Indonesia Air Asia flight QZ 8501 loses contact with ATC

[straitman]

ATC tracks ground speed not airspeed, without upper wind datum they are off little use

In addition to markis10's comments.
At the altitudes being flown the Mach No is the relevant speed indicator. The low IAS is quite normal (at altitude) though without access to some manuals I cannot comment how relevant the reported IAS is.

 

[Sprucegoose]

Very unlikely they would get within 100kms if they had radar, which I doubt, secondary surveillance radar only runs out to 150-200km, it's probable the accident happened outside of radar coverage. Even so, if they did have an accurate last cruise paint, too many variables, loss of transponder at cruise and hull breakup could see a damage trail some 9km long that has been the subject of current and ocean traffic for some 12 hours now. I would hazard a guess the actual search area is going to be 20000 square kilometres or more.

Abbott will send some AP-C3s.

 

[straitman]

Abbott will send some AP-C3s.

????

Do you mean Oz P3-Cs?

 

[ermen]

Now this is very sad...

SINGAPORE: The Briton on board flight AirAsia flight QZ8501 is believed to be Mr Choi Chi Man, who is based in Indonesia, where he is the managing director at an energy company.
He was accompanied by his two-year-old daughter, Zoe, who is believed to have been the sole Singaporean on the flight.
According to a copy of the passenger manifest released to Indonesian media, Mr Choi and Zoe bought their tickets on Friday (Dec 26). According to the manifest, they were seated in the first row, in Seats 1B and 1C.
According to his LinkedIn account, Mr Choi was born at Hull in Yorkshire, England, and graduated from the University of Essex in 1988.
He was Unit Managing Director for Thermal Services at energy firm Alstom Power, a position he held since July this year. Prior to that, he was based in Singapore, where he was a senior executive at Alstom Grid, according to his LinkedIn profile.
Channel NewsAsia understands that Mr Choi’s wife had travelled back to Singapore from Surabaya earlier with Zoe’s older brother.





Briton on AirAsia QZ8501 believed to be Indonesia-based energy executive - Channel NewsAsia

 

[24601]

yes, missing, search suspended overnight. What's going on with airlines in that part of the world?

 

[Major]

The load and Trim sheet has also been published

Kementerian Perhubungan Republik Indonesia - Data Pesawat Air Asia QZ 8501 SUB-SIN Beserta Data Penumpang yang hilang kontak

 

[artemis]

Aviate, Navigate, Communicate

I appreciate that the pilots communicating is a lower priority. My question, though poorly articulated, is why is there not an automated broadcast which is triggered when the aircraft breeches some critical parameter (too slow, too fast, wrong angle, whatever the technical envelope is)? Ie, it's not sent by the pilots who are trying to manage the situation, but sent by the aircraft when it reaches a certain combination of parameters? And ideally broadcast via more than one means.

I'm just a layman, but it astounds me that in this day and age, that entire aircraft go missing!

 

[markis10]

????

Do you mean Oz P3-Cs?

AP-3c's I suspect

 

[jb747]

I'm curious to know, does bad weather, no matter how bad it may be, bring down a modern airliner from >30,000ft? Obviously landing and takeoff is another story, but what sort of weather could suddenly bring down a tried-and-tested A320 from such an altitude? Bad enough weather to give the pax a fright, but not snap a wing off...etc.

Weather, per se, is very unlikely to bring an aircraft down. The structures are more than capable of handling any loads they're likely to run into...

But, thunderstorms are also associated with icing, and icing can have some interesting effects upon angle of attack probes, as well as airspeed and altimeter readings. AF447 was a perfectly flyable A330, that managed to confuse its pilots to the point that they couldn't fly it. I think the ANZ 320 also had some form of probe/icing implication as well.

 

[jb747]

They wouldn't have had enough fuel to still be in the air by now, and what's the likelihood of a safe landing somewhere and not being able to get a radio message out?

Nil.

Can authorities track all the messages from engine feedback etc (sorry, not sure of technical terms) to pinpoint locations?

Whilst engine data can be downloaded, it's not generally a 'live' process. Plus, it has to be paid for by someone, and LCCs by definition, don't pay for anything they can avoid.

And I guess the really big question is - did MH370's disappearance change the way airlines track their aircraft?

It may, but it will take years for such changes to be mandated, and then for the equipment to spread across fleets.

Why no distress broadcasts?

Because they rank last on a pilot's list of things to do.

