Air Asia Indonesia Lost Contact from Surabaya to Singapore

[CONF iture]

Originally Posted by NoD

How do you definitively define "it is stalled"? To a high enough degree of integrity you can remove pitch control from the pilot?

How do you suddenly bother about that ... ?
How do Airbus definitively define "it is going to stall" ? To a high enough degree of integrity Airbus can remove pitch control from the pilot ?

[auraflyer]

So if as I rotate on takeoff, the Stall warner erroneously sounds, the THS drives the aircraft into the ground

I was just putting the logical result of Ian W's suggestion into words as it is an interesting idea and I try to keep an open mind -- but I don't think the solution is more automation, hence why I put "controversially" and why I ended how I did.

I won't get into a fight, since you drive A320s and I don't, but AFAIK existing stick pusher logic includes an altitude minimum (e.g. Q400 only activates > 200 feet AGL), so there's no reason you would not implement equivalent logic *if* you were to do this.

[zzuf]

A stick pusher is a stall identifier, it is not a stall warning.
They are two different systems.

[ekw]

So lets say 2 in every 10 pilots are aces, 3 are average and 5 are dunces. Which group does automation help and which group would be less affected by more automation? The logic is simple surely?

[ASRAAM]

For those suggesting Stick pushers, or a mechanism to set a neutral tail plane at the stall consider this: To have arrived at that situation in the first place a failure has occurred, quite probably with one of the systems that would have been providing the information that the recovery system would be using!

In order for a recovery system to have any validity it would need aircraft data from a COMPLETELY independent source, actually SEVERAL independent sources.

Now, if you are going to do that why not just take those sources and use them to supply data to the original fly by wire so you don't stall in the first place.

[rideforever]

Isn't the real story here that airlines / manufacturers want to fully automate flight. Pilots and crew are seen as expensive.

And so Airbus has tried to start that process. It couldn't go all the way fully-automated because there would be huge resistance from passengers / crew / regulators, but it has implemented a beginning.

The Airbus system comes with a manual of how to use it, makes it sound so easy ... however if something goes wrong it is unclear how to resolve the situation because the system's many secrets are not made available and in an emergency you have seconds to understand what's going on under the hood.

Airbus does not want pilots to be able to switch the system off at will, because that would derail the business plan of full automation.

For the bean counters, it's just money. Lives lost though regrettable are just a matter of insurance.

Automation seems the trajectory of the economy ... unless something changes. And we are now in an intermediate phase were there is an inevitable dishonesty about what is occurring, because automation is being phased in semi-covertly.

If the pilots / crew make a fuss, or passengers / airlines are scared ... then it will slow things down. If new plane technologies come through that require pilots, it will slow things down. If pilots were seen once again as part of the experience, it will slow things down. If the world gets richer suddenly it will slow things down.

[Ian W]

Originally Posted by auraflyer

I was just putting the logical result of Ian W's suggestion into words as it is an interesting idea and I try to keep an open mind -- but I don't think the solution is more automation, hence why I put "controversially" and why I ended how I did.

I won't get into a fight, since you drive A320s and I don't, but AFAIK existing stick pusher logic includes an altitude minimum (e.g. Q400 only activates > 200 feet AGL), so there's no reason you would not implement equivalent logic *if* you were to do this.

I am glad to see that my suggestion triggered some discussion. If I were looking to design something along those lines I would expect to use AOA and probably a variable delay dependent on flight phase. A parameterized delay would prevent spurious warnings triggering trim changes. Although I note from other events that spurious warnings seem to trigger zoom climb in alternate law.

[The Banjo]

Stick pushers bla bla bla

The big picture is these complex machines are designed to be operated by appropriately recruited, educated, trained, current and competent crews who adhere to SOP's, FCOM, Air Nav regs etc etc etc

No amount of anything will safe guard the aircraft and innocent passengers from alleged utter stupidity.

[henry_crun]

Not a pilot, just an avionics guy, so tell me to go away if you wish.

I would suggest the use of totally separate, lane segregated, battery powered gps at the four corners of the airplane. Collectively they could report a dangerous rate of descent. Differentially they could detect inappropriate attitudes.

Gps accuracy is not good in airplane control terms, but it is definitely accurate enough to sense outrageous errors.

Why not?

[Gysbreght]

Originally Posted by henry crun

Collectively they could report a dangerous rate of descent. Differentially they could detect inappropriate attitudes.

More often than not the stall results from an inappropriate rate of climb, and the attitudes can be quite normal.

[TheInquisitor]

Isn't the real story here that airlines / manufacturers want to fully automate flight. Pilots and crew are seen as expensive.

And so Airbus has tried to start that process. It couldn't go all the way fully-automated because there would be huge resistance from passengers / crew / regulators, but it has implemented a beginning.

The Airbus system comes with a manual of how to use it, makes it sound so easy ... however if something goes wrong it is unclear how to resolve the situation because the system's many secrets are not made available and in an emergency you have seconds to understand what's going on under the hood.

