Originally Posted by
patplan
I'm confused had there been any US MCAS incidents?? Can you at least cite me one case?
I will just concentrate on Lion Air Flight JT610.
How do you know the CAPT on that flight didn't perform UAS NNC? Did you get a hold of the CVR's transcript? We know there wasn't any CVR's transcript on Lion Air JT610 Preliminary Crash Investigation because they still haven't recovered the JT610's CVR at that juncture. The CVR was buried beneath a thick mud of Java Sea for almost 60 days before they finally recovered it. And, no official transcript has been released by the officials thus far.
Furthermore, the crew had been briefed about the malfunctions and the fixes by the MX on the ground, plus there was a log left by the previous crews [Flight JT043] written as:
"Airspeed unreliable and ALT disagree shown after takeoff, STS also running to the
wrong direction, suspected because of speed difference, identified that CAPT instrument
was unreliable and handover control to FO. Continue NNC of Airspeed Unreliable and ALT
disagree. Decide to continue flying to CGK at FL280, landed safely runway 25L."
Wouldn't you think the first thing flashed on the CAPT's mind should there be trouble with the aircraft is to recall the previous flight's log entry which explained, among other things, the crews' execution of the Airspeed Unreliable NNC and also ALT disagree memory items?
About 4,000 posts ago on this thread others cited previous MCAS incidents from NASA's ASRS. More recently, others backed me up on that from a previous post of mine.
You're correct about the CVR however the official, preliminary report page 2, the aircraft had a ground speed (from the radar controller) of 322 knots with an altitude somewhere between 2,000 and 5,000 ft ( 23:22:56 UTC) - there is no way the aircraft would be going that fast with 80% N1 per the NNC UAS with flaps extended or 70% clean. Also, if you look at the FDR printout at that time, there is no evidence of a thrust reduction from take-off power (N1, N2, fuel flow).
I would agree that given the previous flight log entry that one would have a greater than normal awareness of an unreliable airspeed potential but evidently that checklist was not executed, given the inordinately high ground speed and the absence of changes to the engine power.