Ethiopian airliner down in Africa

[yanrair]

Originally Posted by wiedehopf

I'm really curious why people don't look at the FDR graphs from the Lion Air flight.
They are readily available.
The airspeed difference between left and right side is about 10 to 20 knots.
The FDR readout is not consistent with a blocked pitot.

The pitot readout as well as the static port readout is corrected for AoA slightly, that is were the Airspeed disagree comes from.
This correction for AoA is small so even with the left AoA reading 21 degrees high the magnitude of the error on speed and altitude is there but both are still in the right ballpark.
I've attached the FDR readout from the first pdf report that was available on the Lion Air crash (with some annotations):


In this graph only the left side altitude readout is plotted, in the preliminary report you can see the difference to the side with working AoA:
https://www.flightradar24.com/blog/w...ary-Report.pdf

Note also that the 100-200 ft altitude dip on rotation is present on the Ethiopian ADSB data as well.
(That alone doesn't mean that there the AoA was misreading in that case as well but i makes it more likely in my opinion)

good analysis Wiedehopf. The ias disagree messsges and stick shakers may have caused confusion. But this was not an airspeed disagree crash like AF447 but a Stabilizer running fully nose down. We know why. It was not noticed &or stopped for reasons yet to be determined. Stopping the STAB and retrimming would have made the plane fly normally. Straight and level. As the day before. Even with IAS DISAGREE The pilots would still have GPS, pitch and power and one IAS would have been reading correctly- possibly two. THE SBY ASI should have been ok. As well as the unaffected side? These are all supposition but are possible scenarios given the info so far. For me the fact that the previous flight had similar problems with totally different outcomes is significant.
I am not sure if the safety office had picked up on the previous incident.