News

• Air France to adapt FAR (Flight Assistance Re-Engineering) to a.o. improve flight monitoring on the ground

BusinessTravel.fr today reported that Pierre Henri Gourgeon, General Director Air France-KLM, announced that Air France will become the second airline in Europe to adopt the FAR program originally designed by KLM and Northwest. In consequence, Air France will reorganize its procedures and processes and will have a person on the ground responsible to monitor and follow all flights.

Source:
Sécurité Aérienne: Air France va adopter le modèle FAR de KLM

Sorry, trying to upload the meteo analysis graphic from June 2009...

I don't find this 'managing attachments' box... Is it gone?

My understanding is that the searches were suspended because the underwater equipment - which is pretty specialised kit - was in demand by other users for other projects, and had been previously reserved.

When would you fly an airliner into a thunderstorm?

Thank you, tubby. :ok:

In re recent report and Tstorm avoidance.

Which one? :confused:

Graybeard posts : I don't remember exactly, but Tstorms have brought airliners down in the past, easy to google I suppose. In my heqad I most usually associate fatal aviation thunderstorm encounters by crews flying directly into them by flying into a radar shadow.
I inadvertently flew an F4 Phantom into a small thunderstorm decades ago near Iwakuni Japan. I don't believe Japan is known for powerful convective storms in the spring time, but that fairly small storm took 2 formation flying F4's (I was the wingman) and spit both of them out inverted and flying near opposite directions in maybe 10-15 seconds. It was the most violent and briefly out of controlflight I have ever experienced. The g-meter pegged at 6 g's and I think about minus 1.5 g's. Would not prefer to be in ANY airliner for that.

Rising Risks
 

I am no Pilot!
Concerning the AF 447 accident and any other airliner accident I have one deep sorrow:
If a technical malfunction or bad design raises any risk during the flight of an airliner, accident investigations will point to it.
If a pilot error leads to an accident the investigations will dedect it.
But what will happe if the risk of an accident just was raised because of some (implicit) strategic decission like: do not divert too erly! Go as straight as possible!

I think it will be very very difficult to find out, whether the choosen route was too risky or extremly risky.

I am not a frequent flyer but I am flying once a month because of my profession and I feel much more at ease in the plane than in the taxi going to the airport. And I am sure, that technically week parts and human bad habits of pilots, if such things exist, will be found out - sooner or later - . But I wonder if a bad trend in saving flight costs can be found out!

2006 was the last one I remember. It was an TU-154M, on route to St. Petersburg, and cruising at 35,000 feet. The pilot diverted from his direct flight path by 20 miles to avoid a thundercell, but inadvertantly flew into a more violent storm, and the aircraft stalled and was lost. The nose rose to about 45 degrees, and IAS dropped to zero at the point of the stall.

Pulkovo Aviation Enterprise Flight 612 - Wikipedia, the free encyclopedia

Radar attenuation was identified as a contributing cause.

Pulkovo 612 tried to intentionally exceed their service ceiling to go over weather. Stall-spin to the ground.

There is also the issue of the "contour hole", where very heavy precip in a cell can result in no radar return, giving the false impression of a hole in the storm. (I'm assuming by shadow you mean that an even worse storm is obscured by a more moderate storm in the direct path of the radar, and the crew don't realize they were in trouble until it's too late.)

Recall the Southern Airways DC-9, which was lost when flying in bad weather over Georgia, in 1977. The aircraft CVR recorded the captain as saying "Looks heavy - nothing's going through that", but only a few minutes later, they flew into the most intense part of the storm.

The only explanation the NTSB came up with was that since the aircraft was already flying through heavy precipitation, the captain misinterpreted a contour hole on their x-band radar as being an area free of precipitation, and headed for it. The captain's comment that things were "all clear left" seems to confirm that explanation. The aircraft altered course to the left at that point, right into the worst part of the storm.

Yes, that certainly was a major contributor, however, encountering the 16,000 fpm updraft in the thunderstorm is what got them in the end. They were flying too close to the edge, otherwise, they might have gotten away with it.

In any event, it was a loss in a severe thunderstorm, which is what the OP was asking for.

