737 Max in the news again

[Hawkmoon]

https://www.msn.com/en-my/finance/topstories/boeing-knew-about-safety-alert-problem-for-a-year-before-telling-faa-airlines/ar-AAAWog6

It's either a good time to sell Boeing stock, or a good time to buy Boeing stock -- depending on how you view these things,

It's coming out that the fact there was no warning when the two angle of attack sensors in the 737 Max disagreed was not a feature after all -- it was a bug, It is slowly coming out that the system was supposed to give an alert in the cockpit if the two sensors disagreed (and, in fact, the previous generation of the 737s had a functional alert for that, as did whichever USAF tanker aircraft also has an MCAS system), but there was a software glitch that rendered the warning system non-functional. And Boeing knew it, but dragged their feet notifying the airlines ... and the FAA.

[Fly320s]

Whoops.

Wait a week and then buy stock.   

[Firethorn]

Too big to fail comes to mind, or at least "too unique of a capability".

We're seeing the old redundancy saying here - one is none, two is one.

If you're not going to be allowed to fail because then your competitor would have a monopoly, then the benefits of having "competition" is limited.

On the other hand, when it comes to extremely large projects like large passenger craft, it seems that having a lot of competition is difficult, because the global market for planes that large is just too limited to support a healthy amount of competition. 

[230RN]

Well, there's always DC-3s. 

[AZRedhawk44]

https://www.msn.com/en-my/finance/topstories/boeing-knew-about-safety-alert-problem-for-a-year-before-telling-faa-airlines/ar-AAAWog6

It's either a good time to sell Boeing stock, or a good time to buy Boeing stock -- depending on how you view these things,

It's coming out that the fact there was no warning when the two angle of attack sensors in the 737 Max disagreed was not a feature after all -- it was s bug, It is slowly coming out that the system was supposed to give an alert in the cockpit if the two sensors disagreed (and, in fact, the previous generation of the 737s had a functional alert for that, as did whichever USAF tanker aircraft also has an MCAS system), but there was a software glitch that rendered the warning system non-functional. And Boeing knew it, but dragged their feet notifying the airlines ... and the FAA.

Sounds like a feature that would benefit from a 3 sensor consensus system.

[Hawkmoon]

Well, there's always DC-3s. 

Probably my favorite airplane of all time.

A friend just sent me a link to a Youtube video. Believe it or not, there is still an active military unit operating DC-3s (they call 'em "Dakotas") on a regular basis.

https://www.youtube.com/watch?v=xjxOyyOU95c

[Hawkmoon]

Sounds like a feature that would benefit from a 3 sensor consensus system.

Or a string from the ceiling of the cockpit with a weight on the bottom end ...

[Fly320s]

Or a string from the ceiling of the cockpit with a weight on the bottom end ...

Not accurate under G-loading.

[Hawkmoon]

Yeah, I know. Like that famous stunt pilot who could pour a cup of tea while doing a barrel roll, and not spill a drop.

But probably no worse than the AoA sensors on the Ethiopian 737 ...


More to the point ... certainly a weighted string is "accurate" (within the limits of the technology  ) in level flight, where gravity is "down." When climbing out, if velocity is fairly constant, how much would g-forces affect it?

[makattak]

Probably my favorite airplane of all time.

A friend just sent me a link to a Youtube video. Believe it or not, there is still an active military unit operating DC-3s (they call 'em "Dakotas") on a regular basis.

https://www.youtube.com/watch?v=xjxOyyOU95c

There's also a company that refurbishes and updates DC-3s in Wisconsin. I watched a documentary on Curiosity Stream about it. Makes them even more STOL, faster, and fuel efficient, IIRC.

[Fly320s]

Yeah, I know. Like that famous stunt pilot who could pour a cup of tea while doing a barrel roll, and not spill a drop.

Bob Hoover.

The string is accurate in steady-state, 1G, right-side-up flight.  And that's all.  It still doesn't show angle of attack. 

[WLJ]

The string worked fine in all the tests on the ground. You must not be using it right.

[230RN]

Bob Hoover.

The string is accurate in steady-state, 1G, right-side-up flight.  And that's all.  It still doesn't show angle of attack.  

Ah b'leeves it would. Try it in a car going up or down hill at a constant speedometer reading.

Terry

[makattak]

There's also a company that refurbishes and updates DC-3s in Wisconsin. I watched a documentary on Curiosity Stream about it. Makes them even more STOL, faster, and fuel efficient, IIRC.

Quoting myself to provide the link to the company website:

https://www.baslerturbo.com

Not just refurbished, "remanufactured" so that the plane has zero accumulated fatigue.

