Ethiopian 737 MAX 8 crash
#431
:-)
Joined APC: Feb 2007
Posts: 7,339
If Boeing hid the issue why was the Brazilian Certifying Authority aware of MCAS and actually listed it as a "B" training item in their OER with a Chief Boeing Technical Pilot listed as participating? Did some authorities bye the "info overload" rationale to not train on MCAS while Brazil did not. But I was surprised that GOL grounded their fleet after the second incident being that per ANAC they would have already been trained as to MCAS existence. Maybe they thought whatever they trained was insufficient.
#432
Agree, the MAX-8 is very stable and flies well. On approach, with DLC, it maintains pitch attitude even if greater sink rate desired. Lands a bit easier than an NG.
#433
Looks like MCAS has been confirmed as active in the Ethiopian crash.
https://www.wsj.com/articles/investi...sh-11553836204
https://www.wsj.com/articles/investi...sh-11553836204
#434
In the "base package" MCAS looks at one AOA at a time but is connected to both, it switches between AOA input after every flight, and defaults to AOA1 after the aircraft is powered back up (after shutting down all electronics, not just engines).
The "option available" is an AOA indication on the respective PFD, and an AOA disagree light. Neither of these are part of MCAS in any way (but off course having an indication that one of the AOA is broken might have helped the pilots figure out what was going wrong).
Presumably the software upgrade will among other things, include free AOA indication for all, and MCAS will compare both AOAs and sit on its hands if they disagree.
#435
Gets Weekends Off
Joined APC: Jan 2006
Posts: 222
Doesn't look so imminent. See here:
https://finance.yahoo.com/news/boein...003510053.html
The MCAS was put in place due to compliance issues after they pushed the MAX beyond the limits of the original type. The change from 0.6 to 2.5 degrees nose down trim was probably done for a reason. Designing it to activate repeatedly after you kill it with the thumb switches was also probably done for a reason. Rolling back all of those will solve the problem of the plane crashing for no good reason (faulty sensor), but may open certification questions. Also, the FAA is in no rush to approve anything now that they have blood on their hands and are themselves under investigation. This can drag for a while.
https://finance.yahoo.com/news/boein...003510053.html
The MCAS was put in place due to compliance issues after they pushed the MAX beyond the limits of the original type. The change from 0.6 to 2.5 degrees nose down trim was probably done for a reason. Designing it to activate repeatedly after you kill it with the thumb switches was also probably done for a reason. Rolling back all of those will solve the problem of the plane crashing for no good reason (faulty sensor), but may open certification questions. Also, the FAA is in no rush to approve anything now that they have blood on their hands and are themselves under investigation. This can drag for a while.
#436
Doesn't look so imminent. See here:
https://finance.yahoo.com/news/boein...003510053.html
The MCAS was put in place due to compliance issues after they pushed the MAX beyond the limits of the original type. The change from 0.6 to 2.5 degrees nose down trim was probably done for a reason. Designing it to activate repeatedly after you kill it with the thumb switches was also probably done for a reason. Rolling back all of those will solve the problem of the plane crashing for no good reason (faulty sensor), but may open certification questions. Also, the FAA is in no rush to approve anything now that they have blood on their hands and are themselves under investigation. This can drag for a while.
https://finance.yahoo.com/news/boein...003510053.html
The MCAS was put in place due to compliance issues after they pushed the MAX beyond the limits of the original type. The change from 0.6 to 2.5 degrees nose down trim was probably done for a reason. Designing it to activate repeatedly after you kill it with the thumb switches was also probably done for a reason. Rolling back all of those will solve the problem of the plane crashing for no good reason (faulty sensor), but may open certification questions. Also, the FAA is in no rush to approve anything now that they have blood on their hands and are themselves under investigation. This can drag for a while.
I think the FAA is like you said in no hurry to do a rush job and have it blow up in their face (again), and they are likely considering other MAX certification issues, perhaps MCAS related, perhaps not.
#437
I don't think the repeat activation was intended as a feature, I kind of gathered that they simply didn't think to limit it to one activation per event (or time period). So I don't think limiting that is going to be a certification issue.
I think the FAA is like you said in no hurry to do a rush job and have it blow up in their face (again), and they are likely considering other MAX certification issues, perhaps MCAS related, perhaps not.
I think the FAA is like you said in no hurry to do a rush job and have it blow up in their face (again), and they are likely considering other MAX certification issues, perhaps MCAS related, perhaps not.
I suppose every one of those decisions is going to be looked at again and revalidated (or not).
An underlying difficulty though is that increasingly the FAA simply doesn’t have the level of expertise of the manufacturers they are nominally regulating, especially now that there are really only two big commercial passenger jet makers in the world. They wind up having to take Boeing or Airbus’s word for things, probably more often than they are really comfortable with.
#438
Gets Weekends Off
Joined APC: Dec 2007
Position: retired
Posts: 992
Had no idea there was DLC on any 737? Haven't heard of that since the L-1011, which a lot of guys just loved.
#439
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Joined APC: Feb 2007
Posts: 7,339
If there is a lock out of MCAS, and on the subsequent maneuver in period of said time, the handling characteristics materially change, isn't that a tecnically new type? If that's the case, then MCAS isn't really needed at all I suppose. IMO, the FAA might, but other regulatory bodies will probably not be satisfied with this fix.
#440
On Reserve
Joined APC: Mar 2019
Position: Passenger
Posts: 10
Ethiopian Airlines Pilots Initially Followed Boeing’s Required Emergency Steps to Disable 737 MAX System
https://www.wsj.com/articles/ethiopi...em-11554263276
https://www.wsj.com/articles/ethiopi...em-11554263276
"After turning off a flight-control system that was automatically pushing down the plane’s nose shortly after takeoff March 10, these people said, the crew couldn’t get the aircraft to climb and ended up turning it back on and relying on other steps before the final plunge killed all 157 people on board."
"The pilots on Ethiopian Airlines Flight 302 initially reacted to the emergency by shutting off power to electric motors driven by the automated system, these people said, but then appear to have re-engaged the system to cope with a persistent steep nose-down angle. It wasn’t immediately clear why the pilots turned the automated system back on instead of continuing to follow Boeing’s standard emergency checklist, but government and industry officials said the likely reason would have been because manual controls to raise the nose didn’t achieve the desired results.
After first cranking a manual wheel in the cockpit that controls the same movable surfaces on the plane’s tail that MCAS had affected, the pilots turned electric power back on, one of these people said. They began to use electric switches to try to raise the plane’s nose, according to these people. But the electric power also reactivated MCAS, allowing it to continue its strong downward commands, the people said."
After first cranking a manual wheel in the cockpit that controls the same movable surfaces on the plane’s tail that MCAS had affected, the pilots turned electric power back on, one of these people said. They began to use electric switches to try to raise the plane’s nose, according to these people. But the electric power also reactivated MCAS, allowing it to continue its strong downward commands, the people said."
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