Boomntown - doubt it. You would need a failure that left the pilots flying, but all radios disabled.

A bean counters job is to count beans, not dictate morality and standards. Their jobs is to the best of their ability to come up with ways to legally save money. Failure to do that is not doing their jobs.

Its other peoples jobs to evaluate those recommendations and consequences of, and they should do that to the best of their abilities.

If some thing is serious enough, as a society we codify it.

Wasn't there a theory going around that the inflated rear exit slide was at first attatched to the severed rear section causing it to float away while the main body sank immediately. The slide subsequently detatching in the swell so that the tail section sank some distance away?

QUOTE:in this instance my money is on the in -flight loss of the empennage as a result of aerodynamic forces imposed upon it beyond its structural limititations.END QUOTE



Can anyone tell me if there has ever been a failure of the empenage in ANY Airbus Product? ;-)

Aerodynamic and Hydrodynamic etc
 

@A0283:


With respect, nothing that I have seen so far leads me to believe that the main body of the aircraft was separated from the aft section prior to impact with the surface of the ocean. If it had separated then one would expect to see a more intact empennage; no burst bulkhead and more of the aft floor section still attached, or some remnants of floor frame. During a water impact, the hydrodynamic scour that occurs forces the floor section upwards, and in the process causes it to become detached from the side frames – exactly what we see in this instance. Ok, the floor frame complex could have pulled out in one if aerodynamic separation was the cause, but that still does not explain the burst bulkhead. The most likely reason for the distance in separation is probably down to the fact that since this part of the intact aircraft probably made first contact with the water ( ie: the aircraft is in a pitched up attitude), the break that occurred between it and the main section was well developed by the time the lower skin of the the main fuselage failed, thus allowing hydraulic surge (impulse) to flow through the cabin in fractions of a second, particularly to the now open ended rear – scouring everything in its way. Given that the APU and other heavy bits appear to have detached, plus maybe some level of buoyancy remaining (inflated rear exit slide ) in the aft section and a 5k current, it is not difficult to imagine the aft section drifting apart from the heavier main body. The rear end of the fuselage, as seen in latest photo, appears to show floor frames – presumably pulled out from the missing aft section once the connections to the side frames failed. There is also the evidence of one of the data recorders being found under the wing. If the aft had detached in the air, then is it probable that the recorder be found under the wing?

Chronus: The terms used in the literature (NASA Langley Research Center – vertical drop tests) for an airframe impact with water are often referred to as Hydrodynamic impact loading. In the past I have also come across the terms Hydrodynamic Ram effect or Hydraulic surge.

American 587 is the most obvious with an in-flight loss of the VS, although in several instances (AF447, Perpignan) it was found floating alone after impact. Of course, that's not the full empennage...

Basic stability means there is a downforce on the horizontal tailplane.

By definition therefore, if the horizontal tail is lost (as you say), the aircraft bunts - hard. Significant negative 'g'. In turn this would likely lead to a very high speed, near vertical impact. Not sure the wreckage supports that at all?

In fact, loss of tailplane can impose sufficient negative g that the wings then fail.

re bj-eng
 

your 14th Jan 2015, 12:56 post I suspect that report was made by someone strictly based on the shape of debris it was under. After all, the horizontal stabilizer is shaped very much like a wing and works the same way. To the casual observer or from a underwater photo of part of the structure, the differences would not be obvious without some sort of scale or other information.:ugh:

"Most comments on stalling are by those who have never stalled a swept wing jet at high altitude except once or twice in a simulator....."

Before we even get to attempting to practise stalling, in sims of dubious fidelity, how many airline crew posters on this forum have NEVER hand-flown their 'frame, at max mass for the max cruise altitude for that mass?

The "bungee cord" flight controls effect plus the momentum versus control effectiveness is indeed impressive, as is the "fright factor", in S&L controlled flight.

Yet I get the impression, due to some perceived prohibition on hand flying in RVSM airspace, that there are out there now, both F/Os and CAPTAINS who have never controlled their allocated craft in such conditions.

If this is indeed true, then we're all on our way to hell in a handcart if that is the xAAs and airline training departments' official policy.

Please, those of you out there still practising the art of airframe manager, prove to me that I'm wrong, and that EVERY current airline pilot has had the opportunity to hand fly a line aircraft full of SLF at max certified altitude/mass until he/she/it are fully aware of and comfortable with the handling characteristics.

If there are any exceptions to this fun experience, may I challenge whether that is a sensible state of affairs?

Which begs the question, per airframe kilometres/nautical miles, are we seeing a real increase in high-altitude LOC incidents/accidents since the introduction of RVSM and the perceived lack of practice in this environment, or is it just my (false) impression? :suspect:

More pictures there in the link.

