Air Asia Indonesia Lost Contact from Surabaya to Singapore

[HeathrowAirport]

Yes. And Sully Sullenberger did not press it. Some wise cracks claim that the airplane would have been salvageable if he had.

Impossible, the airframe twisted quite significantly - so much that the rear cargo doors had opened, not that the hole in the fuselage did anything more. It was an insurance write off as soon as s*** hit the fan.

[JSmithDTV]

training wheels

This photo is supposedly that of an evacuation slide that was retrieved from the debris found in the water. Whether it had actually deployed or not is unknown, unless some one can tell from the picture?

https://twitter.com/Malaysia_Latest/...03613365420032

If the slide/raft had deployed then it would still be inflated... so I'd imagine not.

Evacuation slide (http://en.wikipedia.org/wiki/Evacuation_slide#Types)

Depending on type they often double as a life raft...

Here's a pic of a deflated slide/raft on an A320;

http://upload.wikimedia.org/wikipedia/commons/thumb/e/eb/Deflated_evacuation_slide_on_an_Airbus_A320.jpg/511px-Deflated_evacuation_slide_on_an_Airbus_A320.jpg

[Pawpcorn]

Does Airbus still put a "ditch switch" on their airplanes?

Yes. And Sully Sullenberger did not press it. Some wise cracks claim that the airplane would have been salvageable if he had.

Good writeup on that fact and that incident, ...here... (http://www.flightglobal.com/blogs/flightblogger/2009/01/the_airbus_ditching_button/) :)

[aviator1970]

well a 100 Kt/ even higher speeds are encountered in jet streams and often you have strong up/down drafts close to build ups.... why is this speed so important? after it is ground speed not aircraft speed... what have I got wrong?

[Capn Bloggs]

well a 100 Kt/ even higher speeds are encountered in jet streams and often you have strong up/down drafts close to build ups.... why is this speed so important? after it is ground speed not aircraft speed... what have I got wrong?
1. There wasn't a forecast jetstream for hundreds of miles; the accident was close enough to being right over the equator;

2. An updraft/downdraft does not knock 100kts off your groundspeed.

[slats11]

Tracking would not have saved any lives here. And so you can argue that tracking is irrelevant.

On the other hand, it seems suboptimal to say 'We lost the aircraft at 24000 (or whatever it was) as it disappeared under the horizon. It could have hit the ocean very close to that point. It could have hit the ocean some distance away. Or something else may have happened." What relatives are going to find this acceptable?

With so many transoceanic flights, it is ridiculous that we repeatedly have the following situation:
1. We don't know exactly where the aircraft went down. The plane wasn't being tracked - although it could easily have been. The ELT should have activated on impact, but the antenna may have been sheared off and anyway ELTs can't be detected underwater.
2. The acoustic pingers are extremely short range, and if in deep ocean we will only hear them if we are directly overhead. In other words, the pingers rely on knowing the precise location of the wreck. That's on top of the inadequate battery life.

I accept that in an AF447 situation (and likely also AirAsia), pilots won't have time to communicate. Their priority is to try and recover the situation. But given this truism, it is equally ridiculous that automated systems are not activated until they are either destroyed by impact or rendered ineffective by sinking into deep water. Even a few hits from a 406 ELT during the final few minutes would be helpful in knowing something was wrong and knowing where the plane was at the time. Surely it is possible to come up with some parameters where this was triggered.

The fact is that the technology used today is really designed to find aircraft that have crashed on land or small bodies of water. They are completely inadequate for finding a plane in an ocean - which cover 2/3 of the planets surface.

I think most of us would agree (at least in principle) that this is suboptimal and frankly unacceptable. Surely we can do better than this.


IanW
ALL aircraft have tracking capability. All that is needed is regulation that mandates aircraft operators use the tracking capability that is already on the aircraft.

True, and this will come. All these systems can be turned off however, which I suspect was the thinking behind someones suggestion for an independent system not connected to aircraft power.

727forever
Tracking devices that can be turned off by crew or other persons and render the aircraft invisible except to ground radar is out of date thinking.

Probably a difficult call. On one side we have arguments about electrical faults and fire and needing the capability to isolate all electrical equipment. On the other side we have MH370 and I guess also 9/11.


Whatever we think here, IanW is right. This will happen - and sooner than many people anticipate.

[aviator1970]

"The storm's updraft, with upwardly directed wind speeds as high as 180 kilometres per hour (110 mph),blow the forming hailstones up the cloud."

from Wiki:
Atmospheric convection - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Atmospheric_convection)


well I have been a turboprop most of my life, but from flying over India I know close to the equator these babies can be nasty.... so one shouldnt discount possibility of an updraft..... and there by downdraft.... in a regenerating CB both can co exist. Any answers?

[strake]

How much lower can humanity go? 20 years ago, we would have quietly kept our thoughts to ourselves about these poor people and waited to hear why such a tragedy happened. Now, their remains are discussed like carrion on the roadside. On newspaper websites, we see pictures of pixilated bodies and on TV, reporters breathlessly describe what might have occurred in dramatic and horrifying detail. What is it going to be like in ten years time?

[caa]

Are you talking what on radar or on instrument? The Bus boy way earlier said why bus boys wont comment here. Read between the lines. (sure they all filled forms on this as he said that is why they will not comment). If it turns that way I hope he and others did not wait for many more soles to act on it. Being in training is worse a known or possible defect MUST be reported.

I hope they are wrong and bet they hope too. Inflight break up seems out as per crash site. A stall seems very possible and +20K hours on type/s and training and saying BE Quiet by a bus guys says volumes or is he just a troll?


On here it is simple focus on the pitot system - reality is that alone should not cause a crash. Key is to find all the factors. Lets start with the boss, military training (lots of it) is generally by the book, previous crashes of like type are well known by most that fly type, also weather this time of year is known to this operation.

What was different? I don't know If the ASI's went maybe but a cargo shift in turbulence could throw it all out the window? that floating first photos of a bit of wood certainly has no g rating for restraint.


If your C of G is stuffed so are you! Always more than 1 thing causes a accident.

[aviator1970]

You and I will become unwilling or willing participants in this nasty public display of private moments. I agree this is despicable:ugh::ugh::ugh::ugh:.

[mixture]

slats11,

This:

that we repeatedly have the following situation:


Is exactly the problem with the pro-"lets throw more money at un-necessary additional tracking mechanisms" brigade ....

These scenarios that occur "repeatedly" according to you and your colleagues, are infact rare.

How may flights have occurred globally over the last decade ? How many flights encountered a scenario where additional tracking would have helped ?

Exactly. We're talking statistically insignificant numbers here. We're talking about a minute proportion of rare events that are rare in themselves (i.e. "untraceable" crashes in a world where aviation is the safest mode of transport and therefore any sort of crash is in itself a rare event already... let alone an "untraceable" one).

So please guys, give it a rest with the stupid tracking hamsterwheel. Or at least if you want to continue chattering about it, start a new thread elsewhere on PPRuNe because the subject of tracking is now 100% irrelevant in the case of Air Asia.

[stonevalley]

As one track said, local people will soon find the site/debris in coastal waters.

Anyone who knows SE Asian water will testify that an aircraft coming down in day or night will be seen by someone.

I'm amazed at the obsession with speculation on possible scenarios when its fairly clear that the answers will be found in the wreck.

[lomapaseo]

Aviation safety expert and accident investigator C.B Sullenberger

:confused:

Although I would rather listen to Sully than scary mary or peter Goelz

The issue is credibility of the source of knowledge behind the words expressed. Like what real experts do they go to for their own briefing before being interviewed

[einhverfr]

Well I work in a managerial position in Asia with asians and I experience very little of that kind of behaviour. In my >30 years of experience I find it is the attitude of managers that most dictates the behaviours of subordinates. I really am sick of this nonsense, it rears its head in every thread involving an Asian airline and it smacks of cultural superiority. I've worked with Americans in American companies who spend every second trying to second guess their managers, pitifully fearful of spiteful reprisal at best and career assassination at worst.

In my experience (living in Indonesia with my Chinese-Indonesian wife), most of the alleged deference is cosmetic. What's usually really going on is a different style of discussion when it comes to manager/subordinate relations. The substance is the same, the window dressings are changed. I can see how people *think* there is deference. But IMO, there is a lot less than you would think. It's just that there is a right way and a wrong way to assert yourself, and that looks kind of funny from outside.

[jientho]

@Super -- The concept is sound, but it's never as simple as it may seem at first. For example, you're going to use a distress frequency practically continuously (verbal reporting of all those figures is going to take the whole 30 sec) by an automated device with a non-zero probability of a latching type-1 error (continuous false positive)? With no ability to manually turn it off (see other comments for why that requirement) until the a/c reaches a maintenance hangar?? I can practically hear the outcry already. :ugh::ugh::eek:

[RatherBeFlying]

In AF447, we had considerable speculation about the accident chain. Once the recorders were read, we found an unanticipated scenario.

Possibly this flight got caught by the same engineering and training deficiencies as AF447, but it won't surprise me if there's a different accident chain.

Hopefully the recorder data will be published in the next few months.

[bud leon]

einhverfr, yes I'd agree.

Actually after working in Asia for a while western assertiveness can seem unnecessarily blunt. But you will get bluntness and individualism in Asia when the situation calls for it. I find it quite preposterous that some people think 4.3 billion people would rather die than challenge authority.

[flt001]

The argument that an event is unlikely and therefore not worth planning for I find a bizarre argument in the airline industry and likely a worrying one from a customer point of view.

A plane may ditch successfully (it's happened) and there be survivors (it's happened) who will drown because SAR can't locate the plane (it's happened) in time .

I find nothing unrealistic about that comment, anymore so than needing all sorts of backup systems we have on our planes which will likely never be used.

The whole modern ethos behind aeroplane design is redundancy after redundancy for a very good reason. Yet some here are actually arguing that a foolproof system to locate a crashed plane is a crazy thing to develop. :ugh:

I don't care about planning for the 400,000,000 flights a decade that go to plan, I care about the 1 that doesn't.

[island_airphoto]

The assumption is that if people are alive, they will take the PLBs/ELTs out of the plane with them and turn them on. The case for an auto-jettison ELT is for finding the plane when no one survives and for when the landing is bad enough that some may survive with no chance to get the beacons. Routine in flight tracking is a solved problem with equipemt now being rolled out, as has been mentioned in this thread a few times if you scroll up.

[HeavyMetallist]

@ft001,

You're arguing that risks should be engineered out regardless of how probable they are. Do you seriously believe that's the way aircraft are (or should be, for that matter) designed and operated?

[sAx_R54]

@Mesyfang

What I don't know is whether deference to authority is part of the culture in this part of the world

It is the rapidity in which statements like this are provoked, that make me wonder about the precise definition of 'professional' on this forum!

[mixture]

You're arguing that risks should be engineered out regardless of how probable they are. Do you seriously believe that's the way aircraft are (or should be, for that matter) designed and operated?

Indeed and aside from the question about whether its technically possible or feasible to engineer out 100% of risks, @ft001 also seems to think money grows on trees...

[Ian W]

Quote: Back onto the hamster wheel again

Aircraft already have sufficient tracking. ADS-B and ADS-C and ELTs

With all due respect Ian, MH370 is still missing so I would not call that sufficient tracking. Tracking devices that can be turned off by crew or other persons and render the aircraft invisible except to ground radar is out of date thinking.

MH370 had sufficient tracking systems - some were turned off by the management trying to save pennies, others were 'turned off' by action of someone with access to the cockpit.

What you are talking about is a tracking device that cannot be turned off by someone in the cockpit. There was a continual argument on the gargantuan MH370 thread about having avionics devices on board that cannot be turned off by the crew if they malfunction. The general thought was that this was not a good idea. If you have someone in the crew that can disable all the power buses you are left with a battery powered device that cannot be switched off. I would point you to the fire in the Ethiopian 787 at LHR which resulted in considerable damage caused by a mis-assembled ELT, which is just such a device.

However, note that the existing roof mounted ELTs transmitting to satellite on 406KHz is something that would easily provide tracking and already exists.

There is no need for new equipment, there may be a need for automatically switching the existing tracking systems to an emergency mode. However, you cannot cater for a crew member deliberately disabling the devices (most aircraft fixed ELTs can be switched from the cockpit).

[MrSnuggles]

I would like everyone to look for posts made by Ian W (sorry, can't provide post numbers because they are not always consistent) regarding technical abilities to trace and track airplanes, a task that is perfectly doable in this day and age. But.. someone has to pay for it. And, as said before, this technology works very well over land or in shallow (less that 100m deep) water.

What someone pointed out was that pingers for FDR/CVR and tracking in deep oceans are a bit behind. BEA suggested some solutions to that problem, and I have read some very interesting posts in the MH370 thread. Quick repeat: The big concern about deep masses of water is that water is very "resistant" to radio waves. They scatter within matter of a few metres. Sound waves are the absolutely best way to communicate long distances in waters, something all species of whales has taught us.

I am glad they seem to have found the wreck already. I was truly fearing a new MH370 scenario.

[5000 metres]

Lots of interest in improving/innovating tracking/telemetry.

What I find curious is the, in contrast, often resigned attitude toward severe unpredictable weather...we know it happens, we can only go so far in preparing for it, often we're caught by surprise (several compelling anecdotes of such).

I'd like to think that 20 years from now, the current radar inability to detect a wx threat e.g. a high-velocity updraft (also alluded to in compelling anecdotes) will seem tragically archaic.

[lucille]

Some questions for the Airbus gurus.

Would the automatics eventually recover from any condition resulting from a jet upset? Stall/Spin? Inverted?

So if all hell is breaking loose, would re-engaging the A/P and A/T be a viable option?

Mind you the Capt was an experienced F4 & F16 pilot, you'd think that inverted stall/spin recovery in IMC would be second nature to him.

Will the FBW allow the pilot to pull excessive G? Or will it try to protect the airframe even if it means contact with the ground will be inevitable?

[MtSpeedDemon]

yeah but its a a beautiful part of the world and that's where future business opportunities are

TBH I doubt the safety record in SE Asia is as bad now as in Europe or the States in the 50's and 60's as long as you stay away from the bush airlines

There has been a lot of generalization about airline safety in SE Asia in this thread. Even suggestions to book tickets based on primary RADAR coverage of certain routes which of course is unrealistic for most mere mortal non-professional pilot humans. I've read most of this thread but I can't promise that I have read every post so apologies if this is duplicated info. While not directly pertinent to the specifics of 8501 the links below do offer some relevant info on air carrier safety based on real standards, not just hearsay or where the last few accidents have occurred.

What airlines and countries do the EU and US give thumbs up or down to?

Here are some resources that may help.

EU airline "Black List" or Community list of air carriers which are subject to an operating ban within the Community (PDF) (http://ec.europa.eu/transport/modes/air/safety/air-ban/doc/list_en.pdf) Note some exceptions within the list
European aviation safety air-ban page (http://ec.europa.eu/transport/modes/air/safety/air-ban/)
"To improve safety further, the European Commission – in close consultation with the aviation safety authorities of all Member States – has decided to ban certain airlines from operating in European airspace, because they are found to be unsafe and/or they are not sufficiently overseen by their authorities."


