Indonesia Air Asia flight QZ 8501 loses contact with ATC

[markis10]

And the official version supposedly from the government:

 

[samh004]

I have a feeling the climb was not initiated by the crew, but rather the result of being in an updraft in the middle of the storm, the preceding minutes the lack of comms being a result of the crew navigating the turbulence as they entered the cell.

That's what I had started to think.

 

[QF WP]

Wow, to an uninitiated (me), the dropping speed is indicitative of a stall - 169 kts down to 78. Why does the last plot not have any speed - does that mean there was no forward movement and they were already in a spin?

 

[mjgriffo]

Markis10: How did they achieve a 17000fpm climb rate, based on what I presume is Mode C data?

Isn't climb rate gathered from air pressure change? Considering the ADSB data stream sent the climb rate info, it might be more indicative of probe problems, as JB mentioned.

Happy to stand corrected.

 

[markis10]

<quote> Markis10: How did they achieve a 17000fpm climb rate, based on what I presume is Mode C data? </quote>

Isn't climb rate gathered from air pressure change? Considering the ADSB data stream sent the climb rate info, it might be more indicative of probe problems, as JB mentioned.

Happy to stand corrected.

Reuters data indicated the 17000fpm, ADSB data I subsequently posted indicated 12000fpm, it's probable they're faulty indications but if not I was questioning how it could be achieved by the aircraft alone, without external assistance.

ADSB pumps out barometric and geometric altitude data, a quick comparison of the two would be a good indicator of possible sensor problems. I am not sure what data stream has been used in the above graphics, it's possible it's geometric.

 

[moa999]

I have a feeling the climb was not initiated by the crew, but rather the result of being in an updraft in the middle of the storm, the preceding minutes the lack of comms being a result of the crew navigating the turbulence as they entered the cell.

But the preceding minutes .14-.17 they seem to be travelling in a straight line at constant level, yet not responding to ATC (per the b&w track)
Then at .17 they start to turn left at the same time as climbing rapidly, before seemingly getting into a spiral and stalling

 

[juddles]

This incident is a reminder that no matter what training, no matter what the technology, things can go wrong. That crew were in a hell of a storm and they made mistakes and they died. Everyone should understand that these things happen.

I am a believer in the human element, the requirement for a human pilot to be available to make decisions. But that a pilot can stall a modern aircraft is unforgiveable.

 

[markis10]

But the preceding minutes .14-.17 they seem to be travelling in a straight line at constant level, yet not responding to ATC (per the b&w track)
Then at .17 they start to turn left at the same time as climbing rapidly, before seemingly getting into a spiral and stalling

No doubt what happened in those three minutes greatly changed the fate of the flight.

 

[juddles]

Spiral/storm/stall suggests to me that in that environment which includes the strident automatic warnings, the crew lost basic situational awareness.

 

[jb747]

The very high rate of climb is consistent with the speed loss...i.e speed is being traded for altitude. 12k would also be achievable, for a short period, simply by selecting a high enough nose attitude.

The speed decay is not consistent with an updraft. In that case, the air mass itself is doing the lifting, and if anything, you'll have a large speed increase as you try to stop the climb. Decay would be consistent with downdraft, but you don't climb in them.

I'm prepared to bet that somewhere along the way, one of the flight control protections will turn out to be involved.

 

[Awesom Andy]

I'm prepared to bet that somewhere along the way, one of the flight control protections will turn out to be involved.

I guess we will find out if it was the automatics or the human holding back the stick.

 

[jb747]

I guess we will find out if it was the automatics or the human holding back the stick.

It's the interface that can be the issue. For instance, the aircraft looks to have been stalled, but you shouldn't be able to do that in normal law, so the assumption would be that it has reverted to alternate or direct for some reason or other. Why...it doesn't just do that for fun.

The overspeed protection will cause the aircraft to pitch up, and the pilot cannot stop it. Pitching up, and then running out of airspeed (there was a 340 back in 2000 that almost had a mid air from this sequence...overspeed, pitch up, run out of airspeed, angle of attack protection, fly through (occupied) altitude above.

Holding the stick back made zero sense in the case of AF447. I don't expect the same thing here..but you never know.

 

[clazman]

My first stall training I dropped a wing and went into a spin due to my natural reaction which was apply some aileron to keep me level .... which just stalled the wing more and round and round you go....

 

[jb747]

My first stall training I dropped a wing and went into a spin due to my natural reaction which was apply some aileron to keep me level .... which just stalled the wing more and round and round you go....

Generally that's more a spiral than a fully developed spin. In most cases you need to really get the rudder and ailerons crossed up to get the yaw rate needed. In some aircraft, you can sit in a fully developed stall and simply play with it, as long as you're aware of what the rudder/aileron effects will be. Remember too, that spoilers are involved when talking airliners, and they will continue to work in the correct sense.

 

[juddles]

I guess we will find out if it was the automatics or the human holding back the stick.

Sorry, but I dont see the computer managing the spiral. Reeks of human error.

 

[jb747]

Sorry, but I dont see the computer managing the spiral. Reeks of human error.

By definition, the spiral is not managed. It isn't called a 'departure' for nothing.

Human error can happen at many points. It could be argued that allowing the engineers to include any features that cannot be overridden, but which will drastically change an aircraft's flight path, is a huge error.

Activation of the aircraft overspeed system can (and has) placed aircraft into situations from which a departure could happen. A safety system caused the QF72 pitch down event. A recent Lufthansa event also resulted in a pitch down that could not be overridden. There is no magic button that you can press to get rid of these systems.

 

[juddles]

..... It could be argued that allowing the engineers to include any features that cannot be overridden, but which will drastically change an aircraft's flight path, is a huge error.......

100% absolutely agreed.

 

[MEL_Traveller]

By definition, the spiral is not managed. It isn't called a 'departure' for nothing.

Human error can happen at many points. It could be argued that allowing the engineers to include any features that cannot be overridden, but which will drastically change an aircraft's flight path, is a huge error.

Activation of the aircraft overspeed system can (and has) placed aircraft into situations from which a departure could happen. A safety system caused the QF72 pitch down event. A recent Lufthansa event also resulted in a pitch down that could not be overridden. There is no magic button that you can press to get rid of these systems.

if these are potential design issues, perhaps a law suit against Airbus will go some way to drive a solution?

 

[Deleted member 29185]

if these are potential design issues, perhaps a law suit against Airbus will go some way to drive a solution?

Except we had the exact opposite comment following the MH370 disappearance. That is "why did the aircraft manufacturer build it so the pilots can override or isolate these systems"? I know we're talking about different aircraft systems, but we can't have it both ways. So who is going to be the governing body deciding which are the systems a pilot cannot fiddle with and which are the ones they can? Currently, I'm assuming it's the aircraft design engineers.

 

[MEL_Traveller]

Except we had the exact opposite comment following the MH370 disappearance. That is "why did the aircraft manufacturer build it so the pilots can override or isolate these systems"? I know we're talking about different aircraft systems, but we can't have it both ways. So who is going to be the governing body deciding which are the systems a pilot cannot fiddle with and which are the ones they can? Currently, I'm assuming it's the aircraft design engineers.

some decisions might be considered negligent, others might not. and you can even have it both ways... some systems which can and that can't be overridden.

if on any airplane a design flaw overrides something critical, there is potentially a case to be answered in negligence. A government would then need to overrule the court if it was to decide there should be a system which could lead to the loss of a plane. That's not usually something likely to happen.

As with all these things - it depends on the facts, and what a court ultimately decides.