Air Asia Crash Report : Cracked Solder Joint on Rudder Limit Circuit Board

[Brumby]

No matter what's going on, it's important that somebody flies the damned airplane!!

I couldn't agree more.

Also, that they are properly trained to be able to fly the plane.

I'm all in favour of automation to make the job easier - but IT MUST NOT be allowed to encourage an culture of complacency, dependence or laziness ... and it certainly is NO excuse for allowing pilots to be considered "qualified" at a lesser skill level.

Reducing the skill level is asking for disaster - because its when things go wrong that the pilot really needs flying skills.  If he gets used to "pushing the blue button" to fix some flying problem and one day that blue button doesn't work he's going to have to start thinking about what to do.  I don't know about you, but I'd rather he went through that exercise during his training.

The other thing is flight system design that wants to 'negotiate' control inputs.  This averaging idea sounds stupid and dangerous.  I'd be happier to weld both control columns together through a couple of fixed linkages.  The push-me-pull-you problem would soon be resolved.

I see the same trend in motor vehicle technology.  Stereoscopic imaging systems to automatically apply the brakes if you get too close to the vehicle in front and lane intrusion warnings.  IMHO, this is not making driving safer, it is making it more dangerous.  It encourages laziness and reliance on technology as well as furthering the culture, giving inattentive drivers something to blame if it doesn't work to their expectations.


To promote the Airbus as requiring less skilled pilots is the most irresponsible policy out.


JMHO

(Rant over. Feel better)

[Wytnucls]

So what if the rudder limiter uP failed, the system should simply keep on functioning on redundant systems...

It does, with some minor hindrance, when both channels fail.

This results in lesser pilot training that does not require extensive flight stall recovery maneuvers.

Incorrect. Stall recovery technique practice has been part of initial and recurrent training from day one.

Most reprehensible, irresponsible and a total Dereliction of engineering and management responsibly to humanity is the idea and belief that summing the two side stick controls without feedback is acceptable..

One pilot only should be flying the aircraft (Airbus or Boeing).The first thing one learns on the Airbus, is that there should never be any ambiguity about who is flying the airplane. It requires discipline. In this case, the first officer froze at the controls and the captain didn't know how to override his dangerous sidestick inputs properly.
The only purpose of summing the inputs is to allow the conscious pilot to instinctively stop a manoeuver caused by an incapacitated colleague, slumping on his sidestick, until the priority take-over can be initiated.

[Brumby]

One pilot only should be flying the aircraft (Airbus or Boeing).

..or Cessna.

The first thing one learns on the Airbus, is that there should never be any ambiguity about who is flying the airplane. It requires discipline. In this case, the first officer froze at the controls and the captain didn't know how to override his dangerous sidestick inputs properly.

A training issue, is it not?

The only purpose of summing the inputs is to allow the conscious pilot to instinctively stop a manoeuver caused by an incapacitated colleague, slumping on his sidestick, until the priority take-over can be initiated.

Fair enough - but in the case of the push-me-pull-you situation, it would be good if there was a means to communicate that there were conflicting inputs, so it was immediately clear that there was a need for a priority take-over.  It seems this was not immediately apparent and the pilots spent (however many seconds it was) wondering WTF? before realisation and the initiation of the take-over.

[Brumby]

On reading my previous post, it may seem I am attacking Wytnucls - but please know that this is not my intention.

I am more focussed on the the fact that the pilots were not doing the right thing and that the technology could be a contributing factor.

[Monkeh]

adding some power to completely alleviate the stalled condition.

NO!

The engines on these aircraft are under the wings. In a stall condition you have next to no elevator or aileron authority. Pushing the throttles forward only serves to keep the nose up.

[Richard Head]

777 is not an old model, it was introduced in 94. So why there are still axial caps and reed relays as well as TO transistors?

Probably because they used pre-existing and certified electronics from around the 80's due to the exhorbitant cost of certification. TSO'd electronics is expensive to make and hence purchase.
That's why certified small general aviation aircraft still operate on "steam"gauges.

[Wytnucls]

adding some power to completely alleviate the stalled condition.

NO!

The engines on these aircraft are under the wings. In a stall condition you have next to no elevator or aileron authority. Pushing the throttles forward only serves to keep the nose up.

