Airasia Plane Missing?

[dagger]

Flight data recorder has been recovered. Still looking for cockpit voice recorder.

[internet]

Bit odd, no?

@cnnbrk: Data recorder of AirAsia Flight QZ8501 was found under wreckage of one of the planes wings, search official says. http://t.co/AM6VotLhtE

[Kip Powick]

Bit odd, no?

@cnnbrk: Data recorder of AirAsia Flight QZ8501 was found under wreckage of one of the planes wings, search official says. http://t.co/AM6VotLhtE

I think that with the recorder found under the wing, that would be a good indication that the aircraft broke apart upon impact and not while in the air. Depending on the aircraft attitude and descent rate, it literally could have 'exploded' upon impact, (possible 'pancake') especially if it was in a partial flight attitude and did not 'torpedo' into the sea.

Just a WAG and I'm sure the recorder will solve the mystery.

UPDATE...............

Cockpit voice recorder has been found "under debris" but has not yet been retrieved (CNN @ 5:20am EST)

[Don Hudson]

Both recorders now retrieved. The "wing" being described is almost certainly the horizontal stabilizer section.

Regarding the data, I agree Kip. Unlike MH17 where destruction of the aircraft at cruise instantly stopped the recordings, all available indications point to operating recorders until impact with the sea.

I'm sure there will be NTSB, BEA and Airbus oversight for the opening, downloading and reading of the recorders.

I'm thinking about the distance between the tail and the HS/recorders...that the two separated from the aircraft and sank at different rates, the tail section being more buoyant and affected by current for a longer period. We'll know soon enough.

[DEFCON]

I hope the data recorders were operational, at least long enough to capture the critical information, but other than for our expectations, there's no evidence in support of the notion the data recorders were even operational when the flight began that day?

[Don Hudson]

DEFCON;

Regarding operational recorders, generally a problem with one or two parameters is more likely than an inoperative recorder. Inoperative recorders or a host of broken parameters occurs but generally on older aircraft and in countries where regulatory oversight is poor. I expect these recorders will be fully operational and readable.

[DEFCON]

Let's hope.

[DEFCON]

Just a thought:

The ACARS from the aircraft indicates a climb was underway, which represented over 4000 + feet in deviation from the approved altitude, at a decreasing, or possibly even stable, but decreased airspeed nonetheless.

The next plot, only taken a minute or so later and very close to the previous point indicates the aircraft has lost approximately 12000 feet, is at, or near terminal velocity and absent measurable forward velocity.

The floating debris; the door and the escape slide, appear to have come fro the rear section of the aircraft.

The wreckage was found in an area closely located with the last ACARS data point.

From pre-flight seat selection data, I presume it’ll be easy to determine passenger seating, so I’ll offer a guess and suggest the recovered bodies too will be found to have come from the rear area of the aircraft.

Just speculation of course, but to my eye, the limited evidence we’ve seen suggests control of the aircraft was lost and during some sort of high load aerobatic manoeuvre, the structure failed and opened like a cracked egg, which allowed the aircraft contents near the break to spill into the sea below. The influence of aerodynamics being what it is probably produced a shallower angle and correspondingly longer descent time for the main structure, meaning it’ll be found somewhat distant, but likely not all that far away from the wreckage located to date?

[Guest tailwheel]

Actually, I believe that the Australians have been very helpful in the large number of Indonesian accident investigations.

[Woody Pusher]

Just speculation of course, but to my eye, the limited evidence we’ve seen suggests control of the aircraft was lost and during some sort of high load aerobatic manoeuvre, the structure failed and opened like a cracked egg, which allowed the aircraft contents near the break to spill into the sea below. The influence of aerodynamics being what it is probably produced a shallower angle and correspondingly longer descent time for the main structure, meaning it’ll be found somewhat distant, but likely not all that far away from the wreckage located to date?

When the location of APU is known, the relative drift of the Tail Section will also become known. However, if the DFDR was operational at the moment of impact the last recorded position will be very close to where the APU parted company and took the bottom portion of the rudder with it. I'm not so sure about your in air break-up theory.

The question that bothers me is: Why did the transponder stop working, if not a direct lightning strike?

[Kip Powick]

When the location of APU is known, the relative drift of the Tail Section will also become known. However, if the DFDR was operational at the moment of impact the last recorded position will be very close to where the APU parted company and took the bottom portion of the rudder with it. I'm not so sure about your in air break-up theory.

The question that bothers me is: Why did the transponder stop working, if not a direct lightning strike?

Could it be possible that they turned it off so no one would know they were in the process of climbing, in an attempt to get over the weather,without ATC clearance ???

[Woody Pusher]

Could it be possible that they turned it off so no one would know they were in the process of climbing, in an attempt to get over the weather,without ATC clearance ???

No. The TCAS (Traffic Collision Advoidance System) fitted on all aircraft requires its operation to be effective. It will give an opposing aircraft a climb/descend instruction if it is in danger. Turning it off enhances the chance of a collision with an opposing aircraft.

