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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 11th Jan 2015, 14:50
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Winterymix - convection intensity over the open ocean doesn't vary much day/night since sea surface temperatures have very little diurnal variation. However convection over the land not far from the LKP would decrease overnight leaving more 'airspace' over the adjacent sea for CBs to develop and peak towards dawn (without going into the broader scale MET dynamics).
This paper: Analysis of overshooting top detections by Meteosat Second Generation: a 5-year dataset - Proud - 2014 - Quarterly Journal of the Royal Meteorological Society - Wiley Online Library shows that, at least in Tropical waters off Africa, convection peaks at around 08 or 09 local time. In the ocean far from land it's around midnight and over land it's in the evening. The same is, at least on the day of the accident, true for the region around Indonesia/Singapore. Because there's so much land over there the sea is never truly isolated so we get the 'coastal' convection system with peak intensity around daybreak.
Nice clarification about convective threats in the environment of interest. So...what did the other several flights in the area at the time of interest know or did they simply get lucky?
I think a better question (assuming that weather was a factor) would be: What made this particular flight unlucky?
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Old 11th Jan 2015, 14:52
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Originally Posted by ATC Watcher
Ian W and Air Scotia :

Maybe in the USA where there is an old " CB avoidance" culture and ATFM ( Flow management) organised through a single command centre which has direct access to the US Air Force areas .
Europe is also equipped with an advanced centralized ATFM system , but does not have the same weather pattern as in the equator/tropics or continental US. and there are 40+ airforces around to deal with.

A totally different picture that what is going on the rest of the world unfortunately , and definitively in South East Asia , where each Sate has its own air force and where countries are suspicious of one another and do not cooperate.

ATC is there to separate aircraft from one another also aircraft from penetrating reserved or restricted areas, and to comply with restrictions and demands made by teh next sectors( control centres) .

There is no standard " Miles in trail " separation applied by all. They vary depending on location and surveillance capabilities. , it can be 5 NM . can be 100 Miles (15 minutes) . It can be 5 NM in one sector , and 10 minutes at the transfer point for the next sector in a different Control Centre no equipped with same capabilities. Once established controllers have to follow that.

But, once again , the pilot has the decision on weather avoidance, not ATC . The pilot(s) can see in real time what the actual weather is , ATC cannot. If a request for deviation ( laterally or vertical ) cannot be approved by ATC ( due e.g. restricted or dangerous areas penetration or simply other traffic ) the PIC can deviate on his own bu just declaring on the R/T , " unable, turning or climbing now ". This then becomes an emergency situation , and ATC will help clearing the way. The PIC is always ultimately responsible for the safety of his flight.

To come back to this Air Asia case, I have seen no indication so far that the Pilot of this flight did not jut do that, but he did not tell ATC, so for me I think there must be something else, or the initial request to deviate came much too late.
I will pick up a few points from what you say:

Yes FAA, NAV Canada, and the Member States of ECAC - EUROCONTROL, Air Services Australia have fully fledged Traffic Flow Management (TFM) Systems. Under ICAO coordinated flow management is being developed with GREPECAS, the states of Caribbean and South America. The Asian Pacific Region Air Navigation Service Providers (ANSP) are aware that they do not have a networked TFM system and work is in hand using the auspices of ICAO to put one in place (see http://www.icao.int/APAC/Meetings/20...attachment.pdf )

Miles/Minutes in trail are going to be different as the aircraft moves from surveillance based control to non-radar procedural time based control. In consequence the flow management at boundaries between these sectors becomes complex. As surveillance based control normal separation minima are considerably smaller than procedural.

The statement "The pilot(s) can see in real time what the actual weather is , ATC cannot." is not necessarily correct - and even if true it is too simplistic to just avoid the next heavy rain radar return. Both the pilot and the controller may be able to see weather, their systems are different so they will see different weather. The controller can also see a lot further ahead and can see sucker traps where some flight paths would lead into dead ends, the controller also may have had lots of PIREPS on turbulence. The controller's weather comes from different radars so it will present weather information that is hidden from the aircraft radar by attenuation. It makes real sense for both the controllers and the pilots to work together there is no competition, both want the same outcome and the pilot should accept any help that can be offered.

If the weather is getting a bit too exciting then the pilot should say so early don't wait till things are really bad or until ATC gives you an instruction you can't take. If you can tell the controller that the weather is looking really bad ahead of you or to one side and you may need to take some avoiding action, then the controller will start ensuring that other traffic is kept clear of both you and the weather you are reporting.

