Air Asia Indonesia Lost Contact from Surabaya to Singapore

[foxcharliep2]

When AirAsia Flight QZ8501 crashed, the co-pilot was flying the plane. The pilot was monitoring the flight. And things may have gone wrong in a span of just three minutes and 20 seconds.That's the assessment of Indonesia's National Transportation Safety Committee.



Investigator: Co-pilot flew AirAsia Flight QZ8501 - CNN.com

[toffeez]

So the capt just sat there for 3 minutes while they were out of control and didn't press the takeover button.

[formationdriver]

QZ 8501 FO's family sues AsiaAir 48hrs before FO designated as PF

Interesting timing: FO's family sues the airline (for dangerous & illegal operations) two days before Airline says CVR proves he was the Pilot Flying at the time of the accident. The airline also says 320's FDR shows no mechanical,electrical or weather-related-related malfunctions before steep climb, subsequent loss of control, and crash. The family's suit is based on "illegal operation" ( flying without a route permit on that day), "overcrowded skies" "excessive ATC workload." Lawyers... !!

France-La famille du copilote d'Air Asia porte plainte | Reuters
AirAsia : le copilote français pilotait l'avion au moment du crash

[Volume]

but I find it a bit strange that an aircraft with so many protections built in, will allow the autotrim to trim the stab into a position that you simply can't fly out of.

Since aircraft have grown in size beyond what the pilot can control by his own power, trim has always been a feature that can kill you if wrongly used. This was one of the reasons why the L1011 did not have a trimable horizontal stabilizer with an elevator, but an all flying tail. It was eliminating a possible risk. Due to the complexity of that type of pitch control, the concept was abandoned in favour of cheaper, lighter and simpler systems. Stabilizer trim requires appropriate trim setting, pilots and computers can mess that up (and did in the past). Autotrim is always designed for a certain purpose, and works perfectly for that. If you operate out of the design assumptions, the system can bite you. Even with autotrim installed, it is still the pilot who is responsible for the correct trim setting. Autotrim should assist him, not dominate him. It is the pilots fault if he lets it happen. It is the role of the pilot to check what his systems are doing. All the indications and warnings are there right in front of his eyes. The pilot should just not stop monitoring, which has never failed in all of his life...

Has anyone ever explained why AF447 PF obsessively pulled back?

I think this is pretty self explanatory for anyone who is able to fly an aircraft and read FDR plots in the report. The pilot did not obsessively pulled back unless the aircraft nose dropped by some 25 degrees (between 2:11:45 and 2:12:00, the normal behaviour of a stalled aircraft). However the normal behaviour of a trained pilot should have been different... But for a pilot in panic, pulling when your pitch is -10° is understandable, but should not happen. Especially if a synthetic voice is trying to point out an important detail for about a minute already...

[Sop_Monkey]

When you have an A/C manufacture boasting that one of their latest models are "uncrashable" I think it will happen again but hope I'm wrong

This attitude and arrogance has astounded me ever since.

[HeavyMetallist]

Originally Posted by Machinbird

Quote:
Originally Posted by Machinbird
Suppose the FACs remained engaged in Normal Law and failed to detect a failure of that system. Could the FAC system then activate overspeed protection without an actual overspeed?

I think I misunderstood what you were suggesting had failed; by "failure of that system" I thought you were referring to the system(s) that was applying Normal Law,whereas I now think you're referring to the FAC not detecting a fault within itself? So your scenario would be:

1. ELACs/SECs working normally, in Normal Law
   
2. Controlling FAC suffers a failure, but doesn't detect that failure
3. As a consequence of the failure, the controlling FAC signals an overspeed condition
4. ELACS/SECs carry out pull-up manoeuvre
   

Originally Posted by Machinbird

Quote:
Originally Posted by Machinbird
As to the exact manner the FACs interface with the ELACs and SECs, my reading of FCOM indicates that it is the FACs that have the function of monitoring the flight envelope and invoking the protections (among other functions). The ELACs and SECs would then implement the response. Take a look at FCOM 1.22.40 Auto Flight-Flight Augmentation-and see if you read it that way.