FAA list of countries with airlines they deem deficient based on ICAO standards (XLSX) (http://www.faa.gov/about/initiatives/iasa/media/IASAWS.xlsx) Look for "Category 2 - Does Not Meet ICAO Standards" (Indonesia is in this category)
FAA International Aviation Safety Assessment (IASA) Program page (http://www.faa.gov/about/initiatives/iasa/)
"The IASA program focuses on a country's ability, not the ability of individual air carriers, to adhere to international aviation safety standards and recommended practices contained in Annex 1 (Personnel Licensing), Annex 6 (Operation of Aircraft), and Annex 8 (Airworthiness of Aircraft) to the International Convention on Civil Aviation “Chicago Convention” (ICAO Document 7300)."

[dakarman]

Having read the majority of this thread and others in the past regarding real time tracking in finally find myself needing to ask the question loudly WHY are some people arguing so vehemently against it?
Multiple comments in all the threads indicate existing equipment is in place and potentially the service could be free. To my mind this is what could be called a no brainer so why the arguments against? Even supposing some cost and regulatory issues it is clearly something of benefit in multiple cases just in recent years. We are after all in the communication age not the stone age.
Allow me to propose a simple scenario. The plane you are on at FL350 has decided for whatever reason not to fly properly any more and for whatever reason no radio calls are made as the plane descends. Apologies for the simplistic scenario but in short this has just happened. Do you
A want to be on a plane where SAR is made aware in one or two hours later and your eventual location is known within a few tens of miles or even further if gliding from this altitude? (Previous poster mentioned 6 miles which alone gives a search area of 113 square miles!)
Or do you B want your position known realtime within a few metres on the surface and potentially (assuming a small simple bit of monitoring software) to have alerts out to emergency services before the flight is over whatever the outcome?
I am a regular Slf and occasional pilot and would like to reiterate my question why are folks still arguing against this?

[Ian W]

How much lower can humanity go? 20 years ago, we would have quietly kept our thoughts to ourselves about these poor people and waited to hear why such a tragedy happened. Now, their remains are discussed like carrion on the roadside. On newspaper websites, we see pictures of pixilated bodies and on TV, reporters breathlessly describe what might have occurred in dramatic and horrifying detail. What is it going to be like in ten years time?

What you are seeing a little of is the conversation that happens (or should happen) in any crew room. What could have caused an upset or crash is an immediate discussion topic. That is usually followed by what-if discussions with those experienced in the upset and recovery describing what they did or saw done to the less experienced. It is a way of learning about aviation without having to experience the emergency yourself. Then these ideas may be trialled in sim rides or the events added to sim rides so everyone learns from something that happened. Every accident and incident is and must be a learning experience; otherwise they may be unthinkingly repeated. Of course there will be speculation about what could go wrong but that only adds to the broadening of the knowledge base and increases understanding. In many places it can clear misconceptions both technical and interpersonal.

This is not a gruesome rubbernecking at an accident, this is people some of who fly the same type of aircraft in the same or similar environment getting their heads around the issues involved and assisting everyone to understand what could have gone wrong and, when the eventual reports of what is in the DFDR/CVR are published, there will be another burst of learning.

It may not be apparent to people not in the industry, but this forum greatly increases flight safety, by increasing awareness of issues and bringing in experts in the various disciplines who provide in depth knowledge of rare events and aircraft and systems capabilities and often long experience in aviation.

(Thanks to the moderators for making this possible ;-) )

[NigelOnDraft]

Would the automatics eventually recover from any condition resulting from a jet upset? Stall/Spin? Inverted?Depends what you mean by "automatics"? FBW laws? Or Autopilot?

The FBW Laws will restrict, or return, the attitude to within the defined parameters. What the limits are (if any) depends on what Law is being used.

To have got into a Stall/Spin/Inverted either requires the laws to have degraded already, or a severe external event that overrode the controls. In extermis, it reverts to an "Abnormal Law" if it fins itself in a "UP", in effect acknowledging something has gone wrong and giving the best option for a (manual) recovery.

So if all hell is breaking loose, would re-engaging the A/P and A/T be a viable option?The engagement conditions of the AP are quite strict, so unlikely.

Will the FBW allow the pilot to pull excessive G? Normally no, but in some degraded modes yes.

Contrary to some others here, I would disagree there is a strong requirement for an Airbus pilot to always understand these laws, and know exactly what they are. 99.9% of the time, you fly it like a normal aircraft, and get nowhere near the protections. The only drill I can think of where you "use" a protection is GPWS "pull up"? As the laws degrade, there is a simple sequence (Normal - Alternate - Direct - Mech) but in fact there are multiple "sub-modes" - and sometimes you will not know the details. ECAM gives you some hints e.g. some Speed Protection might be lost, but who in their right mind is intentionally going to fly the aircraft is a manner requiring "speed protection"? Ditto Stall Protection - are you really going to fly differently if this is active or not?

[Orestes]

?Unbelievably? steep climb recorded before AirAsia crash, report says | Fox News (http://www.foxnews.com/world/2014/12/31/unbelievably-steep-climb-recorded-before-airasia-crash-report-says/)

[HeavyMetallist]

I'd like to think that 20 years from now, the current radar inability to detect a wx threat e.g. a high-velocity updraft (also alluded to in compelling anecdotes) will seem tragically archaic.

I'd like to think that, too. However a lot of very bright people have spent quite a bit more than 20 years trying to solve this problem already, without much success in terms of a practicable engineering solution. If you want to make your fortune then you could do it by cracking this one, but don't expect it to be easy!

[JoeyBalls]

@727forever

There is a way to look at the Realtime AOA as well as a many other parameters. even G's via the MCDU................takes all of 2 seconds

[jientho]

Quote:
I'd like to think that 20 years from now, the current radar inability to detect a wx threat e.g. a high-velocity updraft (also alluded to in compelling anecdotes) will seem tragically archaic.
I'd like to think that, too. However a lot of very bright people have spent quite a bit more than 20 years trying to solve this problem already, without much success in terms of a practicable engineering solution. If you want to make your fortune then you could do it by cracking this one, but don't expect it to be easy!


I can't help thinking that if global warming is happening, then the place where climate/weather dragons (never before seen (unexpected) phenomena) will first show is at the already-hottest places on the globe -- the tropics.

[JoeyBalls]

@ Mixture

well, the safest thing would be to never take off...............................how do you think that will play out?

Also, people keep mentioning the CA was an F-16 pilot, so what? Flying an F-16 is absolutely nothing like flying an Airbus. The only commonality is they both are Yoke-less..............

[AreOut]

Indeed and aside from the question about whether its technically possible or feasible to engineer out 100% of risks, @ft001 also seems to think money grows on trees...

with full hindsight MH370 search probably costed already more than all the imaginary tracking would cost to this day

[Propduffer]

The reports of the aircraft hull being located are (all) apparently false.


On Dec 31st 2014 the chairman of Indonesia's Search and Rescue Service stated in an evening press conference, that earlier reports about the fuselage having been located have been incorrect, the search is still ongoing, so far - referring to a report by CNN hitting global headlines - there are no sonar images of the fuselage as well. Correcting other media reports the chairman stressed that none of the bodies recovered so far was wearing a life vest. All valid information concerning QZ-8501 only and only comes from one source, namely the Search and Rescue Service which is currently in charge of the entire operation, the chairman stated with reference to the current information chaos.
Crash: Indonesia Asia A320 over Java Sea on Dec 28th 2014, aircraft lost height and impacted waters (http://avherald.com/h?article=47f6abc7&opt=0)

[CONF iture]

Will the FBW allow the pilot to pull excessive G? Or will it try to protect the airframe even if it means contact with the ground will be inevitable?
Protection of the airframe, and most probably what happened in the late stage for the 320 in Perpignan.

[CONF iture]

The only drill I can think of where you "use" a protection is GPWS "pull up"
You may have to use it also for the WINDSHEAR procedure.
ECAM gives you some hints e.g. some Speed Protection might be lost, but who in their right mind is intentionally going to fly the aircraft is a manner requiring "speed protection"? Ditto Stall Protection - are you really going to fly differently if this is active or not?
For sure a GPWS procedure will be flown differently.

[einhverfr]

Would the automatics eventually recover from any condition resulting from a jet upset? Stall/Spin? Inverted?

Because I suspect this will come up over and over I am thinking about putting a write-up on tech log about automation challenges and issues, and the direction I think things are likely to go.

I think we should remember that automation in aircraft is still really in its infancy and we really haven't figured out how best to integrate pilots into the system. There are a very large number of issues that need to be approached.

Although I tend to be fairly critical of Airbus for a few details (lack of feedback of sidestick inputs is a big one), I think the overall approach of flight laws is likely to be expanded over time in the name of safety, and that really solving the issues of automation are likely to mean better encapsulation and separation of actual duties. This means both giving more tasks back to the pilots (to keep them engaged and in the loop) but also making the plane a bit more autonomous as well. This means better avoidance and recovery regarding upsets, stalls, untrusted instruments, etc.

This of course doesn't mean that you shouldn't have a way to kill a lot of the automation and fly the plane pretty manually (this may happen anyway in even the most sophisticated fighter aircraft -- see the F22/international date line incident).

Obviously there are aerodynamic limits. There are also informatic limits. There are physical limits. A lot of the value is likely to be in avoiding these limits since not much can be done to overcome them.

[xcitation]

Has anyone heard if Air Asia enabled ECAM warning messages to be sent to HQ for their Airbus fleet?
I recall AF447 had automatic warning reporting of the ECAM alerts transmitted back to Air France headquarters during the incident. They were discovered the next day after the missing flight. For years this was the only data available. This can be an important early motivator for pro-active safety directives to be issued before the final accident report is released.

If option enabled and zero warnings received then it would be consistent with a very sudden event.
If option enabled and warnings were received then they should be included in the accident report, analysed asap as a potential benefit for other a/c.
If option disabled then they should seriously consider enabling and integrating the alerts with their operations center.

[gulfairs]

I am and old critter, and the last heavy aircraft(being greater than 12500 kg)
was a DC8 73 and then 747 200 preceded by DC10-30.
Non of these aircraft had all the white mans magic of a dozen different laws etc, just the old ones, Pull stick back equals houses get smaller and push stick forward houses get bigger.
It appears to this fuddled brain, that airbus industries have put so many protection systems in place that the aircraft systems are able to out maneuver the pilots inputs.
This with the new era of pilots who have never witnessed a spin, upright or inverted or even know how a spin in entered and how to recover i.e AF 447 spun for four and a half minutes right down to impact with I have the wheel/stick back why wont the nose come up!
Here in Godzone the local CAA examiner does not accept any spin manouver until the candidate is checked out to be an examiner (A Cat).
Hence all the budding instructors only experience steep turns with stall warning, no aerobatics.
Now we let these people loose on heavy metal which can spin(All aircraft can made to spin) which in adverse met conditions i.e. in amongst the ITZ or other savage meteorological conditions they experience an upset and then the call is "What is happening" and after some time a sudden stop is experienced by contact with the planet.
For interest an IAS of 350 kts or so at FL320 on an Isa +10 day equated to about 495 kts TAS which is close to .85 Mach
My point is: maybe we should revert to cable operated controls and switches.

[captplaystation]

If there is any truth in this, surely this is "the elephant in the room "

http://www.foxnews.com/world/2014/12/31/unbelievably-steep-climb-recorded-before-airasia-crash-report-says/

[peekay4]

If there is any truth in this, surely this is "the elephant in the room "

http://www.foxnews.com/world/2014/12/31/unbelievably-steep-climb-recorded-before-airasia-crash-report-says/
Alternatively, a few posts in this thread already speculated (http://www.pprune.org/rumours-news/553569-air-asia-indonesia-lost-contact-surabaya-singapore-23.html#post8801976) that QZ8501 might have encountered a very strong updraft. And possibly the Mode C altitude readings could be wrong due to the change of air pressure in a storm cell.

[xcitation]

My point is: maybe we should revert to cable operated controls and switches.

This new generation highly automated a/c has resulted in a significant increase in safety. That said refinements will continue to be made, who knows even a big red button to revert to direct control mode.
Spin and stall control have historically been outside the training remit for heavy A/T training because the focus is to avoid that place at all costs. It should also be noted that excursions beyond the flight envelope are only entered into with low energy by the manufacturers test pilots (i.e. gently pushed). Airbus do not flight test deep stalls or flat spins, these a/c are designed for efficient cruise and keeping you there safely.
If you read the AF447 report closely it is clear that the airbus has a superb stall recovery so long as the pilot executes the correct flight controls inputs upon hearing the stall warning.

[Vilters]

Automatic recovery from stall/spin/departures, is already operational in some airplanes, sometimes coupled with automatic ground avoidance.

But? All depends on the sensors.

If the sensors, pitot tubes and/or AOA vanes are partially or comletely frozen up or contaminated? => No automatic system can work when it gets the wrong information.

Modern computers can do a lot but garbage in, garbage out.

The weak link is "the sensors" that are out in the open.

Multiple accidents happened by faulty or not working sensors.

- pitot tubes frozen or FOD contaminated
- static ports frozen or FOD contaminated
- AOA probes and or vanes frozen or FOD contaminated

- Yes even probes that where taped over when washing the airframes and the A/C went flying with the tapes still over the probes => crash

The computes can do the work, the softwares are there, but the probes are the weak link.

[lucille]

Thanks, Nigel.

I posed this question because of the, as yet unsubstantiated, allegation that the aircraft was "slow".

An unintended inverted spin is confusing enough in VMC when tightly strapped into a clean, debris free cockpit. Add in the complication of IMC, the degree of difficulty magnifies by several orders of magnitude.

And now between man and machine there exists a filter (laws). My question was related to whether this filter aided or hindered a recovery or made no difference at all.

Abnormal attitude recovery training in the sim is unrealistic. Clean cockpit and always 1G sensed by your backside.

[DaveReidUK]

BTW: is it just me wondering what the results of Inmarsat location detection would be for the AirAsia flight? I assume AirAsia had the same technology on board and the data would be similar, so this would give a nice estimation on how good the algorithms for MH370 really were ...

I'd have thought that the many thousands of successfully completed flights in the meantime would have provided benchmark data at least as useful as anything generated by the AirAsia flight?

[The Ancient Geek]

Regarding the inadequacies of weather radar in detecting many hazardous conditions there has been a lot of promising recent research using LIDAR.
Meteorologists are very pleased with the ability to better detect convective conditions but this is cutting edge stuff so likely to be many years away from routine use in aviation.

Maybe this will replace our current weather radars in the future. OTOH having a scanning laser on the nose of every airliner may prove to be too hazardous.

