OT 737 Max Really interesting

Loading thread data ...

Yes why? What who where? Brian

Reply to
Brian Gaff

Oddly enough there aren't any Brian.

Difficult to believe is it not?

Anyway, an interesting clip and it's difficult to believe how in such a safety oriented industry a software fix like that should get through.

You would also expect multiple fail scenarios to be tested for on transducers, possibly the weakest link in any control system.

AB

Reply to
Archibald Tarquin Blenkinsopp

As they fitted much larger engines the CofG moved non optimally forward. The SW fix was meant to compensate. The new design is flawed. I'm guessing it will have lower efficiency as well being way out of balance. The A320 was built from the ground up so will always be the superior plane.

Reply to
Andy Bennet

I wasted 5 minutes of my time watching this video, which said absolutely nothing that hasn't been in the newspapers in recent weeks. It totally failed to raise important issues such as:

  • The FAA has pretty much abandoned inspecting planes itself, relying on self-certification by the manufacturers. That's working out well isn't it?
  • It seems amazing that a single sensor failure could be allowed to cause a plane crash and that not a single engineer at Boeing thought about this. Someone working there *must* have noticed but, presumably, the company squashed their concerns.
  • The Boeing response is, apparently, to wire both sensors (there have always been two) to both flight-control computers, so that if they disagree a warning light comes on (plus some other minor software changes to make it slightly easier to disengage the MCAS). This seems wholly inadequate to me. Surely such sensors should be at least triplicated so that if one sensor disagrees with the majority then the computers will be able to work out which ones are accurate?
  • These failures have some similarities to the crash of AF447 in the Atlantic off Brazil a few years ago, except in this case it was the pitot tubes which failed. Here there were two of them, but both of them iced up and therefore failed around the same time, so even a duplicated sensor system was no help. There are other ways of estimating airspeed without pitot tubes but the manufacturers didn't bother to program them in - their solution to the problem was for the autopilot to refuse to work, on the assumption that all pilots are competent to take over in emergency. The relevance of this to self-driving cars must also be obvious to most people, since they are, apparently, also being programmed to simply give up and hand over to a human when they encounter a situation that they can't handle, even if that human has just been woken up from deep sleep.

So, Harry, what in particular made you think that this trivial and superficial video would be interesting to this group?

Reply to
Clive Page

But harry likes the pretty pictures ...

Reply to
Andy Burns

Not that I'm normally interested in the rubbish harry posts, I find it sums up the position that certainly wasn't covered in the stories I read.

The keen competition with Airbus for one.

The push to get things through before a proper engineering test and appraisal is common in all industries, they do compensate for a lack of Engineering standards with reams and reams of useless paperwork though : -)

I did think that the aircraft industry was immune, with multiple fail scenarios being tested. Hence the ban on mobile use and certain electronic items on aircraft.

Boeing policing itself was covered all right, but I think the video puts things neatly into perspective.

Nothing like a bit of light touch regulation to advance industrial progress what?

At least post Brexit Airbus can have full access to a country where they can compete on a level playing field.

AB

Reply to
Archibald Tarquin Blenkinsopp

What does it say?

Reply to
Pamela

It isn't so much what it say's!

It's the complete lack of racist filth that makes the post fairly unique.

I guess harry found his medication.

AB

Reply to
Archibald Tarquin Blenkinsopp

<q>

This is an airplane engine.

