Thanks for the clarification, I appreciate it. :ok:

Hmmm, this .1 nm offset must not have made it to the real world. When FMS planes with GPS pass in opposite directions on the airway they are certainly not 600 or 1200 feet offset in my experience.

why has no one seen this photo of a large shadow on the seabed that they keep going on about?

Disappearance-proof planes...
 

From "The Indipendant".

Canadian airliner, First Air, installes tracking systems.

"After AirAsia and MH370 flight searches, one airline finds way to make its planes nearly disappearance-proof"

Doesn´t say if they are "turn-off proof" :cool:

I would be very surprised if there are any "large" shadows, would have thought much more likely tens of thousands of small ones :uhoh:

yes i was also surprised but since Tuesday the Indonesians have been saying a C130 spotted a A320 like shaped shadow on the sea bed....just curious why this hasn't appeared

Airbubba : No it was refused in the end by ICAO for 2 reasons : mathematically on crossings with offset you increase the collision risk model (risk area is bigger ) and on principle/legal grounds that you cannot voluntary impose a decrease in navigation accuracy.
So yes with augmented GNSS coming in you will cross in opposite directions with the centre bar in the windscreens on top of one another .

Brings us back to making absolutely sure our barometric Altitude accuracy is perfect, especially in RVSM above FL400....

ATCWatcher, Pls recheck the docs:
DF17 velocity squitter (subtype 19) does transmit the difference between baro altitude and GNSS height.
A simple addition then calculates the GNSS height.
All newer transponders do transmit this and I can see it if I want (though it do not know what to do with it)

I'm the one that shall apologize Sir, thank you.

I would be interested in discovering why this 'feature' exists. Is there any flight mode which requires 'full up' trim ?

Apologies for questioning this - I fly simple aircraft where the pilot selects the trim effect he wants without a computer doing it for him.

Island Air Photo...
I am sure there is no SOP in any Airline for pilots to just blast thru CB's.

I have not detected in this thread a cavalier attitude toward thunderstorms;
rather quite the opposite.
While flying formation in an F4 Phantom, my lead flew into an embedded Tstorm near Iwakuni, Japan. Airspeed was 400kts indicated at about 10,000 ft.
Was in the CB for maybe 10-15 seconds. We exited about 90 degrees off original heading and inverted, with lead aircraft on some other goofy heading and far from us. Our G meter showed a reading of a shade over 6 g's and a minus 2 g's. Fortunately there was no hail encounter.

They can quite easily destroy airliners, a fact I am certain the Captain and First Officer of the Air Asia A320 were well aware of.

Get back on topic
 

Boy, is this thread off-topic! Is there another one which I have missed which is discussing QZ8501?

The Guardian is reporting an expert as suggesting the plane landed on the sea, but was overwhelmed by waves.

THS trim
 

@ Rudder

Go find hundreds of posts on the AF447 threads that discuss THS control laws.

The THS only goes as far as it needs to so as to provide full elevator deflection both directions. So it's HAL rolling the big trim wheel like we used to to relieve stick/yoke forces for the desired AoA or gee or pitch attitude..

Only reason the AF447 THS trimmed to the limit was the pilot held back stick for a long time, and HAL obliged. You and I would have rolled the wheel back manually in the old days. Maybe we would have realized it was full back, maybe not.

I can see some conditions requiring full trim of the stabilizer, but rarely. Things like a screwed up cee gee, or loss of flaps or.......

I knew that would come up, which is why I previously posted the case where an SR-71 failed to out-climb a thunderstorm and was destroyed, plus the case in Japan of an A-4 caught in clear air turbulence that was nearly destroyed. A thunderstorm can best any production aircraft ever made. I think the airframe of Chuck Yeager's X-1 was stressed to 25 g, I guess it could survive most things but it's not a production aircraft.

It appears more likely that the plane was shedding occupants on the way down.

To help with getting a perspective on stall recovery in large passenger jets, assuming still air, wings level nose up stall, how much height is lost to effect a recovery, lets say from 35,000 ft or from 20,000ft.

SCMP this morning 0804020115:

Analysts have claimed the pilot of the crashed AirAsia flight may have made an emergency water landing, only for the plane to be overcome by high seas.

