All transport aircraft are required to carry Emergency Locator Transmitters that can be manually deployed by the crew after a ditching. Therefore your point about the delayed rescue after a successful ditching are invalid. However, I'm not sure about the regulations regarding automatically deployed beacons that would be useful in the case of a crash rather than a ditching.

Distress radiobeacon - Wikipedia, the free encyclopedia

@A0283: "Before doing that, my line of thinking on water landing (before I read your reply, so there may be some duplication in it) was roughly thinking about two different and both basic scenarios."


I’m not sure how much more I can add to my previous post without getting too far away from the evidence we have seen so far.

Either of your scenarios are possible, though judging by the condition of the fuselage (slightly pancaked – side bulge flattened top) as shown in the latest underwater pics, it would have been at a very high rate of descent – so I think both unlikely. However, I also agree that the damage to the airframe looks less extensive than the pictures I have seen for the AF447 wreckage, though a lot of bits and pieces can separate when a journey of 4k to the seabed is involved.

Like others on this forum, I am minded to believe that QZ8501 experienced a similar aerodynamic event to that which occurred to AF447, with the airframe basically intact and in a stalled attitude until impact with the ocean. The more important questions that need answering are how did the aircraft enter the uncontrolled state, and why was it not possible for the crew to regain control – was it a technical failure, or was crew incapacitation a cause. However, unlike AF447, we do not need to wait 2 years for the data recorders to be recovered. Hopefully this information should be revealed in the coming weeks or months.

The following link is instructive in providing an idea of how an airframe, a B737) in this instance, crumples when subject to a test 30-ft/s impact velocity, albeit that in this case the impact is on a hard surface.

http://www.cs.odu.edu/~mln/ltrs-pdfs...-3ikus-elf.pdf

Hard surface
 

As already reminded on this thread, water is a hard surface in such circumstances.

Let's now wait for the outcome of the FDR and voice recorder.

The Strait Times reports on the divers conditions:
 

PANGKALAN BUN (AFP) - Clinging desperately to underwater ropes, an Indonesian search leader said his divers appeared to be "flying like Superman" as they scoured the seabed in the gruelling quest to recover bodies and wreckage from crashed AirAsia flight QZ8501.

"The current is so strong that it could rip open our masks or drag us into a whirlpool," said Totok Subagio, in charge of a group that this week found the plane's two black box flight recorders, after a lengthy, difficult search. Trained to swim to depths of 45 metres, the Indonesian navy's finest frogmen were drafted in to scour the seabed for wreckage of the Airbus 320-200 that went down in a storm on Dec 28 en route to Singapore.

But in the Karimata Strait between Indonesia's Sumatra island and Borneo island, they have had to contend with rough seas, powerful underwater currents, and weather that changes from bright and sunny one moment to cloudy and rainy the next. Grainy images from specialist Singaporean search equipment Wednesday showed the plane body resting on the seabed, with part of the Malaysia-based airline's slogan "Now Everyone Can Fly" painted on the red-and-white exterior clearly visible.

Divers now face the grim task of examining the main body of the aircraft in the hope of finding more of the 162 victims who were on board the plane, believed trapped inside the fuselage. Almost three weeks into the search, just 50 bodies have so far been retrieved. - 'Two-metre-high wave is a blessing' -
Ferdy Hendarto, head of the navy's local underwater rescue division, described how divers would descend along ropes attached to buoys on the sea's surface marking the locations of the plane's wreckage.

The currents are so strong they can be dragged sideways and at times appear to be "flying like Superman", he said. The search has been tough even for veteran divers, with some suffering nosebleeds after spending too long at depths of 30 meters. Conditions on the surface have also been rough, with some vomiting on their way out to hunt for the wreckage as their tiny boats were hit by waves four metres high.

"In that search area, a two-metre-high wave is a blessing," Subagio said.

