How many AOA sensors does the 737 MAX have?

Given that it's reported in the media, that one faulty AOA probe activated the MCAS on the Lion Air flight, I was wondering if anybody also knows how an input consensus is reached for the AOA value that gets send to the MCAS system.

  • 2
    $\begingroup$ you have two different questions there. would you like to know how many sensors are there, or how consensus is reached? $\endgroup$ – Federico Mar 12 at 9:24
  • $\begingroup$ aviation.stackexchange.com/questions/57626/… looks relevant. $\endgroup$ – a CVn Mar 12 at 9:24
  • $\begingroup$ @aCVn meh, unsourced $\endgroup$ – Federico Mar 12 at 9:25
  • $\begingroup$ @Federico Indeed, but still a starting point. And there's the recent news that Boeing is changing some piece of flight software in response to the recent crash. (Sorry, I haven't dug into that further.) $\endgroup$ – a CVn Mar 12 at 9:26
  • $\begingroup$ @aCVn chat.stackexchange.com/transcript/message/49433516#49433516 $\endgroup$ – Federico Mar 12 at 9:28

The Boeing 737 MAX has 2 AoA sensors.

However, MCAS only takes input from 1 AoA sensor at a time.


The black box flight recorder data for Lion Air JT610 shows the data from 2 AoA sensors, labeled "Left" and "Right".

Also, if you look at the nose of the 737 MAX, you will see a left and right AoA vane. (The sensors with the red tags are pitot tubes).

"[Boeing] said it will change the MCAS software to give the system input from more than one AOA sensor."

  • $\begingroup$ Thanks @mike, do you happen to know the manufacturer of the AoA vane on 737 max? $\endgroup$ – Nicholas Humphrey Mar 18 at 1:20
  • $\begingroup$ I really enjoy this answer. Concise and documented. $\endgroup$ – Manu H Mar 23 at 19:15

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