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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 15th Jan 2015, 22:40
  #2081 (permalink)  
 
Join Date: Jul 2004
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Originally Posted by Coagie View Post
Although surviving an ocean ditching may be statistically low nowadays, the rafts, life jackets, etc are a bit of a throwback to when a survivable ocean ditching was quite possible. Back in the days when aircraft were much slower and had better glide ratios, in the pre-jet age, ocean ditching happened enough to justify rafts and life jackets. Piston engine aircraft were overall less reliable, so might have to ditch in the ocean, while still somewhat flyable. In today's reliable, but fast jet aircraft, the few times things go wrong, there's a good chance they go very wrong. A compromise in air worthiness often is either non-catastrophic or catastrophic. In the old days, there was an in between, where life jackets and rafts might come in handy. You might call it "Semi-catastrophic".
I personally feel good about the life rafts, etc still being in use, even if they are a throwback.
I agree that is is probably easier to ditch a piston airliner, but.....

Modern jetliners should have better glide ratios than old piston airliners.

Just ask Captain Bob Pearson of the "Gimli Glider", or Captain Robert Piché of Air Transat Flight 236.
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Old 15th Jan 2015, 22:47
  #2082 (permalink)  
 
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Currents and buoyvance

For those still doubting what a 5-6 knot current can do, it's all in the buoyancy of the fin. The impact with the surface of the sea was obviously sufficient to buckle the aft pressure bulkhead, tear off the apu and elevators and dislodge the heavy recorders but leave the fin intact enough to float, gradually sinking as water filtered into its and the rudder's compartments and finally coming to rest when its anchor, the remains of the aft fuselage, snag on the ocean floor.

Did you read about the divers working downwards hand over hand on the buoy cables and being streamed out like flying Supermen? Imagine a semi-floating object, sinking only gradually. I'm surprised the tail was found only 1.7km from the impact point.

Regarding recorders being found "under the wing", at that depth, in murky water, wing or elevator would look the same. I'd assume elevator.

Finally, many divers are by nature consummate risk-takers. I'm not one but have butted heads with a few. it looks as though they've been lucky so far but I hope to hell they're careful over the coming days. Grim work.
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Old 15th Jan 2015, 22:49
  #2083 (permalink)  
 
Join Date: Jan 2015
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Ditching is survivable

The "first" commercial jet to ditch in the open ocean: alm flight 980

ALM Flight 980 - Wikipedia, the free encyclopedia

http://www.airdisaster.com/reports/ntsb/AAR71-08.pdf
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Old 15th Jan 2015, 22:51
  #2084 (permalink)  
 
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Just ask Captain Bob Pearson of the "Gimli Glider", or Captain Robert Piché of Air Transat Flight 236.
Captain Bob did a great recovery. Lucky he was at altitude. But, I'm sure if you give it a second thought, you'll remember that a jet's wings have to trade lift for less drag, so the slower aircraft of yesteryear were generally able to accomplish a slower, softer, unpowered landing than the faster jets of today.
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Old 16th Jan 2015, 00:26
  #2085 (permalink)  
 
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Although surviving an ocean ditching may be statistically low nowadays, the rafts, life jackets, etc are a bit of a throwback to when a survivable ocean ditching was quite possible.
Aa ocean ditching many miles from land is not the only relevant scenario. We have had examples in recent years of landings in rivers at relatively low speeds, and runways with water at one or both ends are not unknown. Lifejackets and rafts may be very valuable in case of accidents in such locations.
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Old 16th Jan 2015, 00:45
  #2086 (permalink)  
 
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Leightman957 (currently post 2062)

'more training' suggested by many seems to offer very few benefits.
IF it was weather related we may finally know in a few days, hopefully!

I, for one, would like to see more training in actual small planes, getting pilots to know the air and what it does, not just some pre-planned prepared sim button pushings. Of course bean counters will scoff at this, but I am thinking Logan Air, Braathens, Buffalo Air, Suzy Air etc. Excellent training for pilots to FEEL the element they are moving in.

