Air Asia Indonesia Lost Contact from Surabaya to Singapore

[wanabee777]

"I’ve sampled the capabilities of BAE’s active side sticks in Gulfstream’s G500 engineering mockup in Savannah. I’m sold. If it were up to me, I’d mandate that all new FBW airplanes with side sticks be upgraded to active inceptors as a condition of type certification."


Fred George, Aviation Week senior editor for business and commercial aviation.

[ExV238]

Alternate Law

Machinbird,

Now take that same alternate law aircraft and start with near full deflection roll inputs in cruise and tell me what happens. That is what happened with AF447 and QZ8501. In both cases, it not clear that either PF knew from the outset he was in Alternate Law. That is a setup for roll PIO. Do you understand the hazard that roll PIO presents?

With great respect, have you flown an Airbus in Alternate Law? At high altitude?

The transition is seamless, and roll control is not so different to Normal Law. with regard to your first sentence above, I wonder how many pilots have actually manoeuvred their aircraft in Normal Law at cruise alts? Not many, I bet. And even fewer would have used full deflection roll inputs under those conditions, which gives 15 degrees per second in Normal Law in the Airbus. I believe that the issue is general unfamiliarity with high altitude/high Mach manual flying and reations to upsets than it is about 'degraded' flight controls.

You have it right when you suggest that pilots should be cautious with control inputs in Alternate Law at high altitude, but so they should even in Normal Law. The aircraft will ultimately protect you, but shouldn't be asked to!

Finally, do you actually mean PIO, which has a very specific meaning? I don't believe that either of the accidents in question showed signs of PIO. Maybe some over-controlling in the case of AirAsia.

[RAT 5]

All this talk about various Laws gives me a headache, because I'm a Boeing oldie. What do other FBW a/c have? e.g. B777 and even military a/c. Is this the common FBW family of in-laws & out-laws or just an AB thing?
What is certain is FBW is here to stay and will most likely become the standard control system in future a/c. Should there not be a common specification for all the 'laws' and how they do things? With FBW & EFIS & EICAS and and .......etc.. in mind I suggest there should be a total review/overhaul of how the pilots for these new a/c are trained. I also suggest that every operator follows the same syllabus designed but the manufacturer, who, after lengthy discussions with the authorities have an approved course. (designers are not always the best at deciding how an a/c should be 'operated' on a line basis. They know how to fly it.) This would emphasise how the a/c was designed to be flown, operated basically, and would then go into all the non-normals and especially all the traps that can catch you out. THEN, and only then would company SOP's be introduced. I've had to teach a real variety of TR syllabi on same/similar Boeing a/c. It is astonishing how some people try to reinvent the wheel and emphasise the SOP over how the a/c was designed to fly/be operated, and how different those SOP's can be to achieve the same task.
Redesigning the basic CPL might be more difficult. At that stage you don't know where or what the pilot us going to fly. They could be single crew air taxi guys, biz-jet pilots or airliners. Each has their own skills. It is easier to oversee airlines with their in-house training depts; less so with the fringe operators. It is not a one size fits all answer; not after the basic PPL and early CPL training.

[gums]

With all respect ExV:

The transition is seamless, and roll control is not so different to Normal Law.

What if otto ( read A/P) had cranked in aileron or rudder trim before it disconnected? With direct control of the ailerons/spoilers, looks like even small stick displacement can result in fairly high roll rates. I could not see the report's graphics clearly, but maybe some have or can.

We saw the system crank in THS trim in AF447, and that was in an alternate law. So one thing to emphasize is the need to manually trim if not in NORMAL, ya think? Also, the difference in control surface displacement required at 300 knots is prolly vastly different that with gear down and flaps extended, huh?

So I would guess a perfectly normal system with a perfectly rigged jet would move to ALTERNATE with no seat of the pants cues and we could go from there 'cause the warning light and tones would advise us to be gentle.

However, that's not what happened in either crash.

Secondly, 'bird means real PIO - pilot-induced-oscillation. He and I and many here have seen it, and not just those who flew lites. The AF FDR traces show a "twitchy" jet and many of us felt the PF was so concerned with roll that much of the initial aft stick was unintended. Problem was holding it back once roll was under control. I was impressed by the PF in the other crash for getting wings back to level, but the troop made same mistake as AF troop.