ST27, thanks, I was trying to look up that Southern DC9 crash and couldn't remember the year or airline. I was just east of Cancun one day in a B727 in the clouds deviating for wx, FO flying, I was flying to Honduras and left the frequency to make a PA. Two minutes later I to came back to flying duties and was surprised to see nothing on the radar and the FO was going back on course. About a minute later we had moderate to higher turbulence when he flew over the cell. He had turned the tilt control to level attitude so wasn't painting the cell any more. Now days you would think every pilot knows how to properly operate the onboard radar. Maybe I am wrong.

Eastern Airlines B727 NYC microburst. 1975
TWA 514 B727 turbulent weather (storm) 1974

Both of the crashes mentioned by MPH were approach crashes - not cruise.
Another thunderstorm-related cruise-phase (of sorts) accident was the Braniff BAC111 accident in Nebraska on August 6, 1966.
The captain had reverted to a widely used piston strategy, and chose to descend to a very low cruise alt (less than A100) in order to mitigate the effects of a severe squall line that was across his route.
A farmer was watching the lightning show, saw the jet fly overhead and into a roll cloud. He heard a loud bang, then saw the aircraft descend rapidly to the ground and explode. Turns out that the horizontal stab broke away from the aircraft due to overload.
There were a few jet crashes attributed to thunderstorm encounters in the 'early' years of their introduction - mainly in the critical take-off/landing phase. Another was a B707 that took off out of Miami and flew into a cell.
But not too many during cruise.

Thanks for all the inputs.

What radar did Pulkovo have in their TU-154?

Southern Airways DC-9 was flying the old x-band magnetron radar, and it sure could lead you into a storm, if attenuation was so great all the energy was absorbed.

The solid state radar since 1982 senses path attenuation, and has a circuit called Path Attenuation Compensation. It can show an alert for display in the direction where attenuation compensation has run out of capability. That's why the BBC/PBS program last year was completely off base. It guessed the pilots didn't see the storm behind the storm. BS.

Delta 191 into DFW 1982 was the old radar and not at cruise alt. Besides, there was no indication on the CVR that they had even looked at the radar.

Just to be picky, that was NW 705, a B-720, in 1963, in case anybody was looking for it.

Storms? Not really. Evidence is starting to point elsewhere...
 

The development of a Loss of Control scenario at night in weather with an autopilot disconnect and perplexing/conflicting instrument indications? .... how far is that from an incipient UNRECOVERABLE attitude? The answer is not very far at all. It's measurable in mere seconds, particularly if Mach Crit and/or stall speed intervene to further confuse the issue..... or if the pilot's reaction and initial control response is incorrect (as in: rolling the wrong way).

And that's where the power of surprise and the differing impressions/reactions and actions/disagreement of those seated at the controls comes into play. Once the nose drops, speed increases and the g comes on, the two junior pilots would be quite out of their element and the disorienting dynamics that ensued...totally beyond their experience..... particularly if yaw and or high AoA was to then induce some engine asymmetry to compound the problem. Attitude flying just isn't available "out the window" when in cloud at night, so it's the first priority to "go out the window" (i.e. priority one.... "fly the jet" is fatally disregarded because of the system alert distractions). INITIALLY, following autopilot disconnect, even though the pilot immediately implements manual side-stick control, the ATTITUDE CHANGE CAN BE QUITE INSIDIOUS as the pilots try to concentrate on making sense of the conflicting array of aural and visual alerts and aural alarms that they are suddenly presented with. Low perceptibility roll-rate thresholds are a major cause of loss of control at night.

We could extrapolate further here and comment upon some other imponderables (that are never covered in flight simulator sessions):

a. Cruising in Ci/CS cloud, as the airspeed probes became gradually clogged with ice crystals, overcoming the pitot-heating capability, would the system have opposed that apparent airspeed loss by auto-thrust increments - resulting in the aircraft flying faster than what was displayed? i.e. dangerously accelerating towards a coffin corner encounter with its control compromising compressibility effects?

b. Would the engines, operating at higher thrust at a high cruise altitude, become more vulnerable to compressor stalling (N over root t exceedance) during any yaw asymmetry or high AoA (i.e. whatever happened after autopilot kick-out).

