China Eastern Airlines flight MU5735 737-800 Crash 17

[Eufalconimorph]

Avherald.

Reuters.

Dash cam footage showing crash angle.

Video of security camera video, straight on (angle of descent looks steeper than reality).

 

[Sym P. le]

In case it was missed, the Boeing 777 is fly-by-wire.

If opposing forces on the two columns pass a certain limit, the link between them is deactivated or "desynchronised" ...

They are not broken and the article does not discuss whom control is passed to.

I believe the 737 is not fly-by-wire (with the exception of spoilers on the MAX) so that is a significant difference between the two incidents (China and CDG).

 

[Alistair_Heaton]

The Boeing version of fbw is different to everyone else's.


They had this keep everything as it was before with the controls in front of you and both could be seen to move when the auto pilot was engaged or other pilot was moving them.

Control disconnects have been a certification requirement since 80's I think on old school direct wire to surfaces. There was a requirement for dual control runs to the flight surfaces. The yokes in the front each had there own set which was then link via a tooth clutch. A handle could be pulled which would separate them. 737 doesn't have them as its base certification is 1960's.

Side stick fbw are not linked but both sides gets pumped through 3 or 4 flight controllers or directly to the actuators in direct mode. If you both waggle the stick an extremely loud "dual input" aural warning sounds on A220. Would have thought there should be a caution if this disconnect feature triggered.

The nose attitude is more to do with aircraft speed. So nose pitch up is to go slower. You want to descend you take the power off and increase drag. Going faster does increase drag but then you start getting the aircraft out of its stabilization energy slot. Personally I would ask for more track miles.

In any case in modern day western procedures it's one person flying on the controls.

There is history with AF on this subject and it seems they haven't fixed the culture since the last crash.

And 737 does not have fbw. Which is the whole reason why they used MCAS to sort out there flight dynamics issues when the max was produced. To note the Chinese aircraft is not a max it's a 737-800 new generation model.

 

some here would just like to disparage Boeing, regardless of facts.

Boeing does more than enough to disparage itself.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[1503-44]

Exactly. If they didn't, neither would I. I've always been a great believer in Boeing products, but they have left me disillusioned to the point of nonbelief when they misused my trust and I no longer wear my Boeing cap, which I did quite regularly before their max-fiasco. I also happen to believe that commercial airliners should not need software to keep them within stable flight envelopes during totally normal maneuvers by use of software. Call me crazy. I don't care.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[LionelHutz]

I also happen to believe that commercial airliners should not need software to keep them within stable flight envelopes during totally normal maneuvers by use of software.

You're just choosing to ignore what the computers of all fly by wire planes do?

 

[TugboatEng]

Fly by wire has benefits and can prevent an incident like this:

https://youtu.be/alpGMjCZ83Y

 

[1503-44]

No. There is a difference. Fly by wire means control input forces are amplified and transmitted to control surfaces by hydraulic/electric actuators, rather than a pilot arm wrestling the controls, much the same way as my car has hydraulic steering. However my car does not need hydraulic steering to stay within its primary operating envelop. Without hydraulic steering, my car will not make a self-initiated 90° left hand turn and run off the road. It does not need a software package to keep it from doing stupid things. It has been a long accepted design principle that aircraft "fly themselves", Taking your hand off the stick during a 15° banked turn from straight and level flight will in effect cause a self-return to straight and level flight. I.e. Removing control input results in stable flight. I accept departure from that principle only for designated aerobatic, military and other aircraft clearly marked "experimental". Basically I want a PIC flying my airplane, as independently as possible of some nurd tallying votes trying to override him at any given opportunity to do so. We aren't at that point where I'm ready to relinquish what little control of my life I have not already given up to some MBA watching CNBC more than his assembly line.

FBW can't do a thing for helicopters, unless the wires are holding the pieces together.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[Alistair_Heaton]

You do get fbw for helicopter's. But similar to fixedwing most of its job is imposing limitations of control inputs so the aircraft remains inside the controlled flight envelope and airframe load envelop.

