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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 18th Jan 2015, 21:01
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A number of posts trying to find alternative explanations, many without due regard to the photographic evidence posted earlier in the thread, the basic laws of physics and how one should fly a modern jet aircraft.

Not in any particular order, no blame or insult is intended:

Vertical dive into sea.
A.Take an empty drink can and with the can on its base stamp on it.
B. Take another empty can lay it on its side and stamp on it.
Do the fusalage photos look like a or b?
Answer b. Therefore it can be infered that the plane hit the sea more or less horizontally.

Ditching.
You do not lose speed by banking the aircraft.
Ditching configuration varies acording to aircraft type but for all aircraft one should land parallel to the swell line with some degree of nose up attitude and wing level.
The time frame available is usually short enough that getting this right is very difficult.
C. Take yet another empty drinks can and scrape it horizontally along some rough concrete. (The sea will be as friendly to an aircraft).
Does the can look anything like the photos? Answer no. Inferance is therefore ditching very unlikely.
Please dispose of your cans in an environmentally friendly manner.
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Old 19th Jan 2015, 02:30
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The Economic Times reports:

SINGAPORE: Singapore's search operation to locate the debris of the crashed AirAsia plane came to end today with its ship that found the jet's fuselage in the Java Sea returning back after days of rigorous scouring.

Singapore's Navy ship, MV Swift Rescue, with 70 men and women on board, arrived at Changi Naval Base here and was received by the country's Defence Minister Ng Eng Hen. He was accompanied by chief of Defence force Ng Chee Meng and navy chief Lai Chung Han.

The arrival of MV Swift Rescue marked the official end of Singapore's efforts in the multi-nation search operation, which started on December 28 when AirAsia plane carrying 162 people from Indonesian city of Saurabaya to Singapore crashed into the Java Sea within less than an hour after take off. Since then, the Singapore Armed Forces (SAF) have deployed more than 400 personnel, two RSAF C-130 aircraft, two Super Puma helicopters, five navy ships and a six-man Autonomous Underwater Vehicle team in the operation.

Many of those who had contributed to the search were also present for MV Swift Rescue's home-coming. As a mark of respect, they observed a minute of silence for those who died in the aviation tragedy. The Defence Minister thanked the servicemen and women for their efforts and for making a difference in the multi-nation search operations. The return of the vessel marks the end of the SAF's 22-day deployment for the search operations, he said.
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Old 19th Jan 2015, 04:39
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Mindboggling stuff, as bad as advanced sailing theory. So presumably non of the boundary conditions for any of these swapover points are known for the A320, and so there is no way of knowing exactly when and how it will stall and or spin? especially if you include such things as changing CofG, weather etc.

If I recall the test regime for the 380 (I guess the 320 was similar) that consisted mostly of slowly going slower and slower as well as faster and faster until things got obviously dangerous, ceasing before you crashed and telling the computer not to let the AC go there. That with the background of fairly low g loading limts for the airframe which would make many escape strategies impossible anyway.

Last edited by DrPhillipa; 19th Jan 2015 at 04:50.
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Old 19th Jan 2015, 06:03
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Automated Spin Response

If it turns out to be a spin then Airbus should deeply think about an automated response by the flight control computer. The pilots have no realistic chance to break a full spin action. However the computer most likely can and has usually an easy and safe indication from the gyro instruments. If it takes 10000 feet so be it given the alternative of an assured crash.
In theory , perhaps a good idea, given that the flight crew would be effectively incapacitated. However, I must ask just what that programmed response would be. Airbus have no data, other that theoretical and computer simulated, concerning how the A320 would behave, and consequently what to tell HAL to do when all hell breaks loose.

Who is going to do the test flights to supply the necessary data to ensure that the programmed response is correct in all situations? That would be a very expensive and arguably fatal endeavour. If that data is not available, and HAL is programmed for a theoretical/simulated response who is going to do the testing necessary for certification ? I'm sure that Airbus has thought of such an 'adventure' during planning and totally rejected the thought for obvious reasons - similar thinking for a full stall.

