject matter experts to participate on the panel. Once achieved we will establish the necessary objectives, work statement, and schedule.

I believe the FAA has effectively addressed Safety Recommendation A-20-36 and consider our action complete. I will keep the Board informed on our progress on Safety Recommendations A-20-33 through -35, -37, and -38, and anticipate providing an update by November 30, 2021.

The attached letter from the NTSB Chairman provides information about the NTSB’s July 14, 2020, report Rapid Descent and Crash into Water, Atlas Air Inc. Flight 3591, Boeing 767-375BCF, N1217A, Trinity Bay, Texas, February 23, 2019, AAR 20/02. The details of this accident investigation and the resulting safety recommendations may be found in the attached report, which can also be accessed at http://www.ntsb.gov.

The NTSB is vitally interested in these recommendations because they are designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendations by number (for example, Safety Recommendations A-20-33 through -38, A-15-7 and -8, A-05-1, and A-10-17, -19, and -20). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, including attachments, please e mail us at the same address for instructions on how to send larger documents.

Please do not submit both an electronic copy and a hard copy of the same response.

This letter provides information about the National Transportation Safety Board’s (NTSB) July 14, 2020, report, Rapid Descent and Crash into Water, Atlas Air Inc. Flight 3591, Boeing 767-375BCF, N1217A, Trinity Bay, Texas, February 23, 2019, AAR 20/02. The details of this accident investigation and the resulting safety recommendations may be found in the attached report, which can also be accessed at http://www.ntsb.gov.

As a result of this investigation, we identified the following safety issues:

• Inadvertent activation of the go-around mode; • Flight crew performance; • Atlas Air Inc.’s (Atlas’) evaluation of the first officer (FO); • Industry pilot hiring process deficiencies; • Awareness information for Boeing 767 and 757 pilots; • Adaptations of automatic ground collision avoidance technology; and • Cockpit image recorders.