Ethiopian ET302 Crash.

[4WD]

Garuda Indonesia dumped a big order today

 

[PimTac]

Originally Posted by madRiver
Apparently the Boeing 737 MAX for Lion Air and Ethiopian Air lacked an extra cost option safety features(an angle of attack indicator and a disagree light) to warning of the system failures.

So now kindly Boeing corporation is going to offer these features for "free" in software and retrofit.




Just for those two airlines? It sounds like a option they decided not to get.

 

[Brigadier]

Originally Posted by 4WD
Garuda Indonesia dumped a big order today



Stupid is as stupid does. If you are an all Boeing fleet, and you dump more 737's and choose ScareBus, that is going to cost a bunch-o-money to get everything airworthy.

Planes, training, special equipment, spare and replacement parts, inventorying two different systems......good grief. Someone made a bonehead decision.

And Garuda is an economy airline - their profit margins are razor thin.

 

[Brigadier]

Originally Posted by ZeeOSix
This video is from a 737 MAX pilot and was made last November after the Lion Air crash. He talks about MCAS and what he says in this video sounds pretty spot on to what's happened in both of these crashes from what we know so far.

One thing he said is that the yoke force bias also changes when the aircraft thinks there is a stall condition to help the pilot take control in a stall condition. The yoke becomes easier to push forward (nose down) and harder to pull back (nose up). So it sounds like when the pilots were fighting against MCAS and trying to pull the nose back up, the yoke would have actually become more resistant in a pull back direction which is opposite what you'd want in the case when fighting a faulty MCAS control system that's continually trying to put the nose down.



So, you reach down and hit the switch to off........training.

 

[Astro14]

Originally Posted by PimTac
Originally Posted by madRiver
Apparently the Boeing 737 MAX for Lion Air and Ethiopian Air lacked an extra cost option safety features(an angle of attack indicator and a disagree light) to warning of the system failures.

So now kindly Boeing corporation is going to offer these features for "free" in software and retrofit.




Just for those two airlines? It sounds like a option they decided not to get.


My understanding is that MOST airlines did not elect to pay for that optional data to be displayed.

Most airline pilots are not used to AOA.

Those of us who flew fighters in the Navy love AOA. It was our life blood in ACM and in carrier landings.

If it's available, I think it should be installed and trained.

But training = $$$, and the people buying airplanes are looking at cost. IF an option costs more money, and it costs additional money in training, then why would they buy it?

 

[PimTac]

Originally Posted by Brigadier
Originally Posted by 4WD
Garuda Indonesia dumped a big order today



Stupid is as stupid does. If you are an all Boeing fleet, and you dump more 737's and choose ScareBus, that is going to cost a bunch-o-money to get everything airworthy.

Planes, training, special equipment, spare and replacement parts, inventorying two different systems......good grief. Someone made a bonehead decision.

And Garuda is an economy airline - their profit margins are razor thin.





Garuda is backed by the Indonesian government.

 

[BusyLittleShop]

Originally Posted by Astro14


If you can ride a moped, you're ready for SuperBike or MotoGP racing. The basics of riding are the same, right?

Not much different, really.... Moped, and race bike? You can ride a moped on a quiet street, it's just like being in a race at 180 MPH on a 200 HP machine...


I learned the basics on a Honda S90 and 43 years later I'm carving an accurate line on the perverted highway on a Honda
Superbike... key word accurate...

1966 Honda S90

Honda RC45

 

[MolaKule]

Here I am not absolving anyone but Boeing is not the only Aircraft manf. with Automation problems:

Quantas Flight 72 and Kevin Sullivan

Article:

Article[ on A330/url]

 

[Number_35]

This statement from Boeing appeared in our local newspaper this morning. Sorry about the poor resolution; I saved it from the e-edition of the paper, and that's how it was. It's too big to scan in one piece.

 

[Wolf359]

Originally Posted by madRiver
Apparently the Boeing 737 MAX for Lion Air and Ethiopian Air lacked an extra cost option safety features(an angle of attack indicator and a disagree light) to warning of the system failures.

So now kindly Boeing corporation is going to offer these features for "free" in software and retrofit.


According to various articles, it's only the disagree light that's going to be free. The AOA indicator will still cost extra. I guess the 3 US airlines have a mix of them.

https://www.nytimes.com/2019/03/21/business/boeing-safety-features-charge.html

(Open in incognito window if you're reached the limit of your free articles. You can always just open a new incognito window when you're out of free articles.)

