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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 21st Jan 2015, 14:20
  #2301 (permalink)  
 
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Cb and Tornado

Emacs thanks for the link,
A0283 thanks or your information,
MrMachfivepointfive for the translation.

Though I had seen in 1982 the original report, after I had left Incident and Accident investigation, I had forgotten the Tornado detail, but remembered the Squall line like frontal system with embedded Cb´s.
But more important is the detail of the extreme high accelerations of +6.8 and -3.2 g. It is a very good indication of the inherent forces in those airstream inside a weather build up.

I know from experience that it is a better approach to the truth by waiting for the investigation results, than starting wild guesses and assumptions. So lets wait and see.
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Old 21st Jan 2015, 15:23
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Some pages ago someone wanted som number crunching: forces needed, etc. I can't find that post right now, but here are my attempts.

Case scenario: (all numbers taken from Airbus A320 family - Wikipedia, the free encyclopedia)

ASSUMPTION: A320-200 flying at cruising speed 828km/h and 11000m with total weight 78t = 78000kg.

Climb 2000m in one minute = 33,333333m/s = 120km/h

828km/h = 230m/s

Baseline kinetic energy = 2,06e+9 Joule (Nm)

Work needed to lift airplane 2000m = 0,64e+9 Joule (Nm)

Interesting fact is that max allowed speed for A320-200 at 11000m is 871km/h and if some of those 120km/h updrafts added a forward component, an overspeed scenario is likely.

I have deliberately calculated with the max allowed weights and cruising speeds, anything slower and lighter than this would of course be greatly beneficial. I did not calculate any inertia because this would be much too complicated and I really don't have time today.

EDIT: I am very happy to see the Indonesians work so tirelessly and be so committed to this. Awesome effort by the divers, I really hope they get recognized for the extremely dangerous and mentally exhausting work they do. I wonder if there is some way to show appreciation from around the world to those guys.

Last edited by MrSnuggles; 21st Jan 2015 at 15:30. Reason: Forgot brave people...
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Old 21st Jan 2015, 15:50
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So far there have been a lot of good suggestions re training for high altitude turbulence, stalling, and even spin recovery. However, as many have pointed out, the first priority is to avoid the extreme weather. There is a long history of jet fighters being lost in large CBs because they lacked any weather radar and yet they were stressed well above airliners' G limits and had much higher control response.

We can't properly simulate really severe turbulence, so the training - as for ditching - has to be rather arbitrary. There is a lot more we can do in regard to weather avoidance at reasonable cost/risk benefit by integrating weather data sources and I hope at least that this tragedy will spur greater efforts in that direction.
....... <snip>
There is a lot of 'noise' in this thread, avoiding the core issue, well written above by RifRaf3 in post #2240.

From my perspective, a humble (former) PPL holder, avoiding the extreme weather, seems to be a minor issue as far as this thread is concerned.

The thinking seems to be that with the aid of technology, experience, and bit of good fortune, a pilot should be able to "thread the weather" (as close as possible), without "getting bitten".

Instead of discussing recovery techniques after the accident, maybe more discussion on prevention ?
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Old 21st Jan 2015, 16:23
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mstram:

From my perspective, a humble (former) PPL holder, avoiding the extreme weather, seems to be a minor issue as far as this thread is concerned.

The thinking seems to be that with the aid of technology, experience, and bit of good fortune, a pilot should be able to "thread the weather" (as close as possible), without "getting bitten".
I absolutely agree. There has been numerous accidents due to bad weather and humans get-there-itis. I saw one interesting piece on some channel a while ago - a plane heading for Little Rock, Arkansas, all the while knowing there was going to be thunderstorms. Of course they crashed. While this crash apperently is featured on TV, there are tons and tons of other crashes where pilots forgot(?) to turn on CAUTION WEATHER in their heads. Delta 191, the Polish President plane in 2010, AirFrance on a few occasions, a Peruvian airline a while ago, TACA airline that suffered double engine flameout over the Mexican Gulf and so on.

So, how should professional airliner pilots begin to avoid obvious weather hazards? Is it not part of common sense? How does one avoid get-there-itis? When does the Capt stand up and say "enough is enough, I've had it, let's get out of here" due to common sense and a wish to avoid damage to anyone on board? How much is Capt burdened by penalties for diverting or holding until it's safe, no matter the late arrival?