Most days divers have had only a four-hour window in the early morning when they can search, before clouds obscure the sun and reduce visibility underwater, rendering search efforts impossible. In the hunt for the plane's two black boxes, divers equipped with devices able to detect the "ping" signals emitted by the devices would inch along the seabed, dropping weighted markers in areas where they picked up the signals.

Digging at the sandy sea floor where the boxes were believed buried, diver Rajab Suwarno succeeded in locating both the recorders, which contain a wealth of data crucial for determining what caused the crash.

One of the boxes - which are actually orange in colour and designed to survive underwater - was trapped under the remains of the aircraft, making it more difficult to retrieve. He described finding one of the boxes: "That morning the sunlight was penetrating the water, it was very clear. We moved some small debris aside and dug in the white sand - and, thank God, we found it."

CVR & FDR update
 

From Pangkalan Bun (Indonesia) (AFP):

The boxes, which are actually orange in colour, have been flown to Jakarta, where Indonesia's National Transportation Safety Committee is leading a probe into the accident helped by experts from countries including France and the US.

Safety committee head Tatang Kurniadi said 174 hours of data had been downloaded from the flight data recorder, and two hours and four minutes from the cockpit voice recorder.

Newly released photo shows additional parts of wreckage
 

http://www.straitstimes.com/sites/st...airsi1501e.jpg

From: AirAsia flight QZ8501: Divers hunt for victims in main body of plane - South-east Asia News & Top Stories - The Straits Times

Wheelsright
This was my understanding too.
Perhaps someone knows if Sully's landing in the Hudson caused the aircraft ELT to work. I have not heard of any water landing/crash where the ELT worked.

I have only heard of military PLB's (SARBE) actually locating people. I was involved in the SAR for a P3 North of Malin head that nobody realized had crashed till we got a report from a small GA aircraft of hearing a PLB on 121.5.

I have only heard of one successful ELT alert that was the crash of a politician in the North US where apparently the ELT worked.

It seems reasonable to assume that the tail section may have downflooded more slowly than the fuselage. We know that there are strong currents in the area. Assume w current of 1.7 knots and assume an hour for the empennage to flood to sinking point and it will be 1.7 miles from the fuselage.

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.

From a previous post:

The underwater currents are put at more than 5 knots. Not only is that relatively fast it will exert a considerable force on light weight aircraft parts such as the empenage plus some fuselage. It may well drag the empenage further and faster once it has started to sink.

I am actually surprised how close these pieces are to each other considering the strength of the subsurface currents.

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. :)

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.

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

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.

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.

Leightman957 (currently post 2062)

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.)

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.

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.

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.

"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?

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?

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.

Far better that the stab trim does not move automatically when hand-flying!

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

Glendalegoon

Your post is right on the money and well put.

glendalegoon:

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...

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.

Only the second of the two links you included mentions trim, unless I've missed it.

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.

As Volume points out these are stall avoidance procedures.
Has anyone recovered from a real full stall in these FBW aircraft at cruise level?

Roseland: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. :ooh:

Reducing AOA does the job right now.

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

There is interesting and relevant discussion on stalls at

Stop Stalling | Flight Safety Foundation

Glendalelagoon...add one more bit...bring up the bird, and let them see trajectory vs pitch, show them with full forward stick, but full THS up, how ineffective the elevator really is..

Didn't need to train Homo Neanderthalis to move the THS. It came naturally to them, but you think it's hard to find pilots that have much general aviation or military aviation experience, try finding a Neanderthal pilot nowadays (Seems like I used to see them a lot in airport lounges back in the '70's).
You'll have to ask him, but I hear that even Australopithecus' dance card is full!
I have and others have brought up the trim issue in this thread more than once, but the "Authorities" cull the postings out for the most part. Not politically correct, I guess.
Considering what trim does on a particular aircraft, in what situation and when, needs emphasis in training, so pilots given sudden control of an aircraft, might realize why their elevator inputs may not have the level of effect they want. They can then adjust the trim in a timely manner if need be.