Weatherwise, a CB in Indonesia is totally different from a CB in Sweden or over bigger parts of the US. In Sweden it is too cold to get any Godzilla CBs and in the US it gets big but it hasn't the ocean current beneath it to make it Godzilla. (Ok, except for the states close to the Mexican Gulf.)
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Old 16th Jan 2015, 00:58
  #2087 (permalink)  
 
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hey, how about making a rule that anyone flying for an airline actually has to have a good amount of experience PRIOR to getting hired.

mrsnuggles, somehow I really don't think your view about this is anywhere near correct.

let's find out what happened. though I think I know what did happen.

And if you learn to feel things in small planes, how does that relate to computer controlled wonder jets?

IN good old jets, it actually FELT different when you flew slowly vs flying fast.
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Old 16th Jan 2015, 01:15
  #2088 (permalink)  
 
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I don't know Glendale...how much general aviation goes on compared to the airlines? Worldwide, I mean.

When I first hired on to a turboprop regional the cover charge was 3,000 hrs twin. My 24 year old contemporaries all had at least that much time. Is that even achievable anymore?

Since the early 70's I think the airlines have quadrupled their fleets while GA has shrunk to almost nothing. My hometown, back in the day, had 13 piston twins, three PA-3Ts and two C-500, almost all crewed by eventual airline pilots. Now there are exactly two private twins.

I wonder how large most Air Forces are now compared to previous decades?

Also, Mr. Snuggles... I suggest you have not tried to pick a way through a North American cold front in the spring/summer. Anywhere in the prairies into Canada you get monster cells.

I find tropical thunderstorms much less daunting than their temperate zone cousins. For one thing the air is close to saturated in those latitudes, giving less change of state to amplify the vertical wind shear. Landing three miles away from a cell at the equator? No problem. In Kansas City? Not so much.

On the light aircraft training...it is a different animal to high altitude, high speed flight. Better would be theoretical training followed by mishandling into incipient stalls at altitude. I don't think that the average SOP monkey has an appreciation of just how fragile a 1.3 G buffet margin is.

Last edited by Australopithecus; 16th Jan 2015 at 01:29.
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Old 16th Jan 2015, 01:25
  #2089 (permalink)  
 
Join Date: Jan 2014
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well, how about this


take an average airline pilot up with a test pilot in a wonder jet. go to FL350 and stall the plane, full stall.

recover

and VIDEO the whole thing from many viewpoints including the instruments, out the window

do it at night too

do it in clouds with nothing outside

show the nose down pitch attitude to recover and the altimeter winding down

show a G meter to show that the plane might go negative if the pitch down is abrupt.

record all the data that the FDR would get and feed it into the sims so we can all do it.

Quite frankly I wouldn't go up in a small plane for training unless I am being paid the full amount that I would get for flying a transport.

well, lets wait and HOPE that we hear soon what happened.
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Old 16th Jan 2015, 09:27
  #2090 (permalink)  
 
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"For example, if there had been a protection state in AFR447 that motored the THS to zero NU as soon as there was a stall indication" - a sensible idea, Ian, BUT now remember you have to build in protection against a false stall warning!

Far better to have homo sapiens trained to move the THS - and do it?
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Old 16th Jan 2015, 09:38
  #2091 (permalink)  
 
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The stall warning was real.

Yes Homo 'sapiens' could do this but then the same could be said of all the protections. However, in this case it just seems an easy thing to do and it puts the the aircraft into a recoverable position.

Out of interest do any of the stall recovery memory items include check trim neutral?
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Old 16th Jan 2015, 10:17
  #2092 (permalink)  
 
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Out of interest do any of the stall recovery memory items include check trim neutral?
The Airbus A330 stall recovery in place at the time of AF447 called for TOGA and 5° pitch (10° below FL200). Unless I'm mistaken, no mention was made of checking trim. See: http://www.smartcockpit.com/docs/A33...ing_Manual.pdf page 204

BTW, I doubt when you're sinking at 10,000fpm (close on 100kts) any amount of power will unstall you without putting the nose down.

