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Ed 737 Max Crashes (was Shutdown caused Boeing crash.)

And they're back in the air. (Or at least they are cleared to be. Sort of.)

From: BBC
US safety regulators have cleared Boeing's 737 Max plane to fly again...Existing aircraft will need to be modified before going back into service, with changes to their design. Safety regulator, the US Federal Aviation Administration (FAA), said the clearance would not allow the plane to "return immediately" to the skies. Alongside the software and wiring changes, pilots will also need training.
 
Segnosaur said:
And they're back in the air. (Or at least they are cleared to be. Sort of.)

From: BBC
US safety regulators have cleared Boeing's 737 Max plane to fly again...Existing aircraft will need to be modified before going back into service, with changes to their design. Safety regulator, the US Federal Aviation Administration (FAA), said the clearance would not allow the plane to "return immediately" to the skies. Alongside the software and wiring changes, pilots will also need training.
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Which is what they were trying to avoid.

The only thing that disturbs me about this is that there doesn't seem to be a lot of transparency about the details of the requirements for return to flight. All I can see to find is this;

- The optional cockpit AoA sensor alert is now standard on all aircraft
- An MCAS software update allows the pilot to regain control more easily
- MCAS AoA input compares data from both sensors.

This is not detailed enough for my liking. With the FAA and Boeing both responsible for the crashes and incidents, I'd like to see an entirely independent review of the process and changes. I don't trust the FAA yet, and I certainly do not trust Boeing.
 
smartcooky said:
And they're back in the air. (Or at least they are cleared to be. Sort of.)

From: BBC
US safety regulators have cleared Boeing's 737 Max plane to fly again......Alongside the software and wiring changes, pilots will also need training.
Click to expand...
Which is what they were trying to avoid.
Click to expand...
True. But I suspect some of that might be along the lines of "Its been over a year since you've been flying... you need to log at least a few hours in the cockpit before you can fly again".

And even if there is some additional skills they have to learn, it will still be easier to train a pilot how to handle the changes to the MCAS system rather than on how to handle all new flight characteristics of a new plane and/or how the plane handles without MCAS.
 
Segnosaur said:
True. But I suspect some of that might be along the lines of "Its been over a year since you've been flying... you need to log at least a few hours in the cockpit before you can fly again".

And even if there is some additional skills they have to learn, it will still be easier to train a pilot how to handle the changes to the MCAS system rather than on how to handle all new flight characteristics of a new plane and/or how the plane handles without MCAS.
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And immeasurably better that not telling them about MCAS at all!
 
Segnosaur said:
True. But I suspect some of that might be along the lines of "Its been over a year since you've been flying... you need to log at least a few hours in the cockpit before you can fly again".
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Uh, no. No pilots were grounded (ETA: At least not by 737 Max, Covid is another story).
 
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theprestige said:
And by "sort of" you mean "not actually back in the air at all".
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Nope. Some airlines might be able to get it back in service by the end of the year, although I think most are looking at early to mid 2021 before they actually start flying.

Of course, not only has boeing run into troubles over safety concerns with the 737, they are also dealing with an aviation industry that is dealing with Covid19.
 
Segnosaur said:
Nope. Some airlines might be able to get it back in service by the end of the year, although I think most are looking at early to mid 2021 before they actually start flying.

Of course, not only has boeing run into troubles over safety concerns with the 737, they are also dealing with an aviation industry that is dealing with Covid19.
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They also appear to have made a complete pig's breakfast of the aerospace side of the business. Starliner is months behind schedule thanks to software problems that makes me wonder if they ever run simulations. Both problems; the clock timer that caused the test flight to fail to reach the ISS, and the one that caused the valve mapping error which could have resulted in the service module running into crew capsule, would have been detected if they had run a complete launch to docking simulation.

And this brings me back to the software issues with the Max 8 - did they ever actually simulate an AoA sensor failure in the five critical phases of flight; take-off, take-off flight path (climb-out), final approach, missed approach, and landing?

Finally, there is this phrase.... "MCAS software update allows the pilot to regain control more easily". I remain very uncomfortable with the idea of flying passengers on an aircraft fitted with a flight computer that can take away control from the pilot without warning, and pitch the nose down (especially on climb-out and and final when airspeed and altitude is critically low) and with no way for the pilot to turn that system off and fly manually.
 
smartcooky said:
Which is what they were trying to avoid.

The only thing that disturbs me about this is that there doesn't seem to be a lot of transparency about the details of the requirements for return to flight. All I can see to find is this;

- The optional cockpit AoA sensor alert is now standard on all aircraft
- An MCAS software update allows the pilot to regain control more easily
- MCAS AoA input compares data from both sensors.

This is not detailed enough for my liking. With the FAA and Boeing both responsible for the crashes and incidents, I'd like to see an entirely independent review of the process and changes. I don't trust the FAA yet, and I certainly do not trust Boeing.
Click to expand...