[Fly320s]

Ah b'leeves it would. Try it in a car going up or down hill at a constant speedometer reading.

Terry

A car is following a fixed surface (plane).  An airplane does not.  The car maintains a stable attitude relative to the road; the wheel base is parallel to the road at all times.  A plane can and does slip and slide through the air, and does not maintain the same attitude all of the time.

A plane can have the wings parallel to the horizon and have anywhere from a 0 degree to a 90 degree (or more, really) angle of attack.  The zero degree angle of attack is when the leading edge of the wing is moving directly forward into the relative wind.  The 90 degree AoA is when the wing is moving straight down and the relative wind is hitting the bottom of the wing straight on.  Think of holding a toy plane in your hand with the wings parallel to the floor.  Now drop it straight down.  That is a 90 degree AoA.  And that is a stalled wing.

An airfoil can be stalled at any airspeed, attitude, and altitude.  The only thing that matters is AoA.

[Hawkmoon]

An airfoil can be stalled at any airspeed, attitude, and altitude.  The only thing that matters is AoA.

Airfoils aren't very good at shielding from cosmic radiation (or Russian EMF transmissions) anyway. You need tinfoil for that.

[Fly320s]

Airfoils aren't very good at shielding from cosmic radiation (or Russian EMF transmissions) anyway. You need tinfoil for that.

The Airbus is made of tinfoil.  So are my undies.  I'm safe.

[230RN]

I think I was confusing angle of attack versus angle of inclination of the aircraft.

Terry

[cordex]

I think I was confusing angle of attack versus angle of inclination of the aircraft.

Better you than Fly.

[WLJ]

Came across this
Somebody dropped the ball on this one
Fast forward to 35:50 or to 38:50 for a more to the point spot

https://www.youtube.com/watch?v=G2EbQuuIN3Y

Swissair Flight 111
https://en.wikipedia.org/wiki/Swissair_Flight_111

[Hawkmoon]

Came across this
Somebody dropped the ball on this one
Fast forward to 35:50 or to 38:50 for a more to the point spot

https://www.youtube.com/watch?v=G2EbQuuIN3Y

Swissair Flight 111
https://en.wikipedia.org/wiki/Swissair_Flight_111

I don't see the connection. What does a fire caused by a short circuit have to do with a faulty computer program affecting flight control systems?

[WLJ]

I don't see the connection. What does a fire caused by a short circuit have to do with a faulty computer program affecting flight control systems?

No connection other than it being an example of a known problem being ignored and people dying because of it. This time by the FAA

[Hawkmoon]

No connection other than it being an example of a known problem being ignored and people dying because of it. This time by the FAA

It's an unfortunate fact of life, and not only with respect to air travel. It's axiomatic that street intersections don't get traffic lights unless/until the body count exceeds "tolerable" numbers. Automobile problems don't result in recalls unless/until they start killing large numbers of people. Yada, yada.

[230RN]

Came across this
Somebody dropped the ball on this one
Fast forward to 35:50 or to 38:50 for a more to the point spot

https://www.youtube.com/watch?v=G2EbQuuIN3Y

Swissair Flight 111
https://en.wikipedia.org/wiki/Swissair_Flight_111

Once again, stuff happens but if (as has been said) there's no body count, fundamental problems may not be discovered in advance.

I'm reminded of the Apollo 1 fire which killed three Astronaurs...

 https://www.space.com/14379-apollo1-fire-space-capsule-safety-improvements.html

But when an electrical spark ignited a fire, flames and smoke swept through the capsule, and the crew was unable to escape. An investigation later was unable to pinpoint the exact initiation spot of the fire, but determined that the plethora of flammable materials (especially Velcro) and pure oxygen environment inside the capsule were partly to blame. (Bolding mine)

So metallized Mylar in WJL's exmple, Velcro (and IIRC, the abundance of aluminum or magnesium in the space capsule's stucture) in the Apollo 1 case, unlubricated jackscrews in the Air Alaska cases, un-warned conflict in angle-of-attack sensors in the 737 MAX cases, masking tape not removed from altitude sensors in another case...

( https://en.wikipedia.org/wiki/Aeroper%C3%BA_Flight_603 )

Boy, when Murphy gets busy... look out !

Terry

[Angel Eyes]

https://www.bloomberg.com/news/articles/2019-06-28/boeing-s-737-max-software-outsourced-to-9-an-hour-engineers

Increasingly, the iconic American planemaker and its subcontractors have relied on temporary workers making as little as $9 an hour to develop and test software, often from countries lacking a deep background in aerospace -- notably India.

Too bad Tallpine doesn't hang out here any more.