c. Because the three probes were the BA variety and equally affected, there'd be no initial prospect of there being sufficient disagreement between systems to trigger any alert. So much for triple redundancy eh? However, ultimately the trending discrepancy between thrust and airspeed and trim would have triggered a tripping threshold and the autopilot would have clicked out (see d. below). That would possibly have been the FIRST indication to the pilots (otherwise concentrating upon the weather radar display) that they'd suddenly had some type of system malfunction. Just "what" wouldn't be clear and would never be sorted by them, as the situation rapidly deteriorated. At this point the ACARS would've robotically started spewing its ether data, but not in any coherent manner or useful order. There'd be no time for a distress call under this scenario....

d. At this juncture, insufficient attention to airspeed and attitude is a crucial factor in what happens next. The airspeed may have appeared "normal" (or slightly low) but may have actually been 30 or 40 knots faster. Why "slightly low" all of a sudden? At a certain point. when the pitot heat has been overwhelmed by ice crystal accumulation, the rate of clogging increases exponentially. It's the same physical process that allows large hailstones to form. As it falls, the hailstone increases its surface area which permits it to coalesce with even greater amounts of freezing water and thus exponentially increase its size and mass during descent. In other words, all of a sudden the pitot tubes become almost totally clogged and that's likely what took the FMGS parameters into imbalance or quite out of tolerance, precipitating the autopilot trip-out. What's the pilot likely to do at this point. noting the airspeed to be "low"? He increases power (engine compressor stall likelihood increases) and lowers the nose to pick up a safer speed. But if he's already close to Mach Crit, that might be all it takes to put him into that dreaded speed regime.

e. Dreaded? My only experience with it was during a descent from 43,000feet in a trainer. I thought that I'd half-roll and pull-through to get down quickly and back into some circuit practise. "Alt & Comp" flown dual had been quite boring, except for the max rate descent. However in a jet that pitched UP upon encountering compressibility (or Mach Crit), hitting that airframe pecadillo whilst inverted made for a quite eventful ride. Inverted, it kept pitching up (which was actually now DOWN into an inverted lower nose attitude) for the next 25,000 feet of height loss. Quite disconcerting when you're a bit bereft about what to do next and simultaneously encounter roll reversal. Luckily you run out of Mach eventually at the lower levels. But if the AF A330 had encountered Mach Crit, penetrating it deeply with a high power set, how would the pilots have coped with the ensuing pitch-up? (assuming that jet pitches up and not down). And what was the longitudinal pitch-trim state anyway - once the autopilot had disconnected?

f. How does the A330's system design compensate in longitudinal pitch trim in such a spurious airspeed circumstance? Whilst on autopilot, does the THS (hoz stabilizers) move and the elevators oppose and hold the (nose up or down?) resultant trim forces? Would the aircraft have been in trim when the autopilot self-disconnected? Or would it have been trimmed for a much slower speed and therefore pitched UP/down upon disconnect? I don't know, I'm just posing the question. In the unfathomable world of malfunctioning flight-control automation, nothing would surprise me. But I wouldn't be the first pilot to disconnect an autopilot and be stunned by what forces it had been holding due to an unalerted system trip (Varicam C/B).

g. So assuming the above scenario has more or less "nailed it" as far as pitot-related developments go, what may have happened next? As said (or inferred) at the outset (above) once you lose it in roll and bury the nose and start pulling g, you end up in a self-sustaining spiral that can be destructive. Clean jets accelerate so fast once the nose is below the horizon. However, given the concentration of the sea-floor debris and the damage analysis of the impact attitude, I'm persuaded that a pitch-up/stall/spin entry and high-rate descent would've been the AF447 follow-through to its high level LOC. As the nose pitched up, if one engine had stalled or flamed out (and especially if the other thrust lever was not immediately idled) a spin entry would've been de rigeur (as the French say). Recoverable? Not really. Think of the vertical spin axis and the resulting centrifugal forces in the cockpit. Even if they hadn't been totally disoriented, there'd have been precious little by way of experience or instrumentation upon which to determine, select and hold the control inputs required for possible recovery. Large B/A ratios in a multi-engine high aspect ratio spin require spin recovery control positions to be set and held for quite a period in order for the yaw/pitch/roll coupling to be effectively countered. We're talking in excess of a minute here. They'd not have been "a propos" that specialist technique.

The lesson for manufacturers and operators [and pilots in particular] is that once a system defect becomes apparent across a certain model (A340/A330 in this case), investigate and extrapolate it into worst-case scenarios and then take the pessimist's course of action. Take the ample precedents as a fortuitous "heads up" threat to safety and just fix it; don't sit on your hands and budget for future modification action or interim alert crews with underwhelming safety bulletins. The Silent Voices from the Tombs always mouth the same words: "Lip-service".