[rideforever]

WRT computer-control : I always wonder what the vision is for Airbus and the European model of automating life. What are human beings, us, supposed to do after the world is computerized? Go shopping and watch TV?

Where is the courage, the skill, the craftmanship that inspired us to want to be part of aviation ?

Actually the human being is already an exceptional computational being, capable of reprogramming itself, of interfacing in multiple channels with other complex sentient and non-sentient systems, healing itself, reproducing itself, and growing itself. It will take man thousands of years to get anything near this level of power. It took Earth about 4 Billion years to create 'man'.

I despair when I hear of novice pilots playing games on their iPads sitting on the control whilst a machine flies the plane. Where is the dignity? Is this living?

It's one thing to die because of the forces of Nature, another when adults act like children.

[Airbubba]

I have not had the "pleasure" of flying in that part of the world, however, a couple of very experienced colleagues that did, for some time, intimated to me that if you did not accept to routinely fly through weather that you assuredly would avoid in Europe, you wouldn't operate any flights.

I also operate in Europe and I'd say that is a fair assessment.

Down low, if you 'never fly through the red' on the radar sometimes you'd never make it to the airport in places like SIN. You can turn down the gain and play with the tilt and try to find structure but often all you have is rain with very little turbulence.

As for up high, several of us have come down to the PPRuNe altar and testified here about those cells that just don't paint but have a tremendous kick.

Just as you get used to the icing, fog and low ceilings in Europe in the winter, convective activity is a common challenge year-round over the South China Sea.

[khorton]

I am and old critter, and the last heavy aircraft(being greater than 12500 kg)
was a DC8 73 and then 747 200 preceded by DC10-30.
Non of these aircraft had all the white mans magic of a dozen different laws etc, just the old ones, Pull stick back equals houses get smaller and push stick forward houses get bigger.
It appears to this fuddled brain, that airbus industries have put so many protection systems in place that the aircraft systems are able to out maneuver the pilots inputs.

...

My point is: maybe we should revert to cable operated controls and switches.

It is interesting to compare the accident rates of the FBW Airbus products against the B747 Classic and DC-10. If we can believe the data on AirSafe.com (http://www.airsafe.com/events/models/rate_mod.htm), the Full Loss Equivalent (http://www.airsafe.com/events/method.htm) accident rate for the FBW Airbus products is 0.10 fatal accidents per million flights (I summed the flights and FLE for A319 to A380 to get this rate). The B747 Classic rate is 1.02 (roughly 10 times higher) and the DC-10 was 0.64 (roughly 6 times higher). Of course, operational practices have changed significantly over the last 50 years, so even with the same type of aircraft, accident rates today should be much lower than accident rates several decades ago.

Comparing the A319/320/321 against the B737 NG, the rates are identical, at 0.08. Perhaps the type of flight control system is less important to accident rates than some would like to think. Given a particular scenario, you can make an argument that one design is better than another. But, over the whole range of real world scenarios, it all averages out.

[cee cee]

I am concerned by what looks like incorrect information being given to the media by non-authorised personnel - similar to the MH370 incident. The grief caused to the family members from the dissemination of such information is unthinkable.

So far, we have:
bodies recovered going from 3 to 40 then back to 3.
bodies holding hands then debunked.
body wearing a lifejacket then debunked.
airframe found under the sea with sonar, then debunked.

Those people involved in the SAR teams, and their superiors (I don't care if you are a general or a minister - SHUT UP) should just keep mum when confronted by media and refer them to the appropriate channels. And the media should not be pushing so hard and diseminating such information so quickly just to get a scoop on the other media organisations.

[smala01]

Would the automatics eventually recover from any condition resulting from a jet upset? Stall/Spin? Inverted?
For the layman trying to understand the pilot/automation interaction take a look at the XL A320 crash.

In this case partial retardation of the automatics due to Angle of Attack sensor icing caused a non-commanded pitch up to point of stall. The crew tried to push full forward on the stick but missed the indication that pitch control was now manual. They ran out of elevator and stalled into the ocean.

No suggestion this happened to Air Asia - but relevant when you ask if self recovery is possible.

Plane Crash Investigation | Mayday XL Airways Germany Flight 888T - YouTube (http://youtu.be/YUk1vvsa97M)

[glendalegoon]

airbubba

kudos to you sir for describing how wx radar should be adjusted and , for lack of a better word, played with to develop a good understanding of what is ahead of you.

long ago I realized that the worst turbulence was the boundry between different levels on the adjusted wx radar, using gain, and tilt to promote a better picture.

but it takes too long to type about, but kudos cuz I think you know of what you speak

[GunpowderPlod]

From Freespeed2 a while back:

About 10 years ago I was flying in the same region. 4 hours into a 7 hour flight. Happy at FL410/M.80 but in a thin wispy flat layer with light ocnl mod turb. Suddenly the aircraft pitched up violently, both FGCs and ADCs kicked out as did the autopilot, autothrottles and trims. All the screen speed info red X'd and the mach indicated on the Flt Director panel went instantly to M.74 as the max cruise speed for this altitude (hence the initial pitch-up). The OAT had changed within 5 seconds from -54C to -27C. This temp is outside all the aircraft performance charts. Both FMS's warned that the aircraft was exceeding its ceiling altitude. The was NO severe turbulence at any stage but the aircraft became almost uncontrollable and I was left flying on a standby manual AOA indicator and the mark 1 eyeball on the horizon until we could figure out what the hell to do next. After about 45 seconds (felt like an hour) the temps returned to normal and everything was sequentially reset. During that time all I could was keep the aircraft flying upright. Manual flying at that altitude is a delicate process.

I was fortunate to be in an aircraft with a lot of spare thrust and a large margin above the stall in normal cruise. To be honest it scared the sh*t out of me. In an aircraft with a narrower margin above the stall control could be lost very quickly with a low chance of recovery.

The subsequent investigation identified the cause as a rapidly rising column of warm air being funneled up from a developing Cb below. There were no clouds at our level and nothing on the Wx radar.

I guess my point from this experience is that;
Don't be too quick condemn Airbus for icing pitots/AOAs.
Don't be too quick to suggest that the pilots stalled the aircraft through some positive or negative action.
Don't be too quick to blame severe turbulence.

From SCMP this morning:

"Radar data being examined by investigators appears to show the doomed AirAsia plane made an "unbelievably" steep climb before it crashed - possibly pushing it beyond the Airbus A320-200's limits, according to a source.

The data was transmitted before flight QZ8501 disappeared from the screens of air traffic controllers in Jakarta on Sunday, according to the unnamed source.

"So far, the numbers taken by the radar are unbelievably high. This rate of climb is very high, too high. It appears to be beyond the performance envelope of the aircraft," he said."

[HotDog]

Having operated through the ITCZ several times I would say the exceedingly high climb rate was probably due to a sudden severe updraught, especially considering that a climb was not authorized due traffic when requested.

[glendalegoon]

gunpowerplod

I flew a certain kind of jet that needed certain temps to calculate takeoff EPR.

RAT probe was heated IN THE AIR to avoid icing.

BUT on the ground the calculated EPR was a nutty value...oops, the plane "THOUGHT" it was in the air and was heating the RAT probe.

Investigated and the OVER RIDE for the landing gear handle thought it was in the air too.

Called MX and fixed the problem


CAN YOU IMAGINE how dependent we have become on computers to do things, and THUS when a NUTTY value comes along the COMPUTER BELIEVES IT AND THEN GIVES UP>

Maybe you flew through an area of extreme temp change...OR MAYBE your computer goofed.

EITHER WAY I WISH we had a "STEAM GAUGE" backup of large enough size
to allow for vibrating eyeballs.

[lomapaseo]

"Radar data being examined by investigators appears to show the doomed AirAsia plane made an "unbelievably" steep climb before it crashed - possibly pushing it beyond the Airbus A320-200's limits, according to a source.

I'm confused

what's a steep climb in this context

rate of change of altitude?

Pitch attitude ?

Isn't the AOA a key to the discussion if one is considering operation outside published limits?

Or for the breakup theorists, wouldn't it be G loads? in gusts

I would think that with decoded radar plots the aero guys could work out possible AOA values and possible onset of stall

Of course we are stuck waiting for actual data before running with somebody's words like "steep"

[gchriste]

Pitch has nothing to do with stall, every student starting out gets taught that. In a severe up draught you could be pointing nose down, and still stalled. It is the angle of relative airflow to the wing. Just like a power on stall pulling out of a loop, low angle of attack relative to the horizon, but still a stall.

If this was indeed a very severe up draught, the plane could very well have been in an immediate stall.

[Smott999]

Anything about flights in that corridor encountering severe weather of requesting changes of course/altitude? Especially flights close behind 8501?

[Propduffer]

what's a steep climb in this context?Rate of climb.

Here's the story.
AirAsia flight may have stalled after 'unbelievably steep climb' | South China Morning Post (http://www.scmp.com/news/asia/article/1672645/airasia-plane-made-unbelievably-steep-climb-vanishing-says-investigation)

"This rate of climb is very high, too high. It appears to be beyond the performance envelope of the aircraft”

Similar information has been given out by Aviation experts from Indonesia close to the investigation. See post #469

[The Sultan]

If there is any truth in this, surely this is "the elephant in the room "
Capt

You answered your own question. Fox News plus lawyer equals no shread of truth.

[Capn Bloggs]

Hang on. An updraft may result in a momentary increase in g and therefore the stall speed, but thereafter, when established in the updraft, either the autopilot or the crew would be pushing the nose down in an attempt to maintain altitude. This will probably result in a speed increase. Certainly, the nose isn't going to pitch up by itself. If anything, as the speed reduces, the nose should drop by itself because the pitch trim is now way out. And this is an airbus; I don't fly them but in normal law, won't the system automatically reduce the AoA/lower the nose if a stall is approached?

A severe downdraft, on the other hand, will result in a big speed decrease if level flight was attempted. But these guys were climbing.

[SAMPUBLIUS]

..." "This rate of climb is very high, too high. It appears to be beyond the performance envelope of the aircraft”

Wouldn't the local change in baro pressure in a major updraft or downdraft give false readings to the transponder instrumention- thus indicating a major change in altitude even in relatively level flight- thus the computer(s) have a garbage in- garbage out issue ?

Or were the so called "radar" readings based on actual target -skin return changes? ( I'm doubtful of skin returns at that distance from radar )

Seems to me would have to wait for combination of readings/g levels from FDR ?

[glendalegoon]

sampublius

I was thinking the same thing a couple of hours ago. it would have to be a MASSIVE change in barometric pressure..4 inches?

but who knows...

I JUST REMEMBER that a great man named BUCK (weather flying) took a B17 through crappy wx during WW2 and learned alot.

and taught us more!

[slats11]

Sadly I am not sure this will be such a rare event in future. A dramatic growth In air travel - especially low cost air travel. More punishing crew schedules with busy nights and all the risks of fatigue. An ever increasing drive towards automation and efficiency. Reduced training budgets. Pilots with less hands on experience who are at increased risk of getting startled by the unexpected.

We are seeing this across society. Increased sophistication and people trained to be reliant on the "system." And increasingly less well prepared to take over when the system fails.

Not saying it will be common. But I fear common enough that tracking is justified.


Wouldn't the local change in baro pressure in a major updraft or downdraft give false readings to the transponder instrumention- thus indicating a major change in altitude even in relatively level flight

An interesting question. What altitude would you like tracked? FL as per altimeter? GPS derived altitude (when available)? Both?

Imagine if we had both and there was a sudden substantial discrepancy. Imagine how useful it would be in a case when it was going to takie time to get the recorders (deep mid pcean).

As an aside, how often is GPS coverage sufficient to permit altitude to be calculated.

[Passenger 389]

lomapaseo

Of course we are stuck waiting for actual data before running with somebody's words like "steep"

Tsk, Tsk. Always wanting "actual data" and facts before you leap to conclusions.

Had we done that on the Colgan (Buffalo) thread, we'd have missed an extensive discussion of how tailplane icing almost certainly was the culprit.

How the flight crew should have responded by pulling back on the column as hard as they could and maybe even reducing power (depending on the a/c type). Albeit one poster did caution that mis-identification of the type of stall (wing v tailplane) could be lethal.

Others chimed in: Cause of the stall? Faulty deice boots on the tail or wing(s).

There was extensive discussion of whether 'ice bridging' was a myth.

Some wanted to GET RID OF BOOTS in all planes, because heated wings/airfoils are the way to go.
OR make the airfoil so robust aerodynamically as not to need anti-ice.

There were calls to require little video cameras mounted on the tail, to spot the icing. And "I guess there should be a ice detector on the tailplane!!!!!!"

But then you put a damper on some of the speculation:

lomapaseo 14th Feb 2009, 01:20

Good video learning about tail stall due to icing:ok:
Lots of discussion following.
But how sure are we that it's indeed tailplane stall:confused:
Are there other possibilities with the information released to date?

[madvillain]

CAN YOU IMAGINE how dependent we have become on computers to do things, and THUS when a NUTTY value comes along the COMPUTER BELIEVES IT AND THEN GIVES UP>


As if the "computer giving up" isn't an implicit assumption from the design team that the pilot will know better to do at that point.

The crux of the matter is that training and improvement continues between human and machine interface so that incidents where the autopilot cuts out aren't "oh :mad:" moment for contemporary pilots.

As a long time lurker, in my observation, post AF 447, PPRUNE accident threads unfold in rather predictable patterns, usually a dichotomy of "airmanship vets" verse "software guys and magenta line pilots (and management)" with each side talking past the other.

I hope that this incident, if found to be caused by poor human machine interface, leads to increased training and awareness of what exactly is happening at the moment of criticality to throw otherwise professional, trained pilots off their game so much to lead to an upset.

[BG47]

In May according to the NYTimes the United Nations sent auditors to Jakarta, Indonesia to rate the countries aviation safety record...their conclusion Indonesia's safety recorded was “well below...global average in every category...scoring 61 in airworthness”. (note it was not specific to AirAsia but to the country of Indonesia as a whole).

http://www.nytimes.com/2015/01/01/world/asia/airasia-flight-8501-indonesia-airline-safety

Another article on the net indicates that the EU bars 62 Indonesian carriers into Europe for safety reasons. This article sites that the biggest issue/concern is proper training with rapidly aviation expansion.

My concerns with this accident is the fact that it is a “Low cost airline” and MAYBE not conclusive the push to get planes in the air vs canceling or delaying a flight as it would disrupt that particular planes day flight legs and the possible loss of revenue/increase cost in revenue that is required to move the pax if a flight is cancelled and the airline needs to sell the seats to another airline to move the pax to their destination.

All accidents are a domino effect as we know and I think the first domino in this case goes back to management wanting to keep airline cost down, then dispatch and obviously the flight crew. There is no discussion on here about dispatch and their role in moving this flight forward by 2 hours...clearly dispatch knew the weather was bad and getting worse...the question is was dispatch pressed to get the fight into the air vs canceling or delaying the flight due to weather. What kind of training and years of experience do AirAsia dispatchers have and how much pressure from management/dispatch in the very early am did the captain of this flight have/feel and/or was he to fatigue to make a proper decision to delay the flight.