The time for 'Communicate' is before things get so bad that all you can do is 'Aviate' then perhaps things won't get to that stage.
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Old 11th Jan 2015, 15:01
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Old 11th Jan 2015, 15:29
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QZ blackbox has been found on coordinate 03.37.21 S/109.42.42 E with depth of about 30 to 32 meters

Tim Penyelam TNI AL Berhasil Temukan Kotak Hitam AirAsia
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Old 11th Jan 2015, 15:50
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QUOTE:
Winterymix - convection intensity over the open ocean doesn't vary much day/night since sea surface temperatures have very little diurnal variation. However convection over the land not far from the LKP would decrease overnight leaving more 'airspace' over the adjacent sea for CBs to develop and peak towards dawn (without going into the broader scale MET dynamics).
This paper: Analysis of overshooting top detections by Meteosat Second Generation: a 5-year dataset - Proud - 2014 - Quarterly Journal of the Royal Meteorological Society - Wiley Online Library shows that, at least in Tropical waters off Africa, convection peaks at around 08 or 09 local time. In the ocean far from land it's around midnight and over land it's in the evening. The same is, at least on the day of the accident, true for the region around Indonesia/Singapore. Because there's so much land over there the sea is never truly isolated so we get the 'coastal' convection system with peak intensity around daybreak.
Quote:
Nice clarification about convective threats in the environment of interest. So...what did the other several flights in the area at the time of interest know or did they simply get lucky?
I think a better question (assuming that weather was a factor) would be: What made this particular flight unlucky?

All the above omits mention of the other driver for rapid high level CB development. That is cooling from above, rather than heating from below. Cold advection [wind backing with height] can and does throw petrol on the fire of a hitherto modest CB. Believe me, it happens.
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Old 11th Jan 2015, 16:30
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Hi,

With all the photos of aircraft parts available so far .. my feeling is a flat ditching of those parts .. little forward speed ... (my two cents)
Can't wait the analysis result of "black boxes" .........
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Old 11th Jan 2015, 16:50
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@ Ian W Acoustics communications

Change the frequency - Remember this is not radio this is sonar a lower frequency in water has a lot more range.
Change the pulse recurrence frequency so that there is one pulse every minute or even every 3 minutes by charging a capacitor bank then discharge that for a greater power outputEncode the signal with the last position from the DFDR/GPS and the aircraft ID

You're right that VLF at 8Khz would give better range than 37Khz but not much more, certainly not in terms on NMs. Water presents just too much attenuation unless the source uses enormous power.

What of the idea that the ULB remains asleep until it is interrogated so extending battery life. , much like transponders that are used by Offshore oil and gas vessels which a give an xyz position Extra information could also be supplied easily depending on the firmware used. All this technology is already available but would imagine it would take years to get through CAA legislation.
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Old 11th Jan 2015, 16:50
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If the crew failed to find the weather on radar that likely took them down, the first warning would likely be the sound of ice pellets hitting he aircraft.

Most of my tactical jet XC work (ancient history) was without available weather radar. The only operational restrictions applied from on high was, "do not fly into Weather Warning areas." As a result, we had the opportunity to fly into and through some otherwise interesting weather. Other than some spectacular St Elmo's fire, it was not that exciting.

For the meteorologists here, did conditions in the ITCZ on the airway that day equate to WW level storm intensity?

I'm betting that the weather is more likely to have interfered with the aircraft's sensors and thus precipitated this accident.
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Old 11th Jan 2015, 17:10
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Flat spin background

Originally Posted by jcjeant
With all the photos of aircraft parts available so far .. my feeling is a flat ditching of those parts .. little forward speed ... (my two cents)
Can't wait the analysis result of "black boxes" .........
Yes, I'm reading the wreckage as a flat impact with wings (+- 15 degrees) of level and low forward speed. This corresponds to a flat spin.

One ominous aspect of flat spins is the eyeballs out g that results from the rotation. This would rapidly disable the crew, particularly if they did not have their shoulder harness locked.

How to get into a flat spin? Not hard once you get real slow. Compressor stall one engine while at high power and high AOA.
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Old 11th Jan 2015, 18:08
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Matching up debris

If this helps anyone ive matched up the tail to approximately where it fits to the rear section.


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Old 11th Jan 2015, 18:14
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flat spin

"MACHINBIRD" IMHO if you'd ever done a flat spin, you wouldn't write :"One ominous aspect of flat spins is the eyeballs out g that results from the rotation. This would rapidly disable the crew, particularly if they did not have their shoulder harness locked."

I 've been teaching aerobatics and spin recovery ( positive, inverted, and positive flat and inverted) spins (in CAT "A" aerobatic airplanes...) for over 20 years and both my eyeballs are securely in place, or so say my FAA and JAR-FCL medicals.
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Old 11th Jan 2015, 18:14
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Originally Posted by Machinbird
Yes, I'm reading the wreckage as a flat impact with wings (+- 15 degrees) of level and low forward speed. This corresponds to a flat spin.

One ominous aspect of flat spins is the eyeballs out g that results from the rotation. This would rapidly disable the crew, particularly if they did not have their shoulder harness locked.

