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.

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?

Weather radar
 

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.

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.

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.

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, the Full Loss Equivalent 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.

Information given to media
 

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.

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

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

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."

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.

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.

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"

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.

Have we heard
 

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

Rate of climb.

Here's the story.
AirAsia flight may have stalled after 'unbelievably steep climb' | South China Morning Post

"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

Capt

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

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.

re# 826 and others and climb rates
 

..." "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 ?

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!

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.


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.

always wanting actual data and facts
 

lomapaseo

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:

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.

NYTimes: United Nations audited Indonesia’s safety record
 

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/wo...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.

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.

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

@ 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.

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 )

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.

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.

or an implicit assumption that the design team simply don't know what to do at that point.

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

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.

YET AGAIN - Why Not?......
 

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?

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.

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: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?

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

What do others think?

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.

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

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.