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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 29th Dec 2014, 10:13
  #341 (permalink)  
Join Date: Nov 2010
Location: USA
Posts: 98

NTSB Special Investigation Report
Wing Failure of Boeing 747-131
Near Madrid, Spain
May 9, 1976


On May 9, 1976, an Imperial Iranian Air Force Boeing 747-131 crashed as it approached Madrid, Spain. Witnesses observed lightning strike the aircraft followed by fire, explosion, and separation of the left wing. The report includes fire pattern studies, structural failure descriptions, trajectory analysis, fuel flammability calculations, gust loading analysis, and an analytical treatment of several hypotheses.
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Old 29th Dec 2014, 10:23
  #342 (permalink)  
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Coffin corner is a left over from yesteryear.
Todays technology has obliterated cc.

If you don't agree, tell us why.
Utter nonsense. Behind the pretty simbols on the PFD the laws of aerodynamics are the same as ever. You tell us how technology has obliterated CC for subsonic aeroplanes.
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Old 29th Dec 2014, 10:26
  #343 (permalink)  
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Confusion abound !

The flight had requested a deviation (due to weather). This was approved.
There was a left turn.

The flight requested a climb (FL320 to FL380). This was not approved.
Subsequently ATC approval was give to FL340
No response was received from the flight.

A radar plot has surfaced in the media showing the flight at FL360 and 353kts.

Clarification please. Is this correct.
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Old 29th Dec 2014, 10:28
  #344 (permalink)  
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Ever heard of something called an FMC?
Or, perhaps an FMGC?
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Old 29th Dec 2014, 10:29
  #345 (permalink)  
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Yes JamesGV, I posted the latest known timeline a couple of pages ago, per briefing from AirNav Indonesia official.
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Old 29th Dec 2014, 10:32
  #346 (permalink)  
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yes the most recent EAD regarding "frozen AOA" indicators (resulting in spurious speed decrease to close to or below VLS causing the nose to pitch down in Normal Law) does seem likely to be the cause. Maybe the pilots weren't aware of the new procedure ?!

You couldn't be more wrong - Two frozen vanes would cause Alpha Prot to erroneously increase up the speed scale. This would cause the stall protection system to kick in and force the aircraft to pitch nose down regardless of any side stick input. In effect the aircraft would be protecting itself from the stall before it needed to - A good thing in the Cb situation but not so good close to the ground.

However, if the pitot tubes became blocked (especially if climbing) then the opposite happens. The aircraft thinks it is going faster than it actually is and either the pilot or autopilot protects itself by pitching up unnecessarily and stalls for real - much worse.
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Old 29th Dec 2014, 10:33
  #347 (permalink)  
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This event, naturally, attracting numerous posts and I apologise in advance for not reading all of the foregoing. Speculation and comments thereof remain classic PPRuNe Rumours and News and is pleasingly encouraged. My take is on Command Selection, Training and demonstrated ability. IF this was a weather related event, I would be disappointed with a crew's handling. Faced with a wall of severe weather, why not turn back ? If that was not an option, why not divert to another airfield a wait it out ? Ty and out-climb a CB is lunacy. I am astonished by one media commentator (retired Airline Capt) who claimed that, sometimes, there was no option but to secure the cabin, secure the crew, reduce speed and , not kidding, quote,........"just take it on the chin ".............!!!!!

OLASEK, post 341, Excellent.

OLBIE, can YOU tell us how modern technology has made the CC discussion obsolete ? I can imagine that modern technology simply will not permit flight at or around limits but don't know if that is what you are suggesting. Lovely old days we could do that and even exceed limits. It is what gave us grey hair at an early age and made us old but not bold pilots.
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Old 29th Dec 2014, 10:46
  #348 (permalink)  
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What we don't know

The P2F or not question has been answered at least twice in the negative in this thread.
But one question I haven't seen dealt with is what is the significance of the instant loss of contact at operating height - if that is what the reports mean. If the aircraft stalled, would the transponder continue to signal in descent for a couple of minutes? Isn't that what AF447 did? If that happened, how would it be recorded? If so, when is it likely to be made public. if it didn't, could it mean the aircraft broke up at operating altitude?
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Old 29th Dec 2014, 10:55
  #349 (permalink)  
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Cheers. Seems like they were "in it" (whatever "it" was) pretty quickly then.
And before the approved climb to FL340.


