Breaking news: Ethiopian Airlines flight has crashed on way to Nairobi

[Evan]

Very early days, I know, but one difference between this and the Lion Air is that the latter aircraft had known flight anomalies on the previous flight or two, but this does not seem to have been the case with the Ethiopian.

True, but a sensor can suddenly fail. The reason the previous Lion Air flight didn't crash was due to correct pilot responses. We still don't know why the Lion Air sensor failed in the first place, but I'd place some money on the bathtub curve and maybe some supply-chain 'economy' choices. I'm expecting that the true story of the Boeing 737MAX will eventually come out and feature instances of corrosive pressure from on high regarding costs and schedule targets as told by reluctant engineers tasked with crutching a mid-20th-century airframe into the 21st-century.

[Evan]

China has apparently grounded all 737MAX aircraft... until 6pm local time?

The Civil Aviation Administration of China said in a statement on Monday morning that all domestic Boeing 737 MAX 8 jets would be out of action until 6 p.m. local time, due to its principle of "zero tolerance for safety hazards."

Ok, zero tolerance until dinner time. I guess. Unless the investigation wraps this up before then. I guess.

[obmot]

Could be indicative of a sudden loss of autoflight...

Thx Evan.

I hesitate to ask what to most here will be a 'duh' type question - and self-spotlight my ignorance in asking - but in a 'typical' commercial flight, when would a flight crew 'typically' (ballparkish) activate the autopilot systems (I'm assuming autoflight in your comment is akin to autopilot/autothrust etc. but - again my ignorance might be at play again lol)?

I mean would it 'typically' be like 30secs after wheels up? Or 5 minutes after? Etc.

[edited for spelling typo]

[flashcrash]

China has apparently grounded all 737MAX aircraft... until 6pm local time?

A mistranslation I believe. The BBC is reporting that the Chinese government has instructed China Southern, China Eastern and Air China to halt all 737 MAX operations by 6pm local time.

https://www.bbc.com/news/business-47519929

[Gabriel]

Looking at the ADS-B, it also doesn't look like a crew dealing with repeated trim runaway, as an MCAS issue would show. However, the end of the ADS-B data is possibly due to a loss of signal in that part of the world and there were obviously events that occurred beyond that point that led to the crash. The real danger with MCAS is that pulling the column back (the first instinctive reaction to runaway) no longer deactives the electric pitch trim, and pilots were not told this, so the flight control issue and related confusion can easily escalate.

If there is any 737-MAX pilot that can be caught by surprise by the MCAS and not know how to handle it, after all the exposure that the Lion Air case had, such a person doesn't deserve to be a pilot.

[Gabriel]

Thx Evan.

I hesitate to ask what to most here will be a 'duh' type question - and self-spotlight my ignorance in asking - but in a 'typical' commercial flight, when would a flight crew 'typically' (ballparkish) activate the autopilot systems (I'm assuming autoflight in your comment is akin to autopilot/autothrust etc. but - again my ignorance might be at play again lol)?

I mean would it 'typically' be like 30secs after wheels up? Or 5 minutes after? Etc.

[edited for spelling typo]

At 400 ft above the runway. Not even 30 seconds in the air.

[thor]

boeing share dropping 10% in premarket trading, think its connected to this accident.

[thor]

Ethiopian airline and china has grounded all 737-max 8 fleet due to safety concerns.

[ikeharel]

My thoughts with the families of those on board.
First thing in mind was, that Boeing, FAA, and NTSB should and will chech the loadsheet entries. 737MAX vs. 737-800 are very different in fuselage design and engins structure are built a bit forward on the MAX.
Wrong entries could stall the engines on missed AOA on T/O, a chain rection thereafter...

Sincerely,
Ike

[Evan]

If there is any 737-MAX pilot that can be caught by surprise by the MCAS and not know how to handle it, after all the exposure that the Lion Air case had, such a person doesn't deserve to be a pilot.

Logical. Now, consider instinct. How do you feel about an aircraft that can contradict veteran pilot instinct for that type and then requires special procedural knowledge to regain control, yet remains airworthy?

I could make the similar statement: after Lion Air 610, any manufacturer that hasn't issued a required emergency software upgrade ensuring that the system cannot operate with a sensor disagreement doesn't deserve to be an airframer. Has Boeing done that?

There is no evidence yet to conclude that this was another case of MCAS error. One witness reported that the plane turned back and was trailing smoke (for what that's worth).

[Evan]

Flight Recorders Found

Considering the fallout, the groundings and the Wall Street reaction, if the cause is pilot error or non-design related, Boeing needs to get these read out asap and issue an immediate news release about the findings. Unless, of course, the findings confirm their worst fears. Meanwhile, Ethiopian will want to blame the aircraft. So this will be interesting.

[birdguts]

if the cause is pilot error or non-design related, Boeing needs...

Evan, I would steer away from "pilot error" as an excuse. The modern planes are expected to fly themselves. No offense to commercial pilots, but I don't see the hubris in their profession anymore.

Boeing needs to ground this model. It will give the planet a chance to breathe anyway.

[B757300]

And here I thought only A.net had people joining to tell everyone the cause and what should be done about it.

[Gabriel]

Logical. Now, consider instinct. How do you feel about an aircraft that can contradict veteran pilot instinct for that type and then requires special procedural knowledge to regain control, yet remains airworthy?

I don't think that any pilot has any instinct developed for trim runaway, let alone disconnecting the trim by pulling hard on the column.

As I understand (and I can be wrong), that feature had been designed to avoid that the AP keep applying nose-down trim if the pilot fights the AP by pulling up. There were a couple of accidents in the 80's (IIRC) where the pilots stated a go around but did not disconnect the AP so as they pulled up the AP was pushing down trying to keep the plane on the glide slope. Now, a pilot can quite easily override the normal AP stick force, but the AP is designed to make this force zero on average by using the trim, so as the pilots pulled up and the AP felt the need to apply a constant nose-down force, it started applying nose-don trim.

The procedure for a trim runaway and the closest that we should have to an instinct should be electric trim switch to stop the motion immediately, cutout switches to stop them permanently, and grab that spinning wheel if all else fails.

BTW, I agree with your other 2 statements.

[Evan]

I don't think that any pilot has any instinct developed for trim runaway

The pilot comments I've read seem to involve a consistent sequence. First, the NG is designed to cut the electric pitch trim if the column is pulled back against the trim movement, so the first instinctive thing to do is to stabilize the upset by doing that. The first procedural, remedial thing to do is to use the cutout switches.

The real danger MCAS presents is that this instinctive reaction yields a different, and confusing, outcome. The pitch is cut for a few seconds, then resumes the movement. The combination of altering the response to an instinctive command, the delayed re-engagement and the fact that none of this was revealed to pilots in transitioning is, collectively, inherently dangerous.