737 Max

Angle of attack has little to do with an inertial frame of reference. One will tell you the orientation of the plane, the other will tell you how the air if flowing over the plane. You have an image in your head of the air flowing over the wing in level flight. You don't need an AoA sensor at tha t point. The problem comes when the plane is not moving in exactly the dir ection the nose is pointed. The nose can be pointed up and the plane can b e moving down. Read about the Air Florida 90 accident. An internal refere nce unit won't tell you anything useful in that situation.

They have images of the AoA sensor online. The outside is a vane which piv ots with respect to the plane body. It has some sensor inside that measure s the angle the vane is turned with respect to the body of the plane which is what you want to know about airflow.

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Reply to
gnuarm.deletethisbit
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So are you doubling down? Buy me a case of Scotch as well? I'll settle for a bottle of Glenfiddich.

There may be an attitude sensor in the cockpit, but that is not the angle of attack (AoA). Two very different things.

I'm looking forward to the Glenfiddich. :)

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Reply to
gnuarm.deletethisbit

snipped-for-privacy@optonline.net wrote in news: snipped-for-privacy@googlegroups.com:

I guess you watched one news item and stopped.

They have already said that it was software.

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story.html

Reply to
DecadentLinuxUserNumeroUno

Here is an interesting paper by someone who knows more about safe avionics design than most of us:

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Reinhardt
Reply to
Reinhardt Behm

Nowhere in this article does anyone say, "it was software" or anything remotely like it.

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Reply to
gnuarm.deletethisbit

snipped-for-privacy@optonline.net wrote in news:7eadcada-282c-4b91-af75- snipped-for-privacy@googlegroups.com:

either

AOA?

You do not know perfectly well. You said "digital sensor". That decidedly shows that you do not know.

You didn't say "sensor with a digital output", putz guy.

And regardless of the transmission method to the computer, the transducer is ALWAYS an analog device. Even a MEMS chip is analog at the mechanism level.

An AOA sensor is a mechanical shaft position that gets sensed so most likely a very fine grade optical chopper wheel. A simple CAV optical disc would work perfectly, but it likely does not need such a fine rotationl position resolution. So analog, putz guy. It could very well send a digitized signal to the computer port it is attached to, however. It is still an analog device. The very meaning of the word transducer demands it.

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@optonline.net wrote in news: snipped-for-privacy@googlegroups.com:

Yes, they have said it.

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@optonline.net wrote in news:11d16472-3c90-4031-a745- snipped-for-privacy@googlegroups.com:

Do you?

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@optonline.net wrote in news: snipped-for-privacy@googlegroups.com:

Pilot license must be of the multiple engine variety and the applicable flight hours have to be on multi-engine craft.

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@gmail.com wrote in news:a991a241-ba97-46df-aa8b- snipped-for-privacy@googlegroups.com:

NOT 'sensor' ya dope... READOUT.

The sensors are elsewhere.

Reply to
DecadentLinuxUserNumeroUno

Reinhardt Behm wrote in news:q7s6uo$uug$ snipped-for-privacy@dont-email.me:

snip

Nice, but I do not agree with #12.

They are complex aircraft, and do and should require a pilot with specific training.

I see everyone banging Boeing on this, but nobody has mentioned the fact that we have never done anything against the two engine Brazilian prop airplane that has the worst record in the industry. And we use them here on short trip commuter flights every day.

There are, in fact, huge numbers of old planes that are falling apart, still out there running.

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

Right there in the title of the article, ya dope.

Reply to
DecadentLinuxUserNumeroUno

I know it won't have any impact on you, but I'll say it anyway. That is not what the title of the article says. It simply says they will update the software.

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Reply to
gnuarm.deletethisbit

I would not call lit a marketing gimmick. A gimmick is something that's a trick, a deception. In this case there was a very real benefit to keeping the 737 Max as close as possible to the existing fleet. It avoided training costs to the airlines, made it easier and safer for pilots to move back and forth between the existing fleet. And in any business, if you have a successful product, you typically don't want to make it different, which then opens the customer up to starting all over again, in which case many will look at other options and say that if they have to start all over,' might as well looks at all the alternatives.

Reply to
trader4

snipped-for-privacy@optonline.net wrote in news: snipped-for-privacy@googlegroups.com:

The Max 8 IS different than other 737s or other planes even.

What they should have done is left the plane in the pilot's control, and get him or her to learn the new craft.

