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Old 29th Jun 2019, 02:08
  #794 (permalink)  
BuzzBox
 
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Originally Posted by DaveReidUK
The 787 generates a synthetic airspeed value by combining inertial data and AoA, to substitute for UAS.

Whether you can do it the other way round, i.e. generate a synthetic AoA from IRS and IAS, isn't immediately obvious.
The B777 ADIRU generates a 'calculated AOA' based on inertial and air data. The calculated AOA is used as a third AOA value for AOA redundancy management. The AMM states:

The AOA redundancy management logic uses a modified average calculation. The modified average calculation calculates an average of three AOA values, the left corrected AOA, the right corrected AOA, and a calculated AOA. The calculated AOA logic receives inputs from the inertial and air data systems to calculate the calculated AOA.
I assume the B787 does something similar?
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