If they turned it off because they left the airway without ATC permission, it will illustrate the culture embedded in the aviation industry in this part of the world. Safety defers to authority.

[Kip Powick]

No. The TCAS (Traffic Collision Advoidance System) fitted on all aircraft requires its operation to be effective. It will give an opposing aircraft a climb/descend instruction if it is in danger. Turning it off enhances the chance of a collision with an opposing aircraft.

If they turned it off because they left the airway without ATC permission, it will illustrate the culture embedded in the aviation industry in this part of the world. Safety defers to authority.

Yes, I know that TCAS works only when the transponder is on but what I am saying is that the Captain might have decided to turn it off and use "eyes only" if he wanted to make a deviation that was not authorized...it is a possibility.

We didn't always have TCAS and, however remote you think the possibility is, perhaps the crew decided to deviate "VFR", (assuming they could see the weather), and didn't want ATC to see them make any changes to their flight planned route.

Naturally the FDR will tell the tale.

[Don Hudson]

Hi Kip;

As you know, the captain was a 20,000hr veteran, highly thought-of. I think it's safe to assume, (and the recorders may tell us, as you say), this it is unlikely that he would decide to deactivate a collision-avoidance system, particular when the very reason for ATC's difficulty in granting a diversion off-route and/or a climb was heavy traffic. As Woody points out, such action would indicate a far more serious, systemic, cultural problem if such was routinely considered "an option"...

Besides, as we know, (even as PNF/PM), the captain has the authority to act in any way he/she chooses to keep everyone safe. Such a diversion would perhaps be prefaced by a PAN or even Mayday call if there was time. I recall doing this once on the Pacific...no HF contact with SFO, had to divert immediately and so lit the airplane up, climbed 500ft, altered course around the embedded thunderstorm, (we were picking our way through a squall line in the ITCZ, moonless night, in cloud, lots of St Elmo's). We broadcast what we were doing on guard and air-to-air frequencies and told SFO when we were able. Perhaps he just ended up trapped between airplanes, thunderstorms and aircraft-engine performance!

Something about this tells me that whatever occurred took this captain entirely by surprise and overwhelmed very rapidly. We can imagine...he'd be watching the radar, scanning above/below, increasing/reducing gain, changing scales as we all likely have, or would have been and was suddenly overwhelmed with an airplane caught in circumstances beyond its ability to counter. Dual flame-out is a possibility but the history of these engines (the CFM) with heavy water ingestion is good - to my knowledge, no examples either in operation or in testing.

Whether such circumstances were up/downdrafts, hail-damage, dual-flameout, heavy icing, lightning-strike or, more likely, a combination of such, hopefully the recorders will tell us.

AF447's engines (not the same engine and no water ingestion, I know), were able to deliver up to MCT thrust all the way down despite extremely high angles of attack.

Indications are that the aircraft impacted the sea intact, nose-up, not stalled, (ie., more forward speed than AF447).

Interestingly, (and perhaps obviously if we think about it), the Airbus protections in Normal Law would not keep the aircraft from stalling due to heavy ice accumulation altering the airfoil and L/D forces. The laws "know" about the normal airfoil...in fact the Airbus airfoil and "Laws" equations are highly proprietary. However, we all know that an airfoil's shape altered by heavy ice renders the stall warning system unreliable (meaning "late"!, on normal airplanes). This would be particularly serious at high altitude where there is very little margin between cruise Mach AoA's and "low speed" buffet AoA's, (about 2deg...) and almost no reserve power to counter the increase in drag.

With available information so far, possibly an initial stall & loss-of-control, followed by recovery at lower altitudes and a "ditching".

I understand that both Airbus and the NTSB are on-site. It's not that I don't trust Indonesian authorities, but as mentioned, the evidence trail needs to be completely, transparently available to all just like it was with AF447, to avoid the obvious accusations. Also, competency in handling the two recorders must be assured.

Don

[DEFCON]

Woody

I think the loss of the transponder signal is interesting too, but it’s not likely we’ll get an answer to that question until the recorders are read.

Don suggests the entire aircraft may have gone in tail first etc. and I have to agree, that’s an entirely possible scenario.

However, if the fuselage location is confirmed at 1.7 miles from the tail debris and data recorders as they are claiming this morning, it becomes increasingly difficult to imagine how the current could separate the main components by this distance in relatively shallow water if breakup had not occurred in flight.

[Don Hudson]

Hi DEFCON...to be clinical about it..."tail first" means a pitch attitude of around 10deg or so, (Hudson ditching was 11, AF447 was about 15).

Loss of Xponder but no loss of ADS-B, (considered reliable and not spurious data), has to be explained.

Has the main fuselage been found...have been looking in other areas this morning...