I do not count "invisible" weather phenomena here, like downdrafts from hills, clear air turbulence or volcanic ash esp during night. Reason: Much more unpredictable and hard to see even in broad daylight.
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Old 21st Jan 2015, 16:34
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Threading weather

There's a lot of focus on the excessive climb and descent rates, and a lot of previous conjecture about why the pilots would have made the wrong decision. Until we are certain otherwise, I prefer to give the pilots the benefit of doubt as to their experience and judgment in the moment, and suggest they may have done exactly what some said they should have done: request an altitude deviation and then when that was not forthcoming, initiate it anyway because they had good reason to. If that happened the pilots could have been responsible for the initial portion of the climb angle, to which was then added an unfortunate happenstance in the form of a strong updraft or other turbulence that contributed the rest of the climb angle, resulting in the (apparent) rapid climb and apparent subsequent rapid descent which conjecture suggests was due to loss of speed and stall.

If the Very Best Pilot would have initiated a climb based on the info he had, made during a period when instruments were completely functional and distractions were minimal or zero (distractions not yet having begun), and chance then gifted him at exactly the wrong moment with the bad luck of a weather condition that he quickly realized was putting, or had already put his AC in a dynamic position beyond its capabilities, and THEN the distractions set in with a vengeance, the very best pilot would have done everything right, according to all the books and best known practices, but had found himself in a situation where recovery was very unlikely. More than one cause, as the quotes have said.

mstram, I think others have clearly pointed out that airline routes are generally established leaving pilots with the task of transiting storm lines by smaller course deviations. As has been written, if pilots had the lattitude to avoid all possibly dangerous weather, a lot of flights would not fly, and those pilots would be out of a job.

Screaming headlines: screaming alarms probably came after things had gone awry, not before. Headlines care less about timing than about screaming.

Last edited by Leightman 957; 21st Jan 2015 at 16:45. Reason: screaming alarms
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Old 21st Jan 2015, 16:41
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AirAsia jet's alarms 'screaming' at crash

From Sydney Morning Herald 22 Jan 2015

AirAsia jet's alarms 'screaming' at crash

Jakarta: Warning alarms in AirAsia flight QZ8501 were "screaming" as the pilots desperately tried to stabilise the plane just before it plunged into the Java Sea last month, a crash investigator says.

The noise of several alarms - including one that indicated the plane was stalling - can be heard going off in recordings from the black box in the Airbus A320-200's cockpit, the investigator told AFP, requesting anonymity.

"The warning alarms, we can say, were screaming, while in the background they [the pilot and co-pilot] were busy trying to recover," the investigator said on Wednesday, adding the warnings were going off "for some time".

The investigator, from Indonesia's National Transportation Safety Committee, said the pilots' voices were drowned out by the sound of the alarms.

The revelation came a day after Indonesian Transport Minister Ignasius Jonan said the plane had climbed abnormally fast before stalling and plunging into the sea, during a flight on December 28 in stormy weather from Indonesia's Surabaya to Singapore.

"In the final minutes, the plane climbed at a speed which was beyond normal," the minister told reporters.

The plane crashed in shallow waters with 162 people on board, but so far just 53 bodies have been recovered.

Divers have been struggling for a week against rough seas and strong currents to reach the plane's main body, which was spotted on the seabed and is thought to contain the bulk of the remaining passengers and crew.

The two black boxes - the cockpit voice recorder and the flight data recorder - were recovered last week after a lengthy search, and investigators are expected to complete a preliminary report next week.

As well as the cockpit voice recorder, the NTSC is examining a wealth of information in the flight data recorder, which monitors every major part of the plane.

They are focusing on the possibility of human or aircraft error, after ruling out terrorism following an analysis of the cockpit voice recorder.

Committee head Tatang Kurniadi said the preliminary report into the crash would be completed on Tuesday, a month after the accident. He said the full report would not be released publicly, but the media would be told some of its contents.

There was a huge international hunt for the crashed plane, involving ships from several countries including the US and China.

All but seven of those on board the flight were Indonesian. The foreign nationals were from South Korea, Singapore, Malaysia, Britain and France.
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Old 21st Jan 2015, 16:42
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Get there itis

Get-there-itis mostly results from the airline schedule which many people depend on. Leaving "sometime today when the weather is good" means passengers will flock to other carriers. A lot can happen, very quickly in a 2, 4 or 12 hour flight when weather varies from the forcast.
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Old 21st Jan 2015, 17:09
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Get there

From what I have read, threading through the Cbs is an absolutely essential requirement if a scheduled airline service is to be provided in this part of the world. 99.99X% of the time flights arrive successfully and everyone is happy.

Now, let's assume that the pilots of this flight did everything right. It might not have mattered whether they were flying an Airbus, a Boeing, or a highly stressed military jet. History tells us that 'Thunderstorms are the world's biggest distributors of used aircraft parts'. Actually they probably aren't but you get the idea. The forces involved in extreme thunderstorm encounters can break aircraft regardless of pilot actions. The question is, what is the value of X such that 100-99.99X% doesn't represent more losses than are acceptable? Improved weather radar, improved training, improved flight planning, changes to FBW philosophies etc may all reduce the accident risk but flying - already just about the safest form of transport - is never going to be 100% safe, and no aircraft is ever going to be capable of withstanding the forces inside every Cb.

