Ethiopian airline crash

[ChicagoBlue]

In this case, it certainly was Boeing's problem, but I was talking more generically about aircraft design and the desire to innovate, and solve problems that aren't really problems.

You could argue systems like auto-land was a problem that didn't need solving, but the industry went ahead and developed it anyway.

Auto land is an essential tool used to allow aircraft to land in weather that is too poor for manual landings. Just used it the other day in Denver. Had it not been available, we would have ended up in another state, delayed almost 200 people and put an aircraft, two pilots and four flight attendants out of position for their next flight...and that is just one aircraft!! Multiply that by 60-100 PER HOUR that can’t land at a major airport and the smaller airports within an hours radius quickly get swamped and nobody gets anywhere.

With the number of flights, and the level of inter connectivity of everything in the aviation system, I’d posit that Autoland is an essential tool in running a safe, efficient aviation system.

YMMV.

 

[ChicagoBlue]

If you switch it off and the pilots know about the issue they can fly the aircraft very easily. It's not a safety issue in that sense.

The “OFF” in this situation is to completely lock out any form of electric trim movement. That is not a non-issue, albeit flyable. It is certainly not a “oh, switch it off, we’ll do it the old fashioned way” system.

Stab Trim Cutoff turns off not only the MCAS, but also the NORMAL TRIM SYSTEM, that’s why it has been in the aircraft for 50 yrs. Uding the Stab trim cutoff for MCAS is a “the TV isn’t working properly, so let’s unplug the power strip containing the TV and the VCR and the SKY Box and the PS4!”

 

[ChicagoBlue]

I may sound a bit simple here but, why would a "safety " system be installed with obvious override systems. In my industry, to override a safety system requires many levels of approval. On the case of this plane it appears it is down to switching it off when the shit had already hit the fan. Something very badly wrong here in my opinion.

THIS safety system’s problem is what I discussed at the start: Single source input which, if erroneous, triggers a “safety system” that is not needed. Compounding that ERROR is the fact that the “safety system” then trims nose down repeatedly and CUMULATIVELY, which was not only previously unknown but also is the killer aspect of the whole thing.

You may recall a Lion Air wrestles with the system repeatedly (as shown by the flight profile of MCAS nose down-recover(ish), MCAS nose down-recover(ish), but it is that repeated, cumulative nose down trim input working against the pilots that they were finally unable to overcome.

At that point, even if they had used the Stab Trim Cutoff switches, the MANUAL TRIM they had available, coupled with an otherwise perfectly flyable aircraft, may have been insufficient to save them.

THIS is what scares pilots...how far can this go before I am destined, regardless of my actions (including turning it off!), to die?

Has ANYONE done this in a fully certified, full motion simulator and lived? How many MCAS activations before they couldn’t survive?

Scary questions, IMHO!

It is clear that looking forward, MCAS as we know it today will no longer be certified. Do, what’s the fix? Software alone? That may not be good enough anymore, IMHO. Hardware? Maybe! Maybe some flight envelope limits need revisiting, especially if it kicks in approaching stall? At a minimum, it is going to require DUAL, COMPARATIVE INPUTS, and the ability for pilot intervention, when activated.

The entire system is a Rube Goldberg work around for 737 type certification. The nuclear option is a different type rating and X hours of actual simulator experiences working with the MAX differences. I doubt this will happen, but some form of training is going to be forced on the airlines, and I’m sure Boring is working on it as we speak!

 

[worsleyweb]

Hello Chicago blue - I like your posts. Don’t understand most of them.

Can I just ask one point?

On my horror flight last week with bad turbulence and an aborted landing would the pilot have been shitting himself and was I in any danger.

 

[HelloCity]

 

[Armchair Supporter]

Some poor "engineer" is going to be thrown under the bus for this when the truth is always a more corporate one.

 

[Henkeman]

The “OFF” in this situation is to completely lock out any form of electric trim movement. That is not a non-issue, albeit flyable. It is certainly not a “oh, switch it off, we’ll do it the old fashioned way” system.

Stab Trim Cutoff turns off not only the MCAS, but also the NORMAL TRIM SYSTEM, that’s why it has been in the aircraft for 50 yrs. Uding the Stab trim cutoff for MCAS is a “the TV isn’t working properly, so let’s unplug the power strip containing the TV and the VCR and the SKY Box and the PS4!”

Sorry, I wasn't trying to suggest it's a total non-issue, more that now you know what the hell is happening, and post the adjustments Boeing will have to make, you can cope with it, as with many systems when they fail.

 

[Henkeman]

As I understand it, and @ChicagoBlue may correct me, the rock and a hard place that Boeing were in was that had they made those safety systems standard, they wouldn't have been able to claim it was a minor adjustment to the model, and thus grandfather the type rating certification.

 

[Machiavelli]

Some poor "engineer" is going to be thrown under the bus for this when the truth is always a more corporate one.

 

[ChicagoBlue]

As I understand it, and @ChicagoBlue may correct me, the rock and a hard place that Boeing were in was that had they made those safety systems standard, they wouldn't have been able to claim it was a minor adjustment to the model, and thus grandfather the type rating certification.

That IS one of the big issues!

The feeling is that in Boeing’s zeal to ensure the aircraft was kept as a 737 type, with zero caveats other than making airlines/crews aware of differences, they not only sneaked the MCAS single source failure problem by the FAA, but failed to include it in the new manual AND didn’t tell the airlines it even existed at all.

We will see how the FAA deals with this now, in light of Boeing’s sleight of hand, which has resulted in numerous deaths.

Rock, meet hard place!