As for the flight crew...at what time did they receive a revised call to leave their home for the new flight departure time was pushed 2 hours ahead (pilot fatigue). Were they a reserve crew? if so what kind of reserve structure does AirAsia have ie a/b/c reserve schedule.

As for the discussion about radar in cockpits...radars are behind the times not only in the airline industry but also in the corporate world...these aircraft/glass cockpit manufactures should have real time weather overlay like the handheld gps that the civil light aircraft owners use they are excellent at navigating around weather. It’s interesting to see even the Indonesia navy pilots searching for this plane had one on their dash as a back up.

[dragon man]

From an article online in the Sydney morning herald.


Mr Soejatman said the plane was equipped with a Mode S radar, a relatively new piece of equipment which sends more comprehensive information, in real time, from aircraft to ground.

Leaked figures show the plane climbed at a virtually unprecedented rate of 6000 to 9000 feet per minute, and "you can't do that at altitude in an Airbus 320 with pilot action".

The most that could normally be expected would be 1000 to 1500 feet on a sustained basis, with up to 3000 feet in a burst, he said.

The plane then fell at an even more incredible rate: 11,000 feet per minute with bursts of up to 24,000 feet per minute.

He said the Air France A330 Airbus that crashed in 2009 killing 228 passengers also reached dizzying ascent and descent rates, but some of the figures cited by Mr Soejatman are higher.

"We can't rule out that the data is wrong," he said, but added that they came from the aircraft itself, transmitted over the Mode S radar.

[ChickenHouse]

He who reports Mode S radar as a relatively new piece of equipment can not be taken serious.

[pattern_is_full]

@ bille1319 & dragon man

Thanks, guys! What I've been searching for through, lo, these 800+ posts.

I'll take the leaked climb rates with a grain of salt. But my suspicion is this crew simply inadvertently penetrated the updraft core of a CB and got tossed out of control. Possibly with some airframe damage (not necessarily a full "in-flight breakup") to exacerbate the LOC.

Why and how they got into that situation will have to wait for the CVR, to find out what they could see out the windows (if anything) and what they could see on the scope (if anything). Along with the other details between "A" and "Z" that we don't know yet.

[ATC Watcher]

Not only that it he does not know how a mode S transponder works as well . The altitude is derived from barometric pressure = Also subject to outside pressure variations .if the values transmitted down by the extended squitter are exsessive and short burst they are unlikely to be real . In other words it is not because you have huge burst of altitudes that you can deduct vertical rates and that the actual aircraft went there . They are just coded alt bursts and that why in ATC we filter them out .
Not saying that is what we have here but it surely looks like it to me .( unless of course the values are increasing over time and the responses sequence , I have not seen them )

[Roseland]

CAN YOU IMAGINE how dependent we have become on computers to do things, and THUS when a NUTTY value comes along the COMPUTER BELIEVES IT AND THEN GIVES UP

NUTTY, as in having a stall warning system that doesn't work when measured airspeed is below 60kts:

If the CAS measurements for the three ADR are lower than 60 kt, the angle of attack values of the three ADR are invalid and the stall warning is then inoperative.

[ramble on]

Roseland, spot on!!

You could add to your post the the ingrained trained response to the low speed scenario is to push the nose down, but now in this system once the pitot block or AOA error is cleared the combined aircaft systems decide thats its now above 60kts and presents "STALL, STALL, STALL".

A totally opposite expectation of action/result.

Analagous to someone reversing the piano keys from high to low on a concert pianist just before the big show - her/his thousands of hours of practice have just gone out the window and now mean diddley squat.

Someone is culpably negligent in such a design flaw.

[Anna Muckel]

As if the "computer giving up" isn't an implicit assumption from the design team that the pilot will know better to do at that point.
or an implicit assumption that the design team simply don't know what to do at that point.

[CaptainEmad]

Mr mach 5.5 (?) I think they mean when airborne. Weight on wheels disables it anyway.

[Roseland]

Makes perfect sense. I don't want to taxi to the active with the stall warning bleeping at me because the wind is playing with the sensors.

That's why every other aircraft company I'm aware of use squat (weight on wheels) switches.

For much of AF447's descent, the stall warning was inactive either because the pitots were iced, or because the airspeed really was that low. When the PF pushed the stick forward and the speed rose above 60kt the stall warning sounded.

[Jetset 88]

I recall, after MX370 disappeared last year, posting a plea for aircraft manufacturers to install a simple water-pressure or salt water-activated device in the upper part of the tail in ETOPS flight aircraft, which could release a simple floating locator beacon powered by a solar battery. Even allowing for currents and wind movement at least the SAR people would know where to start looking. It would now seem that this plea should not be limited to ETOPS aircraft.
Yet again this simple and relatively cheap device would have enabled the Air Asia aircraft to be located almost immediately and spare the distress of relatives awaiting news of their loved ones.
Even allowing for R&D costs it must be worth the expense. Come on all the DGCAs and CAAs of the world. Get a grip on this. Forget satellite interpretations of ACARS transmitted postions and other complicated systems, insist on something simple. The technology is there. Do something about it.
For reasons best known to the Prune moderators my previous post was removed after a few hours. Should I assume that this one will disppear too?

[Mr Optimistic]

I think the mods probably think this has been done to death. Ian W provided several factual posts along the lines that adequate technology is available but it is up to the operators to implement, a situation which it seems is about to be tightened.

[NigelOnDraft]

If the CAS measurements for the three ADR are lower than 60 kt, the angle of attack values of the three ADR are invalid and the stall warning is then inoperative.Roseland, spot on!!
....
Someone is culpably negligent in such a design flaw. At what speed, and how derived, do you suggest the STALL warning is enabled/disabled? At low speed, "how" do you proipose to measure AoA in order to drive the "STALL" warning?

I note Roseland omits the explanation for the 60K cutoff:This results from a logic stating that the airflow must be sufficient to ensure a valid measurement by the angle of attack sensors, especially to prevent spurious warnings on the ground.Do we really want the STALL warning shouting at us until mid takeoff run??

Airbus' and other modern aircraft are clever, but they cannot rewrite the laws of physics. Even my little homebuilt aeroplane has a speed based "cutoff" for AoA (Stall) warnings.


PS I do not see WoW as a "better" solution, since the LGCIUs sense that, and fail relatively frequently, and MEL permits dispatch with 1 U/S. Do we really want to disable STALL watning for simple LGCIU problems?

[Roseland]

PS I do not see WoW as a "better" solution, since the LGCIUs sense that, and fail relatively frequently, and MEL permits dispatch with 1 U/S. Do we really want to disable STALL watning for simple LGCIU problems?

We'll have to disagree. I think having stall warning disabled by low IAS (frozen pitots?) is a significant weakness.

What do others think?

[727forever]

I agree 60 Plus, they need something in place for aircraft going down in deep oceans, submarines have been using similar technology for a long time, something has to be done, because what we have in place is not working, the money they spend and still keep spending on these searches is crazy.

Someone needs to show leadership soon and get the existing technology working or bring other technologies online, this can't go on like it is. They have had so many warnings, they need to act and fix all these issues.

[Mr Optimistic]

How about enabling it if at 30k ft and in alternate law :)

[Caygill]

A few words on critical computer systems and automation from someone involved with regulated medical software, where a fatal outcome is an assumed possibility.

Systems and software are really not intelligent per se. In every system there is a perceived risk, designing complex inherently safe solutions is simply not possibly. That is why designs in general are approach with an obligatory risk assessment for every main functionality or mode.

The simplest formula to categorize risk is LIKELYHOOD x SEVERITY = CALCULATED RISK. Every single risk assessment then contains a mitigation or solution. It can be a required new feature or system, it can be training or in a perceived low risk simply acknowledge the risk, or try to lower the severity.

A long story short, icing of pitot tubes, pilot errors, system crashes, etc., etc. are (should be) all accounted for in design. No-one assumes to design an inherently safe machine, where a fatal outcome is even a remote possibility. The sad part: the only intelligence in design is learning from mistakes, testing, and yes, learning from real-life accidents.

[md80fanatic]

Perhaps if the audible portion of the stall warning could be attenuated below 60 kts that would be sufficient? There would be an added benefit of giving the PF something to differentiate between a classic stall and the rarer event of being under 60kts IAS.

[Roseland]

NigelOnDraft

You say you don’t like WoW as an inhibit for the stall warning because LGCIUs fail relatively frequently.

You will, no doubt, recall the wingstrike at Hamburg (A320, 1st May 2008). The aircraft thought it was on the ground (the LH LGCIU detected WoW) and it switched to ground mode. Even though both pilots had full right stick it wasn’t enough to stop the wingstrike because in ground mode roll control is halved.

What are the implications of a faulty LGCIU triggering ground mode in flight?

[Ranger One]

NoD and Roseland both make persuasive arguments. I do think this is an issue that wasn't given sufficient weight in the AF447 report.

Granted, the crew in that incident had :mad: up six ways from Sunday before the incident got that far; I grant you that without reservation.

I don't know which of you is right. I do know I'm still boggled at the existence of a system that, when things have gone to excrement in every conceivable way, gives you a stall warning when you push forward, and stops the stall warning when you pull back.

You can engineer as many different control laws as you like; Murphy's will trump them all eventually. I do believe the clever chaps and chapesses at AB never envisaged this one, and who can truly blame them?

[henra]

What do others think?

You noticed that no one jumped on it?

Maybe this is because things are anyway strongly amiss when an airliner troddles along at 60kts? And the point of possible/probable recovery will have been long passed at that stage.
Maybe it would be more important to work on preventing getting down to para glider speeds in the heavy iron in the first place...

[HarryMann]

md80fanatic

A good suggestion for an effective (maybe temporary) solution... !

[Roseland]

And the point of possible/probable recovery will have been long passed at that stage.

From 35,000ft there's quite a lot of time to try things. In AF447 at the time the Captain returned to the cockpit the stall warning had either already stopped sounding or stopped a few seconds after, so I don't think he suspected a stall at first:

At around 2 h 11 min 42, the Captain re-entered the cockpit. During the following seconds, all of the recorded speeds became invalid and the stall warning stopped...

[727forever]

How does the Airbus hand control stick work? I remember in the Air France AF 447 crash, one pilot had his control stick pushed forward and the other had his full back, who has control in this situation? I also understand that there were major CRM issues in that crash, because no one took control....

[John Farley]

For the interest of the non pilots here, when I was trained I was taught that should one encounter exteme turbulence in the cruise, you should ignore airspeed and altimeter readings, leave the cuise power as set and just use the controls to maintain the normal cruise aircraft attitude.

I was also taught that if one lost airspeed indication in the cruise you should do the same thing - leave the power as set and maintain attitude.

Of course I do not know what is taught these days.

[island_airphoto]

The NEXRAD display can be useful, but it NO substitute for onboard radar. If you avoid the "NEXRAD" storms, you are avoiding storms that happened 10-20 minutes ago. Sometimes the "clear" area is where the storm went :eek:


@BG47
As for the discussion about radar in cockpits...radars are behind the times not only in the airline industry but also in the corporate world...these aircraft/glass cockpit manufactures should have real time weather overlay like the handheld gps that the civil light aircraft owners use they are excellent at navigating around weather. It’s interesting to see even the Indonesia navy pilots searching for this plane had one on their dash as a back up.

[island_airphoto]

RE 60 knot stall speed:
I can't speak to an Airbus pitot system, but many of the planes I fly can be flown at high enough AOA to have the ASI read 0 knots. Sure the plane is not actually hovering, but the pitot tube is no longer aligned with the relative wind.

[JoeyBalls]

@ 727forever

If one stick is full aft and one stick is full forward the airplane will take the "total input" and give you an average, which in hat case, would be zero (or stick neutral). You can press and hold a button the joystick that will enable you to take "priority". The A/C will tell you, "priority left, or priority right". the last guy who presses the button "wins" . if you hold it for more than 30s, the other stick is completely useless for the rest of the flight.

This is why in the AF crash if the CA would have jumped in, sat down, yelled, "I have control" and pressed and held his button the outcome may have been different. In all the chaos he may not have heard the airplane screaming "dual input" and probably didnt visually see the inexperienced, clueless F/O holding the stick full aft.

It may be an Airbus but the laws of Physics trump Normal, alternate, direct law etc. The A/C is stalled? Unload the wing and get the nose down for Chr--t sake, BASIC FLYING

[intellipost]

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.

[Roseland]

How does the Airbus hand control stick work? I remember in the Air France AF 447 crash, one pilot had his control stick pushed forward and the other had his full back, who has control in this situation? I also understand that there were major CRM issues in that crash, because no one took control....

This is the best description I've seen:

http://www.pprune.org/tech-log/412932-airbus-sidestick-command.html

[Roseland]

Sorry, JoeyBalls, our posts crossed. Your explanation is very clear.

[VR-HFX]

Joey

Clearest and simplest explanation yet. The Bus allows 2 people to work against each other. Boeing does not allow this to happen. I have flown both, but never in a major upset. I know which type I would prefer to be operating in an upset at coffin corner. I know the bus has a God button but in times of max stress no one remembers it is there.

[NigelOnDraft]

We'll have to disagree. I think having stall warning disabled by low IAS (frozen pitots?) is a significant weakness.

What do others think? It took 3x ADR to "fail" (albeit for the same cause), and it then took the crew to misinterpret/mishandle the situation so badly they stalled the aircraft. NB the crew identified they had lost IAS indications, and they then climbed >7,000'/m.

They then got a (genuine) STALL warning, but maintained nose up control inputs. As a consequence the AoA exceeded 40 degrees (!), and TLs were selected to idle (!!). It was only after this we got the speeds becoming invalid and the Stall warning ceasing.

At some point nose down inputs were made, such speed and Stall became valid again - however, AoA remained >35degrees.

The (very) low IAS caused the stall warning to cease, not the frozen pitots AFAIK. I grant you, 3 simultaneous frozen pitots could have caused the issue, but I do not believe it did here.

So if, by definition, the IAS of the aircraft fell below that considered a "cutoff" for the AoA sensors to work, do you still consider that the systems should still have declared the sensed AoA values as "correct"? And I ask again, down to what IAS (CAS)?

If we now move to the consequence of the Stall Warning on/off, clearly it added some confusion to this crew. However, whether an IAS <60K is considered in the certification process I do not know? Let us presume that the Stall warning had remained - do you really think that crew would have correctly recovered from this stall? This was not what we practice in the sim - a slow declaration to a stall warning, and concentrate on a technically beautiful recovery NB never stalled. This crew had ignored the Stall Warning, and got into an AoA / Stall regime I doubt any Airbus has even been in to including with TPs. 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.).