Fbw low level is just a method of getting the pilots control inputs to the flight surfaces.

Second level up is envelope protection high speed and low.

Third is load protection.

Fourth is input method which is what Airbus does with its flight path adjustment logic so you set an angle and then don't touch it and it will maintain it.

The forth has gone out of fashion and I can't see any more new aircraft types using it. Airbus will stick with it but I suspect they will have a revamp of its logic eventually. The lack of control feedback to the pilot is a known issue.

Both emb and BOM fbw systems are third level and my experience on the a220 is its very good. It feels and operates just like a Cessna 150 and when it down grades the plane control method doesn't change. A320 the aircraft changes from flight path back to pitch when it down grades. Which isn't a good idea if things get aerobatic and muscle memory plays a large part of pilot responses.

 

[Alistair_Heaton]

Oh I believe fbw can be used to normalize control inputs to give a linear response as per normal in modern certification standards.

So in the max case in that part of the envelope the gain would follow a curve so the control feel would be the same as normal. This would have meant no messing about with the trim to create an artificial control load.

 

[1503-44]

Thanks Alistair. Actually it's the last bit that upsets me the most. "some MBA watching CNBC more than his assembly line."

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[Alistair_Heaton]

It's worse than that... They are watching fox

 

[1503-44]

Ha Ha Ha. You're gonna catch flak when they wake up over there.
But you're right. Fox fans were complaining about both selling oil from SPR and the high cost of gas at the same time last week. I told them to relax, the SPR bought it for 20 and was selling at 95, making money, reducing the cost at the pump and beating up the speculators all at the same time. Duh. They'd at least know that, if they watched anything else. They moved on to Hunter's laptop being seen in the posession of bigfoot on some DC tourist bus.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[Alistair_Heaton]

Boeing is not the engineering company that everyone quite rightly is proud of.

Boeing now is just the name of MacDonald Douglas which always did have the reputation of issues.

 

[1503-44]

Great MBA stock tactic. Buy the brand, then trash it for everything its worth.
10 years to extract max value then sell off the remains.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[TugboatEng]

1503, in that helicopter video the pilot made a control input that exceeded the envelope of the aircraft which caused the main rotor to strike the tail mast, severing it. FBW could have prevented such an input.

 

[1503-44]

Personally I'd rather have a better pilot. One that knows the limitations of his aircraft, or knows what the green, yellow and a red line on the airspeed indicator mean.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[Alistair_Heaton]

I think it was a Robinson r22.

There is something funny about the rotorhead.

Think it's called a teetering rotor head. They get a thing called mastbumping.

I am not going to even pretend to be knowledgeable about it. Mechanical Palm trees are death traps. Basically from the moment the start button is pressed the pilot has to stop them from spontaneously crashing.

There is a huge amount of opinion and comment about r22's best to Google it yourselves. If they put a fbw system on a r22 there wouldn't be enough performance to get it off the ground.

 

[verymadmac]

FBW may have not prevented that Robinson accident, envelope exceedance can be achieved by failing to slow down for turbulence (seems to be not uncommon issue).

The fundamental issue with Robinsons seems to be its a cheap helicopter, brought by cheap operators who then like to fly them like they have the margins of expensive helicopters.

 

[1503-44]

With emphasis on the later.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[Alistair_Heaton]

They are the base training machine in many organisations.

They are extremely limited. And I wouldn't say cheap although they are cheaper than the rest.

It's also a petrol piston engine.

Compared to fixedwing and say a Piper tomahawk pa38. The r22s safe operating envelope is a postage stamp on the pa38's envelope. And the pa38 official envelop is folded in half of what you can get away with and survive. R22 if you take a 2 ltr bottle of water along and camera bag it can bite your bum.

Training it's the norm to have a relatively inexperienced pilot teaching a student. It's the same with fixed wing. I was the same 200 hours teaching a lady called Joan on my first paid job as a pilot. And to be honest just as I was useful and borderline competent 900 hours 1 year later I went off to fly airlines and another 200 hour instructor took over.