AirAsia Singapore-bound A320 Missing

[allardjd 1,853]

Not much news yet.

 

http://www.foxnews.com/world/2014/12/28/airasia-plane-missing-with-162-on-board-indonesia-media-report/

[hlminx 301]

Just been looking at the newscasts.

Lots of comments about similarities with MH370, but I guess that's to be expected...

Very very sad indeed

[dodgy-alan 1,587]

An Air Asia A320 has dissappeared over the Java Sea after reporting bad weather. 2014 has not been a good year for Malaysian Airlines....

http://www.bbc.co.uk/news/world-asia-30614627

 

EDIT: Post merged by Mutley as subject already posted here.. 

[brett 2,310]

That is a bummer and a half, my thoughts and prayers go out to the families of missing passengers and hopefully any survivors.

 

 

[allardjd 1,853]

Looks like they have found and confirmed aircraft debris (but not yet confirmed to be from THAT aircraft) and unconfirmed reports of bodies. Don't know the location.

 

From the guys at PPRUNE, it's looking like the speculation by the pros is leaning toward a WX related loss of control. One reported dataset indicates going from 32,000 to 36,000 and then down to 24,000 in about one minute. If accurate, that's likely to mean an in-air breakup - not many airframes can stand that.

 

If they have a site nailed down they should have the recorders within a few days and we should have preliminary data reports in a couple of weeks, I would think.

 

Sad thing - lots of dead people and grieving families. Probably preventable, but all of them are, with 20/20 hindsight.

 

John

[J G 927]

Very sad indeed. Now that wreckage and bodies has been found we know the fate of this flight, lets hope that this provides some closure for those directly affected by this sad event.

We should not forget those affected by the Malaysia Airways 777 disaster who still have no knowledge of the fate of there loved ones.

[brett 2,310]

Some bodies found, still a lot of speculation on the cause, here is the latest.

[allardjd 1,853]

They're saying in the linked article that high tides are causing difficulties. High tides???? They're in the open ocean, nowhere near a shoreline and the water is about 100' deep. How can tides cause them difficulties? Next they'll be blaming global warming for their problems. They may in fact be having difficulties and I don't make light of the task they are facing but on the list of things that are hampering them, I don't think high tides is anywhere near the top.

 

John

[hlminx 301]

Maybe its lost in translation. Perhaps they mean swells

The report in the link has a lot of guesses from 'former' navy an ministerial people about the condition of the bodies and how they escaped. Given that the SAR team currently running the operation has managed to get confused over the number they have recovered, sorry to the EX Transport bloke but I'm taking it with a pinch of salt till they get the FDR anx CVR.

[stu7708 244]

The tide part was most likely a translation error as Steph already mentioned. In swedish media the only problems mentioned have been the waves/swells.

 

Last speculation I saw in swedish media was that the pilots managed to pull off a Sullenberger landing in the sea, but that the plane then sunk due to the heavy seas.

 

The evidence put forward towards this theory is the fact that the ELT never triggered indicating that there were no major G-forces in place at the impact, the fact that the bodies found were "un-damaged" pointing away from an in-air break-up and the fact that they found a door with an inflated slide attached to it indicating that it was intentionally opened for evacuation ..

 

Not sure how credible those assumptions are, but I'd guess, based on my limited knowledge, that regardless of the way the door separated for the fuselage an armed slide would have inflated.

[hlminx 301]

Reckon I zeroed in by mistake on the heavy swells aspect without seeing the bigger picture.. it just seened odd that a forced landing in heavy seas with engines mounted below the wings wouldn't have generated enough deceleration GForce to trigger the ELT.

No doubt they'll locate it soon from the black box beacons once the weather improves.

[allardjd 1,853]

@ Micke - What I'm reading on PPrune and elsewhere says the slide was NOT inflated, but detached, along with the door. It's unknown whether the door was manually opened or was torn off by structural damage. The possibility of a ditching remains but the pro pilots on PPRUNE are pretty much lining up against it, though they do concur that the condition of the bodies indicates something other than a high-speed, high-angle impact. It might equally have been a full stall with little forward velocity, ala AF 447.

 

John

[allardjd 1,853]

Everyone probably knows from other sources by now that both the recorders have been recovered. Indonesia says they will be opened, read and analyzed in-country. I understand that technical help has been offered, including by Airbus, Australia and others. If I understand aviation law as it applies in these cases, the country in whose airspace the accident occurred has control but it is required that the country of registration, the owner of the aircraft and the manufacturer all have a seat at the table. Others, such as suppliers of critical components (e.g. engines), MAY be included.

 

It appears likely at this point that the aircraft had a relatively low speed impact with the water, possibly without a great deal of forward velocity, indicating the possibility that it was stalled and fell in much like AF 447. I think there are enough similarities at this point that it is incumbent upon the investigating authorities to either confirm or refute that the events are related.

 

Strong winds and very strong ocean currents may be responsible for separating pieces that went into the water together or close together. Some may have floated longer than others and some may have presented more surface for the wind and particularly the ocean currents to act against. It does not appear that there was any major mid-air breakup of the airframe, though that thought does not preclude that some control surfaces may have suffered damage or separation while still in the air.

 

It is too soon to say with certainty what happened in the cockpit but one potential scenario is that the computers could not deal with what happened and dropped the entire manure pile into the laps of the pilots at high altitude, possibly in an unusual attitude, possibly already stalled, possibly with critical sensors iced or otherwise inoperative. It's what Airbus computers do in certain circumstances, though they refer to it more politely as as dropping out of "Normal Law" into "Alternate Law" (which comes in several flavors depending upon the circumstances) or to a couple of even more basic versions of the software that controls the aircraft, each level offering the pilots less help, less protection from stall, overspeed, extreme attitudes, etc, and more direct control over the aircraft. Unfortunately, this may happen at a time when the aircraft is or is on the edge of being outside the normal flight envelope and maybe no longer even in anything that can be described as controlled flight. When this happens, the pilots have the rest of their lives to solve the problem.

