Duckworth Asks FAA to Publish Advisory Circular on Best Practices for Manufacturing, Testing and Operating Angle of Attack Sensors
Malfunctioning AOA sensors may have contributed to deadly crashes involving Boeing 737 MAX series and faulty AOA sensors recently led to FAA grounding all Cirrus SF50 Vision Jets
[WASHINGTON, D.C.] – Following a series of safety incidents involving faulty or malfunctioning angle of attack (AOA) sensors on airplanes, including the two recent crashes involving Boeing 737 MAX series jets, U.S. Senator Tammy Duckworth (D-IL) asked the Federal Aviation Administration (FAA) today to publish a set of standardized best practices for how to ensure airlines and flight crews are complying with all federal safety standards and regulations. In a letter to Acting FAA Administrator Daniel Elwell, Duckworth requested the FAA circulate a clear and comprehensive “advisory circular” to address AOA sensor problems, which can lead to dangerous flying conditions.
“AOA vanes are on the outside of the aircraft and vulnerable to projectiles and significant wear and tear. Yet, malfunctioning AOA sensors can result in a series of cascading failures that significantly impair aviation safety,” wrote Senator Duckworth. “That is why I am calling on the FAA to issue a clear and comprehensive advisory circular that sets forth standardized best practices for industry and flight crews in regard to manufacturing, operating, testing and maintaining AOA sensors.”
Duckworth is the Ranking Member of the Senate’s Transportation and Safety Subcommittee on the Senate’s Commerce, Science & Transportation Committee. Erroneous data from AOA sensors played a role in the two high-profile crashes of Boeing 737 Lion Air and Ethiopian Airlines airplanes and just last month, the FAA issued an emergency directive grounding all Cirrus SF50 Vision Jets because of erroneous AOA sensors.
A full copy of the letter is available below and online here.
Dear Acting Administrator Elwell:
I write to request that the Federal Aviation Administration (FAA) publish a comprehensive advisory circular that standardizes guidance on best practices for manufacturing, operating, testing and maintaining angle of attack (AOA) sensors, particularly the AOA wind vane component, to ensure effective compliance with all applicable regulatory requirements. High-profile fatal crashes involving 737 MAX series aircraft brought attention to the dangers of malfunctioning AOA sensors. However, problems originating with a damaged or malfunctioning AOA sensor are not limited to any single model of aircraft or manufacturer. Enhancing AOA sensors must be a priority for the entire aviation industry and regulatory system.
A recent FAA emergency airworthiness directive (AD) issued on April 18, 2019 demonstrates the dangers of malfunctioning AOA sensors. This AD was necessitated by a manufacturing flaw in the torqueing of set screws that secure the potentiometer shaft to the AOA vane shaft and the failure to apply thread locker to secure the set screws. It noted that the AOA sensor flaw could result in unintended automatic flight control activations; difficulty controlling the aircraft; excessive nose-down attitude and possible impact with terrain.
AOA vanes are on the outside of the aircraft and vulnerable to projectiles and significant wear and tear. Yet, malfunctioning AOA sensors can result in a series of cascading failures that significantly impair aviation safety. That is why I am calling on the FAA to issue a clear and comprehensive advisory circular that sets forth standardized best practices for industry and flight crews in regard to manufacturing, operating, testing and maintaining AOA sensors.
Thank you in advance for your consideration of my urgent request and I look forward to learning about how FAA will begin developing this critical advisory circular.
United States Senator
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