The investigation will no doubt do its best to fulfill its obligation to try to make recommendations that will reduce the risk of a recurrence However, I believe that for as long as airlines provide a flight schedule that involves threading through Cbs, there will always be a risk of accidents. If there is a risk, then by definition, accidents will occur from time to time.
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Old 21st Jan 2015, 17:12
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Threading Weather

IIRC from my USAF days, USAF aircraft were required to stay 20nm away from thunderstorm cells - and maybe farther on the downwind side (it's thirty+ years ago so I may be misremembering the details). I also seem to recall that at the time, the airlines were using five miles as an adequate safety margin.

Does anyone know if this is still the case? If so, is it possible that the airlines are a little too brave for their own - not to mention their passengers' - good?
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Old 21st Jan 2015, 17:23
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Airlines have their own guidelines but ours are to avoid yellow and worse returns on the weather radar by at least 20nm.

This is, of course, almost impossible in many parts of the world unless you leave the aircraft in the hangar. The area around where the Air Asia was lost is one of them.
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Old 21st Jan 2015, 17:30
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The FAR/AIM also states 20nm.

I am wondering why ATC did not reroute these planes in this area prior to takeoff and during their fights without the crew having to request a reroute or altitude change. It’s very clear that the storm 8501 entered was a large building level 4 or 5 thunderstorm wall running up to the east side of Singapore and then south a few hundred miles (see radar image for that morning). It was clear on the radar to the west of their route. If this wx in this region is typical for this time of year ATC must have a reroute action plan for aircraft in place. Lots of dominos caused this accident.
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Old 21st Jan 2015, 17:34
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Originally Posted by Leightman 957
There's a lot of focus on the excessive climb and descent rates, and a lot of previous conjecture about why the pilots would have made the wrong decision. Until we are certain otherwise, I prefer to give the pilots the benefit of doubt as to their experience and judgment in the moment, and suggest they may have done exactly what some said they should have done: request an altitude deviation and then when that was not forthcoming, initiate it anyway because they had good reason to. If that happened the pilots could have been responsible for the initial portion of the climb angle, to which was then added an unfortunate happenstance in the form of a strong updraft or other turbulence that contributed the rest of the climb angle, resulting in the (apparent) rapid climb and apparent subsequent rapid descent which conjecture suggests was due to loss of speed and stall.

If the Very Best Pilot would have initiated a climb based on the info he had, made during a period when instruments were completely functional and distractions were minimal or zero (distractions not yet having begun), and chance then gifted him at exactly the wrong moment with the bad luck of a weather condition that he quickly realized was putting, or had already put his AC in a dynamic position beyond its capabilities, and THEN the distractions set in with a vengeance, the very best pilot would have done everything right, according to all the books and best known practices, but had found himself in a situation where recovery was very unlikely. More than one cause, as the quotes have said.............................................
............................................................ ...................
I can't imagine a scenario where an airline pilot would attempt to climb to avoid a threatening Thunder Storm. I have requested a climb near thunderstorms many, many times, but it is for for smoother flight conditions and possible better forward visibility. (they may have been in cloud at FL320)

Are you seriously suggesting that they initiated a climb without an ATC clearance because they thought they could out climb a CB in the ITCZ?

Pilots avoid weather every day by flying around it not over it.

Why would you think the ATC authorized course deviation that they had was not enough?
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Old 21st Jan 2015, 17:43
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Radars & radars

Not all radar are the same, like most things on aircraft you can go for the basic spec, i.e. no window blinds cabin or cockpit, monochrome FMC, ACARS, the list is endless, but having flown some recent build aircraft with top of the range multi scan Radar these are a vast improvement over earlier models and in my view essential if you need to thread through CB's

Your airline also needs to invest in the training to understand the risks and how to mitigate against them.
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Old 21st Jan 2015, 17:48
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I have avoided posting until now. If the conditions where really that bad, perhaps they should have just turned around and gone back. And FWIW, I'm a 777 Captain, with 22000 hours.

I think we need to wait to see what the data gives. But maybe it will show there are a few ( remote) times you have to say, we can't do this, and head back home.
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Old 21st Jan 2015, 18:41
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Boeing Stall Flight Test

@tdracer, 19 Jan 2015, 11:22

This sounds similar to what you described, but in a 727 -- written by the Boeing test pilot's daughter:

Seattle Magazine | Arts & Culture/Arts & Entertainment/Literature | Seventeen Seconds in the Life of a Boeing Experimental Test Pilot

"And even though my father had learned from past experience to watch this particular FAA pilot closely because of his tendency to pull back too far on the control column, Dad said he was still taken by surprise when the guy abruptly pulled back so hard that the 727 entered an extreme angle of attack—70 degrees rather than the usual maximum of 25 to 30 degrees—what an aerobatics pilot would do to start a snap roll or a spin. Suddenly, unbelievably, they were in a deep stall."