@ oldchina and formation driver on FR's - CVR and FDR
 

There are roughly 4 different groups of pictures associated with the Flight Recorders of AirAsia 8501 on the web at the moment:

1. Earlier pictures of FR's. We can often quickly eliminate these by the fact that the 'memory module cyclinders' are mounted horizontally. While the AirAsia recorder's 'cylinders' are mounted vertically and positioned at the extreme end of the 'sigar box'.

2. Earlier pictures of FR's submerged in a transparant casing, these can be eliminated because the latching/lid is much different from those on the photos with Gen.Moeldoko. So, his morale boosting visit gets a nice bonus.

3. FR's presented by the chief of the KNKT/NTSC during an earlier press conference. These have 'vertically mounted memory module cylinders. I do not have the exact date of the pictures yet. Low prio. These are undamaged indeed. And me be the exact same type of the actuals.

4. The actual recorders. Vertically mounted cylinders. Parts of supporting / mounting frame attached which are partially deformed. Corner of the CVR 'power cube' dented. I have not seen a picture of the 'outer box', would be interesting to see the damage on that.
During their trip the boxes have changed carrying/transport containers at least four times it seems. First an icebox (white and blue) on board Indonesian vessel Banda Aceh . Then a black box (like the divers use) from Indonesian vessel Banda Aceh to shore. And during the transfer from ship to shore at PB we first see the transparant box. Finally, in Surabaya, a black large box (probably containing the last transparant one), for transfer to Jakarta.
Early on there was one picture showing detailed configuration data of the CVR.

Hope this helps.

No option then to lift the fuselage by balloons or cranes
 

PANGKALAN BUN, Indonesia (AP) — An Indonesian search official said Friday that the crashed AirAsia jet's fuselage will be lifted to the surface after sea conditions again prevented divers from examining the large chunk of wreckage.

National Search and Rescue Agency chief Henry Bambang Soelistyo said that rescue teams discovered more wreckage despite the strong current and poor visibility.

"Apart from the fuselage, we found what we suspected as the aircraft's cockpit and also an engine," he said. "We also found what seems to be a passenger seat in which we thought there still bodies tied on it."

He did not specify whether or not the seat was inside the fuselage section that sits on the seabed at a depth of 28 meters (92 feet). The 30-meter-long (100-foot-long) part of the plane body with a wing attached was sighted Wednesday.

Rescuers believe that many of the bodies are still inside the main fuselage.

Soelistyo said the failure of the underwater examination of the wreckage left no option but to lift the fuselage, either by using floating balloons as the tail part was lifted early this week, or using cranes from tugboats. He did not say when the operation would start.

Earlier Friday, chief of operation of the agency, Suryadi Bambang Supriyadi said the wreckage that appears to be the cockpit was located by sonar imagery about 500 meters (yards) from the fuselage and partly embedded in the mud.

"weather not only factor"
 

not sure what to make of this
"Chief investigator" who seems to have knowledge of downloaded data from CVR/FDR says in interview that weather ("cloud") was not the only factor
(from twitter @nihonmama and Jeff Wise blog)
https://www.youtube.com/watch?v=usdn...ature=youtu.be

After a lot of discussion, Claude Lelaie, special adviser to the Airbus president and chief operating officer, cut to the heart of the remedy for pilots finding themselves in a stall or near-stall condition: “If you push on the stick, you will fly!”

Perhaps it would be more accurate for Claude Lelaie to say,

“If you push on the stick (and trim forward as required), you will fly!”

American & Indonesian air crash investigators share a history:
 

Wall Street Journal
By ANDY PASZTOR

American and Indonesian air-crash investigators share a history of sometimes strained relations stretching back to the late 1990s, which U.S. officials say could impact the current AirAsia probe. That legacy also may partly explain why the two sides are still discussing potential U.S. participation in the probe of Flight 8501 nearly two weeks after the Airbus A320 with 162 people aboard dropped from radar while flying near storm cells en route to Singapore from Surabaya. In Washington, a spokeswoman for the National Transportation Safety Board has said officials are waiting for an invitation to join the multinational inquiry, which already includes French industry and government experts. In recent years, the U.S. agency increasingly has been reluctant to commit significant resources, or send investigators to foreign accident scenes, before wreckage or black box recorders are recovered.