Pictures & News Photos | Getty Images

Photo citations
 

Would those posting photos please cite the source address? Thank you RetF4.

Tail location where discovered is no strong indication of impact location. Partial bouyancy, highest just after impact, is all that is required for drift. With any buoyancy at all the assembly would have been a vertical sail in the current. Some corroboration would be the current direction. Distance could be nothing more than rate of loss of buoyancy until seabed anchoring overcame current.

Barking Mad wrote

"Before we even get to attempting to practise stalling, in sims of dubious fidelity, how many airline crew posters on this forum have NEVER hand-flown their 'frame, at max mass for the max cruise altitude for that mass?"

I have never done that in my current bus for the stated reasons and SOP and for reasons of both practicality and courtesy to my passengers. If I ever had to it would be briefly while clearance to a lower altitude was acquired. I do it in the sim from time to time, but only for a few minutes between tasks.

Having said that, in normal law in smooth conditions it is easy. Add complications and it becomes harder quickly. Add cognitive overload and it becomes very hard indeed.

I have hand flown several other transport jets at max level for prolonged periods without problem, but that requires a current agile scan rate and younger reflexes to make it appear effortless.

Interesting to see an unpackaged life vest in the new photo thread from previous post

Replies to posts
 

RE various posts:
FDR CVR recovery will tell some things about what the aircraft did, and what the pilots did, but not why the pilots did it, which is what prevention really needs to know. What 'new' money would be assigned to finding why pilots acted as they did in future incidents?

RE Algol, last seen at #1966 (though currently pg 99 will not load): ”Having seen the aircraft after the event, and spoken with my colleagues, it was no ordinary CB. NASA commented that the flight probably only penetrated the outer edges before they turned/got spat out. They also speculated that further penetration would almost certainly have resulted in a breakup.”

Virtually all forum comments to date treat cb's as dangerous but infer some kind of ordinariness about them. A quote such as “There are cb's in Europe too” infers European cb characteristics are within a range of characteristics that include ITCZ cb's, enabled by a wide but vague inclusivity of cb characteristics, that also manages an equally wide acceptance of moisture complexities near the equator.

Re FullWings perma:
http://www.pprune.org/rumours-news/5...ml#post8825000
“You had to agressively reduce the AoA by pitching down to a far greater degree than in any other flight phase.”

Given the factors of narrow cruise speed range, limitations of live weather info, and inability of aircraft or pilots from recovering from wx caused or faulty instrument upsets outside of a narrow AOA range, 'more training' suggested by many seems to offer very few benefits.

I personally am far from certain the accident was even related to a CB. Maybe, maybe not. We are only days from knowing the truth, I would refrain from spinning theories that may have little to do with reality.

porterhouse:


You are "spot on" as to what caused the accident.

Having said that, I remain skeptical that we will learn the truth considering the country that has the recorders.

As yet, we don't even know for sure whether there were two functional pilots in the cockpit at the start of whatever chain of events led to this catastrophe. The greater probability is that there were, but nothing can yet be ruled in or out in that regard.

All we know is that a seemingly very experienced captain in terms of handling conditions in that part of the world, and his FO, ended up in the drink.

I hope the interpretation of the FDR and CVR is more accurate than the head of Barsarnas has been of late.

aterpster

I just learned that indonesia is trying to decode the boxes themselves instead of sending them to established and respected labs in other countries.

Highly disturbing.

I am unaware of how things work in that part of the world. But would always like to know how money is flowing, from who to whom...if the cause of the accident completely exhonerates the airline...wellllllll

Photo from NY Daily news
 

Photo from the NY Daily news purports to show an "Airbus Investigator". Interesting, rather low profile.

http://assets.nydailynews.com/polopo...a-airplane.jpg

I disagree, I think we will learn the truth, Indonesia did have their share of air accidents and their investigative body each time did sufficient job. Perhaps their final reports are not as polished and comprehensive but no one ever questioned their main results.

@ BJ-ENG - Aerodynamic and Hydrodynamic etc
 

Latest official information is that both recorders were found under the right wing and/or right wing/fuselage combination.
Latest official information states that only the right wing was located.
Officials have not provided information on the left wing, the cockpit, or the second engine. Spotting the first engine was mentioned earlier. But there is no mention of actual location yet.


BJ-ENG. Thanks for your reply. You introduce some interesting points that I would like to look at.

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.

First scenario, the pilots somehow regained control after losing it (losing it for whatever reason). Then they would probably try a ‘mild’ pitch up approach (would be interesting to know what kind of procedure AirAsia has for water landings). Which might lead to a ‘tail separates first’. The Hudson landing was one of amazing airmanship, but luckily not in ‘open water’. Even there, significant tail damage is visible (there were some good posts on that earlier, thanks). Damage that looks similar but, at first sight, not of the ‘same type’.