So I am less willing than you to criticise the designers and certifiers of the system. I do not know the Fault Analysis tree, and probabilities assigned, in the design. AFAIK the design has not significantly altered since? (but might be wrong). I am not saying the system is perfect, but the events that occurred that night I do not think would have been considered credible. And the cure for that night is not in systems (re)design, but crew training - which IMO has hardly made a dent in the basic flaws. Relevance to AirAsia? No idea...

[jientho]

@Bloggs re: updraft. I think the scenario being considered is that the updraft was so severe that it stalled them immediately, and also caused enough additional pitch-up (they were already in a climb) that there was not enough time and/or authority to restabilize attitude before the next shock (exiting the updraft or other turbulence/upset). Big holes in rapid succession.

[Brookfield Abused]

Maybe someone will read this and ask him?!
When was the respective crews last sim? One needs to look at the last 3 yrs.
Route checks?
When was the last serious sim session with unreliable instruments/airspeed?
Stall recovery?
OR
What is the syllabus at Air Asia?
What quality of training and standards are used for Grading i.e. do the weak continue to fly the Line?

At least if we knew how proficient they should have been, we cold rule out some of the guessing?

[Capn Bloggs]

I hope that this incident, if found to be caused by poor human machine interface, leads to increased training and awareness of what exactly is happening at the moment of criticality to throw otherwise professional, trained pilots off their game so much to lead to an upset.
How about changing the "poor HMI" to suit the humans? The designers should be designing aeroplanes for the pilots, not the other way round.

Maybe this is because things are anyway strongly amiss when an airliner troddles along at 60kts? And the point of possible/probable recovery will have been long passed at that stage.
Nothing like full forward stick and full nose-down trim to fix this situation. Oh, I forgot, Airbus pilots hardly ever/never need to trim... So why would it be second nature when needed?

I think the scenario being considered is that the updraft was so severe that it stalled them immediately, and also caused enough additional pitch-up (they were already in a climb) that there was not enough time and/or authority to restabilize attitude before the next shock (exiting the updraft or other turbulence/upset).
Fair enough. But I don't think an updraught, in itself, will cause a pitchup; if it does, it will only be because the speed increases, although some Airbii do pitch up automatically if the speed goes super fast, I believe. If the aeroplane stalls immediately, the nose should drop pretty soon after.

[ZFT]

You may be asking the impossible. The Airbus data certainly does not support stall recovery in a simulator. (But maybe you knew that?) The only Airbus approved training is Approach to Stall and Initial Stall. Beyond that the data is sorely lacking and there is no guarantee that the simulator response is anything like what would be experienced in an aircraft.

Airbus is strong advocate of not doing stalls in the simulator. They have frequently stated this both in their literature and at conference (although recent proposed FAA requirements will thankfully force them to change).

[Mr Optimistic]

Perhaps if the stall warning was latched off following any operation of the inhibition it may prevent some confusion. In this case there is no indication it would have made any difference, however perhaps in the future it might?

[Roseland]

NigelOnDraft

I’ve seen many times the claim that the FO held the stick back when the stall warning was sounding.

Looking at Appendix 3 of the final BEA report it doesn’t seem as simple as that.
The initial input was nose up, but when the stall warn sounded briefly, FO moved the stick to nose down, and the stall warning stopped.

The only sustained input nose up was between about 2:11:40 and 2:12:30. But even before that started the THS had trimmed full up, and it was game over.

With the benefit up hindsight (and the FDR) we know what the AoA was; they didn’t. They only saw pitch.

Of course, this disaster wasn’t a single point failure; had they had yokes instead of sidesticks everyone would have seen what was happening. Yes, I believe the stall warning sounding when they gained speed added confusion. And yes, had Air France paid the extra to have AoA indicator that would have helped too. And had the THS made a “tick tick” as it motored inexorably nose up they might have addressed it…

You asked at what IAS the AOA sensors should cut off. I maintain if the speed is so low the AoA sensors aren't working then the stall warning should be!

I saw you are less willing to criticise the designers and certifiers. But I am less willing to criticise the pilots. There are, of course, times when it’s clearly pilot error. But when a crew of three all fail to understand what’s going on perhaps it’s all too complicated.

[fireflybob]

I've been pondering about the autopilot and auto thrust response to a large and sudden up gust.

The altitude hold would attempt to maintain the selected altitude by selecting a lower attitude and the auto throttle would reduce power to maintain airspeed.

Quiet often after a large gust in one direction there is a reversal of the original gust.

This might lead to a rapid reduction in airspeed with thrust already at at minimum.

Severe turbulence would require pilot intervention to set cruise attitude and power but in the event of a sudden massive gust we have all the potential ingredients for an upset of some sort.

Comments?

[NigelOnDraft]

You asked at what IAS the AOA sensors should cut off. I maintain if the speed is so low the AoA sensors aren't working then the stall warning should be!You've got me there - I must confess. I always thought the Stall Warning came from the AoA Sensors :ugh: So what sensor drives the Stall Warning?

But I am less willing to criticise the pilotsI never criticised the pilots, but put the base issue to training (or lack of). If we are going to blame the technology every time, there is little point in pilots being on board?

NoD

[tuj]

Here's what I don't fully grasp (and won't until the FDR is recovered): the Captain had time on a F16. My understanding is that the F16 sidestick does not give feedback and moves very little. And obviously the F16 is a FBW aircraft as well. I would think this captain would have had one of the best shots at recovering the aircraft, if it was indeed upset by wx as is suspected. He should have also been very familiar with stall regimes at least on the F16 and I would suspect would have at least tried a few things in the sim.

Thoughts?

[LYKA]

Airbus Weather Radar
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.

Re point 1; Each colour has a 'calibrated range' the range at which the colour is considered representative. Of course attenuation plays a large part too.

Point 3; I am afraid that's standard radar - the FCTM covers this quite well.

Hopefully this is an opportunity for the industry to self reflect and ask if current radar training is effective.

[Roseland]

NigelOnDraft

Of course stall warning does come from the AoA sensors. What I'm saying is that if the AoA sensors are below the range where they give accurate readings then the stall warning should be sounding.

Did you have an answer about the implications of a faulty LGCIU triggering a change to Ground Mode?

[Bergerie1]

John Farley,
I was taught the same - and very good advice it was too!

[lapp]

What is the point of debating AF crash here? We don't even know what has happened in this case, let alone looking for similarities!

Posting about AF here is just trolling and polluting. If you feel the need to attack plane maker A, do it elsewhere. Who is responding should just avoid the blatant, unmotivated provocation that leads to an hamster wheel that is even off topic.

Any other subject would be appropriate, for example noting that acoustic ping search has, for now, failed. No black box 'pings' detected in AirAsia search as officials identify body of flight attendant | South China Morning Post (http://www.scmp.com/news/asia/article/1672645/airasia-plane-made-unbelievably-steep-climb-vanishing-says-investigation)

[training wheels]

It has been reported that the failure to detect any pings from the black boxes may be due to the rough weather being experienced today where 2 to 4 waves have been reported. A case of too much background noise in such conditions, to be able to detect the pings. Hopefully tomorrow will be a better day.

[NigelOnDraft]

Of course stall warning does come from the AoA sensors. What I'm saying is that if the AoA sensors are below the range where they give accurate readings then the stall warning should be sounding.So now, when the pitot tubes ice up (as they did) and the CAS drops off (or any other ADR fault) you want the crew to be distracted by a constant blaring Stall warning - that no matter what you do with the aircraft (pull, push) - keeps sounding? This is a major design philosophy that when a sensor output fails or is deemed "invalid" we get a memory item QRH drill required?

As I said above, I think the 60KIAs / Stall warn on/off, is somewhat a red herring in this accident. If the circumstances and/or crew get an airliner (as this crew did) to below 60KIAS I think it is probably game over, and no amount of training or certification can cater for it? You're better off (as has happened to a degree) stopping the crew getting below 60KIAS / 40AoA in the first place :{

NoD

[gums]

Now that we have had AF447 hijack the thread, I may as well jump in where can contribute.

- The Viper stick might move 1/8 inch nowadays, but moved zero on first 40 or so ( I was in first squadron). So the family model was tuff because you could not see or feel what Joe Baggodonuts was doing up front, heh heh.

- The Viper has stall/AoA protection!! The criteria are vastly different than for the 'bus, but sameo sameo " you can't stall this plane". But wait!! Clever pilots/crews can do so, and procedure is the same for the Viper as for the 'bus.

Pull up and hold a high pitch atttude and then slow down before power can help your energy. You overshoot the AoA limiter. Unlike the 'bus, the Viper has a "deep stall" and not the "deeply stalled" condtion the AF447 crew saw. It has a pitch coefficient at 40 - 45 degrees AoA that prevents nose down and will sit there falling like a rock and happy as can be. Rudder anti-spin control law keeps nose reasonably under control. The elevators are fully deflected to get the nose down, but can't. So a manual switch takes away the limiters and you are in "direct" control of the elevators. Strangely, you still have positive pitch coefficient, so raise the nose and "rock" your way outta the stall.

Hope that helps.

[SAMPUBLIUS]

Cant help but wondering why both a feedback loop and some sort of vibrator on the sidearm controller when a discrepency re position/command is above a certain value say 5 percent. Thus even in a high noise environment, and with shtf, a tactile warning to " get your acts together " would be obvious and not dependant on visual or aural. ( above is a super simplified version- do not mean it is a minor tweak )

[JoeyBalls]

^

Well, what more is the airplane supposed to do? It is yelling "Dual input", the PFD has an arrow telling you you arent flying and lastly, we all learn from day 1, ONLY ONE PERSON can fly the airplane. "I have control" and that should be that.

[ZAGORFLY]

here some to learn regarding the weather radar,
However there is an interesting article somewhere that talk about how to master the Tilt Antenna function.
As you imagine it is important to have a "picture" of the weather in a vertical resolution and beside the fact that all the radars have a "kind" of gyro stabilization there is a simple formula to tilt your radar beam horizontally to the ground so you can judge your alternatives. the procedure if routinely preformed it takes 20 to 30 second.

http://www.nws.noaa.gov/os/aviation/front/14dec-front.pdf

[jientho]

@Bloggs --

But I don't think an updraught, in itself, will cause a pitchup;

?? A severe enough updraft will cause pitchup simply from differential vertical wind speeds between wings/nose and tail.

(But excellent points on "forgetting to remember trim" and "HMI is for the H and not the M".)

Also I am assuming at minimum an automation dropout (if not an outright counter-safety automation action) in AirAsia, until FDR data shows otherwise. (Too much similarity to other such instances.)

@fireflybob -- Remember that in this case they were in mid-climb already, presumably via automation, so I am not getting where you say "selected altitude" by itself would result in "lowered attitude"?

[Clandestino]

This is not AF447 thread

...but it is repeat of it nevertheless with folks brashly parading their collections of aeronautical ignorance way before any solid facts about the accident are known. Why does it never happen when Boeing or MD is written off, I half-a-wonder?

Of course I do not know what is taught these days.Same. For me It's been the same last 18 years. Issue might be nailed by David Learmount quıte a few moons ago:

You may lead the pilot to the best practice but you can not always make him follow it.

...which, of course, may or may not be connected with QZ8501 accident. I suppose it is too much to expect the average PPRuNer to be acquainted with AC Doyle's warning about theorizing without fact.

[fireflybob]

@fireflybob -- Remember that in this case they were in mid-climb already, presumably via automation, so I am not getting where you say "selected altitude" by itself would result in "lowered attitude"?

jientho, yes it was a hypothetical point (sorry didn't make that clear) and agree it would be different in climb

[Smott999]

Possible the tail separated during the upset and is in some location a good distance from current search?

[DGM320]

It has been reported that the failure to detect any pings from the black boxes may be due to the rough weather being experienced today where 2 to 4 waves have been reported. A case of too much background noise in such conditions, to be able to detect the pings. Hopefully tomorrow will be a better day.

I'm wondering what kind of range they would be expecting considering the shallow depth and amount of surface traffic (noise).

[Ian W]

Regarding the inadequacies of weather radar in detecting many hazardous conditions there has been a lot of promising recent research using LIDAR.
Meteorologists are very pleased with the ability to better detect convective conditions but this is cutting edge stuff so likely to be many years away from routine use in aviation.

Maybe this will replace our current weather radars in the future. OTOH having a scanning laser on the nose of every airliner may prove to be too hazardous.

There is a problem that LIDAR does not work in heavy rain as the laser signal is too attenuated while the radar signal will work in all but the heaviest rain but is not good at identifying clear air turbulence. The answer in research was that both should be set up together.

Real issue is that turbulence may be rain wrapped or be sitting just the other side of a curtain of rain waiting for you to fly into it. This is where the human interpretation of the storm structure is needed. Honest research meteorologists will admit that this is not a simple problem every storm is different. This is why the rather less than useful advice is to avoid flying close to Cb. In all areas of the tropics and sub-tropics this would stop flying a large proportion of the time. However, it does lend support to the idea of a 'business trajectory' being used rather than fixed routes based on canned plans.

[ZAGORFLY]

A great source of wisdom and knowledge is : Archie Trammell
google it ...

[Rockhound]

Roseland,
In reference to your post #857, you are incorrect when you claimed that the stall warnings on AF447 stopped shortly after the captain re-entered the cockpit.
The stall warning sounded a total of 75 times during the fall of AF447 to the ocean. By my count, it sounded 29 times after the captain's return to the flight deck. Not once was it acknowledged by any of the crew.
Rockhound

[sAx_R54]

@ Mixture

well, the safest thing would be to never take off...............................how do you think that will play out?

Also, people keep mentioning the CA was an F-16 pilot, so what? Flying an F-16 is absolutely nothing like flying an Airbus. The only commonality is they both are Yoke-less..............

Well the suggestion maybe that the F16 pilot has spent a significant proportion of his time maneuvering his aircraft to extremis of flight envelope in all conditions. A significant proportion of 20k hour commercial pilot time has been spent accumulating an hours actual flying time in every 9hr sector (e.g 30mins landing 30 mins take-off inc departure from ramp), with maybe 50% of the 'hours on type' spent in a 3 axis motion platform. So maybe just a little more than the yoke!

[tuj]

@gums - your posts are real gems, thanks for your insight. I have read them with great interest back in the AF447 days.

Back to the subject, if this Captain was the PF, do you have any idea what type of training he would have received in the Indonesian Air Force? I would think that a fighter pilot would regularly be on the edge of the flight envelopes, but perhaps this is not true with a 2nd-world Air Force? Perhaps his training was limited to bombing runs and BVR interception?

I can't shake the notion that the Captain should have been someone with a chance to recover the plane, having familiarity with FBW and sidestick controls. He certainly wouldn't have 'stirred-the-muck' like the AF447 inputs.

Perhaps one question is, is this another story of the THS going into NU and then the crew forgetting about it when the automatics cut out?

[John Farley]

lapp

You might like to consider post 859 re piloting similarities between extreme turbulence and loss of airspeed.

[Ian W]

An interesting question. What altitude would you like tracked? FL as per altimeter? GPS derived altitude (when available)? Both?