If AirAsia (Indonesia) follow the model of AirAsia (Malaysia), then to a Frenchman F/O, there would NOT be a P2F "option" available to him.
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Old 29th Dec 2014, 10:56
  #350 (permalink)  
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Bilbao Incident

The apparent trigger for the narrowbody Airbus AD

Lufthansa A321 near Bilbao on Nov 5th 2014, loss of 4000 feet of altitude | AeroInside

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Old 29th Dec 2014, 10:56
  #351 (permalink)  
Join Date: Oct 2014
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Outclimbing CB...
Not really sure what you guys are talking about here?
If I approach an area of thunderstorms I would like to get as high as possible while maintaing a margin to maximum altitude.
Why? I get a better view. I get the possibility to fly over the weather, rather than trying to pick my way through the weather at 30000 ft.

It's not unusual to climb and it's not unusual to fly in the vicinity of thunderstorms. Sometimes between, sometimes over. Sometimes I need to deviate 50 - 100 NM because i can't do either. I have never turned back or diverted enroute because of thunderstorms.

This flight was turning and wanted to climb. Nothing unusual about this.

This aircraft will be found, and the cause will be found. This is not an alien abduction, it's an accident.
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Old 29th Dec 2014, 11:08
  #352 (permalink)  
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Indonesian work permits are not easy to access for foreigners. This was one of the issues EageJet suddenly faced with Lion Air, which is a big P2F customer.

I have personally observed training in Europe of Lion Air pilots, and what their TRI's told them to expect when returning to normal line operations with Lion Air.

It's the elephant in the room, everybody who works with these companies knows about these issues, but nobody stands up and speak out!
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Old 29th Dec 2014, 11:08
  #353 (permalink)  
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its a little weird how some people are adamant that nothing can or should be done about tracking of aircraft. the incidence of 447/370/8501 events is rising and joe public must be thinking flying is getting to be a risky business. you can bet that irrational or not, he IS comparing the mobile phone versus aircraft and is not impressed to learn that apparently the desired safety level comes at too high a cost. might not market forces drive a change before long?
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Old 29th Dec 2014, 11:08
  #354 (permalink)  
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i deleted this link - with apologies for the inaccurate details

Last edited by Mimpe; 29th Dec 2014 at 11:54.
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Old 29th Dec 2014, 11:15
  #355 (permalink)  
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Originally Posted by In_Transit View Post
Literally zero
And that is no wonder.
When flying at ~260kts IAS (turbulence Penetration Speed) with a clean config 1g stall Speed of ~170 - 180 kts you have a stall margin of ~2g.
With 150% structural margin required you will probably need >4g to make the wings fail structurally. That would be a whopping 350kts+.
Thus the wing will stall loooong before it will break in cruise at altitude.
Only by entering a dive and trying to recover at lower altitudes and high IAS you will theoretically be able to shed feathers.
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Old 29th Dec 2014, 11:16
  #356 (permalink)  
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Faced with a wall of severe weather, why not turn back ? If that was not an option, why not divert to another airfield a wait it out ?
IF this was a 'weather related' event and if the crew flew this route on a regular basis, it's very likely that they had encountered similar weather conditions on many previous occasions.

After all, monstrous storms are fairly common in this area.

Maybe they just adopted their usual procedure for dealing with what they regarded as a routine situation, but on this occasion luck was just not with them...
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Old 29th Dec 2014, 11:18
  #357 (permalink)  
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Originally Posted by JamesGV View Post

A radar plot has surfaced in the media showing the flight at FL360 and 353kts.

Clarification please. Is this correct.
I posted that radar plot on page one of this thread. There is also traffic UAE 409 at FL360 heading to Kuala Lumpur not too far ahead and left of track on M-635.
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Old 29th Dec 2014, 11:29
  #358 (permalink)  
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Technology Status?

I can buy an INS for $150 that has integrated GPS and three axis-accelerometer, gyro and magnetometer, along with barometer.

It knows its absolute position within centimetres and its attitude to better than a degree in each axis.

This unit is derived from full scale INS so I ask the question why there is a problem on modern aircraft when pitot tubes and whatever are blocked / misreading?

I understand there is a difference between actual air speed components and true ground-speed, but why is this high precision information source not used? Or if it is, why are things like pitot tubes more important and overriding the absolute measurements? Especially over extended period of seconds to minutes?
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Old 29th Dec 2014, 11:36
  #359 (permalink)  
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So do we actually know what its final altitude was? Reports it was around FL360 but they didn't even have permission to climb to FL340 - as that was giving when they didn't respond.......
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Old 29th Dec 2014, 11:38
  #360 (permalink)  
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@Mahatma Kote

I am not a pilot, but I can give a guess. Your device cannot measure airspeed, and airspeed is critical as to whether the aircraft stalls. I don't think there is a compact technology (doesn't kill aerodynamics) that can measure airspeed without sticking something small out into the wind (which makes it prone to icing up).
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