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Would you fly on a Boeing 737 Max?

StephenH said:
The word at Heathrow BA maintainace is It may not fly again 'commercially'. Due to the lack of customer and thus airline confidence.
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That's not a surprise. Public perception is so much more important than reality in this area.
 
scaramanga said:
It needs some engineering - that's perfectly normal with any product as complex as an aircraft.

The important fact is that, when pilots are properly trained, and maintenance procedures followed, it's not life threatening. Basically the same as plenty of other faults that all aircraft from all manufacturers are launched with.
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Only 200 of them were in the air, 2% crashed and killed everyone. That is far from normal. A huge failure rate in aviation terms. It needed some engineering prior to entering service. That much is abundantly clear.
 
scaramanga said:
It needs some engineering - that's perfectly normal with any product as complex as an aircraft.

The important fact is that, when pilots are properly trained, and maintenance procedures followed, it's not life threatening. Basically the same as plenty of other faults that all aircraft from all manufacturers are launched with.
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Just admit you're bloody wrong.
 
scaramanga said:
I've not heard anything to suggest it's not correct. He's certainly not mentioned it.
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It is incorrect. MCAS will still intervene when using the thumb switch. The only method was to manually turn the trim wheel. When the doomed Ethiopian flight pilots could not physically turn this wheel because of the forces at work, they reverted back to the thumb switch, MCAS kicked in and plunged the plane into the ground.

They were close to saving the plane. They followed the correct procedures. However, they should have reduced the speed, and then maybe they could have used the manual trim wheel turning it together. Normally when you can’t trim the plane manually because of the forces pushing down on the flaps, you put the plane into a breif decent to reduce the load. They didn't have the time or altitude to do that.
 
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StephenH said:
The word at Heathrow BA maintainace is It may not fly again 'commercially'. Due to the lack of customer and thus airline confidence.
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I think that is highly unlikely. The Max is 'too big to fail'. Not only would it cripple Boeing - America's largest exporter - it would leave airlines across the globe without new planes. Causing more pollution (flying older planes) and cost.

There are lingering doubts though, the Max doesn't 'fly right'. Squeezing the larger engines under a plane that is too low, has caused it's fundamental aerodynamic characteristics to be compromised. It's nose will lift up unnaturally when climbing. But, the software should take care of it. They just need 2 sensors that check the angle of the plane (2 not 1), pilot training so they are aware of what is going on, and how to control the plane themselves should they need to. Pilots were not even told about how the software worked or that it was there.

It will probably return to service around March.
 
SpurMeUp said:
Only 200 of them were in the air, 2% crashed and killed everyone. That is far from normal. A huge failure rate in aviation terms. It needed some engineering prior to entering service. That much is abundantly clear.
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0% of the US and European (by far their largest markets) airliners crashed - that tells you a hell of a lot more.
 
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SpurMeUp said:
It is incorrect. MCAS will still intervene when using the thumb switch. The only method was to manually turn the trim wheel. When the doomed Ethiopian flight pilots could not physically turn this wheel because of the forces at work, they reverted back to the thumb switch, MCAS kicked in and plunged the plane into the ground.
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I think you've got yourself a bit confused there.

The thumb trim always, always overrides all pilot "feel" systems - even MCAS. MCAS can (and will under fail conditions) kick in between thumb trim adjustments but never during.

With too much velocity and full trim, there's nothing that's going to save any aircraft. The motors operated by the thumb trim are too slow and, as you've pointed out, the pressure is too great to use the wheels. No pilot or FO with anything resembling a suitable level of training would ever let a system get that far out of trim.

SpurMeUp said:
They were close to saving the plane. They followed the correct procedures. However, they should have reduced the speed, and then maybe they could have used the manual trim wheel turning it together. Normally when you can’t trim the plane manually because of the forces pushing down on the flaps, you put the plane into a breif decent to reduce the load. They didn't have the time or altitude to do that.
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That's not true either. You can always trim the aircraft with the trim wheels - that's what they're there for. What you can't do is trim back from high velocity and full trim, which no trained pilot would ever have allowed to happen in the first place.
 
scaramanga said:
I think you've got yourself a bit confused there.

The thumb trim always, always overrides all pilot "feel" systems - even MCAS. MCAS can (and will under fail conditions) kick in between thumb trim adjustments but never during.

With too much velocity and full trim, there's nothing that's going to save any aircraft. The motors operated by the thumb trim are too slow and, as you've pointed out, the pressure is too great to use the wheels. No pilot or FO with anything resembling a suitable level of training would ever let a system get that far out of trim.


That's not true either. You can always trim the aircraft with the trim wheels - that's what they're there for. What you can't do is trim back from high velocity and full trim, which no trained pilot would ever have allowed to happen in the first place.
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Trying to use semantics, nice try. But the fact is using the thumb trim is exactly what the pilots tried, MCAS overrode it. It is well documented.

Only way to override MCAS was to turn off all electronic trim systems and use the manual trim wheel.

As you’ve said there was nothing feasible the pilots could have done. I was thinking they could have tried a ‘hack’ - use the thumb control to adjust the trim then quickly turn off the electronics systems before MCAS overrode their input.

But without know what MACS was and how it works, with limited time and altitude to ply with, that was nye on impossible.

That your 737 pilot pal supposedly thought you could override MACS with the thumb control suggests it was not only ‘garbage airways’ that weren’t equipped to deal with a faulty sensor and MACS.