Imagine if we had both and there was a sudden substantial discrepancy. Imagine how useful it would be in a case when it was going to takie time to get the recorders (deep mid pcean).

As an aside, how often is GPS coverage sufficient to permit altitude to be calculated.

This is an interesting question.

GPS provides a 3D position, it is just that only the 2D position is used normally.
GPS is used (as one would expect) by GPS Landing Systems that provide the vertical as well as lateral guidance. These are made more accurate by ground based augmentation systems (GBAS) but the accuracy is of the order of 8 meters in all directions without GBAS but with wide area augmentation systems (WAAS).

If everyone flew on GPS altitude then the huge (and they are worryingly huge) number of errors caused by mis-set altimeters would go away.

Currently aircraft in cruise follow a pressure level based on 29.92 / 1013 which means as they fly into a low pressure area they descend and in high pressure areas they climb. Crossing some fronts will mean a descent followed by a climb. However, this is keeping them at the same pressure level so might be better for engine economy but that may be lost if the engines reduce thrust in the decent toward a front then increase thrust to climb away from the front.

Some aircraft are using GPS to provide backup speed information by continually cross referring GPS calculated ground speed to airspeed so if the airspeed indicators drop out the GPS system can provide a reasonable airspeed figure.

So expect to see satellite based altitude and speed information continue to creep into aircraft systems.

[lapp]

You might like to consider post 859 re piloting similarities between extreme turbulence and loss of airspeed.


We have zero knowledge about what happened in this case.
There is zero evidence that the two accidents are even just similar.

Keep banking your drum of hate against a plane maker, and keep making a fool of yourself.

[Springer1]

And it's not just 'Asian' crews. Some of the folks I fly with still think it is an entitlement to play video games and watch movies on their tablets while at the controls. After NW 188 overflew MSP five years ago and the feds pulled the pilots' tickets some of this stuff died down but now it's getting worse, not better in my observation.

I started to say something but it was a long trip ahead and some of these folks act like you've taken away their birthday if you mildly imply that the captain is in command. I guess it's a generational culture thing.

Since you are from TN we may have flown for the same airline. Saw a marked difference when I went to the left seat. Stuff I would never do as a F/O without asking the captain happens all too frequently. On a domestic flight, first leg the F/O (PM) pulls out a book at cruise. Next leg F/O (PF) pulls out said book prior to the transition altitude. I tell him to put it away and he ends up pouting for the rest of the trip.

[PersonFromPorlock]

"I have control" is good, but a response of "you have control" is even better. Makes sure everyone is on the same page. It's been a long time since I crewed on a heavy, but I remember that even back circa 1980 the response had pretty much fallen out of use.

[ATC Watcher]

Ian W : Ah the famous debate between GPS and baro altitude! Just like enbedded lateral off-set on FMS , those are wonderful ideas but full of hidden (good) reasons not to do it.
Heavily debated during the ICAO FANS meetings, , if my memory is correct ( long time ago !) main reason against was that WGS84 ( the GPS reference ) is a spheroidal while earth is irregular (a "potatoidal" was the name used) and therefore not suitable in some parts/areas of the world.

Another one was that , at the time , the GPS precision mode switch was still in the hands of the US military , and also in addition, many States would not accept to depend solely on it.

[DaveReidUK]

for example noting that acoustic ping search has, for now, failedSomewhat worrying that the head of the search effort is quoted by the South China Morning Post article as saying that they are hoping to detect the ELT underwater.

Hopefully just a misquote and he really means the recorder ULBs.

[Sunamer]

You can't get AoA or airspeed from INS.

surely, GPS is absolute and doesn't have to be integrated. Based on that you can even get GS, but airplane doesn't care about GS at all.

AoA vanes and pitot tubes are the only direct measurements of those crucial parameters that can be obtained.

[Ian W]

Ian W : Ah the famous debate between GPS and baro altitude! Just like enbedded lateral off-set on FMS , those are wonderful ideas but full of hidden (good) reasons not to do it.
Heavily debated during the ICAO FANS meetings, , if my memory is correct ( long time ago !) main reason against was that WGS84 ( the GPS reference ) is a spheroidal while earth is irregular (a "potatoidal" was the name used) and therefore not suitable in some parts/areas of the world.

Another one was that , at the time , the GPS precision mode switch was still in the hands of the US military , and also in addition, many States would not accept to depend solely on it.

Indeed, but as you say that was a long time ago. Things have moved on significantly since then. The ellipsoid corrections to geoid are taken care of by software corrections for example.

(For the technical: The World Geodetic System 1984 (WGS84) datum surface is defined as an oblate spheroid or ellipsoid, with major transverse radius at the equator. The coordinate origin of WGS-84 is the center of mass of the Earth. This is being replaced in some applications by the Earth Gravitational Model of 1996. The EGM96 geoid varies from the WGS-84 ellipsoid by between +85 and -105 meters. This can be corrected by software with errors reduced to centimeters
see
Evaluation of EGM96 geoid model in the U.S. (http://www.ngs.noaa.gov/PUBS_LIB/egm96.html)
The CARIB97 high resolution geoid height model for the Caribbean Sea (http://www.ngs.noaa.gov/PUBS_LIB/CARIB97_PAPER/carib97_paper.html)
Tutorial: The Geoid and Receiver Measurements | Education | UNAVCO (http://www.unavco.org/education/resources/educational-resources/tutorial/geoid-gps-receivers.html)
)

We are also now in the position that ATC surveillance is based on GPS (or rather satellite based positioning - includes GLONAS, Galileo etc.). As it is one of the little recognized aspects of the move to ADS-B and C reports for the basis of aircraft tracking that the Air Navigation Service Providers are now becoming reliant on GPS.

[formulaben]

The only sustained input nose up was between about 2:11:40 and 2:12:30. But even before that started the THS had trimmed full up, and it was game over.

You seem to dismiss this pilot input as inconsequential. Any sustained nose-up input for nearly a full minute in which auto-trim engages is reckless, no?

[Sunamer]

"Would the automatics eventually recover from any condition resulting from a jet upset? Stall/Spin? Inverted?"

Unlikely, since there are an too many permutations of logical states. In other words - the system is too complex to cover for all possible outcomes.

The only definitive proof that it could would lie in math field - prove it in math - it is 100% guarantee,

One counterexample also - Bus stall warning shutting itself below 60kt threshold, since the AoA readings rendered invalid/inacc. I doubt designers predicted/ thought about that )

[SAMPUBLIUS]

from his book FATE IS THE HUNTER paraphrased somewhat and extracted in describing crashes ..

At these times, Gann says, "... diligently acquired scientific understanding is suddenly blinded and the medieval mind returns. In describing NTSB investigations of crashes, a cause always has to be arrived at, even when the investigators privately know that the true explanation is that "...some totally unrecognizable genie has once again unbuttoned his pants and urinated on the pillars of science". :suspect:

[formationdriver]

Here's the gentleman's background. He was a graduate of a very tough engineering university (CalTech or MIT level), held managerial post at TOTAL, then indeed p2f. Not taking sides in this debate, just providing info:

"Quand la filiale de la compagnie malaisienne est venue, en 2012, en Espagne chez CAE Global Academy organiser des sélections de pilotes de ligne, l’APPAG a présenté les élèves de sa première promotion qui venaient de terminer leur cursus. Rémi Plésel a fait partie des candidats. Ils ont été six à être retenus par Air Asia Indonesia. Ils ont signé un contrat de trois ans. Le quadragénaire totalisait alors 850 heures de vol, affirme son ami. Des heures qu’il avait financé lui-même, avec son salaire, pour entretenir ses qualifications. « Il allait souvent voler aux Etats-Unis ». Il a notamment effectué son mûrissement au pilotage à l’école de pilotage de la compagnie aérienne Delta Airlines, à Sanford (Floride)."

Vol QZ 8501 : Rémi Plésel, un copilote engagé - AéroBuzz : Actualité et Information Aéronautique (http://www.aerobuzz.fr/spip.php?article5558)

[Ian W]

You can't get AoA or airspeed from INS.

surely, GPS is absolute and doesn't have to be integrated. Based on that you can even get GS, but airplane doesn't care about GS at all.

AoA vanes and pitot tubes are the only direct measurements of those crucial parameters that can be obtained.

What you say is true - as an instantaneous measurement. But if for a period of time I have ground speed and track from GPS and airspeed from a pitot tube then I can calculate the ambient windspeed and direction. If the pitot sensed airspeed drops out - I can generate and display an airspeed based on the ground speed from GPS and the previous windspeed and direction. In most cases this will be near enough to provide the pilot with sufficient useful information. Add the pilot selecting the appropriate 'pitch and power' for cruise to that and in most instances the information is sufficient to recover the aircraft. This is on the assumption that there will not be gross changes in wind speed/vector in the short period of time before the air driven sensors come back on line.

[ATC Watcher]

Ian W We are also now in the position that ATC surveillance is based on GPS (or rather satellite based positioning - includes GLONAS, Galileo etc.). As it is one of the little recognized aspects of the move to ADS-B and C reports for the basis of aircraft tracking that the Air Navigation Service Providers are now becoming reliant on GPS.

On the horizontal plane, absolutely ,( GNSS is the "politically correct" term ), but the altitude part of ADS is still derived from Mode S transponder altitude, whose encoder is barometric, and unlikely to change in our lifetime if you ask me .

[John Farley]

lapp

We have zero knowledge about what happened in this case.

I was under the impression that the aircraft was flying towards a known band of weather, had asked for a level change and shortly after this contact was lost.

In my first post and for the benefit of non pilots I was simply outlining the piloting actions I was taught (many moons ago) in the event of encountering extreme turbulence or loss of airspeed indication.

If you see that as me banging a drum of hate I can only apologise for confusing you.

[bille1319]

I can generate and display an airspeed based on the ground speed from GPS and the previous windspeed and direction. In most cases this will be near enough to provide the pilot with sufficient useful information. Add the pilot selecting the appropriate 'pitch and power' for cruise to that and in most instances the information is sufficient to recover the aircraft.

You are assuming 2 things; that SatNav gives horizontal speed and ignores vertical speed components and that SatNav is unaffected by environmental aspects such as electrical weather systems. Existing Integrated INS gyros do all this successfully in vehicles such as submarines to space craft.

[Airbubba]

Just like enbedded lateral off-set on FMS , those are wonderful ideas but full of hidden (good) reasons not to do it.

Lateral offset is SOP these days in the SLOP program, not sure why you wouldn't want to do it. :confused: A good overview here: https://ivao.aero/training/documentation/books/ATP_SEC_SLOP.pdf

Also, you almost always get lateral offsets flying in Chinese airspace, I don't see how you could avoid them. These offsets seem somewhat random and are not always to the right side. Sometimes you even get them on SID's and have to invoke some FMS magic to make them work.

[Sunamer]

"I have ground speed and track from GPS and airspeed from a pitot tube then I can calculate the ambient windspeed and direction"

Right, but it is not the same as getting airspeed from GS, since in that case you have to get GS(gps velocity), last wind readings and you have to have a really nice INS that would give precise enough acceleration measurements (not INS for 150$) so that when you feed all that stuff into some sort of soph. alg (kalman filter or smthg), you would get correct(more or less) "airspeed" reading.

In the lab that I am working in (university lab - aerospace/engineering dept) we got INSsa that cost 10 times as $150 and it's not as precise for supporting that kind of model of obtaining airspeed as it should be.

What I was arguing about is -> $150 might not be enough. :8
-------------------------------------------------------------

"If the pitot sensed airspeed drops out"
caution - conditions that determine that "drop out" might be vague. :}
It is probably easier to let this thing to be decided by a pilot.
-------------------------------------------------------------

If am not mistaken, at least B787 have that mode in which it derives airspeed from gps and (I am assuming, by using INS too). In that video the difference in airspeed and calculated "airspeed" was around 5 kts. But, again - not with a $150 solution )

[furbpilot]

1500 hours on basic airplanes with no or little automation,ideally flown as an instructor constantly practicing stalls and basic maneuvers are a background that no AFDS protection can substitute. Stop P2F and enforce such rule worldwide or more and more people will die. If I had to start an airline I would only hire pilots with FI rating and experience. The US are as usual leading..just follow and take geniuses with no real skills and no qualities other than daddy's money out of airliner cockpits .

[Sunamer]

"but the altitude part of ADS is still derived from Mode S transponder altitude, whose encoder is barometric"

Not always.
At least, ADS-B format retains both ways of reporting barometric as well as gps altitude. Different bit flags in the ads-b message need to be used in order to distinguish different readings.

At least, that is what I got from reading technical docs on the ADS-B message format.
:)

[captseth]

The FO was a P2F? And a midlife career change at that - usually the very worst candidates for a professional flying job are the career change guys. If you don't start this profession at an early age, the innate skills aren't firmly planted.

A factor? We won't know until the CVR turns up.

[island_airphoto]

Question for heavy metal pilots from a light metal pilot:
Many posts seem to be something like "a thunderstorm should not be able to take down a modern jet". Down at the lower levels we are all taught a thunderstorm may very well be beyond the ability of the airplane to stay in one piece and to avoid them if at all possible.. I have been through a couple that were rather sporty with 2,000 FPM + climbs at idle thrust and rain like flying under Niagara Falls. It would certainly be a handful for anyone not on top of their game.
Is the SOP in that area of the world to just blast through it or ????

[Ian W]

Ian W

On the horizontal plane, absolutely ,( GNSS is the "politically correct" term ), but the altitude part of ADS is still derived from Mode S transponder altitude, whose encoder is barometric, and unlikely to change in our lifetime if you ask me .

Of course.

I was just pointing out that the basic surveillance by ATC is slowly moving to dependence on GPS (GNSS's). This was the answer to the point about the precision switch being in DOD hands. This is mitigated somewhat by WAAS and LAAS which may be the reason that the precision switch is not so critical and discussed these days.

[172driver]

Here's the gentleman's background. He was a graduate of a very tough engineering university (CalTech or MIT level), held managerial post at TOTAL, then indeed p2f.

I don't think I would describe the FO as P2F. The article linked only states that he financed his licenses and the A320 TR himself through his salary as a manager at TOTAL. It doesn't say anything about a P2F situation in his employ at AirAsia.

[bugg smasher]

No. Avoid, avoid, avoid. It has become especially important with the Airbus product, most recently in regard to the LH experience involving frozen AOA vanes, loss of aircraft control, and the subsequent generation of an emergency AD to all operators.

We seem to be spending a lot of effort these days trying to outwit all of the 'gotchas' the system designers overlooked.

[Ian W]

You are assuming 2 things; that SatNav gives horizontal speed and ignores vertical speed components and that SatNav is unaffected by environmental aspects such as electrical weather systems. Existing Integrated INS gyros do all this successfully in vehicles such as submarines to space craft.

It is normal these days to integrate the INS and the GPS so that any wander in the INS is corrected and any outage of GPS can be covered by use of INS.