I agree with your interpretation.

[RifRaf3]

5.5g, yes, but without accompanying wings

[Ian W]

Originally Posted by formationdriver

Interesting timing: FO's family sues the airline (for dangerous & illegal operations) two days before Airline says CVR proves he was the Pilot Flying at the time of the accident. The airline also says 320's FDR shows no mechanical,electrical or weather-related-related malfunctions before steep climb, subsequent loss of control, and crash. The family's suit is based on "illegal operation" ( flying without a route permit on that day), "overcrowded skies" "excessive ATC workload." Lawyers... !!

France-La famille du copilote d'Air Asia porte plainte | Reuters
AirAsia : le copilote français pilotait l'avion au moment du crash

The family's suit does not appear to have any merit. The area was not overcrowded, it was standard delay in clearing an aircraft for higher and in any case higher would make an aircraft more susceptible to severe turbulence. This was just luck-of-the-draw finding an active possibly 'dry' cell at the wrong moment.
However, not being an engineer, you probably did not note the items missing in that carefully enumerated list which I have bolded: Software, algorithm, system design are not mentioned. It is possible that all the protections worked as precisely as designed but this is a particular rare occurrence of a 'bus zoom climbing, as the WSJ reports, because the systems worked as designed.

[jientho]

g force

NAROBS, you are confusing speed with acceleration. 55 m/s is speed. You seem to be assuming 55 m/s/s (=~5.5g). That would only be the case if the change in vertical speed all occurred in one second.

[klintE]

AirAsia Flight 8501: Co-Pilot Was Flying Plane at Time of Crash, Officials Say - ABC News

Siswosuwarno said the plane was struggling to recover as stall warnings sounded until the end of the recording.

Audible stall warning in Airbus (or stick shaker in Boeing) is designed to inform pilots that stall condition is approaching, but tracking the fate of an Air France flight 447 we can observe that stall warning appeared many times even when aircraft have already been stalled.

So imagine, you are simply falling with terminal velocity without any lift force on the wings and airplane is saying "watch out, you will stall in a moment"
Isn't that confusing?

[Sop_Monkey]

General

You have every cause and right to be concerned. You are not alone believe me. A/B never learnt from the findings of one or if not the first "computers" to run amuck at Bangalore. It was found to be "too complex an a/c to operate" for the training the crew were given.

Shouldn't operations be keep simple? If it's relatively simple then its relatively safe. When things are complicated humans don't normally cope so well. I am aware the Europeans are true masters at complicating things.

[NigelOnDraft]

GF

but scary at the same time

I would not suggest you need to be

If pilots on such a professional forum start interpreting things

I would not assume many of the posters have done much flying outside MS Sim I can claim to be a 14000hr ex-RAF FJ A320 Captain, but so can they?

The takeaway for me from all these discussions is that nobody really knows how an Airbus is programmed

In software terms, no we do not. But in flying terms, we do not need to in practical terms?

Why is that an Airbus always stalls during turbulent weather

Any aircraft will stall if you pull the stick back and hold it there and the aircraft does not stop you

...and does not allow pilots to get back the control?

It does, but you need to correctly interpret the situation (known as "SA"), and apply the correct procedures - but if you had that SA / knowledge, it is unlikely you would be in the situation on the first place. Catch 22

I, for one, will never fly an Airbus again

I would say an irrational decision. Boeings also crash for "Human Factors". If you want something to be concerned about, it is the "dumbing down" of pilots, their training and role (which the Airbus I will agree is a step towards), "Pay to Fly" etc.

[Vilters]

At the time of the incident the co-pilot was flying?

NO !

First :
The autopilot was flying, the co-pilot in charge of turning the autopilots buttons, but he certainly was NOT flying.

Flying is : "I" have the stick and throttle in hand, and "I" control where the aircraft is going.

For reasons yet unknown to us, the autopilot could not cope with the situation, and left the pilots in an unrecoverable position.

