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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 8th Jan 2015, 17:46
  #1561 (permalink)  
 
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@propduffer

8501 was in a busy airway, with another a/c at 36,000ft (I think?) coming along less than 15 miles behind, and crossing traffic at higher altitude up ahead. If an updraft was taking him through FL360 with dropping airspeed, he might be concerned about ATC not being able to manoeuvre everything else out of his way in time?
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Old 8th Jan 2015, 19:10
  #1562 (permalink)  
 
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Thermalling an A320

Propduffer, I think your post is a bit cheeky. Us glider pilots are generally a very respectful bunch. The suggestion that the pilot was trying to (or perhaps failing to) thermal his A320 is a bit disrespectful. Whatever happened, the pilots were clearly overwhelmed by the situation.
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Old 8th Jan 2015, 19:29
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@dash34 re: Propduffer -- I agree too cheeky in this tragedy, but I think he was (very clumsily) trying to make a different point about possible dangers of an artificially strict adherence to assigned FL (by pilot, but mainly by FMC) in extreme vertical weather. (Gliders seek out and utilize moderate vertical weather; airliners don't.)

Other questions in here about a primitive "fixed (gyro-only) attitude and power mode" for penetrating such weather (i.e. ignoring altitude and airspeed changes (within reason)) are getting at the same question/concern.

I mean there has to be some (rare but sometimes encountered) point where dangers of disorientation and/or FMC-caused extreme attitudes outweigh the danger of encountering another aircraft.

Last edited by jientho; 8th Jan 2015 at 19:49.
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Old 8th Jan 2015, 19:49
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@Volume
This is wrong as well. Please have a look at the available FDR data first. What triggered the trim movement was several short nose up inputs during a time during which the main inputs were left-right. The 4 minutes of stick back (a shorter, but still extremely long time even full back) were applied after the trim had already reached the full nose up stop, when basically all was done already, and the nose was even dropping below the horizon, which can somehow explain why full nose up inputs were given at that time. This does not mean, the systems brought down this plane, of course it was the pilot doing unbelievable errors in understanding the situation and steering the plane ignoring all procedures and hand flying basics. But he was not acting as stupid as it sometimes is stated in an enormously simplified version of the event.

For the time being I can see no link between both cases, except that it happened over water with severe thunderstorm activity in the area. But this time it was early dusk, not pitch dark night. I find it highly unlikely that similar attitude deviations remain unnoticed if you have some outside reference. I find it highly unlikely that a climb was not noticed, when such climb was requested but explicitly disapproved by ATC.
I recall that the trim works as an averaging function of the pilot inputs. PF on 447 was "mixing the mayonnaise" using the side stick with strong bias to nose up function. If he had mixed mayonnaise totally randomly then trim averaging function would have been zero, no trim.

I find it hard to fathom that it could be the same as AF447. However how can we ignore the coincidences: possible ITCZ CB penetration, possible climb towards the top of the altitude envelope in warm air, possible max trim. At the least I think you will agree there is a high probability of pilot overload as a common factor.
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Old 8th Jan 2015, 20:02
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I wasn't referring specifically to this incident, we don't even know for sure if my question relates to QZ8501.

My question was about how any or all transport pilots handle a strong updraft scenario. The glider reference was made just to make the point that being caught in an updraft is not a life threatening event. I left unsaid that I think putting a jet airliner in a vertical dive, especially with full power is almost certain to be a life threatening event. So it seems to me that SOP in the transport world is (in this case) far too focused on avoiding stalls while tending to ignore something far worse.

