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Air Asia Indonesia Lost Contact from Surabaya to Singapore

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Air Asia Indonesia Lost Contact from Surabaya to Singapore

Old 13th Feb 2015, 13:58
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Whut?

xcitation
From an interview I saw with an airbus test pilot, he said that they only test a stall close to the edge of the envelope with high energy.
Exactly what is a "stall close to the edge of the envelope with high energy"? I'm familiar with accelerated stalls, power-on stalls, power-off stalls, PA and CR configuration stalls, etc. but that's a new one to me.
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Old 13th Feb 2015, 14:38
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Energy Management

My understanding is that kinetic energy is the work done to accelerate the mass of the a/c. This is increased by engine thrust or trading potential energy (losing altitude and claiming the acceleration from gravity). If you have low PE and low KE then total energy is low which is very dangerous.

Update: Boeing have a good description here...Aerodynamic Principles of Large-Airplane Upsets (Aero Magazine, 1998 Q3 edition)

Last edited by xcitation; 13th Feb 2015 at 20:47.
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Old 13th Feb 2015, 20:35
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My understanding is that kinetic energy is the work done to accelerate the mass of the a/c. This is increased by engine thrust or trading potential energy (losing altitude and claiming the acceleration from gravity). If you have low PE and low KE then total energy is low which is very dangerous.
It's a while since I did A Level Physics but here goes:-

Gravitational potential energy is the energy stored in an object as the result of its vertical position or height. The energy is stored as the result of the gravitational attraction of the Earth for the object.
So the higher you are (above earth) the more the potential energy?

Kinetic energy is the energy of motion. An object that has motion - whether it is vertical or horizontal motion - has kinetic energy.
KE = 0.5 m (V)squared - where m is mass and V is speed. Double the speed and you quadruple the energy.
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Old 13th Feb 2015, 21:42
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X citation and others

Essentially what is being inferred here is that stall testing is done with a lot of potential energy. ie at a high altitude and not close to the ground.
In this context the comments (some of which have been allowed to stay) make sense. One does not practise stalls close to the ground even in a c152!

However your later comments re selecting flight idle and equating that with low energy are incorrect. For stall recovery the sequence has to be reduce the AofA then a short while later increase power. Selecting toga or equivalent merely causes a pitch up which makes reducing the AofA almost impossible.
Increasing the power does not increase'the energy state of the aircraft'.
In a stall situation you do not go faster nor do you increase altitude, you merely descend in a stable stall like AF.
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Old 13th Feb 2015, 22:13
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Originally Posted by henry crun
Scale effects well known.
Are they? Scale effects are expressed in the Reynolds number, which considers viscosity. Combine that with Mach number, which considers compressibility. Then you'll see the need for full-scale testing.
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Old 14th Feb 2015, 00:47
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To clarify my comment about idle detent; N1 take time to spool up when changing from prolonged idle to TOGA. This is another consideration when a/c is falling out of the sky and flight control is urgently needed e.g. Habsheim incident - low total energy, low N1. The impression I got from the airbus test pilot was that stall testing is done in a very controlled manner changing flight controls as little as possible. This protocol allows the a/c to return to the flight envelope very quickly with only small stall excursions. It's not cutting engines, full stick back, see what happens.
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Old 14th Feb 2015, 05:01
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From an image of wreckage, it seems that the screw was snatched during the impact. It remained attached to THS
http://www.mediafire.com/view/1hh6qg.../jackscrew.jpg
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Old 14th Feb 2015, 11:24
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Avoid stalling your swept wing jet aircraft

Risk avoidance will minimise the number of pprune threads like this one. The multiple factors that conspire to place a crew in risky situations need to be considered by all pilots. By the look of the number of accidents like this one, not all of us spend some quiet time at home thinking about the various scenarios and the choices that might be available to minimise risk.
It is OK to consider and practice in the sim for recovery procedures under difficult circumstances, but wouldn't it be heaps better to recognise the risk? Finally it is up to the captain, but the F/O is not in a comfortable position as the risk escalates. Some captains will have their own reasons why staying at F390 in increasing moderate turbulance is acceptable in an A320. A lower time F/O might accept an insufficient reason, like ATC clearance, reduced endurance, possibility of diversion or increased turbulence at lower levels.
I see no indication on these pages that companies are pressing ahead with avoidance training. Rather there seems to be so much discussion on recovery.

