3. The pilots of the doomed flight did not turn off the trim system and lost the fight at the end -- the pilots will get significant blame and that appears warranted
Well it looks as if there is some progress in not making the poor pilots the scapegoats....QuoteIndonesian investigators have said the Lion Air plane that crashed last month killing 189 people was not airworthy and should have been grounded.
https://www.bbc.co.uk/news/world-asia-46121127
2. The previous flight reported much the same problems and issued a PAN-PAN but continued the flight after turning off the trim system -- this should have been a PAN-PAN without the option to cancel
2. The previous flight reported much the same problems and issued a PAN-PAN but continued the flight after turning off the trim system -- this should have been a PAN-PAN without the option to cancelFrom a systems design standpoint, it is undesirable to create one-way doors IMO. If you make it impossible to cancel an urgency or emergency declaration, you increase the cognitive decision-making hurdle for a human to make that declaration. Aircraft and passengers have been lost from crews not declaring emergencies or otherwise clearly communicating the danger the flight was in. (Avianca 52 is the first one that comes to most people's mind, but there are others.)
There is already some resistance in non-commercial pilot community to declaring an emergency when it seems warranted. (There's another fairly vocal sub-group who argues against this position; I find myself in that group at times.) Pilots fear repercussions, paperwork, an investigation that might turn up something unrelated, etc. It's why the Aviation Safety Reporting System is not run by the FAA and provides immunity to crews, mechanics, and other license-holders, etc. I don't fly professionally, but I can only imagine that the pressure to not lose your job makes rule-following even more high stakes.
IMO, there's good reason for the pilot in command to be the final authority as to the conduct of the flight and would argue against taking that authority and responsibility away in normal ops, abnormal ops, or emergencies.
https://www.eevblog.com/forum/chat/lion-air-crash-jakarta-boeing-737-had-prior-instrument-error/msg1949761/#msg1949761
I want my pilots to be thinking "Aviate, Navigate, Communicate" (in that order of priority). I don't want "Litigate" to be on their minds at all; that can all be done at 0' AGL and 0 knots airspeed.
Two dozen attempts -
It's an automatic system switching in and out, doing retries on its own, and possibly operating with bad noisy sensor data.
You have at least four oscillators. The MCAS software, the sensor(s), the pilot, the co-pilot.
The airplane or the pilot as the ultimate authority is yet another conflict.
Investigators are saying the plane was not airworthy. It should have been grounded as soon as problems surfaced on the previous flight.
One AOA sensor had been replaced, but still a 20 degree discrepancy.
Really need the CVR to figure out all that happened.
An intermittent, something cutting in and out can confuse anyone as to what is working properly or not.
Simply switching off the trim motors leaves the stabilizer actuator where it last was- presumably set at nose down. Maybe it was switched back on to get the motors to move it back, if the sensor data smartened up. Maybe they couldn't manually crank them back in time.
Human psychology is to "blame the victim" and the pilot had 6,000hrs and co-pilot 5,000hrs so they may not have been inept.
Boeing certainly is.
Reading the Preliminary Report, previous flight did OK:
"Airspeed unreliable and alt disagree shown after take off. STS was 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."
"... the airline confirmed one of their maintenance engineers was on board of the aircraft during the accident flight. This was an "anticipatory measure" in the event of technical problems with the new aircraft."
A third opinion who may have added confusion or given wrong instructions or flipped a breaker.
I'm of the view Boeing has blood on their hands for the engineering.
One of the many questions put forth to the FAA by The Aviation Herald:
- Why was the MCAS permitted to operate on the base of a single AoA value showing too high angle of attacks? Why does the MCAS not consider the other AoA value?
The forum poster, about knowing to shut off a system you don't even know about:
"As a captain on Boeing 737, I feel betrayed about Boeing's statements about their documentation. Even as of now, the MCAS has not been incorporated into the FCOM, nor into the FCTM. Their press release is a shameless lie."
Update today , the CVR is recovered, buried 8 meters underneath the mud in about 30 meters deep.
https://www.reuters.com/article/us-indonesia-crash-recorder/indonesian-officials-say-crashed-lion-air-jets-cockpit-voice-recorder-found-idUSKCN1P808C?il=0
Local news mentioned they used ROV with side scan sonar, magnetometer to find it.
Hopefully the recording data is still ok, as from the look, the outer physical unit looks badly wrecked.
Hopefully the recording data is still ok, as from the look, the outer physical unit looks badly wrecked.
WOW, had not looked at the pic before, but damn that thing is busted up. The odd thing is you would expect the damage to be less with an impact with water versus land, but at the speed it must have hit the water it might as well have been land.
Brian
... Just have to hope the data is not degraded from all the overwrites it has had.
Hopefully the recording data is still ok, as from the look, the outer physical unit looks badly wrecked.
WOW, had not looked at the pic before, but damn that thing is busted up. The odd thing is you would expect the damage to be less with an impact with water versus land, but at the speed it must have hit the water it might as well have been land.
Brian
See for youself for.more.photos ...
https://m.detik.com/news/foto-news/d-4383483/penampakan-cvr-lion-air-pk-lqp-yang-akhirnya-ditemukan
The pilot is being misleading, as you do not have to shut off a system you don't know about. You have to shut off the stab trim system.
I think Boeing's position on this is pretty clear: if you follow the procedure, it doesn't matter. Some pilots are saying it does matter. We'll find out.
Another 737: