Originally Posted by Newman55 (Post 31661580)

Its a software issue that engineers from Boeing, the FAA, the EASA and others have been working for months on. It’s a fixable issue.

Originally Posted by chrisl137 (Post 31662080)

It's probably long since fixed, too. But the visibility makes it so that there's a lot of extra caution around declaring it complete, and if any side issues have been discovered (related or not) they're probably chasing those down, too, before they return to flight. I've seen similar with other large, complex, high visibility systems.

Originally Posted by USA_flyer (Post 31659433)

If it's a 50 year old problem then the pilots would have had lots of training on it during their ab initio training and possibly during their recurrence training. If it was as simple a problem as you describe, then they would have known what to do to recover the situation.

That these planes crashed means there was something more going on that the pilots hadn't been trained on.

Originally Posted by goodeats21 (Post 31659625)

To clarify, wouldn't the MAX have been certified without MCAS, but requiring a separate pilot certification?
I thought the whole point of the MCAS was to have it certified under the existing 737 scheme, so it "felt" the same when flying.

Originally Posted by steve64 (Post 31660766)

It was hard for me to decide which post to quote you on for my reply.

You don't understand the concept of "runaway trim".
On the initial phases of a normal takeoff, the auto-pilot will typically issue short bursts of nose down trim as the plane gains speed. The faster speed means the control surfaces are gaining more effectiveness, thus less pressure is needed on the control column to maintain the same pitch angle.
On a 737, there is a manual trim wheel near the Captain's right knee where the pitch trim can be adjusted manually (though slowly). Both pilots also have a "thumb switch" on their control columns where they can alter the trim setting. This is handy ... if they are holding too much physical pressure to keep the plane's nose at the desire angle, then with the same hand holding that pressure, they can "trim out" the pressure with their thumb.

Regardless of who decides to alter the trim setting (auto pilot or a real pilot) the wheel will spin (fast) to indicate to both pilots that a trim change is being made.
It intentionally makes a bzzzz noise in addition to the visual spinning.
Wether it's auto pilot or manual adjustments, the changes on climb out are typically a series of multiple short bursts of adjustments.
Think: bzzzz ............. bzzzz ........... bzzzz

A thumb switch (or the electronics) beyond it can get stuck. And I guess the auto pilot can go haywire. This would be a runaway trim.
Think: bzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
After say the 10th "z", the pilots are trained to hit the 2 cutoff switches ASAP !!

MCAS is programmed to do a short burst of nose down trim, wait 10 (or??) seconds, reanalyze and do another short nose down burst.
When MCAS is reading faulty AoA info that continuously (and incorrectly) says the nose is too high, then the result is a series of short bust every few seconds.
Think: bzzzz ............. bzzzz ........... bzzzz
In other words, think "normal takeoff" until the amount of physical force needed to keep the nose up is finally questioned by whichever pilot is flying.

MAX pilots were not trained that there is a new system that may also (via auto pilot ??) issue nose down trim commands in short bursts.
Boeing contends that the pilots failed to initiate "runaway trim" procedures without letting us know that a runaway MCAS looks like "bzzzz ............. bzzzz ........... bzzzz" versus an "old school" runaway trim that looks like "bzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"
HUGE difference.

Originally Posted by cmd320 (Post 31658239)

I would argue this is even more of a leap than assuming MCAS was the primary contributing factor to the cause of these accidents. At the end of the day, here is the reality: if MCAS had not been installed and had not been functioning on these aircraft, they undoubtedly would not have crashed.

We can dive into the semantics of pilot training at Lion Air and ET for years and sure, admittedly at least in the case of Lion Air it's not great. They have had numerous runway overrun incidents in 737 type aircraft over the years which points to a shortcoming in the training of their flight crews. It is also worth noting that Indonesia suffers from very heavy rain frequently, has questionable runway design and drainage at many smaller airports, and that the 737NG has a relatively high approach and takeoff speed. The 737MAX case is very different from these other accidents and incidents. This is a situation where nothing would have happened to either of these flights had Boeing's need to appease AA and make the MAX fly just like the NG not existed. This whole fiasco screams of incompetence, impulsivity, and inattention to detail on the part of Boeing, AA, and the FAA.