Last edited by autoflight; 16th Feb 2015 at 20:12.
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Old 14th Feb 2015, 21:27
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Xcitation
I take your point re testing in a very controlled manner, however when a real and unexpected stall occurs on the line, those involved have moved very far away from the contrlled environment of testing.
In the Bournemouth incident both crew were pushing full forward on the control column, but were unable to prevent the pitch increasing to arround 45 degrees. My point being that large control input is likely to be very necessary in order to be able to reduce aofa.
Your example proves how far removed real life can be from testing. No one flying on the line wants to go near the stall, but if they do it will be at the most inconvenient momoment and completely unexpected. Having a clear understanding of what to do is vital. Avoidance is the first step then recovery the second.
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Old 15th Feb 2015, 13:15
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I see no indication on these pages that companies are pressing ahead with avoidance training. Rather there seems to be so much discussion on recovery.
I must caution you here: Discussion on PPRuNe bears no resemblance to what companies are pressing ahead with.

Professional pilots are fascinated by other's mistakes (and so they should be) because that's how they learn not to repeat them. The reason threads like these go for hundreds of pages is that professional pilots see a colleague suffer a disaster and they want to know why.

In the impatience of awaiting the final report, they suggest solutions, but most of these solutions come from their creative thinking, not from research of what "those in charge of policy/training/manufacture" are actually doing about it. It's really annoying because those who are actually involved in improving policy/training/manufacture don't jump on PPRuNe every day with an update. Don't they understand the frustration this causes?

However, in direct answer to your question, "avoidance training" is not really something that can be taught in a simulator, or via newsletters/memos, or via flight manuals. This is learned on the line with experience. The only way to learn the best way to fly around thunderstorms is to spend years flying around them under the guidance of someone who has flown around more of them than you have.

Ideally, you fly in the RHS (or in some airlines as a relief pilot/cruise F/O) for many years and learn the avoidance strategies by being exposed to them over many years, with on-the-job guidance and advice from a more experienced pilot in the LHS.

Unfortunately, it doesn't seem to always pan out this way these days. For example, cadetships leading to rapid command promotion in rapidly expanding LCCs, by definition, jump this stage.

The old adage: you start with a full bag of luck and an empty bag of experience. Try to fill the bag of experience before your bag of luck runs out.

But that does not appear to be a factor in this particular accident - the F/O was inexperienced but mature, and the Captain was very experienced. We still don't know why Air Asia pitched up, stalled and stayed stalled. (If indeed that is what happened, we don't know yet.)

The investigators say they know why, but they aren't telling. Again, very frustrating.

In the case of Air France, experience/training was possibly very much a factor, as unfortunately the only chap capable of even recognising the problem (stall) was asleep. The situation may have been unavoidable, the recovery procedure was possibly known to the crew, but they failed to recognise the problem (experience? training?) so did not implement the recovery.
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Old 15th Feb 2015, 13:46
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Originally Posted by autoflight
Risk avoidance will minimise the number of pprune threads like this one. The multiple factors that conspire to place a crew in risky situations need to be considerered by all pilots. By the look of the number of accidents like this one, not all of us spend some quiet time at home thinking about the various scenarios and the choices that might be available to minimise risk.
It is OK to consider and practice in the sim for recovery procedures under difficult circumstances, but wouldn't it be heaps better to recognise the risk? Finally it is up to ther captain, but the F/O is not in a comfortable position as the risk escalates. Some captains will have their own reasons why staying at F390 in increasing moderate turbulance is acceptable in an A320. A lower time F/O might accept an insufficient reason, like ATC clearance, reduced endurance, possibility of diversion or increased turbulence at lower levels.
I see no indication on these pages that companies are pressing ahead with avoidance training. Rather there seems to be so much discussion on recovery.
On the contrary, it is companies that have only been doing avoidance training that has led to the current state.