By contrast, officials in Jakarta have said the U.S. is welcome to participate, all it has to do is ask, and that they expect the NTSB eventually will join the probe. But they added that is likely to happen only after remnants of the plane, sitting in the silt at the bottom of the Java Sea, are brought to the surface. A spokesman for General Electric Co., which helped build the jetliner’s engines, earlier this week said the company fully anticipates participating in the inquiry alongside the NTSB. But he didn’t indicate a possible timetable. Former NTSB officials said prior disagreements between the two countries—sparked by two earlier fatal crashes of Indonesian carriers—appear to be complicating the current situation.

Some of these officials, who were involved in the disputes, remember how tension between the two camps initially erupted. In the wake of the SilkAir flight that went down in a muddy Indonesian river delta in 1997, killing all 104 people on board, U.S. and Indonesian experts joined forces to dissect causes of the tragedy. But they had a falling out over the findings of the final report. In the end, Indonesian experts concluded there was no way to conclusively determine why certain flight-control panels on the tail were put into a dive configuration, or why both flight-data and cockpit-voice recorders stopped operating before the fatal dive. NTSB experts, however, felt the physical evidence and other data pointed to pilot suicide. By 2000, the NTSB’s chairman publicly indicated that no airplane-related failures could explain what occurred, and the only plausible explanation was intentional pilot action.

About 10 years later, there was similar friction after a jet operated by Adam Air, a now-defunct low-cost carrier, went down during a domestic flight, killing 102 people. Indonesian authorities, who said they needed various forms of outside help, persisted in asking the U.S. to foot the bill to try to bring the wreckage to the surface from some 6,000 feet under water. Mark Rosenker, who was NTSB chairman at the time, recalls that an Indonesian delegation came to Washington—and went to visit United Nations air-safety officials in Montreal—as part of a campaign to press for U.S. funding. But safety board officials kept saying no. “It became a point of principle,” Mr. Rosenker said this week, because the U.S. was convinced international law and precedent required Indonesia to underwrite retrieval costs. Eventually, the airline paid for the search to retrieve the recorders.

When it comes to AirAsia, Indonesian officials say data from the A320’s black-box recorders, once the devices are recovered, will be downloaded at a government laboratory in Jakarta, Indonesia’s capital. Government investigators from France, the country that certified the aircraft and where it was assembled, are expected to participate. Amid rough seas and poor visibility underwater in the search area southwest of the island of Borneo, Indonesia has accepted the help of military assets from many foreign nations, including the U.S., China, Malaysia, Australia and Russia.

Australia, which took the lead in the hunt for Malaysia Airlines Flight 370 last year, hasn’t taken such a prominent role this time. But Singapore, another commercial-aviation powerhouse that seeks to become the center of air-safety advocacy in the Pacific region, has provided some technical advice and search equipment. U.S. experts also have been involved in other recent Indonesian crash investigations. A number of NTSB experts traveled to Indonesia to participate in the probe of a Lion Air jet that crashed into the water short of a runway last April while trying to land in stormy weather in Bali. There were no fatalities, but the plane broke into pieces.

CVR playback?
 

Does anyone know if the CVR has been received at the relevant lab? Recovery was what, 2 days ago now? It seems difficult to imagine that the basic cause of this incident isn't very obvious from what will be heard on that recorder. Certainly the FDR will reveal a lot more subtle aspects, but as in AF447, the "big picture" was very evident from the CVR transcript.

From a previous post ..

So, yes, it has been received and downloaded. Standby for the leaks on social media in the next couple of weeks. ;)