The A320-200 left Surabaya, Indonesia early on Sunday and disappeared from radar over the Java Sea during a storm, but it failed to send the transmissions normally emitted when a plane crashes or is submerged.

As search teams battled poor weather in the hunt for the black boxes, experts said the lack of transmissions suggested the experienced former air force pilot, Captain Iriyanto, conducted an emergency water landing that did not destroy the plane.

"The emergency locator transmitter would work on impact, be that land, sea or the sides of a mountain, and my analysis is it didn't work because there was no major impact during landing," said Dudi Sudibyo, of aviation magazine
Angkasa.

"The pilot managed to land it on the sea's surface," he added.

The plane, carrying 162 people to Singapore, was at 10,000 metres when the pilot requested a course change to avoid storms.

Although permission was granted to turn left, the pilot was not immediately allowed to ascend owing to heavy air traffic, and the plane disappeared from radar soon afterwards. Indonesia's search team scoured the sea for more than 48 hours before the first debris was spotted off the island of Borneo after a tip-off from fishermen.

So far, the search team has found eight bodies, but air safety officials said it could take a week to find the crucial black-box recorders.

An emergency-exit door and an inflatable slide were among the first items recovered by the search team, suggesting the first passengers may have started the evacuation process once the plane landed on water.

Coupled with the leaked radar evidence of rapid climb followed by rapid descent and the non-wearing of life jackets by recovered victims, I find this possibility unlikely.

Regarding the steep climb of the aircraft prior to the accident, I can imagine a couple of causes and keep in mind these are not mutually exclusive.

1. What is the barometric pressure variance at a fixed altitude above sea level in this sort of storm? A drop in air pressure (perhaps by an updraft) might artificially increase the apparent climb. Has this been factored in?

2. Strong convection-induced issues?

3. Erroneous instruments?

4. Software bugs (thinking of the MH124 b777 uncommanded climb).

I strongly suspect the fdr will be needed to resolve these questions.

'Controlled' ditching
 

Seems totally implausible, I'm sure if this was a potential outcome, during the descent the CC would have been making sure life vests were donned and barring the one erroneous report, there has been no suggestion that those souls recovered had them on. Such sensationalist reporting gives the poor grieving families a misplaced hope that there may be survivors out there. May those lost in this terrible tragedy rest in peace.

joema:

I believe that SR-71 was lost because both engines flamed out inside the TRW, rather than structural failure. It makes me think of the DC-9 that crashed trying to land on a narrow, tree-lined Georgia road after both engines was destroyed inside a TRW. But, they came out the other side intact.

The engines at issue should be of considerable interest to the investigators.

Terminal velocity would have nothing to do with it though would it? If it's in downdraught !

Likewise, this misunderstanding is exactly why press & media are annoying the hell out of me (and some pruners)
... suggesting that because radar recorded climb rates were so high.. "..it had to be in a stalled condition.

Rubbish !

Depends on stall entry speed, and altitude, as a result of AF447, we have all been required to undergo high altitude stall training, in an aircraft that was advertised as un-stall-able, by engineers that tried to design pilot error out of the system.

This is so good, the design, folks who have never flown airplanes before, can get it under their fingers in just a few months. Simple. We need to do that, sales in Asia are booming.

Now, sadly, we are trying to design the engineers out of the airplane, piloting can't be taught, it must be experienced, an involved apprenticeship that brooks no shortcut of any kind, we are re-writing butchered checklists in the hopes of saving lives.

Nothing like being there, in the cockpit, in the Shiite, to get a real feel for your mortality. And the cloud nine the engineers live on, safe at home in their feather beds.

At the time of the crash the seas were said to include 3m swells. Would the chances for ending up with an unbroken plane after ditching on 3m waves be fairly low?

Mr. Dudi Sudibyo
 

...is not to be taken seriously, IMO.

"piloting can't be taught, it must be experienced"

Do you seriously think the designers didn't have experienced pilots on their teams? The computer logic will take into account all rules of physics regarding flight and can make calculations a thousand times faster than a human. HAL can also be programmed with anticipatory logic so that if one sensor is providing eroneous data he can figure out what is going on. Like humans, if he has been made totally blind, then he can no longer perform safely and so he hands back control...usually at the worst moment. The false logic of some commentators here is that because a computer can't cope in every situation, a human pilot would be safer in every situation. Realistically, I don't think pilots would want the autopilot tripping off everytime the aircraft entered a few bumps.