* Anyone flying manually outside the immediate landing or takeoff gets snitched by FOQA and told to desist: the automatics are better than you are and this avoids the risk of something going wrong.
* If this (alert/instrument fail/behavior) happens then memorize this list of precise instructions and follow them. Get the PNF to read through and check that you have done them and nothing else.
* Sit in this reasonable simulation with critical unrealities every month and improve your by rote response to specific (alert/instrument fail/behavior)

These are all risk avoidance by the aircraft operators. To some extent one can understand their point. However, when the real LOC happens it is nothing like the SOPs/FCOM say and usually multiple things happen at once. Unlike the simulator there is negative and positive g, manuals, drinks, grit, EFBs flying everywhere about your head - you cannot even read the instruments and the ones that you have trusted for thousands and thousands of hours are not working. The training to reduce risk may have gone through the motions but the visceral reactions to unexpected g, airstream noises, perhaps even shouts screams and bangs from the passenger cabin. This sudden and extreme stress puts you right at the wrong end of the 'inverted U' ( Yerkes?Dodson law - Wikipedia, the free encyclopedia ) and leads to cognitive/attentional tunneling usually onto an incorrect area. The training in other words has not prepared the crews for what things could get like. But its difficult and expensive and 'how many of our aircraft will have that problem?' So it is not done. This is unfortunate because as people have said here if you actually _have_ experienced negative g, and recovering from an incipient spin _multiple_ times _and_ been scared a few times then you are likely to perform better. The psychologists call this 'stress inoculation', you are put in the situation and shown how to get out of it. Then when it occurs you are not pushed into cognitive decline by the stress and arousal levels.

The current system is built around avoiding nasty problems around the edges of the flight envelope and training people not to go there. The training is done in comfortable shirt sleeve environments without any physical stresses at all. The training and systems have no doubt increased safety but they have had the unfortunate side effect that when an aircraft is in a sudden upset there is a very much higher chance that the crew will not recover the situation. The very risk avoidance approach has increased the risk of crew poor performance with attentional tunneling due to stress and automation surprise at the very time that they become the sole people capable of recovering the situation.

So now take a many thousand hour fighter pilot and put that pilot in a shiny airliner with two underwing engines and go through all the risk averse training ticking all the boxes. That will NOT include stall or spin recoveries "don't even go there!". Then a few thousand hours into flying the airliner go from bumpy but normal flight in early daylight IMC to all the bells alerts cavalry charges and whistles 2 g zoom climb all inside 20 seconds followed (speculation alert) by a port engine compressor stall as the aircraft approaches apogee with full power on starboard - and the edge of the stall turns into a fast rotation into a flat spin driven by the 'good engine'. Hind brain training kicks in and what were the by rote procedures in the fighter aircraft - and they are implemented. However, the procedures for a fighter with roll/yaw diversion due to a weight concentrated in the fuselage is not quite the same as for a twin jet airliner with a dead engine but that is the practiced response and nobody bothered to erase that response with what to do in _this_ aircraft because we "don't even go there!"

So cautious stay out of trouble training needs to be looked at very carefully. As does the reality of what 'trouble' feels like. If crews felt that once - they may be 'inoculated' against the cognitive stress of its occurrence when it happens.
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Old 15th Feb 2015, 15:09
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Loud & Very Clear

Ian W's post below says it all.


"On the contrary, it is companies that have only been doing avoidance training that has led to the current state.

* Anyone flying manually outside the immediate landing or takeoff gets snitched by FOQA and told to desist: the automatics are better than you are and this avoids the risk of something going wrong.
* If this (alert/instrument fail/behavior) happens then memorize this list of precise instructions and follow them. Get the PNF to read through and check that you have done them and nothing else.
* Sit in this reasonable simulation with critical unrealities every month and improve your by rote response to specific (alert/instrument fail/behavior)

These are all risk avoidance by the aircraft operators. To some extent one can understand their point. However, when the real LOC happens it is nothing like the SOPs/FCOM say and usually multiple things happen at once. Unlike the simulator there is negative and positive g, manuals, drinks, grit, EFBs flying everywhere about your head - you cannot even read the instruments and the ones that you have trusted for thousands and thousands of hours are not working. The training to reduce risk may have gone through the motions but the visceral reactions to unexpected g, airstream noises, perhaps even shouts screams and bangs from the passenger cabin. This sudden and extreme stress puts you right at the wrong end of the 'inverted U' ( Yerkes?Dodson law - Wikipedia, the free encyclopedia ) and leads to cognitive/attentional tunneling usually onto an incorrect area. The training in other words has not prepared the crews for what things could get like. But its difficult and expensive and 'how many of our aircraft will have that problem?' So it is not done. This is unfortunate because as people have said here if you actually _have_ experienced negative g, and recovering from an incipient spin _multiple_ times _and_ been scared a few times then you are likely to perform better. The psychologists call this 'stress inoculation', you are put in the situation and shown how to get out of it. Then when it occurs you are not pushed into cognitive decline by the stress and arousal levels.