Airbus does not want pilots to be able to switch the system off at will, because that would derail the business plan of full automation.

For the bean counters, it's just money. Lives lost though regrettable are just a matter of insurance.

Automation seems the trajectory of the economy ... unless something changes. And we are now in an intermediate phase were there is an inevitable dishonesty about what is occurring, because automation is being phased in semi-covertly.

If the pilots / crew make a fuss, or passengers / airlines are scared ... then it will slow things down. If new plane technologies come through that require pilots, it will slow things down. If pilots were seen once again as part of the experience, it will slow things down. If the world gets richer suddenly it will slow things down.

Some operators have expressed an interest in 'full automation' - but only because they have absolutely no appreciation of the end-to-end costs involved.

If they think pilots are expensive, wait till they see what a theoretical 'unmanned' airliner would cost to design, build, certify and operate.

Not only that, achieving the required level of safety for a passenger-carrying operation simply isn't technically feasible - and won't be in any of our lifetimes - if at all.

[HarryMann]

... in conversation with Leightman 957 it occurred to me (& maybe L957 too) that
stalling in general and higher altitude stalls particularly have been given much less
attention than those at low (more immediately threatening) altitude by safety authorities
and in liine training ?
... over a significant span of recent airliner development.

[TheInquisitor]

I believe 14,000 ft is the highest that any manufacturer flight-tests stall characteristics nowadays.

Couple that with the low-speed limitations of Computational Fluid Dynamics, and we have a whole flight regime for which wide-ranging reliable data doesn't appear to exist.

[NigelOnDraft]

Isn't the real story here that airlines / manufacturers want to fully automate flight

And plenty of posters on here seem to agree e.g. adding technology to solve every problem?

The Airbus system comes with a manual of how to use it, makes it sound so easy ... however if something goes wrong it is unclear how to resolve the situation because the system's many secrets are not made available and in an emergency you have seconds to understand what's going on under the hood

I would disagree with the underlined statements:
A: I do not believe it "unclear" how to resolve situations, but people have either failed to follow the manual / their training, or they have done something completely unpredictable.
B: It is not essential, IMO, to (completely) "understand" what is going on under the hood. Not even what law the aircraft is in. Yes - a level of knowledge is required, and will help in exceptional circumstances. But if you fly the aircraft sensibly, remember it is still an aircraft and not a computer, and apply basic flying skills, then the finer points of FBW are (as designed) usually invisible to you.

Automation seems the trajectory of the economy ... unless something changes. And we are now in an intermediate phase were there is an inevitable dishonesty about what is occurring, because automation is being phased in semi-covertly.

I do agree with the basics of this - initially the benefits of FBW showed up as "protections" prevented some accidents (albeit there was also a learning curve), but there was still basic airmanship and flying skills about.

Now we have a new influx of pilots, who only know FBW, rarely handle the aircraft, the industry relies on the automation. When the automation lets them down, they have nothing to fall back on. Even the older generation pilots have been "deskilled" as well.

[cribbagepeg]

GPS on corners

Isn't this used on some fighters to sense attitude? Phase lock, phase differences? Maybe on the mil band only?

[Mr Optimistic]

I would have thought the logic behind stopping the aural stall WARNING when aoa becomes untrustworthy makes sense EXCEPT when an approach to stall has just been sensed. If the warning is blaring away seems more prudent to let it continue. Think the software is missing a IF....THEN branch on this one. Also, if high THS is a very unusual state for normal ops, is there a warning to draw attention to it?

[HarryMann]

Inquisitor

..out of the profession for many years now but don't necessarily
agree CFD is limited to low speed aerodynamics or altitudes.
no doubt even faster computerd are required and different
mesh/models but think it is a very advanced technology now.

..unless you know different.

[TheInquisitor]

HarryMann,

Not sure, as I have no expertise in the field myself. I was referring to what somebody far cleverer than I told me when visiting a wind tunnel test facility. He seemed to be saying that in the low-speed, high-alpha regime particularly, there were simply too many variables to produce a solid deterministic model, as opposed to computers running out of steam.

Apparently they have it pretty much nailed for high-speed stuff, though.

[HarryMann]

Inquisitor

Sorry I misread...

However I know a bit more about that regime and disagree still

separated flow is complex and agree demands lots of computing power

it's a matter of filling in the gaps with real w/t models studies.

I doubt there's a lot not known.

I don't believe these are the issues here:

isn't this about the cockpit, training, operational procedures human
response etc,

[TheInquisitor]

It's about a lot of things in my mind HM.

I currently work in the unmanned arena, and am desperately fighting those who think that more computers and more automation is the answer to everything.

My own view is that that we have simply replaced one failure mode with another.

it's a matter of filling in the gaps with real w/t models studies.

I'd be interested to know what's out there in terms of real-world collected data, particularly wrt high-alt, high-mach, high-alpha, low-IAS scenarios? My current belief is that a wide dataset here is absent, save for that collected from real-world accidents?