4 ms·
Three AoA sensors is still not enough to generate a confident consensus to allow an autopilot system capable of crashing the plane to function On Lufthansa 182
by konspence 7y ago
Three AoA sensors is still not enough to generate a confident consensus to allow an autopilot system capable of crashing the plane to function
On Lufthansa 1829, two of the three AOA sensors on an A321 erroneously agreed, causing a system similar to MCAS to kick in[1]
The sensors can fail due to being frozen, or also be damaged by birds traveling in flocks
[1] Third bullet point under the A321 heading: https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_the_Airbus_A320_family#A321 https://en.wikipedia.org/wiki/List_of_accidents_and_incident...
- gomijacogeo 7y agoThe thing is 1829 didn't crash, the pilots got an alert, figured out the problem, took manual control, and flew the plane. Defense in layers. It would be ideal to use different technologies for the AoA sensors to help minimize common-mode failures. Integration and crosschecking against other systems (IMU, radar altimiter, DGPS, an open-loop model of the plane based on engine settings and control surface positions, etc) could give the pilots and flight envelope protection systems a better understanding of their situation. Also, the signature of a failed/frozen vane-type AoA sensor is pretty obvious and I'm surprised the software doesn't take that into account. Good writeup on LH-1829: http://avherald.com/h?article=47d74074 http://avherald.com/h?article=47d74074