Edit - I understand the point that is being made by some i.e. that HAL is a bad loser and won't give back control until the last possible moment...at which point the aircraft is on the edge of its flight envelope...but there is an off switch.

Bug

High altitude stall training is all well and good and a step in the right direction.

What stage of stall and recovery of these aircraft are carried out at test? Is it the approach to the stall, threshold of the stall, fully developed stall, or deep stall, at high altitude? If not all, where are they getting the data from, to feed into the simulator?? I suspect it is not only a "T" tail to get into a deep stall. If the elevator on a non "T" tail aircraft is stalled I suspect the situation could be irretrievable from that stage on wards, depending on CofG, CofP and trim etc.

Is there any extra training given to avoid stalling the aircraft in the first instance?? E.G, simply flying an attitude and setting or leaving the thrust where should be, should pressure sourced instruments be suspect or plain useless. Or throttles idle and attitude zero to get down into "better air" then derive a thrust setting for the newer lower altitude? One would hope these are all taught at initial training and should certainly be covered at some stage on type conversion, not waiting for a bad accident. I call it "tombstone regulation". Or don't the basics matter anymore??

The only fact we can reliably work on at present is that two, supposedly highly experienced pilots, wasted a full 38,000 of height in a perfectly good aircraft, and flew into the sea after an updraught upset. On that basis, the comparison with AF447 is inescapable.
I fail to see how an updraught upset can lead to total hull loss without total confusion in the cockpit. No doubt they were in total IMC, which would nearly equate to the total darkness of the AF447 incident.
There is no indication that the aircraft was torn apart by the stormy conditions, it was briefly spotted by two fishermen, still flying in one piece, heading towards the sea.
The talk of a "nearly-successful ditching" is fantasy, the sea and wind conditions in the area were atrocious, and still are atrocious.

Quote

Does anyone agree that the current Airbus Weather Radars aren't as good as they used to be ? I've noted the following :

1) Weather picture suddenly changes from yellow to red as you approach closer to the cloud.

2) Auto-tilt is overly conservative (tilt down). Manual tilt needs to be used often.

3) Gaps between clouds disappear as you approach closer.

I have flown radars from the DC-9-30 all the way up to the newest ones in the single aisle Airbus. I would take auto tilt any day anywhere. I have taken Archie Trummel's weather radar course and understand all about tilt control. All the earlier radars had their faults, and there may be a few with auto tilt, but the reason why we have radar to begin with is to avoid severe weather, not find a way to fly through it. I realize that flying in the tropics is a whole different animal than flying in the states.

We can't even work on that. Only evidence of such is what the media has reported, and much of that (donned life jackets, Airbus-shaped shadow on ocean floor, etc) have been disavowed by officials. We won't know squat until the FDR is retrieved and its data made public.

That image showing the flight at FL363 and 353 knots GS? What a coinkydink someone had a camera pointed at the screen at the exact right moment...

All we really know is the plane didn't reach its destination, some fishermen saw an airplane descending to the water and heard it hit, and that some bodies ID'd to have been on board, along with wreckage consistent with an Air Asia A320, have been found.

All that said, yes, it looks a helluva lot like AFR447. But we don't know that as a certainty.

Question: Would a high rate of descent make sense if the Cptn put the A320 in a steep dive from considerable height -- NOT with any bad intentions, but in a desperate effort to recover from a stall?

Perhaps powered, or initially unpowered but restarting engine(s) along the way?

Earlier in this thread, NigelOnDraft said (in reference to AF 447)
[D]o you really think that crew would have correctly recovered from this stall?
The Nose Down attitude to recover (30+nd?) would have been horrendous, and I am not sure I could have been convinced to push that hard for that long (and I'm a current aerobatic pilot, ex-mil fast jet, RAF ex-QFI etc.).


Flight 8501's Cptn reportedly flew fighters in the military. Like some other pilots, after AF 447 he also may have thought about how he would respond if ever in a high altitude stall.

If the odds were high the plane would crash if nothing were done, would a steep dive be a reasonable response - trading altitude for speed and hoping to regain control before reaching the deck? It certainly would void the warranty, and might push some control surfaces past their limits - but would there be a better alternative once in the proverbial soup?