 

[ZeeOSix]

Originally Posted by Brigadier
So, you reach down and hit the switch to off........training.


Obviously, but there are many other factors involved in these two crash incidents - as Astro14 said earlier, every crash scenario is kind of perfect storm where multiple factors all have to happen to result in disaster. I'm sure every pilot in the world understands by now that turning off automatic flight control systems is something they should do ASAP and start flying manually if the airplane starts crazy flight gyrations for no apparent reason.

 

[ZeeOSix]

Originally Posted by Astro14
Most airline pilots are not used to AOA.


AOA and airspeed are two very important parameter of flight dynamics ... why in the world would airline pilots not use AOA information? If you could only have two parameters to use to fly an airplane it would be airspeed and AOA.

 

[Astro14]

Originally Posted by ZeeOSix
Originally Posted by Astro14
Most airline pilots are not used to AOA.


AOA and airspeed are two very important parameter of flight dynamics ... why in the world would airline pilots not use AOA information? If you could only have two parameters to use to fly an airplane it would be airspeed and AOA.


There weren't any airliners that were instrumented for AOA presentation until recently. Sure, stall warning existed, but not regular AOA, all the time in the form of a gauge.

So, if it's not made available, then it's not trained or flown that way.

New airplanes, with HUDs and integrated EFIS displays have the ability to display the AOA all the time, and some operators choose to do so, but most don't, for cost/simplicity reasons.

I would say that you could fly an airplane, in VFR, with a compass, AOA, and altimeter, if you knew how to fly.

But, I would argue that in normal flight, if I have AOA, then I could do without airspeed, and vice-versa.

 

[thescreensavers]

Same pilot linked previously, talks about stopping MCAS


https://youtu.be/xixM_cwSLcQ

 

[oil_film_movies]

Originally Posted by MolaKule
So are you saying the partial differential equations used in those Transfer Functions do not take into account any non-linear behavior?
Looking at your previous post showing the image with the "Airplane Transfer Functions" block:
That block is NOT what the autopilot and/or stability augmentation on-oboard computers implement. That block is derived from the physics of flight, the EOM (Equations of Motion), used when doing analytical simulations in control systems development. Those are linear ordinary (not partial) differential equations expressed in laplace transform terms. No non-linear stuff in those transfer functions.

Transfer functions implemented inside avionics (flight control computers) are usually designed as Laplace transfer functions and run as converted z-transforms since its all digital computing these days (since about 1980). .... Inside flight control computers, a few linear transfer functions reside alongside many non-linear elements to make up the total autopilot, actuation, and stability augmentation algorithms implemented in software.

 

[oil_film_movies]

As long as an airline pilot is flying to the right airspeed targets in the phase of flight they are in, they don't absolutely need to know current AoA.
I do like to cross check what the AoA is for a given airspeed target to make sure the weight calculations match reality though! For a lighter aircraft (partial fuel, few passengers), you can fly slower and still have enough AoA stall margin, for example.

Originally Posted by ZeeOSix
Originally Posted by Astro14
Most airline pilots are not used to AOA.
AOA and airspeed are two very important parameter of flight dynamics ... why in the world would airline pilots not use AOA information? If you could only have two parameters to use to fly an airplane it would be airspeed and AOA.
Stall AoA is important, not values of AoA less than that. I don't care if AoA is 5 degrees or 10 degrees, for example, if stall AoA is up there at 20 degrees for my current wing configuration.

The key is how airspeed and AoA is used when flying an airliner.
AoA changes more quickly than airspeed, and pilots respect the maximum AoA at or near stall, information used to warn them to pitch the nose down to avoid stall.
Airspeed changes more slowly. With fixed throttles, airspeed is controlled with pitch. When holding an altitude (or targeting a vertical ascent/descent rate) with pitch, airspeed is controlled by slow throttle movements.
Stall limit AoA is put on some PFDs in the form of a 'Pitch Limit Indicator' to help some pilots avoid stall. Not on that many aircraft though.

 

[oil_film_movies]

http://www.boeing.com/commercial/aeromagazine/aero_12/attack_story.html

Heard a report in the media that the planned change is simply to kill (disable) MCAS pitch trim when the 2 AoA vanes disagree too much, for too long.
Probably something like 2 seconds worth of AoA disagreeing by +/-2 degrees would be signs of trouble enough to kill MCAS.