Do you have any piloting experience? If not, on what do you base your opinion on? There is no negativity intended. Just curious.
 
Segnosaur said:
True. But I suspect some of that might be along the lines of "Its been over a year since you've been flying... you need to log at least a few hours in the cockpit before you can fly again".

And even if there is some additional skills they have to learn, it will still be easier to train a pilot how to handle the changes to the MCAS system rather than on how to handle all new flight characteristics of a new plane and/or how the plane handles without MCAS.
Click to expand...

RecoveringYuppy said:
Uh, no. No pilots were grounded (ETA: At least not by 737 Max, Covid is another story).
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To carry passengers in the USA, a pilot has to make 3 take offs and landings in an aircraft of the same category, class, and type in the last 90 days.

https://www.ecfr.gov/cgi-bin/text-i...mc=true&node=pt14.2.61&rgn=div5#se14.2.61_157
 
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mike81 said:
To carry passengers in the USA, a pilot has to make 3 take offs and landings in an aircraft of the same category, class, and type in the last 90 days.
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Read back through the conversation and think about the issue we are addressing here. One of Boeing's goals was to avoid considering this plane to be a different type. They wanted to get away with an amended type rather than an entirely new type certificate. That's what smartcooky was addressing, that Boeing has now failed to avoid the need for type training.

And besides, read what Segnosaur said: "Its been over a year since you've been flying..." No, it hasn't. (ETA: By Boeing's original goal for the 737 Max, pilots have been flying that type continuously for a long time now)

This training requirement is not what Segnosaur said, it's something more along the lines of what smartcooky is saying, a recognition that this plane is different enough to require specialized training of some kind. It is not that the pilots themselves are rusty.
 
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RecoveringYuppy said:
Read back through the conversation and think about the issue we are addressing here. One of Boeing's goals was to avoid considering this plane to be a different type. They wanted to get away with an amended type rather than an entirely new type certificate. That's what smartcooky was addressing, that Boeing has now failed to avoid the need for type training.

And besides, read what Segnosaur said: "Its been over a year since you've been flying..." No, it hasn't. (ETA: By Boeing's original goal for the 737 Max, pilots have been flying that type continuously for a long time now)

This training requirement is not what Segnosaur said, it's something more along the lines of what smartcooky is saying, a recognition that this plane is different enough to require specialized training of some kind. It is not that the pilots themselves are rusty.
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Indeed.

To review (for other readers) the Max 8 is aerodynamically different from previous 747 models. This difference is caused by the positioning of the engines further forwards and upwards*, the result of which is that under high power settings (especially during take off and climb-out), the aircraft has a tendency to pitch up. Such a situation would mean that pilots flying the previous 737 models would have to re-certify to fly the Max 8; a very expensive exercise involving training and an simulator time.

The whole rationale for MCAS in the first place was to make the Max 8 fly like other 737s, by using software to pitch the nose down on those situations mentioned above, so that the aircraft would respond identically, i.e. would have the same look and feel, thereby avoiding pilot re-certification, and allowing Boeing to offer airlines the Max 8 as a direct replacement/supplement for their existing 737 fleet.

Essentially, Boeing tried to cheapskate their way to making sales, and got burned... and 346 people paid for it with their lives.



* The reasons for this change in engine position is another fascinating story in itself.
 
smartcooky said:
Indeed.

To review (for other readers) the Max 8 is aerodynamically different from previous 747 models. This difference is caused by the positioning of the engines further forwards and upwards*, the result of which is that under high power settings (especially during take off and climb-out), the aircraft has a tendency to pitch up. Such a situation would mean that pilots flying the previous 737 models would have to re-certify to fly the Max 8; a very expensive exercise involving training and an simulator time.

The whole rationale for MCAS in the first place was to make the Max 8 fly like other 737s, by using software to pitch the nose down on those situations mentioned above, so that the aircraft would respond identically, i.e. would have the same look and feel, thereby avoiding pilot re-certification, and allowing Boeing to offer airlines the Max 8 as a direct replacement/supplement for their existing 737 fleet.

Essentially, Boeing tried to cheapskate their way to making sales, and got burned... and 346 people paid for it with their lives.



* The reasons for this change in engine position is another fascinating story in itself.
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And???? That's one of the first questions that came to mind, why move the engines? Surely there was a good (enough) reason to do so, right? Right?

And if they can get these things in the air again, who's going to want to ride in one.

Fun throughout but relevant at 3:05

Carlin, NSFW, obviously.
 
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Mike! said:
And???? That's one of the first questions that came to mind, why move the engines? Surely there was a good (enough) reason to do so, right? Right?
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I will gladly defer to anyone with more experience with aviation.