@RAT

You prolly had more "laws" than you realized in the 777. Even in the older planes there were reversion "laws" for yaw and pitch dampers, aileron-rudder-interconnect and such. Even 707 and its heirs depended on a good yaw damper, and we lost a KC-135 due to dutch roll when its damper went AWOL.

In the Viper we did not use the term "laws". As with the 'bus we had fixed gains if we lost air data - STBY GAINS lite came on and we had gains for about 300 knots and another set for gear down and maybe 150 knots or so, I can't nail it down. We also had our leading edge flaps "lock" if we had to use alternate flaps or we turned the suckers off, as I did when one of mine failed and folded up ( see my interview)

All of us knew the "real" laws, but called them limiters, and we did not have a plethora of backups, being a simple system and requiring a vastly expanded maneuver envelope.

In any case, RAT, I feel your pain, heh heh.
.

[ZeBedie]

Basic flying training:

Push=Down, Pull=Up.

But this is a stall - Pull = Down even faster, Push = Survival.

The second piece of information is to be put aside and not to be used at any time, until one dark and dirty night in ten years time, when something awful is happening and you're already disorientated...

[RAT 5]

The second piece of information is to be put aside and not to be used at any time, until one dark and dirty night in ten years time, when something awful is happening and you're already disorientated...

Zebedie: spot on. What has been asked; and will someone please explain unequivocally for us non-AB guys, is what warnings does the AB, and other FBW a/c give you? In an old stick shaker a/c it can not be missed. It is audible & tactile. One hopes it would break through any level of panic you had and training would kick in. That, in part, is the philosophy of repetitive training. It can become an automatic response when all else fails. So, does the AB stall warning achieve this? Some spoke of a visual unmissable flashing red light. I wonder. We know that stress cancels out the ears first, and can be eyes 2nd. I'v seen guys in B737 sims fly around with the yellow MC attention getter burning holes in their foreheads for minutes endnote re-set it. They cancelled it out. Same for the flashing red A/T disconnect light. After 15 secs or so they filtered it out. I can imagine that, when is deep horrific WTF is happening scenario the audible "STALL STALL" is filtered out as you stir the pot. The visual flashing red light shortly afterwards, but would anyone mistake the muscle shuddering stick shaker? Would you really be able to filter out all there training and keep pulling?
Do FBW, side sticks or yokes, have stick shakers?

[joema]

Originally Posted by Machinbird

One of my instrument instructor's favorite tricks was to tell you to look down at your lap while he roughly maneuvered the aircraft, freezing the attitude indicator in a near upright position, then rolling nose high or nose low inverted and saying, "You have the aircraft." We did not have a standby attitude indicator. We had to recover to level flight by needle-ball-altimeter-airspeed techniques.

Interesting, yet isn't it true in both AF447 and AirAsia cases the EADI horizon on the PFD was fully functional throughout each event? I just re-read both reports and I don't see any indication they were malfunctioning.

If so it wasn't a case of the pilots having to decode the attitude from other instruments. Rather the EADI was accurately showing pitch attitude.

How could the EADI show a big blue sky, extreme pitch angles, yet either PF or PNF be confused about why the aircraft was buffeting and acting funny? Even the original Sperry artificial horizon from 1929 was painted blue and black to immediately convey an instinctive grasp of aircraft attitude.

There is a picture of the 1929 Sperry horizon here, and some discussion of how pilots can nonetheless get spatially confused even with newer designs. However most of these involve a tumbling horizon:

THE SOLUTION

Has there been any discussion or human factors research on why the AF447 and AirAsia pilots did not take action based on the indicated EADI pitch attitude?

[ZeBedie]

Do FBW, side sticks or yokes, have stick shakers?

Airbus ones don't. I agree that a tactile stick shaker is a far better warning than an audio "STALL-STALL", which will be be filtered out by an overloaded brain.

joema - I thought the same thing - if you'd just zoom climbed into a stall, you ought to know you're stalled because you more or less deliberately stalled it yourself!