Of course, then you wouldn't have the stall-prevention MCAS in manual flight when AoA's disagreed. ... Could be they think AoA disagree is rare enough to accept the slightly increased risk of stall due to the larger, more forward engines. When AoA disagrees happen, a pilot should be able to avoid stall by pitching down a little harder to overcome the stall tendency at those high alphas. And that's if the pilot lets airspeed go down enough in the first place to even need to pitch down hard. Should be fine.
I might have chosen to use "inertial alpha" which is pitch angle minus flight path angle, predicated on healthy airspeed pitot-static sensors & pitch angle signals at the time of usage which is easily detected as usual. ... Pick the mid-value of the three AoA sources (2 vanes & inertial alpha) and use it to run MCAS pitch triim.

 

[ZeeOSix]

Originally Posted by oil_film_movies
Originally Posted by ZeeOSix
Originally Posted by Astro14
Most airline pilots are not used to AOA.
AOA and airspeed are two very important parameter of flight dynamics ... why in the world would airline pilots not use AOA information? If you could only have two parameters to use to fly an airplane it would be airspeed and AOA.
Stall AoA is important, not values of AoA less than that. I don't care if AoA is 5 degrees or 10 degrees, for example, if stall AoA is up there at 20 degrees for my current wing configuration.

The key is how airspeed and AoA is used when flying an airliner.


Originally Posted by oil_film_movies
http://www.boeing.com/commercial/aeromagazine/aero_12/attack_story.html


Like I said ... and the Boeing article mentions: "AOA is one of the most important parameters for understanding airplane performance and handling."

And yes, every airplane has it's own flight dynamics envelope defined by the airplane design with respect to airspeed, AoA, gross weight and weight distribution. How did pilots ever fly airplanes before they became automated? [rhetorical]. And obviously the stall speed as a function of all those parameters is what defines the maximum safe flight dynamics envelope of any airplane.

I can certainly see how the flight dynamics envelope has become heavily automated by computer controlled flight systems as airplanes have become larger and more complicated. But I'd assume part of any airline pilot's flight simulator training is how to fly the plane totally manually with basic flight information like airspeed, AoA and altitude if all automated flight systems are lost or need to be shut off for some reason.

 

[ZeeOSix]

Originally Posted by thescreensavers
Same pilot linked previously, talks about stopping MCAS

https://youtu.be/xixM_cwSLcQ


That's a good video ... this guy seems like a very good pilot, and is very knowledgeable on how all the systems work on the 787 MAX. A pilot well in tune with the aircraft.

Obviously the key to saving any kind of runaway situation is to be able to identify things are not acting normally and to start down a recovery procedure in logical order like they showed in the simulator.

One thing I have not heard or read yet on these two 787 MAX crashes is what position the automatic STAB TRIM cut-off switches were found to be in - or if the black box recorded their position. It's possible that the pilots turned the STAB TRIM system off, but if it's done way too late in the recovery process they still might not have gained enough manual control to prevent a crash ... especially if their altitude didn't allow enough time to react in a proper manner.

 

[oil_film_movies]

Originally Posted by ZeeOSix
.. why in the world would airline pilots not use AOA information?
Originally Posted by ZeeOSix
Like I said ... and the Boeing article mentions: "AOA is one of the most important parameters for understanding airplane performance and handling."
You asked why don't pilots use AoA. ...Again, it's not important for airline pilots to monitor AoA values below stall AoA when manually flying. They respect Stall AoA, not the AoA state variable, by flying fast enough, as was said above. Airmanship skills are tracking the right airspeed within reasonable pitch angles to avoid stall as Rule Number One. Pilots of course do that while controlling vertical speed (ascent/descent) or positioning an aircraft's velocity vector as needed. .... Basically, if you're going fast enough, you won't stall and you don't think about AoA much.

Originally Posted by ZeeOSix
I can certainly see how the flight dynamics envelope has become heavily automated by computer controlled flight systems as airplanes have become larger and more complicated.
That's been the Airbus approach since the 1980's, not Boeing's, who runs stick shaker to warn of stall on all their planes. ... The 737 Max8/9 uniquely also nudges the nose down using autotrim... . Boeing has not had automatic stall avoidance in manual flight until this new MCAS system was there on a Max8 on May 22, 2017, very lately. .. Airbus aircraft since 1988 have kept the pilots from stalling by pitching down automatically, while Boeing has just warned traditionally til this particular model.