Airasia Plane Missing?

[DEFCON]

Reading tea-leaves is a good way to describe our science here, but because crashes can make for a good detective like mystery, the debates that arise are too interesting.

The fuselage has been found and early footage being released appears to show a fairly together structure that includes they say, one wing.

[Don Hudson]

Re, "Reading tea-leaves is a good way to describe our science here, but because crashes can make for a good detective like mystery, the debates that arise are too interesting."

Well said!

If I may be permitted a slight diversion, such tea-leaf reading includes daily flight data analysis which is best described by what you've written!

[Don Hudson]

Qatar Airways CEO Akbar Al Baker said the carrier is trialing the use of constant data uploads from flight data recorders and cockpit voice recorders, aka black boxes, of its aircraft.

Speaking at the recent customer launch of the first Airbus A350, Al Baker said, “We want to … introduce full-time black box data uploads across all our aircraft,” he said, adding that the airline’s management was convinced it should be a mandatory technology across all IATA-compliant carriers.

Al Baker said that as part of its commitment to the principle, the airline had started testing such a system supplied by a leading provider. The technology uses data streaming to allow black box data to be transmitted continuously to a remote monitoring center.

Al Baker said Qatar wants to be the first airline to introduce full-time, pilot-independent aircraft systems monitoring and reporting across its fleet, and would also be pushing for industry-wide support through its role as an IATA board member.

“IATA should be leading the move to introduce [aircraft] tracking that is [independent of] any pilot input,” he said.

IATA set up an Aircraft Tracking Tack Force (ATTF) following the disappearance of Malaysia Airlines Flight MH370, a Boeing 777-200 in March. In December, the ATTF issued a report with non-mandatory recommendations to improve continuous tracking of airliners.

Al Baker added that no airline could “guarantee there would be no safety issues” on all of its aircraft all of the time, but that training and preparedness to “the highest standards to avoid getting in to trouble” were the most effective approaches to potential safety issues.

http://atwonline.com/avionics/qatar-pushes-live-aircraft-data-streaming

[Don Hudson]

DEFCON - new (yesterday) photos of the fuselage show a relatively-intact fuselage and right wing, (wing-tip missing); in other words, not a high-forward-speed impact, nor a purely vertical one like AF447 but a "somewhat-flying, not-stalled" impact. The section of fuselage that is visible is clearly compressed by vertical forces but otherwise appears intact. In AF447, the fuselage was a pressurized vessel at impact and, combined with high vertical accelerations at impact, shows greater fragmentation and "blew" much of the debris outwards which was later found floating. This isn't the case here.

The 1.7nm separation of the tail section from the tail section has a number of possible causes, the most likely being a combination of an initial skip after the impact by the tail with the rest of the aircraft travelling forward a short distance, and strong currents which may have carried a floating-then-sinking fuselage & wing(s) further along the path of flight, (same direction as the underwater current which is around 6kts...15 minutes to sink to the bottom X 6kts = ~1.5nm - again, all conjecture). Loss of horizontal stabilizers causes an immediate pitch down so finding the section forward of the wing/wing-box will tell us more about how the impact occurred.

[DEFCON]

Don

Some of the creases and fractures we can see in the photo that’s taken from the right rear quartering view are intriguing. I’ve looked closely, but wouldn’t want to hazard a guess as there just isn’t enough of the wreck shown. For instance, from the picture, how can we be certain the aircraft didn’t impact the water at something close to a 90 degree left roll angle while missing its tail, perhaps even more structure? I haven’t seen anything yet that conclusively rules out the possibility the vehicle shed pieces all at once, or over a short period during the descent as over-speed and indirect loads were imposed on it. Nevertheless and regardless of that possibility, your theory is no less plausible in my mind at this time either.

A problem with the flatter heads up style entry into the water; how could you impart enough energy on impact to cause the wings to fail, yet the flimsy fuselage structure remains essentially intact? I’ll add; for me, it’s all about reading tea leaves at this time; I do appreciate that term, thank you.

I’m not sure I buy into the theory that the fuselage exploded on contact with the water because it was pressurized; I’m just as inclined to believe the structure depressurized somewhere higher up, but again, other than those that have seen the data now, anything remains possible.