It is not a perfect system but it can provide a pseudo airspeed indication. Had it dropped in when the AF447 ADIRUs lost the plot and they just picked up a generated airspeed instead the FMC could have stayed in normal law with just an ECAM message of the airspeed sensor failure, then when they came back a minute later - the system could have reverted. I believe (someone may confirm) that the 787 has something like this built in.

[SaturnV]

Here's the gentleman's background. He was a graduate of a very tough engineering university (CalTech or MIT level), held managerial post at TOTAL,

He was born on the Caribbean island of St. Martin, and graduated from the Universite Pierre et Marie Curie in Paris (UPMC is part of the Sorbonne). UPMC is well-regarded in the sciences, it does offer engineering, but I believe the Sorbonne's principal engineering school is the Université de Technologie de Compiègne. Supposedly English fluent.

[AirScotia]

On Twitter, purported to be leaked radar screenshot:

https://twitter.com/TheGlobalflight/status/550743644765159424/photo/1

[threemiles]

This is interpolated radar data from a refresh rate of probably a couple of seconds.
Geo vertical rate is not available from Mode-S nor is Ground Speed or Track with a resolution of 1/100.
Nothing worth in my eyes.

[acad_l]

He was born on the Caribbean island of St. Martin, and graduated from the Universite Pierre et Marie Curie in Paris (UPMC is part of the Sorbonne). UPMC is well-regarded in the sciences, it does offer engineering, but I believe the Sorbonne's principal engineering school is the Université de Technologie de Compiègne. Supposedly English fluent.


According to the link posted, he did not graduate from either, but Ecole Nationale des Ponts et Chaussees.

As to Université de Technologie de Compiègne, I don't believe it is anywhere near the same level. Engineering at UPMC look fairly good OTOH.

[ATC Watcher]

Airbubba : we are talking 2 different things, I was reffering to the global 0.1NM EMBEDDED in the FMS to counter GPS nav accurracy. ( disccussed in ICAO on initiative IFALPA ATS committe after the Sioux Lookout collision in 1995.) long debate about it, also here on PPrune . But off topic .

Sunamer:ADS-B format retains both ways of reporting barometric as well as gps altitude
Yes but the ICAO standard chosen was Mode S/Baro, not the GPS Alt. No single a/c ADS equipped flying today uses and transmit GPS Alt.

Ian W : the precision switch is not so critical and discussed these days.
Agreed , and this will disapear completely with Gallileo coming in. However a future hypothetical switch from barometric to GPS Alt would have to be globally coordinated on a specific date ( similar to RVSM) and old airframes retrofitted, which has always been THE main problem , especially on your side of the Atlantic (since you still use Jurrassic jets overthere:E)

[Propduffer]

@AirScotia (http://www.pprune.org/members/433793-airscotia)

The location given places PK-AXC about 17 miles south of the earlier reported LRP.
It is also about 6 miles west of the location given on George Hatchers' site.

I can't imagine where these minor discrepancies are coming from - unless someone is trying to trace leaks.

[captplaystation]

furbpilot said



"1500 hours on basic airplanes with no or little automation,ideally flown as an instructor constantly practicing stalls and basic maneuvers are a background that no AFDS protection can substitute. Stop P2F and enforce such rule worldwide or more and more people will die. If I had to start an airline I would only hire pilots with FI rating and experiencdr. The US are as usual leading..just follow and take geniuses with no real skills and no qualities other than daddy's money out of airliner cockpits ."


With you there :ok: , but, the problem is the "suits"/ accountants ain't gonna let it happen, as FO's are now a revenue source too, and, well, one or two crashes every couple of years is still affordable . . . right ? :}

[ATC Watcher]

AirScotia: I agree with Threemiles, this is not a Mode S Extended Squitter data block. So this was not transmitted by the aircraft.

If this is genuinely coming from inside AirNav indonesia , then maybe a track extrapolation of the flightplan processing system. But guesswork.

[Airbubba]

Airbubba : we are talking 2 different things, I was reffering to the global 0.1NM EMBEDDED in the FMS to counter GPS nav accurracy. ( disccussed in ICAO on initiative IFALPA ATS committe after the Sioux Lookout collision in 1995.) long debate about it, also here on PPRuNe . But off topic .


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.

[Livesinafield]

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

[MaxJack]

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" (http://www.independent.co.uk/news/world/americas/after-airasia-and-mh370-flight-searches-one-airline-finds-way-to-make-its-planes-disappearanceproof-9953136.html?cmpid=facebook-post)

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

[captplaystation]

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

[Livesinafield]

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

[ATC Watcher]

Airbubba : Hmmm, this .1 nm offset must not have made it to the real world.
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....

[threemiles]

ADS-B format retains both ways of reporting barometric as well as gps altitude

Yes but the ICAO standard chosen was Mode S/Baro, not the GPS Alt. No single a/c ADS equipped flying today uses and transmit GPS Alt.

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)

[lapp]

...
If you see that as me banging a drum of hate I can only apologise for confusing you.
I'm the one that shall apologize Sir, thank you.

[FullOppositeRudder]

But even before that started the THS had trimmed full up

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.

[SKS777FLYER]

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.

[Rob Bamber]

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 (http://www.theguardian.com/world/2015/jan/01/airasia-crash-first-body-returned-family), but was overwhelmed by waves.

[gums]

@ 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.......

[joema]

Question for heavy metal pilots from a light metal pilot:
Many posts seem to be something like "a thunderstorm should not be able to take down a modern jet".

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.

[Propduffer]

The Guardian is reporting an expert as suggesting the plane landed on the sea (http://www.theguardian.com/world/2015/jan/01/airasia-crash-first-body-returned-family), but was overwhelmed by waves.It appears more likely that the plane was shedding occupants on the way down.

[mickjoebill]

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.

[GunpowderPlod]

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.

[einhverfr]

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.

[BR36]

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.

[aterpster]

joema:

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.

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.

[HarryMann]

He was sceptical, however, that the figure cited of up to 24,000 feet per minute descent was possible, saying that terminal velocity is nowhere near that speed."


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 !

[bugg smasher]

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.

[md80fanatic]

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?

[Smott999]

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

[ekw]

"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.

[Sop_Monkey]

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??

[onetrack]

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.

[StallStal1]

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.

[DCrefugee]

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.

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.

[Passenger 389]

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.)

[StallStal1]

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.

[ekw]

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?

[peekay4]

some fishermen saw an airplane descending to the water and heard it hit
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.

[Sop_Monkey]

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.

[smala01]

Keep banking your drum of hate against a plane maker, and keep making a fool of yourself.

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

[DCrefugee]

@peekay4:

Yeah, that too...

[StallStal1]

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.

[training wheels]

1500 hours on basic airplanes with no or little automation,ideally flown as an instructor constantly practicing stalls and basic maneuvers are a background that no AFDS protection can substitute. Stop P2F and enforce such rule worldwide or more and more people will die. If I had to start an airline I would only hire pilots with FI rating and experiencdr. The US are as usual leading..just follow and take geniuses with no real skills and no qualities other than daddy's money out of airliner cockpits .

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.

[training wheels]

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.

[glendalegoon]

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).

[ThreeThreeMike]

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.

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. (http://www.mirror.co.uk/news/uk-news/airasia-flight-qz8501-flight-attendants-4900788)

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.


Indonesian aviation analyst Gerry Soejatman believes the aircraft rose up as fast as a fighter jet and then dropped back into the ocean almost vertically into the water.

And the extreme weather which Airbus 320-200 encountered meant the pilots were helpless to save the passengers and crew on-board, Soejatman told Fairfax media after he examined figures leaked from the official air crash investigation team.In contrast, aviation expert Peter Marosszeky, from the University of NSW, told the Sydney Morning Herald that the extremely low speed of the aircraft’s descent - as low as 61 knots - would suggest the plane was heading almost straight down, explaining why it has been found in water just 10km from its last point of radar contact.

Mr Marosszeky surmised that a climb rate of at least 6000ft a minute would indicate a “severe weather event,” because that rate of climb was a ‘domain for jet fighters.’

He said “It’s really hard to comprehend [the plane acted in a way] bordering on the edge of logic,” as it plunged into the water “‘like a piece of metal being thrown down.”

Mr Soejatman believes the crash occurred because the aircraft was caught in a severe updraft, followed by an equally severe ground draft, with the leaked figures showing that it climbed at a staggering rate of 6000ft to 9000ft per minute.

The aircraft then fell at 11,000ft a minute, with bursts of up to 24,000ft – in marked contrast to regular circumstances, when a plane would climb between 1000ft to 1500ft on a sustained basis, gaining 3000ft in a burst.Dudi Sudibyo, a senior editor of aviation magazine Angkasa, said: "The emergency locator transmitter (ELT) 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." "The pilot managed to land it on the sea's surface."

[RatherBeFlying]

The many suggestions of using GPS and/or INS for backup airspeed come up short when it comes to correcting for wind, especially in turbulent conditions with the up and down drafts throwing off vortices.

I modestly propose force transducers on the radome mounts. The forces from the transducers could be algebraically summed to produce a net force which could then be processed against radome drag coefficient to produce airspeed.

Differentials between opposite sensors could even be used to derive AOA and yaw.

I hope those suffering boredom from trawling through the hamster wheel may have found some amusement ;)

[training wheels]

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.

And I notice that many of these so called experts aren't airline pilots themselves. I don't believe any current airline pilots would dare damage their own credibility and say anything to the media at this early stage because the fact of the matter is, we won't know what happened until the FDR and CVR has been recovered and analysed.

The media, especially in Indonesia, will continue to milk the story for a few weeks; the same as what happened previously with the Sukoi SJ 100 CFIT.

[lomapaseo]

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?

I don't know what to make of subjective words like "high rate of descent" etc. without verified data.

But if you want to restart engines you should be thinking of controlling your speed within restart limits, while at the same time extending your glide to give yourself enough time to benefit from a restart attempt. If they really are screwed up, they will be very sluggish in spooling back up at altitude and easily fool you into thinking they have flamed out (ala the China Air dive bomber on the way to SFO)

Then again the structure of the aircraft doesn't like vertical overspeeds as well. Make of it what you will but I doubt the pilots would command something of great extent

[jientho]

@HarryMann -- Do the math. Downdraft of 250+ mph?? I mean I'm the one speculating about unprecedented tropical weather phenomena, but that is beyond even my ability to conjecture.

[bapak]

Several days ago, SIN announced in was sending Sonar Locators. Nothing heard since.

[furbpilot]

Leaving a managerial position at Total to join P2F for Air Asia with that education..with all respect for the poor guy seems odd. I happen to have friends in Air Asia recruited as direct upgrade FO .... they actually paid for their upgrade as well. Time to say enough with P2F.

[HeavyMetallist]

I don't believe any current airline pilots would dare damage their own credibility and say anything to the media at this early stage because the fact of the matter is, we won't know what happened until the FDR and CVR has been recovered

That apparently doesn't apply to many posting here. Perhaps anonymity allows them to ignore your very sensible point, particularly when it comes to sticking the boot in to Airbus or its engineers, for some reason.

[Mahatma Kote]

I modestly propose force transducers on the radome mounts. The forces from the transducers could be algebraically summed to produce a net force which could then be processed against radome drag coefficient to produce airspeed.

That's not an altogether stupid idea. The only problem is changes in apparent drag due to accumulated ice or water striking the surface in rain.

Back in my micrometeorolgy days I'd considered and discarded this approach when looking at low cost wind speed and direction sensors.

But 10/10 in the lateral thinking stakes!

[Weheka]

"We found parts of the plane which could be part of the wing or the plane's interior," he said on local television channel MetroTV, displaying a white wooden structure about 1.5 by 1 metres with part of a corrugated hose attached.
Jesus wept!:rolleyes:

I see your photo Mach2point7, wooden airframe parts in an A320....seriously??

[Mach2point7]

http://www.channelnewsasia.com/blob/1563172/1420165195000/qz8501-debris-data.jpg

[chefrp]

.... they actually paid for their upgrade as well. Time to say enough with P2F.This is the topic that mass media will not discuss...not even the affable Richard Quest...

It is off limits! :=

I think you are right, there needs to be a discussion about this business practice. When lives are at stake, you need 2 equals up in the cockpit who can figure things out together. The FO needs to step in if need be.
Does P2F compromise this? That is the question...

[multycpl]

For all against P2F.
Even if this was P2F, l would have thought that after over 2000 hrs he would have leaned a lot more than just asking if the Captain wanted sugar in his tea.

[MaxJack]

First funeral held for passenger on AirAsia flight QZ8501 (http://www.news.com.au/travel/travel-updates/first-funeral-held-for-passenger-on-airasia-flight-qz8501/story-fnizu68q-1227172146899)

Hope that they did not miss to examanine "cause of death"

The news report only says that victims are being identified.

[ATC Watcher]

Mach2point7 : if this photo is a debris from the aircraft we are talking about here, then this kills the "nice smooth " water ditching theory of some journos.

[chefrp]

Even if this was P2F, l would have thought that after over 2000 hrs he would have leaned a lot more than just asking if the Captain wanted sugar in his tea.

Yes I would agree too, but not sure to what extent...

I think the real issue is the dynamics in the cockpit. Is there true respect and and positive working environment? or is it dysfunctional with the with the old air force pro wary of jumping off to the toilet for a few minutes?

[Axel-Flo]

For those of us who actually do this for a living, for those who have done so previously or even are just really interested, not to say incredibly knowledgeable, in aviation as a whole this is a Rumour Network so people can and do say, declare and claim their bit of rumour, theory or supposition.

That said of course when we who know something look at the sensationalism and wild ass claims of the media with their so called experts in, well to be frank, any thing really, are we really suprised that it is so wrong. Not only that, if you take aviation as a single subject and look wider across All news from finance to auto motive or conflict to the culinary arts say. Journos are the self licking lolly pop that sensationalises everything to grab the interest of the lowest common denominator and give them "Facts" of News that they can talk about. When we see from our part of ship the tripe they and their experts come up with is it not somewhat indicative of the made up and hyped nature of pretty much everything else within the media circle we read about, listen to and watch. Simply declaring their facts not surrounded by subterfuge, gossip, rumour and sensationalism wouldn't be half as interesting to the general public.....
This, our Rumour Network, also has Wild Ass guesses of reason and cause but we can sift it and discredit it amongst ourselves....relying on the commercial media to give us our facts, well quite frankly, maybe worth an over view but then leave it in the back ground. Eventually more real facts wil come out and we can look back, say " ah so that's why it climbed, descended, pitched, rolled and our companies will like as not throw in some delayed but enhanced training package as mitigation of what we have found out was sadly lacking before.
So rumour on and let everyone have their say............:)

[cwatters]

AirAsia flight QZ8501: Families of victims 'evicted from their hotel on New Year's Eve' - Asia - World - The Independent (http://www.independent.co.uk/news/world/asia/airasia-flight-qz8501-families-of-victims-evicted-from-hotel-on-new-years-eve-9952635.html)

Families of the passengers on board the crashed AirAsia flight were reportedly evicted from their hotel rooms without warning on New Year’s Eve, despite apparent assurances from the airline.