[Uplinker]

Has there been any discussion or human factors research on why the AF447 and AirAsia pilots did not take action based on the indicated EADI pitch attitude?

It seems to me that the PF of AF 447 and the Colgan crash thought that to avoid a stall, one should pull up ???!!!!! What the hell had their TRIs and training managers been teaching them?



On Airbus sidesticks, there is a small oval panel at the top secured by two screws. It appears to have no function, except as a place to rest one's thumb.

It seems to me that this panel could be replaced by a vibrating element, like that found in mobile phone batteries - to give tactile feedback to a pilot that his plane is stalling. The logic to identify the stall already exists - to give the "stall stall" warning, so one only needs to use that to energise a vibrating element in the side stick to create a haptic attention getter - like that of a stick shaker.

[Machinbird]

Originally Posted by ExV238

With great respect, have you flown an Airbus in Alternate Law? At high altitude?

The transition is seamless, and roll control is not so different to Normal Law. with regard to your first sentence above, I wonder how many pilots have actually manoeuvred their aircraft in Normal Law at cruise alts? Not many, I bet. And even fewer would have used full deflection roll inputs under those conditions, which gives 15 degrees per second in Normal Law in the Airbus. I believe that the issue is general unfamiliarity with high altitude/high Mach manual flying and reations to upsets than it is about 'degraded' flight controls.

ExV238, I'm just one of the guys, and I don't take offense easily so do not worry about an adverse reaction. Just speak your piece and don't hold back.

First, to be absolutely clear, I am a tactical jet pilot by experience and at heart. The closest I came to multi-pilot transport operations was flying the Navy C-1A transport on logistic runs and cross countries at a couple of duty stations. But before you think, "just another keyboard commando," you might wish to take into account my experiences and historical perspective on aviation.

Unlike most of those here who are flying the line, I have had some experience with roll PIO and those few seconds of PIO were so gut-wrenching that I remember them clearly to this day. This was in a visual simulator no less! Can you perhaps imagine the sensation of the poor souls flying AF447/QZ8501 who understood that "This is for real and it is all on me to save the day?"

. One of the things about AF447 that stands out was the initial roll oscillation that lasted for 30 seconds or so. Everyone looking at the data was saying it wasn't that bad of an oscillation and he got it under control in 30 seconds. But if your were looking at the data from the inside view, I could see clear signs that the pilot had to develop a strategy to attempt to control the roll oscillation and that this strategy had actually prolonged the oscillation. (He was attempting to get ahead of the oscillation by accelerating his roll inputs.)
This fits the definition of a PIO. If it had not been a PIO, he should have been able to stop the oscillation immediately.

On QZ8501, the aircraft got to 54 degrees bank angle before the roll correction was applied. In addition, the FAC system is responsible for re-configuring the PFD airspeed display for Alternate Law but the FACs were disabled. I expect the only place he might have quickly seen that he was in Alternate Law was on the ECAM display.

A strong roll input was applied and the aircraft reached 6 degrees of bank in less than 2 seconds before it reversed and reached almost the same initial bank. FCOM states that in roll direct in a clean configuration, the maximum roll rate is about 30 degrees per second. When you consider that the roll rate had to be decelerated to reverse, it is clear that peak roll rates were easily in the maximum range. In hands of an inexperienced pilot in cruise flight, this type behavior should be looked at as roll PIO until proven otherwise.

With regard to the concept of a seamless transition from Normal to Alternate, think back to your initial training on Alternate Law. Weren't you first briefed on it and told to be gentle with the controls? Then you had a clear transition to Alternate Law, and after about 15 seconds, you had the feel for it and afterwards it was no big deal. Contrast that introduction with what the pilots flying AF447 and QZ8501 received. No warning, no briefing, no previous experience, a confusing transition to Alternate Law with other factors in play, and then a hurry up and try to catch up with an aircraft that is rolling. No wonder they over-controlled.!

Now for the Boeing guys here, this is primarily an Airbus training and probably a design problem as well. Something that Airbus would rather not be addressing under time constraints. But don't let your guard down. I can post a video of a triple 7 doing a roll PIO on short final and into the touchdown if you need motivation.