The current system is built around avoiding nasty problems around the edges of the flight envelope and training people not to go there. The training is done in comfortable shirt sleeve environments without any physical stresses at all. The training and systems have no doubt increased safety but they have had the unfortunate side effect that when an aircraft is in a sudden upset there is a very much higher chance that the crew will not recover the situation. The very risk avoidance approach has increased the risk of crew poor performance with attentional tunneling due to stress and automation surprise at the very time that they become the sole people capable of recovering the situation.

So now take a many thousand hour fighter pilot and put that pilot in a shiny airliner with two underwing engines and go through all the risk averse training ticking all the boxes. That will NOT include stall or spin recoveries "don't even go there!". Then a few thousand hours into flying the airliner go from bumpy but normal flight in early daylight IMC to all the bells alerts cavalry charges and whistles 2 g zoom climb all inside 20 seconds followed (speculation alert) by a port engine compressor stall as the aircraft approaches apogee with full power on starboard - and the edge of the stall turns into a fast rotation into a flat spin driven by the 'good engine'. Hind brain training kicks in and what were the by rote procedures in the fighter aircraft - and they are implemented. However, the procedures for a fighter with roll/yaw diversion due to a weight concentrated in the fuselage is not quite the same as for a twin jet airliner with a dead engine but that is the practiced response and nobody bothered to erase that response with what to do in _this_ aircraft because we "don't even go there!"

So cautious stay out of trouble training needs to be looked at very carefully. As does the reality of what 'trouble' feels like. If crews felt that once - they may be 'inoculated' against the cognitive stress of its occurrence when it happens."
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Last edited by formationdriver; 16th Feb 2015 at 16:30. Reason: spelling
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Old 15th Feb 2015, 15:36
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"The current system is built around avoiding nasty problems around the edges of the flight envelope and training people not to go there."

Even that gives the current strategy too much credit. It is in fact just about reducing costs and making money. For money-men pilots are an inconvenience to be eliminated as quickly as possible.

Pilots used to be almost worshipped ! The captain of the skies. It was an honour to meet one or visit the cockpit and see those stripes on the shoulder.

Travelling to Asia used to be a once in a lifetime thing, a strange world with strange food and exotic culture. Now busloads go and sit in concrete boxes and etc...

For those in the industry, like in all industries in this age, one must be quite sly to get the best out of it. You must know the money-agenda of the corporations ... no matter what their PR people say in public.

They demand that you robotise your flying behaviour to keep your job ... and yet you may meet a situation where only your skill wits and knowledge is going to save your backside.

If I was a pilot I would certainly be plugging into the simulator all the serious air incidents that affect the models I fly, and going over them until I know exactly what to do to get the best outcome. Without necessarily telling the company what I am doing.

It is interesting if these pilots tried to switch off the computers. It may indicate that they were trying to avert AF447 but hadn't studied the case well enough.

It's one thing talking about life-saving manoeuvres on the internet, but unless you have disciplined yourself to practice them over and over and over again until you are certain, absolutely certain what and why and how ... if you haven't, then if the time comes you will either sit like a rabbit in headlights ... or make a mess of it.
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Old 15th Feb 2015, 18:42
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They demand that you robotise your flying behaviour to keep your job ... and yet you may meet a situation where only your skill wits and knowledge is going to save your backside.
rideforever, that is so true - one of the best statements I've seen on PPrune for quite a while - thanks!
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Old 16th Feb 2015, 19:54
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UPRT Needed

As Ian W stated in his previous reply (excellent insight!), we really have a problem with getting all commercial pilots to train for unexpected upsets to react instinctively - not with primitive brain (which seems to be pull, pull, pull!!).