More to the point: Lessons Learned

Dash34
I am a glider pilot. And my point wasn't about "thermaling", is was about heads up seat of the pants flying. Realizing what is dangerous and what is not.
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Old 8th Jan 2015, 20:16
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Propduffer:
What I was taught for thunderstorms by an old time airline pilot was what he called "soft ride". Autopilot in wing leveler mode - all heading and altitude controls off - power for Va, and keep wings level. Let the plane ride the up and downdrafts with gentle corrections and ease the plane back to your heading. Sure to drive ATC nuts but keeps stress low.
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Old 8th Jan 2015, 20:24
  #1567 (permalink)  
 
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island_airphoto

That makes sense to me.
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Old 8th Jan 2015, 20:38
  #1568 (permalink)  
 
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8501 was in a busy airway, with another a/c at 36,000ft (I think?) coming along less than 15 miles behind, and crossing traffic at higher altitude up ahead. If an updraft was taking him through FL360 with dropping airspeed, he might be concerned about ATC not being able to manoeuvre everything else out of his way in time?
Is TCAS useful in that situation?
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Old 8th Jan 2015, 21:10
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Is TCAS useful in that situation?
TCAS would alert other aircraft, of course, but it's a last resort, and other a/c may be equally challenged by the conditions and not well placed to take evasive action.
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Old 8th Jan 2015, 21:52
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@propduffer

In all my thermalling in gliders, I never once was in fear of having its wings fall off. That's because the gliders I've flown (ASK25/Discus/Duo Discus/Nimbus) are rated to +6/-3G, plus margin.

You're forgetting that an airliner does not have those limits, they're only rated from +2.5/-1G, a load factor *easily* achieved or exceeded when penetrating or washing out of a hefty CB updraft. That's why in the Airbus flight control computer logic, load limitation ranks supreme to the point of deploying spoilers to decrease lift and positive G moment. Also, you're forgetting that turbulence near the performance envelope's end is a very different story than down low where you have ample reserve to deal with over/under speed situations. At FL360, the A230 has probably 30 odd kts of range between overspeed and onset of the yellow ribbon... that's not much to play with when your coffee goes flying over the dash and into your controls. Speaking of which, there's another theory for the theorists amongst you: avionics malfunction due to spilled coffee in turbulence. >:->

But in terms of flying my 744 into a CB, I will do anything I can to avoid overstressing the old lady, and any equally trained airline pilot will, too. That includes announcing an altitude block to ATC (formally it's a request, but ATC knows there's nothing I can do so they comply).

Perhaps we can just this once exercise restraint at blaming incompetent crew. Just because they're flying for a third world low cost carrier doesn't mean they weren't decent pilots. The only evidence we have thus far is

1) some combination of airframe and cockpit crew was likely responsible for this crash
2) lots of other flights in the vicinity did not encounter problems

hell for all I know they got hit by a meteorite.
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Old 8th Jan 2015, 22:08
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Yes I think Propduffer was being a bit irreverent...

On the glider pilot /updraught debate it has been my experience that when entering a thermal/updraught things in practice are not necessarily what one might imagine, as far as threat of a stall is concerned.

Because there is a net addition of energy to the aircraft 's frame of reference by buoyant rising warm air airstream, equivalent to an accelerated state, there is little or no danger of stalling... and leaving the pitch state and trim alone is a very reasonable course of action.*

...with the proviso on freedom of altitude change**

The danger is having net aircaft energy (PE + KE) reduced... classic wrong end of windshear
or entering downdraught - what a glider or low wing loading pilot would call 'going over the falls'.
that's when we need to stick forward and keep the a/c flying.

... it is unfortunate that these basic micrometeorology principles seem a world apart from a modern pilots training or experience.

and I think a point worth thinking through.

On another tack... I am reflecting on any part the Maint. Tech may have played if in the cockpit.

** in CB weather / ITCZ regions why are aircraft being vectored with no regard
for prevailing or likely weather/upset. Common sense would dictate much wider margins
And altitude freedoms ?

Last edited by HarryMann; 8th Jan 2015 at 22:45.
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Old 8th Jan 2015, 22:09
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physicus sez:
hell for all I know they got hit by a meteorite.
By Jove, that's the first sensible thing said in this whole thread!
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Old 8th Jan 2015, 23:26
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A couple of things: Is that the FDR at the bottom of the photo in post #1570 ? And in the photo in post #1567, it appears that we are seeing the from the 'C' in the registration number forward on the left side (PK-AXC, that piece being upside-down). The break being behind that, wouldn't this be the forward section of the plane (or part of it)? Not the tail.