If I'm all wet, just say so. (And yes, my question presumes recovery from an actual stall, which has been suggested by some but thus far remains speculative. I also refrain from using technical terms such as "fully developed stall" or "deep stall", recognizing the limits of my knowledge and not desiring to make a complete fool of myself.)

CEO Mr. Fernandes - tell us about their simualtor training?
 

Simulator training? What a joke. My first high altitude stall scenario came after AF fell into the ocean. That was also the last time I have done high altitude stalls. As I remember it, it took a decisive push on the stick to get the nose down and then it took forever for the speed to build enough to start to pitch to level flight. As for loss of air data, what makes a pilot think he has to do anything to correct for it? What was the airplane doing just prior to the event? Level flight, constant power setting? Leave it alone. If the auto thrust tries to react to erroneous speed information, turn off auto thrust. The system is already compromised, so turning off auto thrust is not going to harm anything. Pitch and power, baby.

Curious and curiouser. Maybe they thought they were fighting a downdraft - engines roaring and stick full back? - not noticing stall because they were below 60kts?

On the other hand if the fuselage really is intact and upside down as some reports have said, then vertical speed can't have been that high? If they were gliding then it was more likely to have been a double flame out, but then why no comms? Maybe the RAT didn't supply enough power for transmission?

We don't even know that for sure.

Many fishermen from different islands think they saw / heard something. But they all told different stories, about possible aircraft at different locations, altitudes and states.

Some of those stories may or may not coincidentally match other things that's been reported.

Passenger 389

Oh no, don't be afraid to ask and no you aren't making a fool of yourself. None one knows all the answers. If we all did, a/c wouldn't be dropping out the sky, with the consequent carnage.

Hilarious - do you actually know who John Farley is?!!

@peekay4:

Yeah, that too...

High altitude Stall
 

Quote:

Curious and curiouser. Maybe they thought they were fighting a downdraft - engines roaring and stick full back? - not noticing stall because they were below 60kts?

I would find it hard to ignore the PFD down in the barber pole, or the pitch above 15 degrees. I would think that if an updraft were encountered, the first reaction would be for the airplane to pitch down to maintain selected altitude (if in level flight). Then as airspeed increased to MMO, it would automatically pitch up to keep from exceeding MMO (by 6 knots). If the pitch required to do that exceeds limitations, auto pilot drops off and it is all yours. What happens when updraft peeters out? Speed would disappear in a hurry at a super high angle of attack. High altitude stall follows and recovery would take a lot of altitude while falling through a very active thunderstorm. This is one scenario where I would like a button to push the airplane into alternate law.

Totally agree with you there, but believe it or not, airlines in this part of the world don't even consider your single engine piston time as relevant when it comes to applying for jobs. Anything below 5700 kg (jet) or 19 seat turbo-prop won't be considered as part of your total time. That's why you see log books of FO's here with TT the same as their time on type, because all the flying they do at flight school gets logged in a separate logbook, and doesn't count for time on Part 25 (Air Transport Category) aircraft.

Latest news from the local TV is that a team from France specializing in searching for the black box has arrived on the scene with their specialist equipment and will begin searching.

ekw

if I had over 30000 feet below me, I would not fight a downdraft into a stall or anywhere near a stall.

in the AIM, you can find thunderstorm do's and don'ts. And if you have to RIDE THE WAVES it is what you do and don't hold altitude too closely.

Now, the plane may have done something different on its own, perhaps even do to ''garbage'' information making a computer conclude the wrong thing and act in the wrong way (over simplification here).

Some of the conjecture by so-called media "experts" is just stunning in its nonsense. It is hard to believe that these statements are being printed and given credence.

Quote:

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Experts say the absence of any crash transmission means the experienced former airforce pilot Captain Irianto may have executed the perfect emergency landing before being the plane was overcome by high seas and sank.

While the hunt is on for the black boxes, several aviation experts believe the absence of any usual crash transmission data means the plane could have touched down safely with all 162 people on board.

After leaving Indonesia early on Sunday, the Airbus A320-200 disappeared over the Java Sea during a storm but the emergency transmissions made when planes crash or are submerged in the sea were never emitted.

So flight experts now believe it's entirely possible that experienced former airforce pilot Captain Irianto may have safely landed the plane on water - before it was overcome by high waves and fell to the bottom of the sea.

---