Now you know why Airbus puts so much emphasis on avoidance.
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Old 19th Jan 2015, 07:47
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At least QZ 8501 had less kinetic energy in the vertical direction
Given the same water entry parameters, KE is proportional to mass..... and A320 is a lot lighter than A330...
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Old 19th Jan 2015, 08:04
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stall testing transport jets

I am quite sure this is true for any modern large transport certified after the 70s.
Apparently not so:

B787: https://www.youtube.com/watch?v=SvEMgmirldc
Includes interview with Boeing chief test pilot

MD11: 1990: MD-11 Memories | Things With Wings
The stall test comments come at the very end of the report

Last edited by 172driver; 19th Jan 2015 at 08:39.
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Old 19th Jan 2015, 08:07
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cogito ergo sum

If you believe (and told so) that your aircraft is protected from stall, you may not avoid it as actively as if you know it can kill you…
Bravo, the essence of the problem leading to these fatal accidents in a few words. (but let's wait for the data, to be sure)
You may not avoid it as actively and you may not know how to recover from it.
Bottomline it is difficult to say, if the computer protection has saved more lives than its presence has lured management and pilots into negligence regarding their skills of handling the aircraft at the borderlines of aerodynamics and costing lives in the process.

Last edited by Interflug; 19th Jan 2015 at 08:24.
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Old 19th Jan 2015, 08:15
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If it turns out to be a spin then Airbus should deeply think about an automated response by the flight control computer. The pilots have no realistic chance to break a full spin action. However the computer most likely can and has usually an easy and safe indication from the gyro instruments. If it takes 10000 feet so be it given the alternative of an assured crash.
Problem with that is that from past evidence, unusual attitude / loss-of-control has occurred because the automated systems have given up due to conflicting/unverifiable data and dumped the whole lot back on the pilots to make something of it. If it is possible to get the aeroplane to “self recover” from spins, etc. then there is enough information to stop it happening in the first place, which I would suggest is the prime goal.
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Old 19th Jan 2015, 08:20
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Why is ther so much discussion about stall spin? Have a missed a statement ?

The aircraft looks fairly intact almost as if it was in a semi controlled state when it went in, the pictures of the af447 wreckage look a lot different
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Old 19th Jan 2015, 08:33
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AT what point in the crash do you think the tail separated from the fuselage?

The reason I ask I assume when the tail separated, the CVR and FDR went with it and and that will be the last data recorded.
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Old 19th Jan 2015, 10:17
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CVR

Some information regarding the content of the CVR:

When asked if there was any evidence from the recording that terrorism was involved, Hananto said: “No. Because if there were terrorism, there would have been a threat of some kind.“

“In that critical situation, the recording indicates that the pilot was busy with the handling of the plane.”

Investigators said they had listened to the whole of the recording but transcribed only about half.

“We didn’t hear any voice of other persons other than the pilots,” said Nurcahyo Utomo, another investigator.

“We didn’t hear any sounds of gunfire or explosions. For the time being, based on that, we can eliminate the possibility of terrorism.”
Source: AirAsia crash investigators find no evidence of terrorism | World news | The Guardian
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Old 19th Jan 2015, 10:28
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"...the pilot was busy.."

Perhaps only one pilot in the cockpit at the critical moment?
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Old 19th Jan 2015, 11:04
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More info re CVR:

"From the (flight data recordings) so far, it's unlikely there was an explosion," Hananto said. "If there was, we would definitely know because certain parameters would show it. There are something like 1,200 parameters."

The final minutes of the AirAsia flight were full of "sounds of machines and sounds of warnings" that must be filtered out to get a complete transcript of what was said in the cockpit, said Hananto, who has been an air safety investigator since 2009.

The first half of the two-hour long cockpit voice recording has been transcribed. That includes audio from the previous flight and the beginning of Flight QZ8501, which crashed around 40 minutes after takeoff.

The team, which is working with French, Singaporean and Chinese air safety investigators, hopes to finish transcribing the recording this week, Hananto said.