Gums, thank you for your recent input.

The gents suggesting a stick shaker for the Airbus have it right. The sooner the better.

But there is a lot that can be done to make the transition to Alternate Law uneventful.

[CONSO]

RE Haptic Stall warning

uplinker said

On Airbus sidesticks, there is a small oval panel at the top secured by two screws. It appears to have no function, except as a place to rest one's thumb.

It seems to me that this panel could be replaced by a vibrating element, like that found in mobile phone batteries - to give tactile feedback to a pilot that his plane is stalling. The logic to identify the stall already exists - to give the "stall stall" warning, so one only needs to use that to energise a vibrating element in the side stick to create a haptic attention getter - like that of a stick shaker.

From this mere SLF- what a great idea. Why doesn't everyone join in and send letter or petition to Airbus re this elegant solution- perhaps it could be patented. I use the vibrate on my cell phone in my pocket and it does get my attention. IMHO a heavy duty version set at a freq which would NOT interfere with electronics tied to stick, etc would be ' relatively' simple to check and perhaps incorporate or retrofit.

But it wont happen until enough pros jump up and down and SHAKE THE BCRATS INTO ACTION

[EMIT]

DREAM ON

An MD82 stalled at high altitude over Venezuela and with stick shaker rattling all the way, the interconnected yoke was pulled fully back until the ground was hit.

A Q400 near Buffalo indicated an imminent stall by shaking the interconnected yoke and the startle reaction was a pull that did induce the stall, which led to a wing flip from which recovery was not anymore accomplished.

An MD83 stalled over Mali, flipped over its left wing and with stick shaker rattling all the way, the interconnected yoke was pulled fully back with full right aileron all the way until the Sahara was hit.

Yeah, surely, interconnecting side sticks and providing stick shakers or haptic buzzers on them is gonna save Airbusses from pilots stalling them.

[EternalNY1]

Pitch + Power = Performance

Serious question here ... with all the automation, couldn't the system be designed so that it rolls wings level at an appropriate pitch + power setting?

If I was flying AF447 or any of these other flights with odd indications, I'd level myself and set the power manually to approximately where it "should" be, bypassing the autopilot.

I am beyond confused on why other pilots are pulling BACK on the stick when they are getting a stall warning. If stall warning, overspeed, anything ... level the plane and set an appropriate power setting. Then you at least know the alarms are incorrect and can go from there. No?

[Machinbird]

DREAM ON
An MD82 stalled at high altitude over Venezuela and with stick shaker rattling all the way, the interconnected yoke was pulled fully back until the ground was hit..........................
Yeah, surely, interconnecting side sticks and providing stick shakers or haptic buzzers on them is gonna save Airbusses from pilots stalling them.

EMIT,
This old Phantom Phlyer used his rudder shaker to good advantage in the busy traffic pattern around his aircraft carrier. It was one of two signals telling him to add power after pulling power to dirty up in the break over the ship. (The other signal was the GIB with his sarcastic, "Don't you think you need to power up?") Haptic signals like that rudder shaker are good triggers for a properly trained conditioned response. The real problem is that we have a lot of poorly trained pilots out there, and some of them have a lot of flight time. How to fix that training problem is going to take a big investment and a lot of study. In the meantime, the best we can do will be to avoid rattling their heads too badly.

I can tell you that I am here, still making trouble, because when the chips were down, I did not snatch the stick back as the ground was rushing up. It is all in the training. Flying properly is an intellectual enterprise, not a rote response task. The thinking, calculating mind must be in control.

[Olive61]

The appropriate pitch and power for just about any modern aircraft at cruise altitudes, and not stalled, is a Body Angle of approx +2.5 deg and 80% N1. This will stabilize the aircraft safely and allow troubleshooting/descent to follow. Stabilized descent will be achieved with Body Angle Zero and Thrust Idle. The problem is - many pilots don't have this fundamental knowledge, and many airlines do not require their pilots to regularly practice loss of air data/loss of airspeed at altitude. If a stall is imminent at cruise altitude the manufacturers immediate recovery actions are required - the first of which is always immediate and significant reduction of Body Angle (A of A). Excessive A of A is the ONLY reason that a wing will suffer aerodynamic stall.There are numerous cyclic training programs out there with numerous carriers. The unfortunate truth is that some of them are simply bogus box ticking exercises, and we will continue to have hull losses of the kind recently experienced until professional training to professional standards becomes universal.