Sitting on my porcelain throne using glory-glory.co.uk mobile app
 
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SpurMeUp said:
Trying to use semantics, nice try. But the fact is using the thumb trim is exactly what the pilots tried, MCAS overrode it. It is well documented.
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I'm not sure what claims you've seen that the pilots were using thumb trim, because the flight data I've seen suggest that they only started trying that once the trim was heavily down (around 9 MCAS cycles).

SpurMeUp said:
Only way to override MCAS was to turn off all electronic trim systems and use the manual trim wheel.
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Again, I think you've misunderstood.

The only way to turn off MCAS was to turn off all electronic trim (which they should have done after the second MCAS cycle), but it could be overridden in every cycle with the thumb trim.


SpurMeUp said:
As you’ve said there was nothing feasible the pilots could have done. I was thinking they could have tried a ‘hack’ - use the thumb control to adjust the trim then quickly turn off the electronics systems before MCAS overrode their input.
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There's nothing they could have done once they'd let the aircraft get completely out of control, yes that's obviously the case. They had plenty of opportunity (as other pilots previously had) to stop it ever getting that far.


SpurMeUp said:
But without know what MACS was and how it works, with limited time and altitude to ply with, that was nye on impossible.
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They should have known what MCAS was, you're right. After Lion Air, Boeing put out an updated protocol that reinforced the existing measures to deal with runaway trim (again, standard procedure). Not much Boeing can do if the airline doesn't update manuals and the pilots don't take their time to learn them.

Even worse than that, the pilot didn't even need to know what MCAS was to know how to deal with it.

MCAS is runaway trim. Admittedly an unusual and specific form of runaway trim, but runaway trim it is. There's been a method of dealing with runaway trim in Boeings ever since automatic trim first started showing up decades ago - turn it off. That's how all other forms of runaway trim are dealt with, that's how MCAS is dealt with.

When training for a particular aircraft there are two types of routines or procedures a pilot learns - written and memory. Both come with a simple 3-6 step instruction card, but the memory ones are (unsurprisingly) supposed to be committed to memory. Runaway trim is a memory procedure. There isn't a (properly trained) 737 pilot in the world who cannot repeat that procedure by rote in about 3 seconds. They can do it with the roosterpit lights in failure state whilst being shaken around like the contents of a good roostertail.

Now, even before that diagnosis was made.....

The pilots had a stick shaker when the sensor failed. If you're still on ascent when a stick shaker happens (they were) then there are three things you absolutely must do, in the following order.
  1. Keep speed low (I'm guessing in a 737 that's around 50-60% thrust)
  2. Keep flaps down
  3. Radio the tower and return to where you left
Care to guess how many of those the EA pilots got right?

At low thrust, MCAS is revsersible.
With the flaps down, MCAS can't engage.

The EA pilots did neither of these things. Many have suggested it's part of the untrained pilot's need to get into autopilot territory as quickly as possible. I won't comment there but it wouldn't surprise me.

SpurMeUp said:
That your 737 pilot pal supposedly thought you could override MACS with the thumb control suggests it was not only ‘garbage airways’ that weren’t equipped to deal with a faulty sensor and MACS.

Sitting on my porcelain throne using glory-glory.co.uk mobile app
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I still don't think you understand. MCAS can only work between uses of thumb trim. Simply touching the thumb trim will disable that round of MCAS every time. So a pilot constantly using thumb trim (as all good pilots do) would never have let it get into that mess.

Your argument here is like claiming that a clutch can't stop an engine. You're right that it can't, but it can override the actions of the engine until you remember the really simple, long-standing instructions about how to turn off the engine.
 
Just have to look at the altitude graphs of both planes to see the pilots were constantly fighting MCAS. The pilot would trim the plane correctly to gain altitude. MCAS would kick in and dip the nose. The zigzag graph clearly shows this. With MCAS winning the battle.

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SpurMeUp said:
Just have to look at the altitude graphs of both planes to see the pilots were constantly fighting MCAS. The pilot would trim the plane correctly to gain altitude. MCAS would kick in and dip the nose. The zigzag graph clearly shows this. With MCAS winning the battle.

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That's not trim, that's using the stick.

MCAS is supposed to work against the stick, it's a stick feel component.
 
Boeing CEO now in the second day of grilling by the US Congress.
Lots of "new" information being revealed - All pretty damning !!!!
Doesn't look good for Boeing.
 
Kenyan Spur said:
Boeing CEO now in the second day of grilling by the US Congress.
Lots of "new" information being revealed - All pretty damning !!!!
Doesn't look good for Boeing.
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Interesting reading on it.

Looks more to me like yet more people who know nothing whatsoever about the airline industry asking someone who does a load of questions about his salary.
 
scaramanga said:
Interesting reading on it.

Looks more to me like yet more people who know nothing whatsoever about the airline industry asking someone who does a load of questions about his salary.
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Don't be selective.
Salary was ONLY one of the MANY questions.
He admitted that they had made GRAVE mistakes.
Congress doesn't spend 2 days on salary alone.
 
Kenyan Spur said:
Don't be selective.
Salary was ONLY one of the MANY questions.
He admitted that they had made GRAVE mistakes.
Congress doesn't spend 2 days on salary alone.
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Congress knows nothing about the airline industry. I wouldn't expect their questioning to be any more relevant or any less alarmist than that of the gutter press.
 
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