Second scenario, they did not regain control, or not enough. Which would probably lead to a ‘one wing first’ (there is quite a swell in the area...), followed by a slam on the water, leading to a break ‘somewhere forward of the wing’, and the - by then rotating aircraft (along the longitudinal axis) - losing the horizontal and thereby wringing the lower part of the tail section off.
The widebody jet crashing close to a beach in Africa was not recovered as far as I know. If there is information, that would be interesting.

The second option appeared more probably to me. It would also explain something of the ‘giant hand’ damage on the aft section, pressure bulkhead and some other parts. What made it less probable – at least to me, and until now – was that I would expect the second scenario to lead to quite a different debris field from the one we have. A surge through the fuselage would sweep out a lot of material that floats. Hope you can give your views on that.

Also hope they find the cockpit and the other wing, which will tell us more.

Debris Field Map
 

We need a detailed large scale Debris Field Map/Chart, with accurate coordinates.

There has been plenty of time for the Navy to publish an accurate and up to date one.

I can not find one.

Does anyone have one, or a link to one, other than the basic one posted a few days ago ?

With regard to the airframe itself, it seems very odd that all that seems to have been located so far is the tail, cvr, fdr, and the central part of the wing/fuselage. So far as I can gather, three of the traditional four corners are still missing, the nose, and both wing tips. What about the main engines and pylons ?

The reports that the cvr and frd were found with "the wing" is odd.

The ths looks like a wing to most people, especially to a navy diver in the murky depths, or perhaps it is a language translation issue, perhaps even a "jounalist" issue.

It seems likely that they were with the missing sector of the pressure bulkhead, since they were attached to the structure right next to it. Did that part, remain with the bottom of the fuselage as it fracured longitudinally, and subsequently folded under the remnants of the rear fuselage and wing as it sank and settled on the bottom (in which case the "under the wing" may make sense and be correct), or did that section separate and go with the ths, apu and the remainder of the bottom of the rear part of the empenage ?
So, have they found the ths and/or apu or not ?
Can anyone clear that up ?

Next point.

An engine has been mentioned, but which engine, and where is it ?
Was it the apu ?
Was it a main engine ?
If so, where is the other main engine ?

Why have they apparently wound back the search as reported ?

Are they assuming that the recoders will tell all, so no further recovery is required ?

As HarryMann said a few pages back, anything is possible hitting the water at anything over 100 knots airspeed. A wing low at impact could cause a cartwheel, breaking off the tail, cockpit, and a wing which all float and then sink at different rates being carried by the current.

Why? It's exactly what they did in the Russian crash two years ago.

https://en.wikipedia.org/wiki/Mount_...rjet_100_crash

I won't say the report was the best thing I've ever read but they did a good enough job with it. I have full confidence that the Indonesians can handle this crash investigation properly.

It wont just be the Indonesians looking at the FDR and CVR information. There will be Airbus reps, Australian FR/CVR specialists etc.

I'm not sure who "we" are but the official report should be able to provide that info. The public does not have a right to this stuff before the investigators complete their work.

I agree. I think all must understand that Indonesia has a new, highly progressive President: Joko Widodo. It is in his and the countries best interest to improve air safety in Indonesia and repair their image abroad.

Corruption runs rampant in Indonesia, and it seems that this has been unearthed in the Aviation sector. Expect major clean-up, including criminal investigations by the highly effective KPK (corruption eradication commision).

Not really. Flimsy plastic lifejacket containers designed to be opened in a hurry are not going to be crashproof. Aircraft accidents have been known to strip layers of clothing off people.

I haven't seen the photo, but perhaps it was an attendant's demo life vest? ;)

@glendalogoon: 'I am unaware of how things work in that part of the world. But would always like to know how money is flowing, from who to whom...if the cause of the accident completely exhonerates the airline…wellllllll'

Tony Fernandes (Air Asia) is not an idiot. He's running a sophisticated, international operation.

Hydrodynamic forces in accidents
 

If you want an insight into the forces and effects involved, have a look at this crew:

-The Bluebird Project | Home

They have done an astonishing job, and that includes very detailed forensic analysis of what happens when water meets metal at high speed.

(It's a fascinating project and website in any case)

Do you mean this photo? (cropped)

Sorry, I don't find it interesting at all considering the condition of the wreckage.

http://i2.photobucket.com/albums/y17...6.jpg~original

It is very hard to imagine that a horizontal stabilizer fails due to overload (or a "hand").
Having significantly less span than the wing, high "twisting" loads due to roll are impossible, the wings will stop the aircraft rolling fast enough to create significant loads on the stabilizer.
Any high up or down forces would immediately result in big AoA changes, at cruise speed that would mean enormous g-loads, which would most probably rip of the wings before the stabilizer.
So the only aerodynamic scenario I could call remotely likely would be an asymmetric actuator fault, meaning one elevator deflecting up and the other one deflecting down (commanded by the computers to counteract the pitching moment caused by the faulty actuator). Given the fact that there are two actuators per elevator, and we never experienced such scenario, I would not consider this likely.
Thinking of the Alaska Air trim actuator accident, a scenario like that might be possible, but that would have most likely also resulted in an in flight breakup and a much wider field of much smaller debris.