Last edited by Roseland; 16th Jan 2015 at 14:45.
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Old 16th Jan 2015, 10:28
  #2093 (permalink)  
 
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Originally Posted by Flagon
"For example, if there had been a protection state in AFR447 that motored the THS to zero NU as soon as there was a stall indication" - a sensible idea, Ian, BUT now remember you have to build in protection against a false stall warning!

Far better to have homo sapiens trained to move the THS - and do it?
Far better that the stab trim does not move automatically when hand-flying!
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Old 16th Jan 2015, 11:45
  #2094 (permalink)  
 
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Three to four years ago Airbus introduced new stall recovery procedures which I imagine all Airbus pilots would now be familiar with:

http://www.ukfsc.co.uk/files/Safety%...une%202010.pdf

http://xa.yimg.com/kq/groups/1048360...0Procedure.pdf
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Old 16th Jan 2015, 11:48
  #2095 (permalink)  
 
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Glendalegoon

Your post is right on the money and well put.
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Old 16th Jan 2015, 11:57
  #2096 (permalink)  
 
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glendalegoon:

And if you learn to feel things in small planes, how does that relate to computer controlled wonder jets?
Ok, I may have been vague here. I'm talking about "small" planes, turboprops, think SAAB 340 and the like, not tiny Cessnas with four seats. My favourite would be the DC-3 or DC-4... ;-D

The reasoning behind this is if you learn to feel how the winds and air affect the plane, those physics translate even to one of those big shiny ones albeit big and shiny has more resistance to weather events due to their size.

Austral...

Also, Mr. Snuggles... I suggest you have not tried to pick a way through a North American cold front in the spring/summer. Anywhere in the prairies into Canada you get monster cells.

I find tropical thunderstorms much less daunting than their temperate zone cousins. For one thing the air is close to saturated in those latitudes, giving less change of state to amplify the vertical wind shear. Landing three miles away from a cell at the equator? No problem. In Kansas City? Not so much.
You are correct. I have not flown in the US only in Europe. I extrapolated from what is known about storm cells and convective air over ocean currents. Sorry if I offended anyone, I realise I did make that clear before.
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Old 16th Jan 2015, 12:11
  #2097 (permalink)  
 
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Three to four years ago Airbus introduced new stall recovery procedures which I imagine all Airbus pilots would now be familiar with:
Only the second of the two links you included mentions trim, unless I've missed it.
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Old 16th Jan 2015, 12:24
  #2098 (permalink)  
 
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The Airbus A330 stall recovery in place...
The fundamental misunderstanding is, that this is not the stall recovery procedure, but the procedure to be applied when the stall warning starts to sound. It actually is a stall prevention procedure in case you get close to stall. And as such, it works perfect.
Large aeroplanes are not intended to be stalled, hence there is no procedure required to recover from a fully developed stall.
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Old 16th Jan 2015, 13:07
  #2099 (permalink)  
 
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Originally Posted by mcloaked View Post
Three to four years ago Airbus introduced new stall recovery procedures which I imagine all Airbus pilots would now be familiar with:

http://www.ukfsc.co.uk/files/Safety%...une%202010.pdf

http://xa.yimg.com/kq/groups/1048360...0Procedure.pdf
As Volume points out these are stall avoidance procedures.
Has anyone recovered from a real full stall in these FBW aircraft at cruise level?
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Old 16th Jan 2015, 13:27
  #2100 (permalink)  
 
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Roseland:
...I doubt when you're sinking at 10,000fps (close on 100kts) any amount of power will unstall you without putting the nose down.
At altitude, doubly so, because of less dense air, in turn directly related to LESS ENGINE THRUST AVAILABLE, as well as slower engine windup rate.

Reducing AOA does the job right now.

BTW, Roseland, do you mean 10,000 fpm, not fps?
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