They all differ. Instead of implementing a system which might be deemed wholly unfamiliar and confusing to a pilot (and apparently the computer), just let them learn how the new bird flies. Make sure that all pilots have familiarity with it from the right seat, and then the pilot's seat. No auto-fix needed, just pilot experience, and a smart AOA alarm to alert the pilot to trim down well before the numbers get bad. I have heard "pull up" "pull up" in movies, my sim software, in cockpits. So they can make an alarm that tells them to push the nose down.

Reply to
DecadentLinuxUserNumeroUno

On Sunday, March 31, 2019 at 1:57:43 PM UTC-4, snipped-for-privacy@columbus.rr.com wrote :

a disable switch *is* an acceptable way to mitigate the possibility of the MCAS malfunctioning. Ask the aviation industry. I'm pretty sure they hav e fairly similar rules across the globe or international air travel would b e very, very difficult.

But what is not acceptable is needlessly introducing a whole new method to cause severe runaway trim by a really, really bad MCAS design that relied on just one sensor, even when another sensor and other data were available. And a design that would not give up. And a design where if that AOA sensor is stuck, it's not checked by the software on the ground, instead it just suddenly pops up at one of the worst possible moments, following takeoff.

me

ng

t

oeing,

ure

crash took place is where the really scary stuff needs to be explored. Your points above do not even begin to go into how the plane was given the gree n light to fly after all the awfulness that you mention above.

They basically followed that what you are advocating is OK and made the sam e mistake Boeing made initially. They put too much faith in pilots being competent. Boeing figured that if the single AOA failed, it's just another runaway trim and though that is a very dangerous, hazardous event, pilots are trained for it and will identify it and follow the very simple, very logical procedure. That lead to the first crash. Then Boeing, FAA and similar the world over, figured that with all the publicity following LA and the urgent Boeing directive, now pilots will be aware and follow their existing training for runaway trim. What they needed to realize was that we've seen many cases where pilots can't handle an emergency and what should be a survivable incident, turns into a disaster. That's why you need a good design, that avoids all this to the extent possible. MCAS failed that test in many ways.

An interesting additional question:

How many incidents a year are there with runaway trim and what happened the re, how did the crew respond? I bet it's very low and also most probably didn't just appear on their own, eg it was probably a stuck trim switch, happened as the pilots were adjusti ng the trim, was only there briefly not constant, etc.

y for

ghts.

blem

es,

s good to go. If Boeing knew that 200 hours was not enough then they would have, at a minimum, recommended a minimum amount of simulator time for pil ots. Boeing wooed everyone into believing that these pilots were acceptable for this aircraft. You cannot have it both ways...namely that Boeing push es the MAX as an easy plane to fly (an exact flying experience to the 737) and then crap all over the pilots when the plane crashes because the pilots are no damn good.

Reply to
trader4

Boeing doesn't set the minimum qualifications for pilots around the world. The civilian aviation authorities do. In the USA the minium is 1500 and you;d be hard pressed to find a co-pilot in a passenger 737 or larger with just 1500 hours.

Nonsense. That's like saying that GM wooed everyone into believing that a for hire driver was acceptable. The ones that wooed people into believing those pilots were acceptable was that Indonesia and Ethiopian civil aviation authorities and the airlines.

Sure you can. Boeing doesn't set the standards for pilots, enforce them, train them, set the airline procedures, etc. Making a plane very similar to existing 737s doesn't change any of that.

Reply to
trader4

Well duh? Of course we care because we want to stop this extremely dangerous even from happening again! You can get on a plane without caring, I won't.

It seems unlikely that such a simple design would have multiple different failures, especially in brand new planes, but we don't know, because, shockingly nothing has been said, AFAIK, no inspections have been ordered, etc.

Reply to
trader4

But they could have repeated that process until the plane ran out of fuel or they correctly identified it as runaway trim and followed the simple procedure. The LA pilots flew for about 10 mins, until control was transferred to the co-pilot and he stopped doing trim up. I agree that this is an extremely dangerous situation, it's an unacceptable design and they initially only have a very short window to initially counter the down trim and in that period it's certainly possible to crash the plane in the initial confusion. We don't know the details of the other crash yet either.

That's certainly possible.

Reply to
trader4

ion at

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what

he software development process. It's like saying you have lost nothing if someone makes a copy of your book and shares it with a friend. It cost yo u nothing, right? Oh, but that ignores the many hours you spent writing do esn't it?

I understand perfectly well. If someone illegally copies your book, that's called "lost potential revenue", it's not part of the "cost" of the book. Basic accounting.

Reply to
trader4

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