Exactly. Not only that. In a deep stall at high altitude, one may have to trim the aircraft manually nose down to regain some elevator control and forward speed.

[Wytnucls]

On reading my previous post, it may seem I am attacking Wytnucls - but please know that this is not my intention.

I am more focussed on the the fact that the pilots were not doing the right thing and that the technology could be a contributing factor.

There should never be a 'push-me-pull-you situation' in any aircraft. The captain just shouts 'I have control' and the first officer has to sit on his hands. in the unlikely event that the pilot doesn't let go of the stick, as easily seen from the other side, priority take-over applies.
In my experience, the full priority take-over procedure is seldom trained for, except at the initial Airbus conversion. That may change now, after this incident.

The EgyptAir captain of the Boeing 767 flight 990 didn't have the luxury of a priority takeover button, which could have saved the aircraft:

'The NTSB determined that the only way for the observed split elevator condition to occur was if the left seat pilot (the captain's position) was commanding nose up while the right seat pilot (the first officer's position) commanded nose down.'

https://en.wikipedia.org/wiki/EgyptAir_Flight_990

[Rupunzell]

So what if the rudder limiter uP failed, the system should simply keep on functioning on redundant systems...

It does, with some minor hindrance, when both channels fail.

Why did the pilot of flight QZ8501 reset the uP after it failed the fourth time in flight, previous to this incident the same problem occurred over twenty times?

This results in lesser pilot training that does not require extensive flight stall recovery maneuvers.

Incorrect. Stall recovery technique practice has been part of initial and recurrent training from day one.

If stall recovery training was part of initial and recurrent training from day one, explain why the pilots involved with Air France flight 447 and Air Asia flight QZ8501 unable to recover from the stall they initiated which proved fatal to all passengers, crew, and airframe?

Most reprehensible, irresponsible and a total Dereliction of engineering and management responsibly to humanity is the idea and belief that summing the two side stick controls without feedback is acceptable..

One pilot only should be flying the aircraft (Airbus or Boeing).The first thing one learns on the Airbus, is that there should never be any ambiguity about who is flying the airplane. It requires discipline. In this case, the first officer froze at the controls and the captain didn't know how to override his dangerous sidestick inputs properly.
The only purpose of summing the inputs is to allow the conscious pilot to instinctively stop a manoeuver caused by an incapacitated colleague, slumping on his sidestick, until the priority take-over can be initiated.

In the idealized world, that could be true. What Airbus failed to consider are the human factors under the stress of emergency situations that come into effect. The majority of human beings are right hand dominate which gives the pilot on the right hand side of the Airbus side stick better ability to control the side stick. The pilot on the left hand side of the Airbus is forced to use the left hand which puts this pilot at a dis-advantage unless the pilot is left handed or ambidextrous. Adding to this problem, if one is forced to hold down the take-over priority button, it changes the hand-arm's muscle system's ability for fine control again altering the ability of the pilot to control the side stick. The problem of handed control advantage does not happen with a center yoke or center stick control, It only happens with side stick controls on located on the handed side of the aircraft.

All those proceeders and theoretical expectations can go out the window when the pilots are trying to keep  the aircraft flying in out of the ordinary situations. Difference between recovery from a serious in flight problem can be a matter of seconds, how much time does that allow for error and dealing with flight control bureaucracy? What matters most is to absolute limit the stress workload to the pilot under these conditions allowing the pilot to completely focus on keeping the aircraft in flight and getting it on the ground intact.

What is abundantly clear, the Airbus side stick control ergonomics is driven by engineering folk in denial of decades of experience learned and gained from other aircraft control design.  It appears tone French Nationalism and wanting to be different that drove Airbus to design in their side stick centric control system rather than using well proven and accepted aircraft control systems.

This side stick -vs- center yoke control has been debated since Airbus introduced it from the beginning with no end in sight.


Bernice

[Howardlong]

This problem was fixed a very long time ago. It didn't stop inadvertent rudder inputs though.

[Scrts]

I wonder if that solder is lead free crap...

I'm pretty sure that all equipment installed into transportation vehicles (trains, cars, planes) is exempt from Lead Free crap.
They knew that it was less reliable, and they wanted to avoid being called in courts..