So I do (so far) not believe in any horizontal stabilizer failure scenario. It all looks more like the Aircraft hit the water first with the tail, which caused all the damage.

With respect to cutting the tail section, I found the upper skin panel just behind the pressure bulkhead very interesting (don´t have the link to the photograph currently): All stringers are buckled, so obviously there has been high up-bending loads on the tail. Either due to high forward momentum from the VTP with high horizontal deceleration, or due to impact forces on the tail from below, indicating an impact with high AoA. Cutting in that area is probably destroying some evidence...

We have codification not only in transport but currency, food and many other areas of life because there have ALWAYS been 'cheapos', scammers, fraudsters and the rest of them. Don't kid yourself the past is a halcyon period where everyone did everything right without scrimping. Some areas it hurts the pocket, others it has often been lethal - food for example.


BBC News - 10 dangerous things in Victorian/Edwardian homes

A real time empennage failure from the archives...
 

For those of you born too late, Google "MD 80 test flight crash" to find a youtube video of a intentional hard landing. The tail separates, and that's at about 1200 fpm descent from memory. Imagine hitting water instead of a runway with the gear down and its not too hard to expect to see exactly what is being seen in this debris field.

If the EASA emergency AD relating to blocked AOA probes is relevant then this investigation could get very messy. I guess we will know soon enough.

What, exactly, does "trying to decode" mean?

An important learning point for SLF arising from the Ethiopian crash off Comoros mentioned above (Ethiopian 961 in November 1996) is that there were a few survivors, but it was reported that many more might have survived but that they inflated their lifejackets before exiting, so couldn't get out (and probably blocked others). We're always told "don't inflate before exiting", and that's why,.

The DFDR memory module contains a long string of 0’s and 1’s, called “bits”. Twelve bits comprise a “word”, many words are contained in a 1-second “subframe”, 4 subframes form a “frame”. The meaning of the thousands of words in a frame is defined in a “Decoding Document” that is submitted to the authorities when an airplane obtains it registration. The first word in each subframe contains the date and time of the subframe. Each of the subsequent words is dedicated to one or more of the thousands of parameters recorded.

In addition, before you can get to those 1s and 0s, you need to decompress the data, which is stored in a special and proprietary format which compacts the data to be able to store as much as possible in as small memory as possible.

The decoding document above is basically an OEM thing, but the FDR manufacturer is the one who knows how it's compressed. that's another set of special software required, with the right decoding info too.

I believe the 9/11 truthers have been trying for 12+ years to decode one of the "raw" FDR files from one of the aircraft that they somehow acquired, with no success because no-one who knows how to do it - which is a pretty closed community - has any interest in providing the information required. In this case, it's won't be the same reluctance, but it's a bit of an art, so if you've never done it before, even with the right info it might take a while ...

Importance of locating ocean crashed rapidly
 

Quite some number of contributors have expressed the opinion that location of wreckage after and ocean accident is not particularly important. These opinions also extend to the relative importance of investigating the primary cause of the incident versus the blow by blow analysis of every aspect.

I think these attitudes are probably statistically appropriate, but they do not accurately reflect the general consensus and policy that has been adopted more or less since the start of aviation.

The statistical chances of surviving ditching in the ocean are very small. Yet, every passenger aircraft has life jackets, rafts, passenger safety briefings and so on. Clearly, it is the intention of the air travel industry to give the passengers at least a reasonable chance of surviving a ditching event.

In those circumstances, I find it extremely difficult to understand why a practical and effective systems to locate ditched or crashed aircraft have not been mandatory for many years. If you survive a ditching you will not survive for long in the ocean without rescue. Surely location is a vital ingredient? In addition, a collateral benefit would be to reduce resources being wasted on SAR.


For those that suggest that it is difficult or impossible to design an effective device for locating an ocean crash site; I would suggest you are as wrong as wrong could be. It would be a simple project even in grade school.


If it is our intention to abandon aircraft and passengers at sea, in the event of ditching, then please remove the emergency safety equipment and stop these pointless passenger safety briefings.

For the scenario you draw up, there are ELT's and rafts. A survivable water landing and successful exit has been provided for. Now, is it sufficient to the task? In New York it was, but that was not "out at sea" but on a river in the biggest city in the nation. How many at sea ditchings have happened in the last 40 years that were survivable? What were the cues that got search and rescue teams to the location?