[PrivtPilotRadarTech]

Meatware Failures

I think more and better training is a great idea, I'm totally in favor, but automation is only going one way: more. These accidents are unacceptable. The aircraft is telling the "pilots" it is stalled, but they are ignoring the warning. One of the sim videos posted has the AirBus softly bleating "Stall. Stall." How about "Stall. Stall. Stall m-----------r! What part of "STALL" is it you don't understand? Push the friggin' nose down or DIE!" If that doesn't work, the computer should say "My aircraft." And take control, wings level, AOA and thrust to a standard level.

Same with CFIT. With a GPS, digital terrain map, and computer calculating close rate there is no reason that should ever happen again. Hal should say "Sorry Dave, I can't let you fly this aircraft into the ground. My aircraft."

[ve7pnl]

Stall Warning

Reminds me of a talking depth sounder I designed many years ago for fishermen in the shallow regions of the Bering Sea. It would call out the depth on a speaker out on deck every 15 seconds - faster and with a tone when below the alarm depth.

An initial software error cause the voice to stutter on the first syllable of each depth call out when within the alarm range. That stutter got their attention!

Now, back to flying talk.

[CONSO]

RE Haptic Stall warning

Yeah, surely, interconnecting side sticks and providing stick shakers or haptic buzzers on them is gonna save Airbusses from pilots stalling them.

Lets ASSUME the combination of interconnect and sidesticks prevents ONE 100 plus passenger aircraft going splat in say 10 years.

Please compute the cost- benefit ratio OF NOT doing it and provide it to the few survivors or families of those who did not survive along with your message of condolence.

Why would anyone NOT want to use or have available ALL three senses ( light- sound- physical ) when the fit hits the shan ?

Granted adding such is not a cure all- and never will be absolute, but it would add a few nines to the human error probibility equation.

[_Phoenix]

Puzzle picture 1/2 stall recognition, 1/2 THS position awareness

Maybe both, more situational awareness training combined with design improvements are needed. At high altitude, it is crucial to distinguish between overspeed and stall. For stall condition, how about to show on PFD Red/Brown colors (instead Blue/Brown). Separation line to be at FPV (flight path vector) location, the red above with big text STALL on it.
However, stall recognition is only half of the puzzle, the second one is THS position awareness.
Off the top of my head: West Caribbean 708, Air Algerie 5017, Birgenair 301, XL888, AF447, ROT381 have two things in common
- THS NU
- pilot error (stalled the airplane)

...and a good candidate for Guinness book :
https://www.youtube.com/watch?v=FJViilcDTyw
(sadly pilot error again)

[CONF iture]

Originally Posted by PrivtPilotRadarTech

If that doesn't work, the computer should say "My aircraft." And take control, wings level, AOA and thrust to a standard level.

Then what happen next time there is a false stall warning on take off due to a damaged AoA probe ...
More automation is certainly not the solution, I prefer your suggestion for more training.

Originally Posted by EMIT

Yeah, surely, interconnecting side sticks and providing stick shakers or haptic buzzers on them is gonna save Airbusses from pilots stalling them.

If both guys agree to pull the yokes or one guy is lost enough to let the other one to pull his yoke, there's not much we can do, but in both cases for AF and AIrAsia the PM had no idea what the PF was doing with his sidestick and knowing how that sidestick was commanded could have been a tremendous piece of information to help him to understand the situation.
Yokes or at least coupled sidekicks provide information that independent side sticks do not.

Originally Posted by FDMII

In AF447, the THS was driven full NU and remained there because of full-up stick inputs. If the stick had been placed full-forward, the THS would follow-up and return close to a neutral setting.

My question is why Airbus made an automatic operation on that THS to help the guys to set the airplane in a pronounced and comfortable stall ... ?