Best regards

Cars are strictly lead free. They can use lead in medical and military only afaik.

[Wytnucls]

Bernice, it shows that you have no experience flying Airbus machines. You're just scaremongering, regurgitating past uninformed drivel. I'm not interested in a war of words about Airbus versus Boeing. I have flown many Boeing and Airbus airplanes. So have a lot of my friends. There is no great debate in the industry about which ones are better. I can assure you that both constructors are committed to make their products as safe as possible and no one should be afraid to fly on them.

[Rupunzell]

Not a matter of flying experience, this is basic human ergonomics. Nothing more, nothing less.

Why no answers to the question put forth given your expertise experience  in flying both Airbus-Boeing?



Bernice

Bernice, it shows that you have no experience flying Airbus machines. You're just scaremongering, regurgitating past uninformed drivel. I'm not interested in a war of words about Airbus versus Boeing. I have flown many Boeing and Airbus airplanes. So have a lot of my friends. There is no great debate in the industry about which ones are better. I can assure you to both constructors are committed to make their products as safe as possible and no one should be afraid to fly on them.

[Monkeh]

I can assure you to both constructors are committed to make their products as safe as possible and no one should be afraid to fly on them.

I am rather curious about this statement from the FCTM, though: "The effectiveness of fly-by-wire architecture and the existence of control laws eliminate the need for upset recovery maneuvers to be trained on protected Airbus aircraft."

[Howardlong]

Not a matter of flying experience, this is basic human ergonomics. Nothing more, nothing less.

Why no answers to the question put forth given your expertise experience  in flying both Airbus-Boeing?



Bernice

Bernice, it shows that you have no experience flying Airbus machines. You're just scaremongering, regurgitating past uninformed drivel. I'm not interested in a war of words about Airbus versus Boeing. I have flown many Boeing and Airbus airplanes. So have a lot of my friends. There is no great debate in the industry about which ones are better. I can assure you to both constructors are committed to make their products as safe as possible and no one should be afraid to fly on them.

With respect, I think Wytnucls has responded and answered more than adequately. What hasn't helped your cause is repetitive referral the Airbus as Scarebus which started off mildly amusing, then became irritating, and then then became a rant. Then you make accusations of French nationalism. I think we can draw our own conclusions on which side of the fence you're on, and are unlikely to want to be open minded enough on this to ever sit anywhere else. And by the way, I'm speaking as a yoke-only pilot!

[Wytnucls]

I can assure you to both constructors are committed to make their products as safe as possible and no one should be afraid to fly on them.

I am rather curious about this statement from the FCTM, though: "The effectiveness of fly-by-wire architecture and the existence of control laws eliminate the need for upset recovery maneuvers to be trained on protected Airbus aircraft."

It is a strange statement. Airbus probably meant that an aircraft upset is very unlikely in normal law. Regardless, upset recovery is being practiced in the simulator.

[Brumby]

There should never be a 'push-me-pull-you situation' in any aircraft. The captain just shouts 'I have control' and the first officer has to sit on his hands.

While I have no quarrel with this - the fact is, it physically can happen.

My question is: WHEN conflicting inputs are being given HOW do the pilots find out?

[Monkeh]

There should never be a 'push-me-pull-you situation' in any aircraft. The captain just shouts 'I have control' and the first officer has to sit on his hands.

While I have no quarrel with this - the fact is, it physically can happen.

My question is: WHEN conflicting inputs are being given HOW do the pilots find out?

The aural warning 'dual input' should sound, and both sides of the cockpit have a visual indicator as well.

[cimmo]

I fail to understand why Airbus have not implemented haptic (force) feedback technology in their sidestick.
The problem (as is frequently demonstrated) is that humans suffer from sense channel overload. Sure, there are red lights and green lights and aural warnings when sidestick priority is requested, but when the proverbial is hitting the other proverbial the cockpit is FULL of flashing lights and audio alarms.

Expecting a human in a panic (who is trained to the minimum legally required standard) to differentiate one particular light or aural warning is naive.