00:05 It's sitting in a field in Bishoftu, Ethiopia? part of the wreckage of Ethiopian Airlines 00:09 Flight 302, which crashed on March 10, 2019. 00:13 157 people died. 00:16 This was just a few months after another flight, Lion Air 610, crashed in Indonesia and killed 189 people. 00:24 These two flights were operating the same plane: The Boeing 737 MAX 8. 00:30 And its engine is the key to understanding why this particular plane 00:33 has caused so many problems. 00:36 But there's nothing actually wrong with this engine. 00:39 In fact, airplane manufacturers raced to put them on their new planes. 00:43 That's where the problem started. 00:51 The two biggest airplane manufacturers in the world are Airbus and Boeing. 00:54 And they have a fierce rivalry. 00:56 If one of them can offer a better plane, the other could lose a lot of money. 01:01 That's exactly what was about to happen in 2010. 01:04 Airbus announced that they would update their most popular model, the A320, a single-aisle 01:09 airplane that services many domestic flights. 01:11 You've probably been on one. 01:15 For this new plane, Airbus had a big update. 01:17 It would have a new kind of engine. 01:20 It was much larger than the previous engine, 01:22 but it would make the plane 15 percent more fuel efficient. 01:25 And just as importantly, this upgrade wouldn't change the plane that much. 01:29 A pilot could walk into the new model, with little additional training, and be on their way. 01:35 It was called the A320 NEO, and it would save airlines a lot of money. 01:40 This was a problem for Boeing. 01:43 To compete with Airbus, Boeing's obvious move was to upgrade the engine on their single-aisle 01:48 plane, the 737. 01:49 But there was one issue. 01:51 Here's a sketch of the 737 next to the Airbus A320. 01:56 Notice how the 737 is lower to the ground than the A320. 02:00 This meant Airbus could slide a new engine under the wing of their A320. 02:05 But there wasn't enough room under the wing of the Boeing 737. 02:09 But a few months later, Boeing's product development head had big news. 02:14 He said: "We figured out a way to get a big enough engine under the wing." 02:20 Their solution was to move up the engine on the wing, so that it would be slightly higher 02:25 and it would fit on their 737s. 02:28 Here's a promotional video of that updated 737 in the air. 02:31 You can actually see that the top of the engine is above the wing. 02:35 Boeing called this model the 737 MAX. 02:39 And just like Airbus with the A320, Boeing said their new plane was so similar to its 02:44 predecessor that pilots would only need minimal additional training. 02:49 The 737 MAX became the hottest selling plane on the market. 02:54 And it helped Boeing keep up with AirBus. 02:57 Except, moving the engine up on the 737 had a side effect. 03:02 When the 737 MAX was in full thrust, like during takeoff, the nose tended to point too 03:07 far upward, which could lead to a stall. 03:10 This was a problem, because these planes were supposed to behave exactly like the old ones. 03:15 So Boeing came up with a workaround. 03:17 Instead of re-engineering the plane, they installed software that automatically pushed 03:22 the nose downward if the pilot flew the plane at too high of an angle. 03:26 They called it the Maneuvering Characteristics Augmentation System, or MCAS. 03:33 But because Boeing was selling the 737 MAX as pretty much the same plane as the 737, 03:39 they didn't highlight the new MCAS system. 03:42 Many pilots only got a two-hour iPad course before entering the cockpit for the first time. 03:47 And the "training material did not mention" the MCAS software. 03:52 In 2018, several American pilots complained to the federal government that the 737 MAX 03:57 was "suddenly nosing down." 04:01 On October 29, 2018, Lion Air Flight 610 took off from Jakarta. 04:08 In the flight report, which shows the plane's altitude over time, you can see that the plane 04:12 was in full thrust during takeoff. 04:15 But at a certain point, the nose of the plane kept lurching downward. 04:20 The pilots couldn't figure out why this was happening. 04:23 The captain "asked the first officer to check the quick reference handbook." 04:26 They couldn't find the solution. 04:28 The pilots continued to fight with the MCAS. 04:31 The plane struggled to gain altitude. 04:34 Reports show it was likely because the computer was getting incorrect sensor data, pushing 04:38 the plane toward the earth below. 04:41 12 minutes after takeoff, the plane crashed into the Java Sea. 04:51 In the Ethiopia crash, the report shows that the pilots were actually able to disable the 04:55 MCAS, but it was too late to overcome the malfunctioning MCAS sensors. 05:00 For now, nearly every 737 MAX 8 in service has been grounded. 05:06 And the Federal Aviation Administration is facing scrutiny over how they rushed this 05:09 plane through certification. 05:12 Boeing's response has been to apply a software update and make the MCAS "less aggressive," 05:16 while also saying they'll increase pilot training on how to turn it off. 05:22 This problem started with a company's race to compete with its rival. 05:28 It pushed them to pretend like their new plane behaved exactly like their old one. 05:34 Even when it didn't. </q>

Or, you could just click the link and watch the video.

Reply to
Richard

Moving the CofG forward would cause the nose to dip rather than to rise leading to a stall. However if the centre of forward thrust is below the centre of drag then use of more powerful engines on full power would cause the nose to rise more than before. I think it was that that MCAS was intended to stop.

Reply to
Michael Chare

I don't have time to watch through some random video without knowing the purpose.

Your transcript says the FFA misguidedly left testing to Boing who are not a neutral party but we knew that weeks ago.

Reply to
Pamela

Actually I was poking fun at Harries eternal tendency to put no explanitory text whatsoever on his links. I still don't know what is on the end of the link since I do not click them without some knowledge that for a start it has sound and is safe. Brian

Reply to
Brian Gaff

Well I have now viewed it and it says nothing not already reported widely does it. I guess as we hear all too often it takes people to be killed for 'lessons to be learned' Until the next time of course. Many many years ago there was a cartoon in Computer Shopper of a plane hurting toward the ground the pilot and co pilot having ejected with the caption saying. I told you those curly brackets were important. Brian

Reply to
Brian Gaff

Well, yes and no.

A forward C of G requires up trim to compensate which means power on nose up is the order of the day. However I dont think this was the issue. Thg issue was that the engines were angled up for ground clearance

However if the centre of forward thrust is below the

And the angled thrust line

Reply to
The Natural Philosopher

No it wasn?t. The A320 neo is identical in concept, the original A320 with new bigger engines. The difference is that it has longer legs so it fits in the same position on the wing without scraping on the ground.

formatting link

Reply to
Jac Brown

formatting link

shows two commercial pilots in a 737 simulator trying to cope with the situation both crews in the crashed aircraft faced and the manual effort required to try to overcome the two aircrafts ultimately successful attempt to destroy themselves. For once newspaper reports of "wrestling with the controls" appear to be much more accurate then normal.

Reply to
Peter Parry

Supposedly those two "stab trim" switches remove all electrical power from the jack screw, so would stop the plane from fighting ...

Reply to
Andy Burns

Not ANGLED up, mounted higher so that the top of the engine is actually above the top of the wing.

There is no angled thrust line.

Reply to
2987pl

Well then you'll never know will you, so stop whinging on.

Reply to
harry

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.