How to get into a flat spin? Not hard once you get real slow. Compressor stall one engine while at high power and high AOA.
You don't need a compressor stall - high AOA and a small input to the rudder can put you into a spin relatively quickly. It was the standard method to enter a spin way back. Do it a fraction before the stall and you can have max lift on one wing and the other stalled. I would think that one of the Normal Law protections would stop you getting there unless it was all tied up with an overspeed protection because of a sudden increase in OAT.

I wonder if we are getting to a point where test pilots are going to be required to test departures from the flight envelope to see how the aircraft behaves and how to get it back? Otherwise a LOC for whatever reason that puts the aircraft immediately out of the envelope requires the crew involved to become test pilot capable in seconds.
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Old 11th Jan 2015, 18:21
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Originally Posted by formationdriver
"MACHINBIRD" IMHO if you'd ever done a flat spin, you wouldn't write :"One ominous aspect of flat spins is the eyeballs out g that results from the rotation. This would rapidly disable the crew, particularly if they did not have their shoulder harness locked."

I 've been teaching aerobatics and spin recovery ( positive, inverted, and positive flat and inverted) spins (in CAT "A" aerobatic airplanes...) for over 20 years and both my eyeballs are securely in place, or so say my FAA and JAR-FCL medicals.
Wouldn't the g experience in the cockpit depend very much on the center of rotation of the fuselage? In a Cat A aerobatic aircraft the cockpit is not a lot forward and indeed may be on the center of rotation - probably with the design intent to reduce g when the aircraft is rotating. Now in a larger non-aerobatic aircraft that is not a design decision.
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Old 11th Jan 2015, 18:28
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Spin?

There is no where near enough wreckage for me to start concluding what the impact angles or energy may have been. However, there is one piece of evidence that has come in and must be taken into account. With the destruction of the aft pressure bulkhead I don't think it is possible that the impact of the tail was low energy. One POSSibility may be that the tail came down as a separate piece and the open end of the tube hit first with the hydraulic effect opening the pressure bulkhead and the bottom of the fuselage.
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Old 11th Jan 2015, 19:09
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VS damage: sideways on impact, starboard side down

Edit: with linear witness mark from subsequent impact with port HS?
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Old 11th Jan 2015, 19:12
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I have been wondering about this strange tail section torn off and went and took a look at a pretty recent water event - this one with a very successful outcome for everyone onboard. Also an A320.

Sorry, the pictures are small but I have links to highres pics at the end of the post.

Notice the similarity in the tail section. This is fron the transport of the recovered plane so no stabilizers...




The actual plane on the museum. Stabilizers are put back to place. Surprisingly similar damage as seen on AirAsia.



Some links to highres photos:

http://journeysbyjill.files.wordpres...2/img_0168.jpg

http://smithsonianscience.org/wordpr...light-1549.jpg

http://tinyurl.com/m978xrt

EDIT; Seems like the last picture won't show properly sometimes. I have saved it on my computer if someone is really really interested...

EDIT 2: Followed advice and used tinyurl.

Last edited by MrSnuggles; 11th Jan 2015 at 20:10. Reason: strange link - added tinyurl
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Old 11th Jan 2015, 19:27
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I can no longer find the NTSB report for 1549. Angle of the plane on impact would be interesting for those of us unfamiliar with it, if anyone can recall. Believe speed was approx. 153kt.
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Old 11th Jan 2015, 19:42
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Modern airborne radar is better than the "crap" we had 30 years ago? Surely you jest.

I could see the control tower on an airport from 5 miles out with the old radars, I could see individual airplanes parked on the ramp. I could see the weather clearly and make my own decisions as to the amount of water carried by parts of the cloud and thus make my own decision as to the parts to avoid. I flew years and years in the tropics and experienced hundreds of severe encounters at some of the worst levels (around 13,000 to 15,000 feet).

I give you the new radars are easy to use and they do the deciphering for you, but often they are wrong and always exaggerate. They are useless for fine work, cannot do even a small part of what was done by the older radars. They are cheaper to buy and to maintain, and are much lighter, so I see the reason for them, but don't kid yourself that they are better for the purpose they were built.
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Old 11th Jan 2015, 20:02
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susier

Here is, I believe, the full report:

http://www.ntsb.gov/investigations/A...ts/AAR1003.pdf

I just found another angle showing how/why an aircraft can be ripped apart from below...


Last edited by MrSnuggles; 11th Jan 2015 at 20:11. Reason: adding image
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Old 11th Jan 2015, 20:04
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flat spin

Good point, IAN G, about center of rotation. But, as you know, its real tough to get into a flat spin... which requires deliberately held full back stick (as AF# 447) AND out-spin aileron, i.e. a crew trying to stop the spin with ailerons (toward the high wing) instead of rudder. Anyone who has ANY unusual attitude/spin training KNOWS this is wrong. Dead wrong. From the French BEA report, AF # 447 wasn't in a spin, but a long (4 minute...) falling leaf configuration... in and out of stall, with wings alternately rising and falling as the nose remained close to, or above, critical AOA.
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