"After losing nearly 4,000 feet in altitude, the wings finally regained normal lift and the 727 leveled off."

"When the flight test data recordings were later analyzed, the angle of attack trace was off the scale. For seventeen long seconds the elevators were full down (control column full forward) and no air speed data were recorded as the 727 simply fell back and down toward the earth, seconds that felt like an eternity to those onboard."
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Old 21st Jan 2015, 19:05
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Why oh why

Saigon I completely understand the reasons why climbing near a cb would not be wise. The uniform opinions by posters here do nothing but confirm that. But we can't exclude that possibility as the pilot's best solution in the moment, hypothetically based, as I said, on a best case scenario with few distractions and all instruments operational and accurate. We all would like to think that everything performed perfectly because if it didn't, trying to figure out what exactly did happen just gets a lot more complicated. Others here have stated that if suitably motivated they would do what they felt necessary and then inform ATC. 8501 would have known (and even perhaps had time to check) that they were not CLOSE to the other flights in the area but had a 15 mile separation, as other posters here have also pointed out.

What a pilot initiated climb rate at that altitude does do is reduce the weather's role that resulted in the steep climb that people are currently trying to justify only by weather. That is not at all so say that weather by itself couldn't have caused the climb, but it does reduce the severity of the weather necessary to cause the climb, increases the probability of weather as a contributing and not primal role, and reduces the magnitude of the pilot's error closer to the actions a broader spectrum of pilots might have taken. That in turn helps bring the event back out of the 0.0001% probability range by some orders of magnitude ie, brings it back closer to real life rather than a rare exception.

If you prefer, don't give the pilot the benefit of doubt and assume he made a bad decision to climb. He would have made a 'normal' climb, not the high rate of climb that radar apparently shows us. Discounting for the moment some other cause, the pilot's climb rate was augmented by something else with the combined rates producing an unsustainable rate.

And I don't mean to ignore nose, cabin and other such posts:
http://www.pprune.org/rumours-news/5...ml#post8834676

>Why would you think the ATC authorized course deviation that they had was not enough?

Combined human actions did not prevent an accident, that's really all I can say.

Last edited by Leightman 957; 21st Jan 2015 at 20:45. Reason: add automation, cull flippancy
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Old 21st Jan 2015, 19:21
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my first impression is that the 7000 fpm climb is not necessarily pilot induced but instead it is a 7000 fpm updraft in a CB .

Which in turn will strongly reduce IAS and increase AOA : hence the stall .

Is nobody there thinking about this ?
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Old 21st Jan 2015, 19:30
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Dual pitot static failure

In normal law a dual pitot static failure, (ie ICE)
will cause a result similar to this.

Logic is the computer follows the two inaccurate ASI which over read ie barber pole.
This will Cause alpha floor and with 15 degrees air nose up. See standby ASI, decreasing (good indication) see power vs attitude in qrh.

Full stick down will not respond in normal law.
I tried this in the simulator some time ago in 2001 (it may have changed.)
Quite scary for the poor trainees.
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Old 21st Jan 2015, 19:35
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I have avoided posting until now. If the conditions where really that bad, perhaps they should have just turned around and gone back. And FWIW, I'm a 777 Captain, with 22000 hours.

I think we need to wait to see what the data gives. But maybe it will show there are a few ( remote) times you have to say, we can't do this, and head back home.
Am with you! I believe I made this point very early on in this thread.

Certainly I'm aware of colleagues that have done so on quite a few occasions when involved with flights close to the ITCZ etc
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Old 21st Jan 2015, 19:38
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Tragic

glendalegoon

I think THEY hit an energy enhancing event (ie updraft etc). the plane reacted by trying to hold altitude, OVERSPED, then pulled up, trimmed up, THEN GAVE UP

and the pilots suddenly were in alternate 2 or direct law and forgot to manually trim nose down

stall,
Ice crystal icing, blocked pitots, the aerolane thinks it oversped, then pulled up, overriding the pilots, stalled, got confused and gave up.

How many Airbus incidents have had confusion over what the laws were meant to be doing in the control environment? And, yes I have nearly 5000 hours flying the euro version.

Last edited by maggotdriver; 21st Jan 2015 at 20:17. Reason: nose,cabin posted as I was writing, I agree completely..
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