Lots of people are talking about AF447, do pilots have to practice these scenarios in simulators as part of ongoing training?

Yes, but. There's an almost infinite range of possible scenarios. Secondly, different countries, and airlines, have different requirements for what is done in sims, and how often. Sim sessions cost substantial dollars, and can be part of an airline's cost saving process...i.e. do the minimum mandated.

 

[jb747]

The suggestions of the aircraft being too slow? reminded me of what jb747 recently posted on the Ask The Pilot's thread where he mentions the "available speed margin is often very narrow...." quoted below.




Anyway this is purely wild speculation by me, an armchair novice, that the pilots were flying pretty slow initially due to the weather, requested to climb? which they did, but at the same time did not accelerate enough? which compounded the decreasing speed with going upwards, and consequently stalled ....... with lots of computers warnings in the coughpit, plus with the likely nasty weather they were in - rain, hail, thunder, noise - things were pretty hairy up there, hence a la AF447.

The aircraft was supposedly at FL320 initially. That's relatively low for a flight on a (roughly) 2 hour sector, so presumably, he's been blocked by traffic from going higher. At lower levels you are less likely to be over any weather, but, in reality, most of the weather in that part of the world is very high anyway, so you don't go over, you go around. As you climb, the margin between your maximum speed, and your minimum speed narrows...until eventually there is no margin in either direction....that's the classic 'coffin corner' and is the reason that we never cruise at the maximum possible altitude. So, whilst being lower is more likely to have you in the weather, it also gives a much broader speed range, and so is actually a safer place to be. Some manuals specifically mention descending up to 4,000 feet to improve margins if you are in a situation of not being able to avoid weather.

You don't slow down to climb. You simply add power, and climb at the current mach number.

The aircraft would NOT stall unless it has dropped out of normal law. That's where the interest in icing and the various probes comes into play.

 

[jb747]

Surely they must be able to locate the wreckage within a kilometre based on current modelling and last data. The GPS would be on until impact and radar until it got below a certain altitude? You would hope a light aircraft and navy would be there within a few hours of first disappearance.

Yep, the aircraft would know where it was....

 

[jb747]

Weather was indeed a shocker

Not all that unusual for that area though....clear would be out of the ordinary.

 

[jb747]

I appreciate that the pilots communicating is a lower priority. My question, though poorly articulated, is why is there not an automated broadcast which is triggered when the aircraft breeches some critical parameter (too slow, too fast, wrong angle, whatever the technical envelope is)? Ie, it's not sent by the pilots who are trying to manage the situation, but sent by the aircraft when it reaches a certain combination of parameters? And ideally broadcast via more than one means.

I'm just a layman, but it astounds me that in this day and age, that entire aircraft go missing!

Unless it is mandated, then it won't be paid for... Passengers chase cheap fares, and one way that is fulfilled is by equipping aircraft with only whatever is mandated. And remember, different countries will mandate different levels of equipment.

Having said that, those of us who fly them are not surprised. There are vast swathes of the planet that see minimal human activity, and yet aircraft transit them quite regularly. Any of the southern oceans are extremely empty...and even the satellite coverage is sparse. Whilst satcom and data links have made great inroads in the last 15 years or so, it's still very common for both to be unavailable, and to have to fall back to HF radio. Which is just as likely not to work either, and which NEVER works in the vicinity of any weather. Even the static charge that the aircraft picks up in cloud will make HF useless.

 

[tgh]

Really nice to read JB's calm voice of reason , thanks for your participation.
Perhaps a heads up for us everyday passengers , we are very lucky to have a National carrier that puts safety high on it's priority list.
Time for some tightening up worldwide ?

 

[Captain Halliday]

Thanks for sharing your wisdom jb.

 

[browski]

Has anyone yet suggested that we start the search near Perth?

 

[joyvee]

One of the great things about this forum is that you can learn so many new things. I appreciate the time and effort jb and others put into sharing their expertise in easily understood language. My beloved even contributed by telling me that it was"mark" and not "match" as I was pronouncing Mach.

 

[Pushka]

Thank you jb. As we are currently flying throughout this area and indeed the day the plane went missing I appreciate your contributions.

 

[clazman]

On what is suggested the flights "load and trim" sheet, it has Adult PAX weighing in at 75kg.

That weight seems a little light, when you factor in average human weight and a carry on.

Do these numbers change upon geographic location eg US would be closer to 90kg?