If that is the FDR, actually mounted to the pressure bulkhead, and if this is where the fuselage broke, the recorders could be in the debris between the sections.

And now that the tail (and other parts) have been located, has anyone reported hearing a pinger?

Last edited by EEngr; 8th Jan 2015 at 23:27. Reason: fixed missing word
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Old 9th Jan 2015, 00:01
  #1574 (permalink)  
 
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From what I've read here and elsewhere it seems that if a transport pilot who is trying to climb finds that he is ascending at a high rate (say 9,000 fpm), with airspeed dropping, the reaction from the pilot (or Hal inthe case of Airbus) is to pull out all the stops and push the yoke or the sidestick forward as far as it will go and even adjust stabilizer trim to get more nose down pitch - right?
Boy it's nauseating reading all the amateur speculation on this thread. What is written above is akin to saying " From what I've read it seems that if a builder who is trying to build a house finds that the walls are falling down, his reaction is to whip out his mobile phone and order the concrete truck to return and then put more concrete in the foundations while using stainless steel brackets to reinforce the internal walls".
Seriously, that's how stupid it sounds to an airline pilot.
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Old 9th Jan 2015, 00:16
  #1575 (permalink)  
 
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Someone mentioned earlier in the thread, that this crash seemed like the one where the Air New Zealand plane was coming off lease and was being checked, before being returned to Air New Zealand from a German airline. It crashed into the Mediterranean, because both angle of attack sensors froze due to water getting in them, when the plane was pressure washed instead of dusted off. They worked fine at first, then froze at altitude. The computer didn't have the right inputs and didn't realize anything was wrong, and the pilot wasn't able to figure out the problem and take over from the computer in time, because everything happened so quickly. That was in good weather. This Air Asia crash, if it's similar to the Air New Zealand crash, was in bad weather making diagnosis and recovery even harder, so even with the best pilots, they may not have had a chance to recover. All their effort had to go to working the problem, so that may explain why ATC couldn't get them on the radio, even though they still saw them on radar for little while.
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Old 9th Jan 2015, 01:16
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woora

the title of the forum is PROFESSIONAL PILOTS...etc

granted a commercial pilot license would qualify too, forgive me comm

do you earn your living as a pilot? if not, at least state it in the body of your post...I won't take the time to look up your profile.
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Old 9th Jan 2015, 01:47
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location of tail

Translation of some reports regarding the exact location of the tail are here

AirAsia Tail Location Mystery: Solved?

It is suggested that it is at

-03 38′ 39″ 109 43′ 43″ (degrees minutes seconds)

This is about 2.5nm South East of the last SSR/ADS-B location
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Old 9th Jan 2015, 02:06
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The color looks right, so is it what they are looking for?

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Old 9th Jan 2015, 03:08
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A nice chronology of events mapped out on 3D Google Earth. Not sure how accurate it is, but helps to put things into some perspective.



Source: Twitter
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Old 9th Jan 2015, 03:14
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The pings from the blackbox have been detected according to this article.

PANGKALAN BUN (REUTERS) - Indonesia search and rescue teams hunting for the wreck of the missing Indonesia AirAsia passenger jet have detected pings in their efforts to find the black box recorders, Santoso Sayogo, an investigator at the National Transportation Safety Committee, told Reuters on Friday.

He said it appeared that the black box was no longer in the tail.

“We received an update from the field that the pinger locator already detected pings,” he told Reuters. “We have our fingers crossed it is the black box. Divers need to confirm."

"Unfortunately it seems it’s off from the tail. But the divers need to confirm the position,” he said.

- See more at: http://www.straitstimes.com/news/asi....E18uRxPA.dpuf
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