Last evening I came across a photo of a large chunk of severely mangled structure apparently located somewhere within the main debris field. I was able to improve the quality a bit by manipulating the light levels and although I couldn’t be certain where the structure originated, it did bear a resemblance to the cockpit end of the aircraft. Manipulating light levels brought something more out of the image; there appeared to be most of a body wearing a white short-sleeved shirt floating horizontal within the structure. The body appeared to be trapped in place by wires etc. and unable to float upwards. I was unable to re-locate the picture on the net anywhere today, which makes me wonder if others noticed the same features and the pic was pulled in the interest of respect?

The r/h wing root appears to show some interesting tear like looking fissures that run 90 degrees to the fuselage wall and extend out approximately 4’. If in fact they are tears in the metal, I’d like to know what kind of imposed load would produce that result?

[DEFCON]

PS When I click on the link you've provided, I get film footage of a WWII military test gone bad.

[Don Hudson]

Ach, that "test" shows how critical the tail feathers are...I was thinking of how quickly the aircraft would pitch down with such a loss, and it is very rapid! I corrected the link to go to AVHerald where the photo of the fuselage is.

Yes, tea leaves...I got the term in turn from a friend in Bielefeld, Germany. Good term.

I'm just going on the fact that there are very large sections fo the airplane remaining rather than a debris field that looks like AF447s, (by the way, it was AF447 I was referring to in describing a pressurized vessel, not this one - we don't know what the cabin altitude of this one was, yet). I think such sections falling from high altitude would not remain as intact as we see here.

It will be of great interest to know whether the recent AD was enacted, (shut down two of 3 ADRs to take the airplane into alternate law if the airplane pitch is uncontrollable due to AoA probe icing). I rather doubt it but it has to be proven / dismissed.

[IFG]

DEFCON - new (yesterday) photos of the fuselage show a relatively-intact fuselage and right wing, (wing-tip missing); in other words, not a high-forward-speed impact, nor a purely vertical one like AF447 but a "somewhat-flying, not-stalled" impact. The section of fuselage that is visible is clearly compressed by vertical forces but otherwise appears intact. In AF447, the fuselage was a pressurized vessel at impact and, combined with high vertical accelerations at impact, shows greater fragmentation and "blew" much of the debris outwards which was later found floating. This isn't the case here ....

Hi, Don - I don't recall reading about a 'pressurized' impact explosion of the fuselage wrt AF447. IAC, I'm thinking that with the sort of descent rates being suggested here (much in excess of even AF447's precipitous fall), the cabin altitude would certainly have 'caught' the outside pressure altitude on the way down.

Cheers, IFG

[DEFCON]

Sorry Don, now I understand the purpose of the video.

The recorders should provide the full pic, but in the meantime, if we knew the location of the APU, the engines and, or could get a more complete perspective view of the wreckage, we’d be able to better visualize the breakup. If my early guess was correct and the tail structure failed in flight, the change in aerodynamics and flight characteristics could also account for the condition of the main wreckage; i.e., the majority portion of the aircraft fell in some kind of cartwheeling / spinning fashion resulting in a more gentle impact than if it had continued at terminal velocity until it contacted the surface?

I know next to nothing about the Airbus FBW system, but if we were to assume, and I know that’s never wise, that the aircraft flight controls system reverted back to a state that gave the pilot full authority and late in a terminal velocity dive he were to gain visual and apply full up elevator to arrest the dive; is it not likely that various structures in the tail will break? Small details make the difference too and I can only wish we had access to some of them. The Journey Log for instance would tell us if there was any history of damage and related structural repairs in the area of the fuselage break?

With respect to the pressurization issue; I understood you were referring to AF 447. I was commenting on the media and local experts suggestion of a similar slap bang break-up at the surface.

So many questions, too few answers, but an interesting issue to contemplate nonetheless.

[Woody Pusher]

I've been having a look at the superficial evidence thats now available on the web, and have made use of the little bits of info I found. It's reproduced in the following graphic, not as a matter of fact, but rather as a possiblity as to how the aircraft impacted with the surface (in this case the Java Sea).