With seven computers and various audio equipment, the small NTSC laboratory dedicated to the AirAsia investigation is split into two rooms; one for the cockpit voice recorder and the other for the flight data recorder.

Analysis of the flight data recorder would take longer, Hananto said, because investigators were examining all 72 previous flights flown by the aircraft.

Investigators hope to finish a preliminary report on the crash early next week. The full report could take up to a year, but will not include the entire cockpit voice transcript.

"In Indonesia it remains undisclosed," said Tatang Kurniadi, chief of the NTSC. "Just some important highlights will be included in the report."
Source: Indonesia says no evidence so far of terrorism in AirAsia crash | Reuters

Nurcahyo Utomo, another investigator from Indonesia’s Transportation Safety Committee, said nothing heard on the audio recording so far suggested pilot suicide played a role in the crash.

“So far we’ve managed to transcribe only half of it because there are so many noises,” he said. “We hope to complete it in a week.”
Source: http://www.wsj.com/articles/airasia-...667736?tesla=y

Last edited by Boomtown; 19th Jan 2015 at 11:15. Reason: Add WSJ article quote
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Old 19th Jan 2015, 11:07
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Perhaps only one pilot in the cockpit at the critical moment?
Perhaps not:

“We didn’t hear any voice of other persons other than the pilots,”
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Old 19th Jan 2015, 11:31
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Originally Posted by FullWings
Problem with that is that from past evidence, unusual attitude / loss-of-control has occurred because the automated systems have given up due to conflicting/unverifiable data and dumped the whole lot back on the pilots to make something of it. If it is possible to get the aeroplane to “self recover” from spins, etc. then there is enough information to stop it happening in the first place, which I would suggest is the prime goal.
I am not sure that is true.

The spin self-recovery could be a basic protection that is not lost. As it can use GPS Alt, and Inertial Nav to identify the aircraft is dropping fast and rotating in a particular direction. Then the system takes over and carries out the recovery.

Entry into a stalled/spin condition could be extremely fast in severe turbulence at cruise level with sudden wind reversals and OAT changes and yes even pilot mishandling. In some cases there may be no gentle and considered 'approach to stall'.
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Old 19th Jan 2015, 12:07
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I think the continuous references to "HAL" have misled some people into thinking that the Airbus flight control system is far more capable, in the sense of intelligent, than it is. It's actually fundamentally very conservative in design, only flies the aeroplane itself in quite benign parts of the flight envelope, and uses simple rules (albeit perhaps in too many combinations for some peoples' tastes) for its protections. It would be a massive change to give it the capability to reliably identify spins, quite possibly in the presence of sensor failures or anomalies, and then somehow act like the autopilot to end all autopilots in recovering from that spin, without the benefit of prior data on spin characteristics and best recovery methods. It's not going to happen, at least anytime soon.

Last edited by HeavyMetallist; 19th Jan 2015 at 12:18.
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Old 19th Jan 2015, 12:30
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As posted above the Airbus has a very basic FBW system. Spins have so many modes and types that it can be very difficult to identify if the aircraft is spinning and what mode. Even more advanced FBW systems incorporating rate motion feedback can't recover from a spin. In fact the most important step in spin recovery for the F18A was to disconnect the FBW computers and go to direct electrical link. The Airbus does not allow pilot selection of that option.
You would also have to do extensive spin testing on the aircraft in order to determine the proper recovery inputs for each spin mode and CG situation.
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Old 19th Jan 2015, 13:06
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Analysis of the flight data recorder would take longer, Hananto said, because investigators were examining all 72 previous flights flown by the aircraft.
So they are not only examining the famous "what does it do now", but also "did it do that before"? Interesting that they look at all the previous flights, is there some pre-existing malfunction suspected? Do they need to calibrate some models?

That includes audio from the previous flight and the beginning of Flight QZ8501, which crashed around 40 minutes after takeoff.
100% Audio coverage is a very positive thing. That may help a lot.

Overall it looks like some more professional people are now on the job. The Statements given do make much more sense than previous ones...
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Old 19th Jan 2015, 13:21
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Heavy Metallist: bravo.

