Air Asia Indonesia Lost Contact from Surabaya to Singapore

[Hogger60]

ATC recording from Surabaya on the morning of the crash.

Leaked: Communication between AirAsia flight QZ8501 and Air Traffic Control | The New Paper

[Propduffer]

a. the radar image was obscured (heavy rain shafts)

Although I don't know the location or the type of radar that "Tracked" QZ8501 I don't believe it possible for even heavy rain to attenuate the return from either passive or primary radar.

I have been recently posting about ADS-B data which wouldn't have come from radar. I remain puzzled by the releases of radar information re: QX8501. It seems to have been primary radar that is being referenced, not ATC radar.

I have tried to find out which primary radar might have been the one tracking the flight but I've come up to a dead end - it was apparently a naval radar that tracked the flight. I have a list of IAF radar locations but they don't seem to include the one that covered that area. A radar coverage map for Indonesia is here:
Ministry of Defense Will Add Air Force Radar
(pprune won't display just the coverage picture)

b. highly effective dislocation of the aircraft i.e. severe upward or downward displacement at a rate too swift for radar to reacquire.

Not possible.

c. in air fragmentation

This is possible but not known one way or the other. I believe it may have shed some parts.

is it true that in the modern era, no large airliners have been downed strictly by turbulence and none by lightning strikes?

I'm no historian in aviation matters but I have heard of a 707 that went down because of lightening as well as an Iranian 747.

[training wheels]

Pictures of the tail section. Source from twitter.







The first appears to show the registration of the aircraft PK-AXC, and it appears the aircraft is lying upside down.

[xcitation]

Looks like the paint is scraped off down to the base metal in the registration area (PK-AXC). The scrapes run parallel with the length of the a/c. You can see the rivets exposed.
Registration location image

[ana1936]

23:12 until 23:17?

Unfortunately the leaked secondary radar screen shot does not seem to have a time attached to it anywhere.

However, we can assume it is about 23:17:00 plus or minus a minute, I guess.

In that case we can deduce that for the next five minutes after the FlightRadar24 recording cut out at about 23:12:00, the a/c kept on at about 480 knots on average (to cover the 75 km in between positions), it turned left slightly to head at a bearing of 307 (instead of 310), and it climbed to 36300ft from 32000ft.

However, it then had just suddenly slowed to 353 knots and changed heading to the right by the time of the screen shot.

[jolihokistix]

PK-AXC in two liveries.

8 Dec 2012
PK-AXC Indonesia AirAsia Airbus A320-216 - Planespotters.net Just Aviation

19 Dec 2014
PK-AXC Indonesia AirAsia Airbus A320-216 - Planespotters.net Just Aviation

[aussiepax]

So does that leaked ATC tape identify what accent was on the radio comms e.g. Indonesian captain Vs Nigerian French 1st officer, and does any of that then give a clue as to who was PF // PNF please

[ATC Watcher]

Amazing all those questions , which were already answered here 2 or 3 times before .

something else :

There is no big money involved, and "if there is, we will act", its safety and standard director, Mr Wisnu Darjono, was quoted as saying yesterday.
"They are clean," he added, referring to the organisation and its air traffic control personnel. "Look at their dull faces. Not possible for them to have lots of money."

Fantastic statement ! ( It he really said this ) says a lot about the culture in a country and the company " Safety and Standards Director !

[Sir Richard]

xcitation

Those "paint scrapes" look more like a kelp seaweed.

[MartinM]

So does that leaked ATC tape identify what accent was on the radio comms e.g. Indonesian captain Vs Nigerian French 1st officer, and does any of that then give a clue as to who was PF // PNF please

The one talking to CLD indeed had a french accent. But that was one ground. Nothing unusual that an FO obtains clearance.

[bobdxb]

@MartinM

Listening to ATC tape and a/c airborne looks like Capt was PNF...

[Ber Nooly]

Regarding that leaked ATC recording, she clears him with a squawk of 7005, but later it had 7001. Would this change enroute be normal or are we talking about a recording from a different day?

"Wagon Air eight five zero one clear to Singapore, mike six three five level two four zero initial, RAMPY one alpha departure squawk number seven zero zero five,” a female voice from the ATC was heard. - See more at: Leaked: Communication between AirAsia flight QZ8501 and Air Traffic Control | The New Paper

[training wheels]

Originally Posted by aussiepax

So does that leaked ATC tape identify what accent was on the radio comms e.g. Indonesian captain Vs Nigerian French 1st officer, and does any of that then give a clue as to who was PF // PNF please

After airborne, the Captain is heard on the radio as the Tower hands them off to Surabaya Director. That's definitely the captain talking as he referred to the female controller as 'mbak' (which is Indonesian for 'sis') in a typical Javanese accent. (At 10:59 on the audio timeline).

So, we can deduce form this that the FO was PF and and Captain was PNF (or PM in this part of the world)

And it's usually standard practice for the Captain to taxi out and the FO performs communication duties whilst on the ground.

[training wheels]

Originally Posted by Ber Nooly

Regarding that leaked ATC recording, she clears him with a squawk of 7005, but later it had 7001. Would this change enroute be normal or are we talking about a recording from a different day?

You can hear Surabaya Director asking him to change the squawk code to 7001 once they were airborne (at 11:20 on the audio timeline). That sometimes happen when departing Surabaya due to traffic originating from Bali having conflicting codes.

[onetrack]

So does that leaked ATC tape identify what accent was on the radio comms e.g. Indonesian captain Vs Nigerian French 1st officer, and does any of that then give a clue as to who was PF // PNF please

Nigerian?? The FO was originally from the island of Martinique in the Caribbean.

[thcrozier]

Underwater visibility looks like 10 to 12 feet to me. Maybe more, as one shot shows sunlight penetrating from the surface in the background.

[Australopithecus]

That paint scrape looks more like a kink line where the paint popped off. You see that in buckled skin after impact deformation.

[captains_log]

I agree with Sir Richard thats seaweed not scrapes..

[bobdxb]

@Australopithecus

you are 100% correct, paint went off due mechanical force (xtreme bending)...seaweeds?? at 30 mtrs or so??

[Ian W]

Originally Posted by scard08

Calculating the speed based on adjacent ADS-B data points will not work. The data is just not precise enough to do this. Suppose that second data point was actually received at 23:11:00.999. If it had been received a thousandth of a second later then it would be timestamped a second later and the first delta t would have been 4 seconds instead of 3 and the second would be 3 seconds instead of 4. That would change the caclulated speeds by about 1/3, which is a couple of hundred knots.

A similar but smaller problem comes from the precision in the coordinates. If the delta in the latitude is .004 in one 3 second interval and .005 in the next, that does not mean the speed changed by 25%.

ADS-B data carries the time at which the aircraft generated that GPS position. So it does not matter when that was received as each ADS-B report is perfectly valid. This is to ensure that delays in transmission do not cause the errors you describe.

The problem the receiving system has is that these reports do not come in with the same delay each time, especially if the receiving system is using several remote antennae or even several different receiving stations. This can result in position reports coming in at random intervals and in extreme cases out of order. This is why it is important to use the original data from the aircraft which will carry the timestamp of the GPS position. It is not clear that FR24 and other services do this.