 

It is also possible that the aircraft was in control at the time of impact and made an attempt at ditching, which would be highly unlikely to be successful given the wind and sea state at the time.

 

Much is to be learned yet and it is hoped that the authorities will not hold the information secret for too long, regardless of whose face the egg is on.

 

As always thoughts and prayers for the victims and their families are in order. Aviation is pretty safe, but unlike highway accidents, these directly affect very large numbers of people and are often spectacular, attracting heavy media coverage.

 

John

[hifly 925]

Thanks John, what I fail to understand is why ac fly into storm areas in the first place. Ah! yes, economics, go round the storm and use more fuel, the bean counters and management don't like that.

 

Pressure on the pilots to save the airline money and time may have been a factor here. Of course, someone else, taxpayers, have to pick up the tab for the SAR and recovery.

 

I understand that there is the technology to track ac real time giving its position and other data that could provide clues as to what has happened.

 

Until the facts of this disaster are revealed, (provided there is no face saving involved,)  we can only speculate as to its cause.

[allardjd 1,853]

Look up Intertropical Convergence Zone (ITCZ). In certain parts of the world, if the airlines were not willing to dodge storms there would be no flying at all at certain times of the year. AF447 and this flight were both in ITCZs. Of course it must be done carefully and conservatively with intelligent use of on-board WX radar.

 

They've got the boxes and will know beyond a shadow of a doubt what happened and why. It only remains to be seen how much will be made public.

 

John

[hifly 925]

Point taken John, in my experience of storms having been to that region is that they are vicious but are over quickly. In Singapore I could set my watch by the 3 o'clock thunderstorm every day, it would be over in about 20 minutes.

 

I guess the lesson here is that nature is unpredictable and despite our best efforts nature still has the last word.

[britfrog 180]

well at least they now have the fdr and cvr so there will be no more guessing as to what happened.

 

[stu7708 244]

The preliminary analysis of the Flight Data Recorder data was published earlier today. 

 

According to the data the plane entered a climb with a Vertical speed of 6.000 feet per minute resulting in decaying airspeed and the plane then appears to have entered a stall it couldn't recover from. No mention of the reason for the climb is given though, but I assume it must have been related to the weather it was going through...

[allardjd 1,853]

It MAY have been frozen or otherwise compromised pitots and/or AoA vanes, which could have erroneously given the computer(s) the idea that the AC was approaching an overspeed. The computer(s) would have commanded an extreme nose-up control input based on overspeed protection programming.

 

John

 

EDIT: Another possibility is that they flew into an extreme updraft, which would have caused an increase in altitude but should not, in and of itself, have caused a stall, since the vertical displacement of the AC could have occurred without any change in pitch trim. It would be a case of entering an air mass that was moving upward rapidly. That would account for the climb but not necessarily the stall. The stall, I guess, COULD have been from wind shear when entering or exiting the rising air column but that sounds a little far-fetched to me. I think compromised sensors causing the computer(s) to react inappropriately makes more sense and seems more likely based on what's known so far, which is still very little.

 

JDA

[allardjd 1,853]

It would be interesting to know where the "decaying airspeed" data in the report came from. IF they are simply reporting IAS as seen by the computers/ADC and IF there were compromised sensors, that may not have been real, but in any case, the stall was real and they rode it, stalled, all the way to the sea. In that respect it is very much like AF447, though the initiating series of events may have been different. One important difference is that we now know that AF447 was recoverable and it may be that this one was not.

 

I believe there are other ways to derive airspeed from other data but if I understand correctly that is less precise, less reliable and lags reality much more than pitot-derived airspeed.

 

The FDR has approximately 1200 channels or parameters of data recorded and all will be known eventually, if the authorities choose to release it.

 

John

[J G 927]

I think it is pointless to speculate at the moment. Further analysis will no doubt shed more light. The aircraft entered some very severe weather and anything could have happened to it there.

At this time it is important that the black box has been found, and that the family and friends of those lost at least know the fate of their loved ones. Closure is very important to those who live on, somthing that those with relatives on board the missing Malaysian still don't have.

[allardjd 1,853]

I think it is pointless to speculate at the moment.

 

 

I think it is also harmless to speculate at the moment.

 

I have a feeling that they are not going to find most of the rest of the bodies.  Unless the remains are still belted in the seats and the seats are still attached to the structure, the currents will scatter them far and wide.  I've seen reports that the divers are dealing with currents of 6 knots or more - which is a lot like being in a 100 mph wind, except you can't see either.

 

John

[J G 927]

I agree with you about the bodies John, There wont be anything to find that isn't secured to a large lump of aircraft. A six knot current would disperse any loose objects rapidly.  

 

I have done a dive in a five knot current, great for a drift dive, but you couldn't fight against it at all.  I doubt it would be murky though as the water is deep. visibility would probably be good in the warm waters down there, but not an easy dive at all.  

[allardjd 1,853]

I don't envy those guys that work for several reasons.

 

John

[stu7708 244]

Just thinking loud without proper knowledge of the aerodynamics here, but if it was an updraft that lifted the aircraft at that rate, couldn't that potentially disrupt the flow of air over the wings enough to cause a stall dispite the forward motion?

Still doesn't explain the apparent loss of airspeed though, or could the flow in to the pitot also be effected by such unusual movements?