The solution is simple - make the sidestick move when inputs are made by the other pilot (but not by the autoflight system). As it stands there are no aerodynamic forces fed back to the sidestick - it just uses a centering spring.
However, IF one pilot could FEEL (a completely different and unsaturated sense channel) when the other pilot has deflected the sidestick from neutral then this provides a prompt for that pilot to investigate WHY the other pilot is making a sidestick input.

As a bonus, when the priority button is pushed AND THAT SIDE NOW HAS FULL CONTROL, then the feedback can be removed to let the pilot actually in control know that the other input is being ignored (by using that spare [tactile] sense channel).

As an extra bonus - vibrate the sidestick that is overridden by the other side priority button to prompt that pilot to get his hand off the damn thing.

This tactile feedback is essentially what happens in a Boeing - the mechanical linking of the control wheels achieves this. But since force feedback technology in joysticks is now consumer grade cheap, I am at a complete loss to understand why Airbus haven't implemented this at all, given that there now is enough evidence to show that the current system could work better.

As some here have suggested, maybe it does come down to engineering arrogance?

[Wytnucls]

There should never be a 'push-me-pull-you situation' in any aircraft. The captain just shouts 'I have control' and the first officer has to sit on his hands.

While I have no quarrel with this - the fact is, it physically can happen.

My question is: WHEN conflicting inputs are being given HOW do the pilots find out?

The aural warning 'dual input' should sound, and both sides of the cockpit have a visual indicator as well.

Yes, but the system is not installed on all machines. it is unclear if the AirAsia plane was equipped with the upgrade, but anyhow the captain was aware of dual inputs, as he pressed his priority button.

[Monkeh]

There should never be a 'push-me-pull-you situation' in any aircraft. The captain just shouts 'I have control' and the first officer has to sit on his hands.

While I have no quarrel with this - the fact is, it physically can happen.

My question is: WHEN conflicting inputs are being given HOW do the pilots find out?

The aural warning 'dual input' should sound, and both sides of the cockpit have a visual indicator as well.

Yes, but the system is not installed on all machines. it is unclear if the AirAsia plane was equipped with the upgrade, but anyhow the captain was aware of dual inputs, as he pressed his priority button.

The report seems to indicate that it was, however the alarm was suppressed by the stall warning. That is a flaw which needs rectifying.

[Paul Moir]

I fail to understand why Airbus have not implemented haptic (force) feedback technology in their sidestick.

The Bombardier Q400 has a stick pusher which pushes the stick forward when it thinks it really really is a good idea.  Unfortunately on Colgan Air 3407 the pilot just pulled back harder when it tried to push.

The correct solution to a problem is to identify the root causes and eliminate them.  Band-aids as permanent solutions are rarely a good idea.

[cimmo]

The correct solution to a problem is to identify the root causes and eliminate them.  Band-aids as permanent solutions are rarely a good idea.

Presumably you think that the root cause of this problem is inadequate pilot training?
I agree.

But why NOT provide some form of additional system protection to mitigate against the inevitable human failure modes? There are hundreds of system backups and redundancies in aviation that are only there because the need for them has been demonstrated with a body count.

Sometimes, 'band-aids' ARE the next best solution when the primary problem (humans) CANNOT and never will be fixed - unless we remove them from the cockpit entirely? (DroneBus?)

[cimmo]

however the alarm was suppressed by the stall warning. That is a flaw which needs rectifying.

My point exactly.
Haptic feedback would be the perfect solution, but Airbus will never implement it as it would be an admission that their design philosophy is fundamentally flawed.

[Brumby]

There should never be a 'push-me-pull-you situation' in any aircraft. The captain just shouts 'I have control' and the first officer has to sit on his hands.

While I have no quarrel with this - the fact is, it physically can happen.

My question is: WHEN conflicting inputs are being given HOW do the pilots find out?

The aural warning 'dual input' should sound, and both sides of the cockpit have a visual indicator as well.

Yes, but the system is not installed on all machines. it is unclear if the AirAsia plane was equipped with the upgrade, but anyhow the captain was aware of dual inputs, as he pressed his priority button.

Assuming that system was not installed and/or the alarm was suppressed, my next question would be "How long did it take the captain to work it out?"  I'm sure the FDR would have that information - but if it was a number of seconds, then those were precious seconds indeed.