A simple Google search "loss of control LOC airliner accidents" turned up an interesting article:

http://ntrs.nasa.gov/archive/nasa/ca...0100030600.pdf

that systematically looks at over 100 Loss of Control accidents (they are even listed in the Appendix). We have a serious problem and only radical training can deal with it. When we had Controlled Flight into Terrain as the most serious accident cause, the airline industry spent large sums to deal with it in adding the Enhanced Ground Prox system. Unless we design and incorporate a FlyByWIre Upset Recovery System, we must spend the sums to train our pilots to focus on Push-Power-Roll sequences that will save the aircraft. That same Google search pointed to a company that is already providing the type of upset training that is required -
Upset Recovery Instruction, Aerobatics Flying, Spin/Stall Flight Training - take a look!

Last edited by whitav8r; 16th Feb 2015 at 19:57. Reason: typos
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Old 16th Feb 2015, 20:48
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Hope they know what they are teaching. Aerobatic aircraft techniques will have the tail separating from a big jet.
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Old 16th Feb 2015, 21:08
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IcePack

I dont think aerobatics a large passenger aircraft would be in the syllabus somehow.

I would think they try and teach the recognition and the best way to recover from usual attitudes, by putting the least amount of G on any aircraft.
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Old 16th Feb 2015, 21:59
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Hope so, but the way some talk on this thread the mind boggles.
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Old 16th Feb 2015, 23:06
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@rideforever

Even that gives the current strategy too much credit. It is in fact just about reducing costs and making money. For money-men pilots are an inconvenience to be eliminated as quickly as possible.

Pilots used to be almost worshipped ! The captain of the skies. It was an honour to meet one or visit the cockpit and see those stripes on the shoulder.
And yet... Flying now is indisputably safer than when pilots were 'worshipped'. Would you like a few more deaths from avoidable accidents just so the self loading freight down the back could be reminded just how much respect they need to show the pilot? Maybe the odd manufactured 'emergency' to remind them how grateful they should be to the gods of the skies? Yep, turn off the automatics and lets get back to it being a man's game, where there are no old bold pilots but by God the passengers went down screaming the captain's name out of respect rather than terror when he screwed up and killed them all.

When deciding that is the case, perhaps you should also ask the surgeon the next time you go into hospital if he wouldn't relive the glory days by operating on you half cut with a fag in his mouth and without using any modern machines. After all, medical personnel also used to be gods - back in the days when many more people died on operating tables.

Taking the train was much more adventurous back in the day as well of course, before automatic train protection systems and all that bloody technology came in to stop every boy dreaming of being a train driver. OK, so a few people died, but hey the driver was having more fun and that's what's important right? Turn off the TPWS and lets have the oil lamps and semaphores back.

I'm afraid it's happened to every industry. It's called maturing. The first few people are pioneers, who succeed on luck as much judgement. That doesn't last, and eventually professional standards take hold, and the old guard moan that it was more fun when the odd ****up (even if fatal) was a risk it was acceptable to take. Plus ca change. The only difference is that pilots got the god-complex bug even more than most.

Travelling to Asia used to be a once in a lifetime thing, a strange world with strange food and exotic culture. Now busloads go and sit in concrete boxes and etc...
And you see that as a bad thing do you? All those bloody peasants, being allowed to travel! Don't they know aviation is only for the elite, for heavens' sake?!
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Old 16th Feb 2015, 23:53
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Originally Posted by Slfandproud
Flying now is indisputably safer than when pilots were 'worshipped'.
We do have a chip on our shoulder, don't we? The main reason that flying safety has increased is because of things like TCAS, EGPWS and FMS based approaches. It's got almost nothing to do with the lessening of the macho heros. In fact, you're very lucky flying was as safe as it was in the old days; only because of the skill of the pilots. Now that the beancounters, aided and abetted by the regulatory authorities, have diminished pilot's flying skills by reducing/eliminating SIM practice time to compensate for reducing on-the-line hand flying, we are seeing a rise in the number of LOC accidents. So how about giving the pilot/doctor-bashing a break?

pointed to a company that is already providing the type of upset training that is required -
This could easily be achieved in our current Sims. There just needs to be the will.
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