But, from what I understand, newer, more efficient engines tend to be wider/shorter than their older counterparts. (If you look at a picture of the earlier 737-100 and 200, the engines are narrower and longer, and go all the way under the wing.) The new engines simply wouldn't have enough ground clearance if they tried to mount them under the wings in the same configuration.

See: Wikipedia
 
Segnosaur said:
I will gladly defer to anyone with more experience with aviation.

But, from what I understand, newer, more efficient engines tend to be wider/shorter than their older counterparts. (If you look at a picture of the earlier 737-100 and 200, the engines are narrower and longer, and go all the way under the wing.) The new engines simply wouldn't have enough ground clearance if they tried to mount them under the wings in the same configuration.

See: Wikipedia
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Its called a high-bypass geared turbofan. As you say, the intakes are wider and deeper and there is simply no room to fit them under the wings of the 737. The gearing of the fan lowers the fan rotation speed, and that lower fan speed allows a higher bypass ratio, which in turn leads to reduced fuel consumption and less jet noise noise.

Here is a video about why the two Max 8's crashed, but I have queued up to a brief, 90 sec explanation of why the engines were moved up.

https://youtu.be/H2tuKiiznsY?t=103
 
Mike! said:
And???? That's one of the first questions that came to mind, why move the engines? Surely there was a good (enough) reason to do so, right? Right?

And if they can get these things in the air again, who's going to want to ride in one.

Fun throughout but relevant at 3:05

Carlin, NSFW, obviously.
Click to expand...

Segnosaur said:
I will gladly defer to anyone with more experience with aviation.

But, from what I understand, newer, more efficient engines tend to be wider/shorter than their older counterparts. (If you look at a picture of the earlier 737-100 and 200, the engines are narrower and longer, and go all the way under the wing.) The new engines simply wouldn't have enough ground clearance if they tried to mount them under the wings in the same configuration.

See: Wikipedia
Click to expand...

smartcooky said:
Its called a high-bypass geared turbofan. As you say, the intakes are wider and deeper and there is simply no room to fit them under the wings of the 737. The gearing of the fan lowers the fan rotation speed, and that lower fan speed allows a higher bypass ratio, which in turn leads to reduced fuel consumption and less jet noise noise.

Here is a video about why the two Max 8's crashed, but I have queued up to a brief, 90 sec explanation of why the engines were moved up.

https://youtu.be/H2tuKiiznsY?t=103
Click to expand...

Not geared, but GE's CFM's competitor for P&W's GTF, the LEAP-1B. Otherwise, basically correct. Higher bypass ratios lead to greater efficiency, but also to bigger fans. This has been a problem for Boeing since the 737-300, because the airplane sits so low to the ground. Hence the flattened bottom of the nacelle on the -300 through -900.
The LEAP was enough bigger that this was no longer enough, so the engine had to be moved forward to enable it to be moved up. Changing the flight characteristics of the airplane.
Raising the airplane wasn't practical because even as short as they are, the main landing gear "legs" bring the wheels almost completely together when retracted and even then the wheels don't make it completely into the wheel well. You can see the outboard tires protruding through (with an aero hubcap) when one flies over.
What's been needed for quite a long time is an actual replacement. Which I was working on there 15 years ago and still has not been able to make the "business case" work.
 
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Mike! said:
And if they can get these things in the air again, who's going to want to ride in one.[/SIZE]
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Almost NOBODY knows what kind of plane they are in. They might know if it's wide or narrow, or if they're in an A380, but that's it.
If the seat pocket placard says "Welcome aboard this Boeing 737-8" they'll be saying "Whew! Glad it's not a 737Max!"
 
Trebuchet said:
Not geared, but GE's CFM's competitor for P&W's GTF, the LEAP-1B. Otherwise, basically correct. Higher bypass ratios lead to greater efficiency, but also to bigger fans. This has been a problem for Boeing since the 737-300, because the airplane sits so low to the ground. Hence the flattened bottom of the nacelle on the -300 through -900.

The LEAP was enough bigger that this was no longer enough, so the engine had to be moved forward to enable it to be moved up. Changing the flight characteristics of the airplane.

Raising the airplane wasn't practical because even as short as they are, the main landing gear "legs" bring the wheels almost completely together when retracted and even then the wheels don't make it completely into the wheel well. You can see the outboard tires protruding through (with an aero hubcap) when one flies over.

What's been needed for quite a long time is an actual replacement. Which I was working on there 15 years ago and still has not been able to make the "business case" work.
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Not 100% sure about this, but I recall reading that even if it had been technically feasible, it would still have an enormous economic disadvantage in the marketplace. If the ground clearance changes, that plane would not be compatible with other 737 luggage loading equipment or require a unique protocol on existing equipment. Much like the training issue, the cost of the plane alone isn't the whole story on how good of a "deal" it is.
 
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