In general terms, I believe the aircraft's horizontal vector was likely a little east of north and rotating clockwise - possibly a flat spin. The pitch attitude about ANU+10 degrees, moving horizontally about 40kts, and effectively stalled with a vertical speed of -11,000 ft/min. On making contact with the sea surface the port side forward of the aft preassure bulkead was ruptured and torn away, causing the tail section aft of the bulkhead to break clear. Some buoyancy remained, possibly in the Vertical Stabilizer until water ingress eventually caused the section to sink and snag on the seabed. That explains the drift to the SE from where I believe the APU will be found, i.e. close to where the Flight Data recorders were recovered from beneath the Horizontal Stabilizers.

On contact with the surface the rotation was arrested, and the major parts of the aircraft broke up while moving horizontally on northerly vector.

The debris field I believe is quite small, and the major parts of the aircraft will be found within a radius of 600m. The parts with inherint buoyancy will have travelled further to the east.

Lastly, I must say that the divers who have worked in currents approaching 6 knots have been extremely brave - if not foolhardy. They deserve respect.

Edit - to conform with initial damage to bottom port side, and clockwise rotation. - Woody 19/0127z

[DEFCON]

Woody

"the aircraft's horizontal vector was likely a little west of north and rotating anti-clockwise - possibly a flat spin. The pitch attitude about ANU+10 degrees, moving horizontally about 40kts, and effectively stalled with a vertical speed of -11,000 ft/min. On making contact with the sea surface the starboard side forward of the aft preassure bulkead was ruptured and torn away, causing the tail section aft of the bulkhead to break clear."

The spin impact theory is an interesting one too. I've attached a picture of the wreckage below. If my orientation isnt wrong, it looks to me like the structure opened as youve suggested, but on the port side somewhere near, or along the floor line, which means the spin would likely have been clockwise?

More difficult questions, but wouldnt an intact aircraft spin nose down to some degree? If the aircraft did spin in some fashion, would the engines remain attached and if not, how would that affect aircraft cg and spin attitude? Finally, if the tail section came off at low altitude in a spin, wouldnt the attitude be slightly nose high, especially if the engines had departed?

Your charts are of a far better quality and more useful to the exercise than anything the media, or experts put out. While we're waiting for the technical data from the recorder, Im looking forward to knowing where the engines and APU came to rest.

[Kip Powick]

Lastly, I must say that the divers who have worked in currents approaching 6 knots have been extremely brave - if not foolhardy. They deserve respect.

A current of 2 kts is an extreme challenge for most recreational scuba divers.

A current or 2.5 kts to 4 kts is very close to the limit of a qualified "Rescue Diver" and in the vast majority of cases the diver has to be tethered.

Over 4 kts, a diver can not work unless they are on an underwater motorized "scooter" and then all they can really do is "look", no other physical activity would be successful.

"Hard-hat" divers that are tethered and wearing an appropriate suit and weighted boots would even find 4 kts barely tolerable.

Personally I have been diving and encountered about a 2 kt current, (Phuket Thailand), and after about 10 minutes, gave up, surfaced and waited for a pick-up.

Much prefer ZERO current!!!

[boestar]

Agree with you Kip. I did a dive in Mexico on a reef with a current in the 2kt range. You basically just drifted along and saw the sites. Trying to stop and look took far too much energy. We were at about 40ft and from the drop off point to the pick up point was a couple of miles. Was way cool though.

[Kip Powick]

Agree with you Kip. I did a dive in Mexico on a reef with a current in the 2kt range. You basically just drifted along and saw the sites. Trying to stop and look took far too much energy. We were at about 40ft and from the drop off point to the pick up point was a couple of miles. Was way cool though.

Sounds like the infamous "drift dive" in Cozumel....

The only trouble with any "drift dive" is that if you see something you really want to go look at again, you expend a lot of energy, (and air), going back ....

[Woody Pusher]

Just in case there is any doubt about the current flow rate in the Java Sea, its worth noting that a body was picked up 2 days ago near the SE corner of Borneo, having drifted for about 350NM (650km) !