Originally Posted by spin88 (Post 31653711)

Boeing is in a world o'hurt. My guess is the CEO is toast, they will announce a few more billion in costs (pusting it to over $10B in costs) making the decission to go with the MAX one of the worst in history, it will cost them more than a clean sheet design would have, and they end up with a tainted dud of a plane...

The big (as in billions and billions more) question is if they get regulatory approval before they are forced to shut down the MAX line for a period of time....

Originally Posted by mduell (Post 31663757)

They do have training for trim runaway, it's even a memory item and has been for decades.

That the prior flight by Lionair didn't crash shows someone was trained enough to recognize it.

Ceteris paribus, the MAX is not certifiable without MCAS. There are other approaches to get an MCAS-less MAX certified, but it would need something.

One large problem with your comparison here is that MCAS is inactive when the autopilot is engaged so there should be no ambiguity there regarding which system is activating the trim. I haven't seen any claims that the autopilot-active lockout on MCAS had any faults or issues. If you're getting autopilot like trim activations with the autopilot not engaged, you have an identifiable issue.

Given Ethiopian's history of repeated 737 crashes over the last decade, I'm not convinced an MCAS-less MAX wouldn't have lost an airframe there.

I disagree from the perspective that any new clean sheet airplane would have had it's own cert/EIS woes. Recent history is plagued with cert and EIS issues at the both airframers and several engine manufacturers. Boeing got lucky LEAP didn't have any significant issues, but the overall pattern is not smooth for new programs.

Originally Posted by mduell (Post 31663757)

Given Ethiopian's history of repeated 737 crashes over the last decade, I'm not convinced an MCAS-less MAX wouldn't have lost an airframe there.

Originally Posted by JimInOhio (Post 31664861)

Why would the pilots have assumed it was anything other than the auotpilot causing the repeated trim actuation?

Originally Posted by ajGoes (Post 31665146)

That's really the whole point. It doesn't make any difference which system is causing runaway trim, and figuring that out isn't the pilot's job. The solution is the same: turn off the electric trim system.

Originally Posted by JimInOhio (Post 31664861)

Why would the pilots have assumed it was anything other than the auotpilot causing the repeated trim actuation?

Originally Posted by JimInOhio (Post 31665169)

If the faulty MCAS actuation resembles the correct autopilot actuation, then why would the pilots instantly think they're in a runaway trim problem?

Originally Posted by jsloan (Post 31665222)

Because the autopilot wasn't engaged. MCAS cuts out when the autopilot is engaged -- the autopilot doesn't care what the aircraft feels like, so MCAS isn't needed. Its only purpose is to assist human pilots when the autopilot is disabled.

Originally Posted by JimInOhio (Post 31664861)

Why would the pilots have assumed it was anything other than the auotpilot causing the repeated trim actuation?

Originally Posted by cmd320 (Post 31664955)

For what reason? There was only one other ET 737 accident and this was clearly a mismanagement of the aircraft's speed and altitude in poor weather conditions.

Originally Posted by mduell (Post 31665448)

Just looking at the last decade as the modern era, I count two, 409 and 4030.

Originally Posted by cmd320 (Post 31665656)

4030 was a cargo flight that had a runway overrun and as stated above, 409 occurred under very different circumstances and had nothing to do with a runaway trim event. Neither relate to the MAX accident in any way other than that they happened to be the same airline and same aircraft family.

Originally Posted by mduell (Post 31665725)

Yea, they have nothing do do with MAX except they're the record of the same operator having a high rate (keep in mind the entire fleet is only about 30) of crashes with the same aircraft family.

Originally Posted by cmd320 (Post 31665844)

I mean, the 737 in general has a high rate of crashes relative to other aircraft... that's has about the same amount of relevance.

The point still remains true that there is nothing to indicate either of these accidents would have occurred had MCAS not been installed on the 737MAX.