[DEFCON]

I came across this picture. The burn marks on the structure jumped right out. The next observation is of the worker cutting the structure with a torch? Now, I dont pretend to know what theyre up to, but seeing this sort of activity along with the technique they employed to haul up the structure does make me wonder if anyones on site that knows what theyre doing and calling the shots?

[DEFCON]

Here's a link Don.

http://www.cbsnews.com/news/airasia-flight-8501-fuselage-black-box-found/

[conehead]

I came across this picture. The burn marks on the structure jumped right out. The next observation is of the worker cutting the structure with a torch? Now, I dont pretend to know what theyre up to, but seeing this sort of activity along with the technique they employed to haul up the structure does make me wonder if anyones on site that knows what theyre doing and calling the shots?

No idea why that man would be cutting apart the wreckage with a torch. Seems counter-productive to a crash investigation?

[J.O.]

Holy crap, it's not like they're trying to rescue someone from a wreckage. I remember the TSB getting hot under the collar when someone showed up at an accident scene with a can of white paint. I can't imagine what they'd have said if there'd been a cutting torch involved!

[Don Hudson]

Thanks DEFCON. Progress...

The rear-left, (L2, I believe), door in the image shows the tremendous deceleration forces involved.

I would expect the Airbus and other involved authorities, (as per Annex 13) would have okayed this action.

Either that or it's more evidence concerning the state of accident investigation and prevention in Indonesia.

[Kip Powick]

Ah..well..., OK, I'll tell the story anyway, (the other guy is long gone).

It happened out of YOW

I was flying as FO with a newbie Captain on the A310 (with WD)...he was a good guy but like all of us, not extremely conversant with the A310. as we had only been on it for about a month or so.

It was a beautiful VFR and winter day, could see for miles.(YOW-YYZ)

Captain was PF

We took off on RW25 cleared to 5000 feet

We had a light load and as we rolled out on the runway, :Whip-lash" said to me..."I want to try a max climb departure, no reduced thrust"....and away we went.

She climbed like a homesick angel and it was pretty obvious to me , that we were going to overshoot our assigned altitude as I was calling "altitude/altitude" and peering into the sky for traffic.

With the VSI pegged at max we sailed through 6000 feet as "Whiplash" attempted to level without a "zero G" buntr and descend and as we passed 6000, I turned off the transponder.

Whiplash managed to get the aircraft over the hump and started down to our assigned altitude.

At about the same time OW departure stated, "we have lost your transponder".......I immediately said, "Standby, I'll recycle for you".

Whip-lash settled in at 5000 feet and I turned the transponder back on,,,yes I know, perhaps not very professional but it was a split decision decision and I really didn't want the Captain to chalk up a possible violation and in my opinion, with it being CAVOK, eyes out there, and no ATC advice about any traffic in our area I thought a short "off/on" was OK...

My point is, it may not matter how many hours one has, there may be times when the rules are "bent" for one reason or another.....Anyhooooo..the Black Boxes should tell the tale.

[Woody Pusher]

Here is an enlarged look at the current debris field. The black stars are objects that haven't positively been indentified.

[DEFCON]

Don; there’s no question, the door frame does appear to show evidence of substantial compression overload, but after watching the gutted structure being hauled up over the stern of the tug, I’d like to know for certain the recovery crew didn’t place a force on the frame during the lift and cause some, or all of the deformation. When they drag the structure up and onto the deck, you can see there’s a large piece of unsecured sidewall flopping about; I think it’s the piece they later cut off with the cutting torch? All of that aside, it looks like the seats, the floor and the entire lower fuselage were ripped away from the area of the break right back through the APU and tail cone. I don't know what that might mean, but I do think it's an interesting piece of the puzzle.

The bent structure / compression loads affecting the door frame you’ve mentioned are likely the result of a relatively high energy impact with the water as I think you’re suggesting. Nevertheless, I just can’t imagine how an intact aircraft could descend at terminal velocity on a fairly vertical trajectory from FL 360+ to sea level and then be brought under control at the last second in an attempt to conduct a controlled ditching in what must have been impossible conditions; heavy rain, poor to zero visibility and giant waves, not to mention what must have been, a seriously degraded aircraft. I guess it’s possible, but I still favour the idea the aircraft broke in one, or maybe more places on the way down. In the event the aircraft was to have remained relatively intact and maintained the reported rate of descent & trajectory until impact, I can’t see there being much of the structure left intact following.

But then there's the fate of AF 447 to consider; what are the odds that a similar loss of control scenario unfolded all over again?

Woody...Thanks for the charts, they're really informative.

[Don Hudson]

Hi DEFCON;

All conjecture on my part! So much that isn't known this evening will be known by the weekend. FWIW, there is good aeodynamic evidence that AF447 could have been recovered from the stall as low as 15,000ft, perhaps lower had either pilot held the stick fully-forward to unload then unstall the wing. The horizontal stab & elevators were effective during the entire descent.

Whether any of this applies to QZ8501 is just reading tea leaves. ;-)