[Don Hudson]

Sorry for the 'late' reply - been on the road.

IFG, DEFCON, I think I was incorrect regarding AF447 being "pressurized" at impact - I'll re-read the BEA reports - I had recalled something like that being said, so now must make sure either way!

Woody, again many thanks for your important graphs - concur with DEFCON's remark.

In re the above comment re "pressurized", the one puzzle for me anyway is the condition of the fuselage in the b&w images...collapsed, (airline logo which is painted on the side of the fuselage appears on the top in the image), but otherwise intact including wings attached whereas AF447 was "shattered", to me, as a result of being a sealed pressure vessel that impacted at ~100kts onto a hard surface, (albeit water!).

Don

[John S.]

. . . .

Lastly, I must say that the divers who have worked in currents approaching 6 knots have been extremely brave - if not foolhardy. They deserve respect.

Back in post #35 I made a comment about the current. That comment was followed up by some posters saying that any parts that floated down would be affected by the current but once any piece hit the bottom it would stop moving.

Is that true? Or is 6 knots of current on the seabed strong enough to move something like a tail section or a fuselage one it is resting on it?

[Kip Powick]

Hi John,

Ocean/sea currents will vary depending on depth, surface wind and time of year. It is not unusual to have a strong mid level current (relative to depth) and a lesser current on the sea/ocean bottom. A sea/ocean current is seldom if ever constant from the surface to the bottom.

If a tail section impacted the water and "started to sink" it's relative position after impact, (on the bottom), would depend on how fast it sank and any flotation it had that would cause it to "drift" with the current until it was fully saturated and then it would sink to the bottom. Because of the angles of the tail section, the odds of it rolling along the bottom is any significant current are pretty slim. Part of the structure would probably impale itself in the sand or hit some sea bottom object and stop. The same holds true for the fuselage.......impact-then slowly sink while drifting in the current ...............and then rest on the bottom. Even a Coral Bloom could stop any large pieces from moving once they hit bottom and it should be noted that there are very few areas of the ocean/sea bottoms that are smooth like a beach. The Java sea, in the crash area, has a significant amount of deep mud on its bottom..

Light debris with a high percentage of flotation would drift on the surface and then may possibly drift just under the surface for a long time and may never sink.

The human body normally sinks very quickly but if the body is fairly well intact, it will then surface, normally within 48-72 hours in warm sea water, due to internal gases expanding and can drift, with strong winds and current for miles, unless it encounters predators and the gas is "relieved"..

Not a pleasant visual scenario but unfortunately that is a fact of death........... in the water..

[DEFCON]

Don

Some of the creases and fractures we can see in the photo that’s taken from the right rear quartering view are intriguing. I’ve looked closely, but wouldn’t want to hazard a guess as there just isn’t enough of the wreck shown. For instance, from the picture, how can we be certain the aircraft didn’t impact the water at something close to a 90 degree left roll angle while missing its tail, perhaps even more structure? I haven’t seen anything yet that conclusively rules out the possibility the vehicle shed pieces all at once, or over a short period during the descent as over-speed and indirect loads were imposed on it. Nevertheless and regardless of that possibility, your theory is no less plausible in my mind at this time either.

A problem with the flatter heads up style entry into the water; how could you impart enough energy on impact to cause the wings to fail, yet the flimsy fuselage structure remains essentially intact? I’ll add; for me, it’s all about reading tea leaves at this time; I do appreciate that term, thank you.

I’m not sure I buy into the theory that the fuselage exploded on contact with the water because it was pressurized; I’m just as inclined to believe the structure depressurized somewhere higher up, but again, other than those that have seen the data now, anything remains possible.

Last evening I came across a photo of a large chunk of severely mangled structure apparently located somewhere within the main debris field. I was able to improve the quality a bit by manipulating the light levels and although I couldn’t be certain where the structure originated, it did bear a resemblance to the cockpit end of the aircraft. Manipulating light levels brought something more out of the image; there appeared to be most of a body wearing a white short-sleeved shirt floating horizontal within the structure. The body appeared to be trapped in place by wires etc. and unable to float upwards. I was unable to re-locate the picture on the net anywhere today, which makes me wonder if others noticed the same features and the pic was pulled in the interest of respect?

