Originally Posted by
HPSOV L
If the stick shaker activates after lift off and power, pitch, flap position, aircraft performance and primary and secondary Airspeed indications are normal the decision whether or not to perform QRH Airspeed Unreliable actions is purely discretionary.
If you look at the DFDR data, the indicated airspeeds were already diverging from liftoff, so no, they were not "normal".
The preliminary accident report contains a synopsis of the discussion between the Captain and the First Officer. At 400', the FO selected VNAV and the Captain called for "Command", but the A/P did not engage. The Captain called out for "Command" again. The A/P did not engage. He asked the FO to change to a new ATC frequency. The FO checked in with radar, received an ATC instruction, and responded. The Captain called for flap retraction, and the FO responded. The Captain asked the FO to request runway heading from ATC. The FO did so.
What is conspicuously absent from the dialogue is any attempt to confirm that their airspeeds were indeed "normal". They were
not. Despite having multiple warnings that are explicitly stated in AD 2018-23-51 (the 737 AD published post Lion Air), this crew made no apparent attempt to determine this crucial fact. If they had done so, then performance of the Airspeed Unreliable non-normal would have been anything but discretionary.