Earlier at a press conference the AirAsia Indonesia boss Sunu Widiatmoko had admitted that rooms were hard to find on New Year’s Eve, while the hotel reportedly said they had been fully booked and that the airline had sanctioned the move.

[BG47]

Area covering 1,575 square nautical miles will be scoured by three vessels equipped with underwater detection equipment, said Admiral Abdul Aziz Jaafar.

KUALA LUMPUR: In Day 6 of the search for the missing AirAsia flight QZ8501, the search zone has moved 30 nautical miles east from the previous day, while an area covering 1,575 square nautical miles has been established as the “Most Probable Area” where the wreckage will be found, according to the Malaysian Chief of Navy.

“This is the most likely area of the missing plane,” said Admiral Abdul Aziz Jaafar on Twitter on Friday morning (Jan 2).

Three ships – KN Baruna Jaya 1, KN Hidayat and MV Geo Survey - have been tasked to The Most Probable Area, which spans 45 by 35 nautical miles, he said. All three vessels are equipped with underwater marine detection systems, including side-scan sonar and pinger-locators, to help search for the missing plane.

Also on Friday morning, France's air accident authority, BEA, announced that it will send a specialist black box search team to assist in the search. The team is expected to arrive at the search zone on Friday.

The crash investigation agency will bring detection equipment including hydrophones to the search zone, in the hope of detecting signals from the flight recorder - commonly known as the black box - from the missing AirAsia plane, said the BEA.

[HarryMann]

"Jientho"=@HarryMann -- Do the math. Downdraft of 250+ mph?? I mean I'm the one speculating about unprecedented tropical weather phenomena, but that is beyond even my ability to conjecture.

Look...it isn't 'Math' it's primary school arithmetic !

Terminal velocity concepts apply only within the air mass you exist in...

if your T.V. is say 120 kts down and you're in a downdraught of the same it would seem to radar that you are descending faster than terminal velocity, by a factor of two (and you would be)

So quite possible to descend much faster than T.V. and climb much faster than the aircraft max. climb... and there is also no presumption the aircraft would be stalled either.. ask any glider pilot.

[BlankBox]

...and more wreckage

https://www.facebook.com/ngenghen.defenceminister/photos/pcb.754286817997913/754286654664596/?type=1&permPage=1

...picked up by Singapore Navy...

[Sop_Monkey]

cwatters

"it is our priority to look after the relatives and love ones of the passengers".

[khorton]

The big thing affecting recovery from a stall at high altitude is that there is very high drag at such low speed, and little thrust available from the engines due to the low air density. You need to descend to allow the speed to increase. In the high altitude flight testing I've done on transport category aircraft (various business and regional jets), it usually takes a descent of 2000 ft or so to build enough airspeed so the drag is low enough to allow the available thrust to be sufficient for a reasonable acceleration.

At 20,000 ft, the engines have much more thrust available, so it should be possible to recover from the stall with less than 1000 ft altitude loss, assuming a sharp pilot (but a sharp pilot should never have stalled in the first place, so we can't assume he suddenly becomes razor sharp during the stall recovery).

All the stalls I've done on large airliner types (various Airbus products, in direct law, to confirm Airbus's claimed CL Max value) have been at lower altitudes, but the same should apply to them at high altitude. The interesting thing about aerodynamic stalls in the Airbus is that from the perspective of the pilot's seat it is very difficult to identify the moment when the aircraft stalls. Light buffet starts prior to the stall, but there is no aircraft wing drop or nose down pitch to identify the moment of the stall. We relied on the flight test engineer in the back, who was monitoring the output of the flight test instrumentation, to call out "CL Max", as the point to initiate the recovery.

Note: all the above comments are with respect to an aerodynamic stall - i.e. the angle of attack has exceeded the value for maximum lift. If the pilot recovers at stall warning the drag is somewhat lower, and thus less altitude loss is required for the recovery.

[NigelOnDraft]

khorton

Thanks for your insight... I think many on this thread are missing the difference between a "Stall Warning" (which AF447 got prior any stall), and a "Stall" which you cover. Your post indicates the difficulty in recovering from a genuine stall, albeit seemingly (in AoA terms) approximately at the stall?

AF447 got way beyond this, 40 AoA, long period >35AoA, so the recovery would have been far more difficult one assumes?

Finally, your post refers to the thrust required to recover from the stall. Clearly our "QRH Drills" will differ from your Test procedures, but our drills require us to recover from the stall without the use of power (certainly none added, and reduce in case of pitch authority issues). We only add power once the Stall Indications are removed. This can only add to the difficulty / height loss / nose down attitude required to recover?

Any insight / estimate you could give as to the height / pitch / technique required to recover a modern Airbus from a 40AoA stall would be much appreciated :ok:

[Pearly White]

Quote:
He was sceptical, however, that the figure cited of up to 24,000 feet per minute descent was possible, saying that terminal velocity is nowhere near that speed."
24,000 fpm = approx 250 knots. How could that be anywhere near terminal velocity?

[MrSnuggles]

A plea to potential journalists who seek yummy stories out there.

ELT's do not always work. That's a fact. They are NOT 100% reliable, not even on land. Many fatal accidents have happened without ELT even whispering about it. On land.

In water and especially in the ocean they do not work at all (ELT is radiowaves = EMwaves) unless someone survived a ditching and managed to activate an ELT in a life raft.

Absence of ELT activity means diddly squat. You can draw zero conclusions on this. So PLEASE stop reporting about magical scenarios. Do some research. And please for once, ask some insightful follow up questions next time.

And for all of you prunes who want real time streaming of FDR data, please look up what "data congestion" means in networking terms before even attempt to bore me again, please.

(Yes, I come across as somewhat annoyed in this post. That's because I am. I like to think that I know enough to know I know nothing, but I do know when I see someone who thinks he knows everything but really hasn't got a clue.)

[etudiant]

...and more wreckage

https://www.facebook.com/ngenghen.de...e=1&permPage=1 (https://www.facebook.com/ngenghen.defenceminister/photos/pcb.754286817997913/754286654664596/?type=1&permPage=1)

...picked up by Singapore Navy...



Thanks for the link.
Pretty suggestive of forceful breakup when composite panels are sheared this way.

[chefrp]

assuming a sharp pilot (but a sharp pilot should never have stalled in the first place, so we can't assume he suddenly becomes razor sharp during the stall recovery

The most wise statement of have heard yet on this thread...

[Sop_Monkey]

chefrp

Agreed. His post was excellent.

[Toruk Macto]

Would an ex military pilot be more comfortable to fly through storms and carry less fuel than pilots from other back grounds ?

[MrSnuggles]

Pretty suggestive of forceful breakup when composite panels are sheared this way.

Suggestive yes. This is the interior wall of the cabin. If you look closely you can see the snap-ons on the lower parts of the wall. These are for easy removal during various in-depth checks of the aircraft.

The lower part of the interior wall seems pretty intact, a little crushed from the above maybe. What this tells us is not much though, unless seen in context with other parts of the adjacent structures.

[AirScotia]

Presumably it's possible for the Indonesian authorities to make a good guess as to who was flying the plane at the time, as I imagine whoever asked for FL380 wasn't the PF, and the accent should be fairly easy to identify (Indonesian vs French)?

Also - and echoing an earlier post - no information has come out about the cause of death identified in the bodies brought back to shore. Distressing as it is to the families, the condition of the bodies may be an important clue as to what happened to the plane.

[Gysbreght]

Yes, khorton's post was excellent.

However, recovery from a stall requires:

1. reduce AoA, and
2. regain airspeed

Training emphasis has recently shifted towards the first, and I miss that in his post.

[BG47]

Strait Times reports:PANGKALAN BUN/JAKARTA - An Indonesian Navy vessel detected an object suspected to be the tail of AirAsia flight QZ8501 on Friday, Metro TV reported.

"At 7.34am, we detected a piece of wreckage suspected to be a plane's tail," said KRI Bung Tomo commander, Colonel Yayan, in a phone interview with Metro TV on Friday.

The ship's sonar detected the object located 29 metres deep in the Karimata Strait.

According to the report, visual checks are needed to confirm if the object is indeed a plane's tail.

[HarryMann]

24,000 fpm = approx 250 knots. How could that be anywhere near terminal velocity?


As I've been trying to make clear... terminal velocity has little meaning when there are massive vertical up or downraughts about...

[Nemrytter]

jientho -- Do the math. Downdraft of 250+ mph?? I mean I'm the one speculating about unprecedented tropical weather phenomena, but that is beyond even my ability to conjecture.Up/downdrafts of similar speeds would be extreme but not beyond the realms of possibility. We've measured updrafts of around 195kts and were only prevented from measuring higher values by equipment limitations. Those were over the Atlantic but I suspect the region where this aircraft went down would see similar.

[Sheep Guts]

Just watching BBC. Now 30 bodies recovered. Mainly being recovered by the USNAVY ship that's in attendance for this search. Pinger searching by the Singaporean and Indonesians for the wreckage/FDR CVR, ineffective due weather.

[jientho]

@Nemrytter -- Thanks! It seems that even my imagination regarding tropical extremes, which was so far "out there" that a comment got mod-deleted (in fairness maybe because I referenced global warming :)), nonetheless was apparently "on the bubble". What would be the limit of conceivability given current knowledge, up/downdraft of 300kts? 400?

[Suastiastu]

"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"


Journos don't make stuff up. You are quoting a Walkley award winning Australian journalist of high standing. They look for people of credibility and standing and report what they say. Its been mentioned elsewhere that Professional Pilots hold back their views until the evidence is in - so who is going to be quoted in the early days of a tragedy when the public is interested to know a reason presented at a level they can understand?


Newspapers in Australia target a mass audience not an audience of professional pilots with ultimate and superior expertise and experience - although I have seen a few wacky ideas on this forum too.

[Suastiastu]

"Hope that they did not miss to examanine "cause of death"

The news report only says that victims are being identified"


In this country a cause of death will not be stated on a death certificate unless an autopsy is done. Muslims prefer their departed to be buried quickly. Hint for foreigners who don't understand: They died from a plane crash.

[AirScotia]

Circulating on Twitter that AirAsia have had their route permit for Surubaya to Singapore revoked.

Gerry Soejatman ‏@GerryS 37m37 minutes ago
Just heard Indo Air Asia route permit for Surabaya to Singapore has been frozen/revoked by Indo govt. Ouch! #QZ8501
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TunasKelapa ‏@ArvinTunas 23m23 minutes ago
@GerryS On what ground?
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Gerry Soejatman ‏@GerryS 21m21 minutes ago
@ArvinTunas they said Air Asia flew more than it was permitted to and didnt ask for changes or extra flights. #QZ8501 is turning into a mess

DIPURNAMA's Pix | TwitrPix (http://twitrpix.com/c7pmu)

[MrSnuggles]

We've measured updrafts of around 195kts and were only prevented from measuring higher values by equipment limitations. Those were over the Atlantic

It seems that even my imagination regarding tropical extremes, which was so far "out there" that a comment got mod-deleted

Actually, in Sweden, our "gust" record is 81 m/s (Tarfala, 20 december 1992) according to Väder Väderprognoser Klimat- & Vädertjänster i Sverige | SMHI (http://www.smhi.se) - this would translate to approx 158 knots.

Sweden being far, very far, from the worst action windwise, I have no doubts that wind speeds up/down/however in the tropics would far exceed this humble record.

The current non-tornadic wind speed record has been set in Australia. The new record is 408 km/h from 1996, about 220 knots. This measurement was taken in regular wind conditions, not in any up/downdraft but as you see, hard winds are not unheard of in that region.

If wind conditions are of any interest to this investigation, we have to see. I'm just giving out a few numbers for those interested in what Mother Nature may throw at you in different places on this earth.

[AirScotia]

In this country a cause of death will not be stated on a death certificate unless an autopsy is done. Muslims prefer their departed to be buried quickly. Hint for foreigners who don't understand: They died from a plane crash.

It might be useful to rule out signs of burning / explosion / bomb? If there is evidence of drowning, that would suggest the aircraft impacted the water gently enough to keep passengers unconscious but alive. The bodies may hold clues that the plane broke up at altitude, which has implications in the search for the fuselage.

These are unpleasant thoughts, but I'm surprised the bodies have been returned to relatives so promptly. Not all the passengers were Muslim.

[AirScotia]

Is it possible the pilots were not properly informed about the weather en-route?

Air Asia QZ8501, Surat BMKG Ini Picu Jonan Marah * | -nasional- | Tempo.co (http://www.tempo.co/read/news/2015/01/02/078632491/AirAsia-QZ8501-Surat-BMKG-Ini-Picu-Kesal-Johan)

Google translation:

TEMPO.CO , Jakarta -Minister of Transportation Ignatius Jonan moved quickly after finding irregularities in procedure QZ8501 departure of Air Asia , which fell in the waters Karimata . He had rebuked a director of PT Indonesia Air Asia during a surprise visit to the office of a number of airline operations at Soekarno - Hatta Airport , Cengkareng , Tangerang , Banten , January 2, 2015 .

Jonan Minister questioned the attitude of Air Asia who do not hold a direct briefing for pilots happenings aviation weather information . The pilot was only receive the information document downloads , and do not take physical weather data documents . The reason the AirAsia , bring documents that old school weather .

Jonas has previously received a letter from the Head of the Meteorology , Climatology and Geophysics ( BMKG ) Andi Eka Sakya dated December 31, 2014. This letter informed him that Air Asia QZ8501 late taking weather data . " From the log book at Juanda BMKG Station , Surabaya , it was found that the new take Air Asia weather information material at 07.00 pm after the impact of lost contact QZ8501 and not before take off . " ( Read : Evidence - AirAsia - QZ8501 - Lax - It - Make -Johan - Upset )

Letter from BMKG is addressed to the Minister of Transport Ignatius Jonan , limited follow-up meeting on 29 December, on the incidence of Air Asia . This meeting was chaired by the President of Joko Widodo and attended among others by the Minister of Transportation Ignatius Jonan ; Minister of Research , Technology , and Higher Education Muhammad Nasir ; Head of the National Search and Rescue Agency Marshal F.H.B. Soelistyo ; TNI Commander General Moeldoko ; as well as National Police Chief Gen. Sutarman .

Head of Data and Information BMKG Juanda , Bambang Setiajid , confirmed information that Air Asia QZ8501 not ask weather briefing . Though BMKG data showed growth cumulonimbus cloud remarkable since 02.00 .

[Suastiastu]

"It might be useful ..."
Maybe useful to you and a sense of curiosity shared by tabloids- but not to families who want to bury their dead, preferably in tact.
similar happened here after the bombing which killed 202 - westerners wanted to do more forensics locals wanted to clean up and bury their dead and spiritually cleanse the area.