The r/h wing root appears to show some interesting tear like looking fissures that run 90 degrees to the fuselage wall and extend out approximately 4’. If in fact they are tears in the metal, I’d like to know what kind of imposed load would produce that result?CNN's consultant Mary Schiavo is reporting she's been told the people reading the data recorders have indicated that more than the weather was responsible for the crash?

Other agencies & MS are now all reporting the cockpit section has been identified with the pilots inside and an engine as well. There isn't anything I can locate that pinpoints the location of these finds...Woody?

[Woody Pusher]

Other agencies & MS are all reporting the cockpit section has been identified with the pilots inside and an engine. There isn't anything I can find that pinpoints the location of these finds...Woody?

DEFCON,

Let's backtrack a little. To start with there was a LKP reported at 2314z when QZ8501 requested ATC clearance to deviate from the M635 airway. There were then countless efforts using FlightRadar24 data contradicting the position given by the Indonesian authorities. Then on day 2, an image was leaked showing the aircraft climbing through FL363 with a GS of 353 Kts at about 2318z, and shortly after another image showing PSR data of the aircraft descending through FL240 with a VS of -11,518 ft/min at 23:19:46z.

Bodies were being recovered some distance to the east on day 3, and it was about then that an effort was made to go back and look more closely nearby the final radar positions. That's where the first unidentified objects were located on the sea bed. The Tail section was the first to be identified by divers, and recovery was by dragging over the stern of an Anchor Handling Tug Supply vessel.

During this time, faint ULB signals were detected, and a 5 NM radius area was declared restricted to unauthorised vessels. As weather conditions improved, triangulation pinpointed the ULBs to be about 20 meters apart and 1.67 NM to the NW of where the Tail section had been located. Divers, were then able with the aid of detectors establish that the ULBs were located (i) under a wing (probably the Horizontal Stabilizer) and (ii) buried in sand. An 'engine' was found nearby (assumed to be the APU), and a few days later the mid section of the fuselage (complete with starboard wing) was identified by a tethered ROV launched from the Singaporean vessel "Swift Rescue". The satellite AIS position of the vessel matching the time noted on the published images, established the position of this Mid section of the fuselage.

More recently, divers have identified the Nose section and published info stated it was about 500 yards from the Mid Section. That figure doesn't mean too much, as it is rather vague, but an assumption was made by me that it would probably be in line with other parts that had sunk immediately. I may well be mistaken.

My description earlier of a possible spin scenario, may well be right, except on reflection I should have had the spin clockwise, as the initial impact damage was to the aft bottom port side. As the recorders were located low on the port side and just aft of the rear pressure bulkhead, that would explain why they were separated from the recovered Tail section. I'll go back and correct that shortly.

[Woody Pusher]

Back in post #35 I made a comment about the current. That comment was followed up by some posters saying that any parts that floated down would be affected by the current but once any piece hit the bottom it would stop moving.

Is that true? Or is 6 knots of current on the seabed strong enough to move something like a tail section or a fuselage one it is resting on it?

John,

If a flat piece of steel was lying on the seabed, the likelihood of a 6 knot current moving it would be small, however if the same flat sheet was to sit upright with its flat surface area facing the current flow, it would undoubtedly be moved. So basically its down to surface area presented to the current and the specific gravity of the material involved.

[Don Hudson]

Indonesian investigators said on Monday they had found no evidence so far that terrorism played a part in the crash of an AirAsia passenger jet last month that killed all 162 people on board.his team of 10 investigators at the National Transportation Safety Committee (NTSC) had found "no threats" in the cockpit voice recordings to indicate foul play during AirAsia Flight QZ8501.

The Airbus A320-200 vanished from radar screens on Dec. 28, less than halfway into a two-hour flight from Indonesia's second-biggest city of Surabaya to Singapore. There were no survivors.

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."

Utomo said that investigators could hear "almost everything" on the recording contained in one of the flight's two "black boxes". The other is the flight data recorder, and both have been recovered from the wreckage at the bottom of the Java Sea.