Be it autopillot or sensor failure feeding wrong information to the autopilot is another discussion.

On a second side note:
Concerning general flying.
What ever happened to basic attitude indicator flying?????

Looking back at the AF447 video, the attitude indicator is clearly showing a WAY nose high attitude from start till impact.

Whatever, whenever fails, go back to basics.

Attitude, attitude, attitude. Wings level, nose ON the horizon, ball centered.

On a third note:
Basic aerobatics should be MANDATORY for ALL pilots.

IFR aerobatics on instruments should ALSO be made MANDATORY simm training.

Simple upset recovey is clearly NOT sufficient.

Well, the results are here. Pffft, unfortunately, again.

[Lonewolf_50]

What ever happened to basic attitude indicator flying?????

Possible answer: it has been replaced by Flight Director flying? This would imply that the scan has fewer items in it as a matter of habit, and thus scans used in attitude flying atrophy from disuse.
Am prepared to be wrong in this guess.

[NigelOnDraft]

Looking back at the AF447 video, the attitude indicator is clearly showing a WAY nose high attitude from start till impact.

But your "modern" pilot does not fly attitudes - they consider "Manual Flying" to be moving the stick to centre the FD bars Ask them to fly an approach with the FDs off, and they struggle.

Elsewhere asked "why did AF447 climb / stick back?". Noteworthy that in the mode changes the FDs went off and then reappeared as systems restored themselves. Of course, in these circs they come back in "basic modes" - vertically current V/S. So:

1. FDs disappear (due ASI issue)
2. For reasons various (see above) and in absence of AP/FDs PF pulls back
3. FDs reappear in V/S climb
4. However, due decreasing speed, and inappropriate pitch attitude selected by PF, that V/S is unattainable
5. PF continues to "pull" to match FD and is still trying as aircraft stalls and gives up - but pull is still maintained

No doubt this will be Airbus' FD "at fault".

As you say, if we wish to prevent this then regular manual flying (without FDs) required on the line. Actual visual UP, then Instrument UP recoveries required in appropriate aircraft - and not just trained, but currency maintained.

The issues are not the individual pilots' fault, but the current state of the industry. I doubt they will have the inclination / $$$ to solve it, just accept the odd accident and blame the pilots

[Rananim]

IF it wasnt icing

Sorry if this was discussed before..but I read somewhere that when making a cruise climb in an Airbus and speed has been rolled back prior to climb THR set,that ATHR will actually command idle thrust.Can this be true?
If so,this might explain how they lost their speed margin,so critical at altitude in bad weather.In an effort to climb quickly,I can see how someone might roll back the speed selector prior to climb THR set and not notice(thrust levers dont move on an Airbus,no tactile feedback)what ATHR is actually commanding.
Could some Airbus pilot please clarify?I am used to FLCH/LVL CHG where full climb thrust is automatically commanded even if speed selector rolled back.

[DrPhillipa]

For reasons yet unknown to us, the autopilot could not cope with the situation, and left the pilots in an unrecoverable position.
Be it autopillot or sensor failure feeding wrong information to the autopilot is another discussion.

This is rank speculation. What caused the AP to disengage and how Normal Law was left has not yet been revealed at all. Gysbreght's idea of Alpha-prot inspired panic followed by wrong decisions sounds a good possibility to me but I only fly couches nowadays.

[NigelOnDraft]

Rananim

You describe what I earlier referred to as a "French quirk" in the Airbus.

What you say is partially true, however it should not result in an issue since the outcome is really just a slow start to get the climb going - and of course, the pilots should be monitoring it. After all, in a non-Airbus, do you assess thrust from where the TLs are? Or what the gauges say? Is an engine failure indicated by the gauges? Or the TL retarding itself

[NigelOnDraft]

What caused the AP to disengage and how Normal Law was left has not yet been revealed at all

Do we know the AP disconnected?

Do we know Normal Law was lost?

[DrPhillipa]

Nigel: probably we do not even know that

though, again from my couch, it seems unlikely to me that an A320 can fly that self destruct path under AP in Normal Law with full protections.