Would I blame the pilots or the weather? Not really, they were set up - as were all A340/A330 crews and pax. AF447 was just the unfortunate first crew to thread the needle.

Very thought-provoking, Shadow. Thanks. :D

Excellent analysis Shadow. Well done!

Theshadow

It's a lot of words but if I read you correctly your thesis boils down to:
(1) Plane runs into problems gradually.
(2) Autopilot deals with problems gradually
(3) gradual problems accumulate until autopilot is overburdened and disconnects.

SURPRISE!

(4) befuddled pilots who didn't even know anything was wrong get disorientated, or confused, or lose spatial awareness, etc.
(5) Plane crashes.

With respect, that's not exactly a new thesis or a new problem. I don't know if it's true in this case; it wouldn't surprise me given the facts we know.

Out of the Interim Report n°2 Page 68 (english Version):
... At the time of the accident, F-GZCP was equipped with C16195AA probes.

(highlighted by me)

#314 by B-757 Re: Air Trans DC-9
 

B-757 Thanks for the video of the Air Trans DC-9 thunderstorm incident. I agree, it might be relevant to to the Air France accident. I had to shake my head tho as I watched the video.

I was about 20 miles behind that aircraft flying the same route to ORD. The thunderstorms were very intense but scattered (about 10-15 miles apart). I commented at the time it looked like coins had been placed on our radar display. Almost perfectly round, and very sharply contoured returns.

We asked for a westerly diversion and Atlanta Center said they were unable due to traffic. After our third request and denial, we just told him we were doing it anyway. 'Approved'. Air Tran continued thru the thunderstorm area with the unfortunate results on your video.

It mentions there would be an investigation as to why he continued that direction. Do you know the outcome?
Thanks.

No, it's not new, agree. But it has not been tackeled, at least not effectively, only by lengthy and a$$ covering bulletins.

I have for a long time criticized the described chain of events. Once the autopilot can no longer cope with a situation, it simply throws the aircraft back at the pilot. Good thing for the company and manufacturor, because they can always detect pilot error as a cause for the accident.

This happens on B's and A's. What bothers me is that on the A's, even when throwing the problem at the pilot, the automatics still interfere with commands, through protections or limitations etc.
With the B's at least you can very rapidly oversteer with some force. That's what many have asked for an eternity now to be implemented in A's: A rapid automatics disconnect button.

To what extent this might have helped in the AF accident is doubtful. The main problem is that a manual recovery is poorly designed and even more poorly trained. The sims are simply not programmable for such manoevers.

I have witnesses sim sessions with windshears, upsets and RAs that uncover a frightening lack of flying skills in many pilots. Just take away the flight director and autopilot on a simple take-off, give an early level-off combined with a turn and observe .....

Having worked in three companies that all propagated manual flying skill sessions, the outcome was almost consistently very poor, but ..... They all reacted by simply abolishing these sessions.

Why?

221340, sorry I don't know anything about the investigation concerning the Airtran-flight..Haven't looked at the NTSB-site either...Anybody ???

AirTran DC-9
 

There is a summary of the incident on the AOPA site that you might find informative:

AOPA Online: Too Close for Comfort

Not mentioned in the summary was that while the captain, Benton West, was set back to FO after the incident, he retired as a captain when he turned 60, about 4 years later. Shortly after retirement, he died in a traffic accident.

Relative to pitot tube icing and potential results, see Post #918, Pg.46, Post#1083 & 1084, Pg.55 both in the Tech Log, AF447 discussions.

Also refer to: EASA AD No.: 2010-0271 (22 December 2010) for modification of responses to erroneous air speeds.

As I interpret this AD, when at high altitude cruise in normal law, AP & AT on, the pitot tubes begin to ice leading to disagreement and the controls come out of normal law into Alt law causing the FD to disappear while disconnecting the AP & AT. But then, the icing becomes equalized in at least two pitots, indicating the return of FD and the ability to revert to AP & AT once again. If the AP & AD are immediately re-engaged, the air speed may be falsely high and a pitch up and N1 reduction may be called for by the AP & AT leaving the aircraft in an immediate and potentially stall condition, while leaving the flight crew in a situation where a stall warning and speed warning are received at the same time, confusion?