He declined to give details about what was said during the doomed flight's final moments, citing Indonesian law.

Indonesian authorities have said that bad weather was likely to have played a part in the disaster.

According to Hananto, evidence also showed that an explosion was unlikely before the plane crashed, disputing a theory suggested by an official from the National Search and Rescue Agency last week.

"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."

Reuters

[Seeker]

Both recorders recovered and good data, apparently. At least with this one we'll eventually know what happened.

[Kip Powick]

Indonesia Minister states...... quote......." aircraft climbed very rapidly then stalled " (CBC News)

Updraft?.......... Pilot-aircraft handling?

[Don Hudson]

The question of what an Airbus does in strong updrafts has been the subject of discussion as has the level of mythology vs. fact concerning what Airbus protections can and cannot do.

Regardless of who or what set these original mythologies in play, in 1988 it had more to do with sales than accuracy. I can recall them from training on the 'bus in 1992 - the key was never believing that the Airbus was anything other than just an airplane despite the marketing. This said, the airplane's automation is a significant advancement in flight safety and the airplane is a remarkable machine; one must understand it and not judge the design unfairly against other equally good but different designs, (apples & oranges argument). Being skeptical and knowing it was just an airplane was easy for pilots who flew the DC9, B737, etc. Not so, today - another thread.

The first fact is an aviation truism and there's likely no one here who doesn't know that if one doesn't understand one's airplane then sooner or later one is going to get into trouble. When technology is being marketed as heavily as it is today by those who don't understand aviation, one needs a healthy dose of good old fashioned "sez who...?" But computers and gaming "put out their eyes..."

Understanding one's airplane is the responsibility of the pilot him/herself, in cooperation/coordination with the manufacturer and the air carrier to provide sufficient training. Exceeding the minimum requirements by half is just a beginning. Continuous learning and refreshing exists in all three professions that must handle risk to life...engineering, medicine and aviation.

Editorializing notwithstanding, Embraer's experiments with one-pilot operation and others who believe in pilotless flight for commercial transportation are focussed in the wrong direction - more salesmanship and marketing to beancounters..., that it can be demonstrated successfully does not mean it can or should be done: it is folly; no "auto" system, and no secretary for the one pilot can take the place of on-board, real live pilots - again, another thread.

Every wing can stall if the AoA is sufficiently high. I am not convinced that every pilot knows this. I am not sure that those who fly it know that the Airbus is nothing special. If they believe it, they don't know the airplane.

At high altitude, the cruise AoA is around 2.5 to 3 degrees; at cruise Mach Numbers, stall can occur at 5 or 6 degrees AoA* but getting the wing to that state at that speed takes significant effort. Pitching the airplane up to 15deg pitch attitude will do it in about 40 seconds. A sudden, high-speed updraft will effectively do the same thing very swiftly. Many here would understand that inside a thunderstorm, the updrafts are strong enough to break the structure or exceed the AoA at which the wing stalls - Woody may know exact numbers regarding updrafts - if we think of two vectors, (the old wind diagram but vertically oriented) - one vector being the cruise speed and AoA, the other being the updraft speed and angle in relation to the axis of the aircraft), they would be strong enough to increase the AoA even at the high-forward cruise speed.

Depending upon how an airplane is tossed around and for how long and how bad the resulting disorientation is, recovery of some fashion can occur if one gets the airplane right-side up and unloads the wing sufficiently to get it flying again by pointing the airplane down. Those who were in the airforce or the navy will know this intuitively. Trying the AF447 scenario in the sim, unstalling the wing took about 15,000ft and about 10deg nose-down, (full-forward stick) for around 45 seconds.

If anyone here has had the experience, it would be of interest! If they got into a thunderstorm, I can't imagine what this crew faced or what attitudes the aircraft achieved and how the C* Laws and the protections behaved. It seems as if we'll know soon enough.

AF447 initial stall warning 'blip' was at 6deg & the stall warning started at 7deg. It stopped when the airspeed was no longer valid, (NCD - no computed data) - a reasonable assumption in the design at the time.