There are problems with protections and envelope constraints: they rely on fallible sensors for their information. So, back to "Data Processing 101" : Garbage In= Garbage Out. True in 1971, doubly so now.

For the uninitiated- the aeroplane relies on its flight control software to implement the control laws complete with protections to address the needs of 99.99X% of all flights. On a very very few flights the sensors get compromised, all of the laws, protections and load relief goes away and the now betrayed crew is left with a lightweight, flexible, undamped aeroelastic, auto trimming nut case with a one-eyed determination to save the day by diving or stalling the aeroplane into the ground.

Bad sensors. Like bad rumours, mixed up lab results and WMD intelligence, they lead to grave misjudgements and irrevocable error. The problem of an uncrashable aeroplane is the same as an unsinkable ship: The crew has to politely smile at the marketing, understand its limitations and, if called, be able and willing to step up and act like an old fashioned master, not someone who is just along for the ride. (EMPHATICALLY NOT SUGGESTING THIS IS THE CASE WITH THE ACCIDENT FLIGHT, by the way. But I suspect that it is an industry problem. )

The flight guidance system at this stage is too rudimentary to provide guidance out of unusual attitudes. That's the stuff that we are supposed to be experts at after 15 or 20 minutes of training every couple of years. Oh...and the mythical aerobatic experience as a teenager followed by the fighter training and pylon racing, I guess.

Since recovery from inappropriate energy states and attitudes is actually pretty binary it might be possible to quickly develop a recovery guidance mode to facilitate the lowest common denominator crew** to follow prompts or director cues to the correct attitude to regain normal flight paths and loads. That would be the missing half of the promise that fly-by-wire makes: (This aeroplane is not stallable. If, however, you do stall it, it will tell you how to undo your error)

**: this is relative, obviously. Any one of us could be the lowest common denominator depending on skill, experience, fatigue and other intangibles on the day.

To recap:
1:FBW is a huge improvement on the pieces of sh1t that I used to fly when I was a zygote. So is almost everything else
2:FBW has probably reduced the incidence of serious incident by at least an order of magnitude. (And hence the accident rate is equally reduced)
3: Auto flight, at least on the approach, is not as smooth as the hypothetical experienced, well rested crew.
4:Like all numerically controlled machines, modern aeroplanes rely on sensors. Lots of them. They are lightweight, built to a price, and they fail from time to time.
5:Spurious warnings, cautions and whatnots are far more common that real ones.
6:Spurious alarming data is not immediately distinguishable from actual alarming data.
7:Active protections can save passengers from random dumb crew mistakes.
8:Spurious protection triggers can expose passengers to random dumb designer mistakes. (Too trusting of sensors without appreciating the "what if" hypothetical scenarios. Which happen from time to time)
9:"Golden Rule" instructions are all predicated on the presence of a very experienced, jaded yet competent crew to fly manually like a conventional aircraft when any unexpected or sub-optimum performance is demonstrated by the automatics, however subtle.

On edit, added: 10: the altitude capture mode, called "Alt star" presents peril when it engages during a high rate of climb manoeuvre. It locks in the current rate of climb, in this case, if it engaged, at over 1000 ft below the target altitude. If the wind shear dissipates and or the updraft fails, the aircraft will be left with a rapidly decaying airspeed and an autopilot disconnect at high alpha.

(At my peak I used to manually fly 1000+ hours every year. On raw data. While doing star shots and smoking black coffee and drinking unfiltered Luckies. And listening to disco music on the ADF receiver. While keeping an eye on that pesky number 13 cylinder on number two.

Today I get about three minutes of manual flying per week. I am considered a thrill-seeker for doing that much. Incredibly, an entire industry has grown on the convenient lie that the old skills, if ever attained, remain honed after decades of neglect.

Last edited by Australopithecus; 21st Jan 2015 at 11:58. Reason: Corrections, amplifications, clarifications. Post hoc B.S.
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Old 19th Jan 2015, 13:44
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Entire industry grown on a convenient lie

One of the most educated and intelligent posts read on this forum. But what of the folks who were /are NEVER even taught the "old skills...?"
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