Wed Mar 13, 2019 10:01 pm
In the Lion Air JT 610 flight accident, the aircraft was in climb at around 2,150 ft msl FL/UP (2,117’ aal) when MCAS was apparently activated and resulted in a very sudden descent to 1,475’ msl (1,442’ aal), a total 675’ altitude loss, with GS increasing from 260 kn. to 327 kn. This initial descent was arrested around 1,475’ msl. The increase altitude/decrease altitude trend (indicating MCAS active) continued after this initiating event until the accident.
In the Lion Air JT 43 inbound flight to WIII Jakarta (same aircraft reg. no. as flight 610) it was at around 5,425’ msl (5,411’ aal) when MCAS was apparently activated. It then suddenly descended to 4,900’ msl (4,886’ aal), with a total 525’ altitude loss, and GS increasing from 291 kn to 310 kn, before the descent was arrested at this altitude. The flight was then controlled by the crew after this original event and showed no more MCAS behavior.
In the Ethiopian ET 302 accident flight, if the FRadar24 data is correct, there was no sudden, significant drop in altitude as the two Lion Air flights had experienced which would indicate an MCAS initiation. Instead, if the FRadar24 data is correct, the issue after takeoff was a major inability to climb. No MCAS initiation behavior (like the two Lionair flights which incurred sudden 525’-675’altitude loss) seems to have occurred.
Must be that “satellite tracking data” noted by the Canadian Transport Minister today is significantly different data than what FRadar24 (ADS-B) data shows. If it’s not, it is difficult to objectively see an MCAS initiation and immediately following behavior noted with the two Lion Air flights. IMO the data more indicates that the ET 302 aircraft faced highly deficient climb capability (lots of root causes associated with that) from takeoff to end of flight.
In any event, Boeing needs to fix this MCAS/AoA system issue immediately. All just my opinion.