It is unclear how the AD came about, AF447 or prior upset events that were analyzed.

How do you say, "pitch plus power equals performance" in French?

Unless there was a change in altitude wouldn't the blocked pitot tubes result in a fixed airspeed, not a gradual loss of airspeed? Once the pitot is blocked it is essentially holding air at a fixed pressure on that side of the system, leaving only the static source to create a change in the differential pressures used to determine airspeed.

Otherwise, great analysis of one possible scenario.

"...a. Cruising in Ci/CS cloud, as the airspeed probes became gradually clogged with ice crystals, overcoming the pitot-heating capability, would the system have opposed that apparent airspeed loss by auto-thrust increments - resulting in the aircraft flying faster than what was displayed? i.e. dangerously accelerating towards a coffin corner encounter with its control compromising compressibility effects?..."

He speaks of a trend of lower ias. (unidentified trend = danger). Gradual icing reporting lower (erroneous) speed, with autoflight increases (inappropriate) in Thrust. Once blocked, pitots can still report now a consistent airspeed. Yes?

A gradual accumulation of ice in each pitot is perhaps not uniform, so now discrepant and low airspeeds befuddle the AD's. Added thrust, too fast, the autopilot drops out, and..... back to the shadow.

bear, the picture The Shadow paints is an approach to, or arrival at, the coffin corner, or at least one of the legs of the angle with CC at its peak, with the crew utterly unaware of their flight condition changing.

Question for 330 drivers: how noticeable is the change in engine noise/pitch when you move the throttles forward at altitude. Is it as noticeable in the cockpit as it is in the cabin?

I ask due to thinking through the scenario that The Shadow presented. If a change in airspeed input to the system was insidiously slow, so also would be the increases in throttle, would it not?

I have a picture in my mind of a frog being ever so slowly boiled ... :eek:

"...bear, the picture The Shadow paints is an approach to, or arrival at, the coffin corner, or at least one of the legs of the angle with CC at its peak, with the crew utterly unaware of their flight condition changing...."

something like: "... (unidentified trend = danger)."

I think there has been a lot of "either, or" here on thread, and myself included.

Coffin corner is not impossible, but unnecessary to explain what happened. The key is that we think the a/c lost control due to surprise, among other things. Something happened to down this a/c. "A perfectly good a/c".....

This accident could have occurred well shy of CC extremes, and I think probably did. It looks like next week there will be more information. I have put myself in the moccasins of the several principal players, and attempted to understand any possible bias. Although I think much is left to improve, it is understandable why each has a "dog in the hunt". I would be happy, no thrilled, to have been wrong in every way that may end up damaging the position of anyone, especially the families. Safety is what is left, and the Truth of the matter.

AKAAB...

"How do you say, "pitch plus power equals performance" in French?"

Pitch would translate into "assiette".

Power could translate into "puissance ou poussée".

I don't know if there is a direct translation or an equal French expression but here it goes...

Assiette plus puissance égale performance.

Those who don't understand what "Pitch" and "power" means shouldn't fly a commercial plane.

OK, bear, leave the coffins for the undertakers, and replace with the prospect of airspeed being (ubeknownst to crew) slowly edging up much higher than desired for flight in turbulent conditions ... the water in that pan is still plenty hot for the frog.

There's more, pard. Carrying the extra speed, what happens when the autoflight groks an actual velocity that is, well, excessive? BUT, if a/p is back in, the ias is low, so the nose drops, adding even more speed. Raise the nose and lose some power?? Wait, what if autoflight is gone for now, and the pilots suss extra speed? Raise the nose? And Stall? if power is left unaddressed, how quickly does even more speed build after the nose drops?? What if g prot and AOA prevent nose up?? Lower thrust and the nose drops, more speed? We don't know how long the a/p was reselected for, only that it dropped, again. If a/p is playing cutesy, and the pilots are unaware of low or high speed, they are not ahead of the a/c, even the a/c is not up with the a/c. The a/p (associated automatic) warning was INTERMITTENT. In/Out, In/Out ?

Mmm! Auto pilot drops out. On an Airbus that only means that the guidance has dropped out. Autopilot is still in, bit like CWS on a Boe. You only get to No Autopilot in direct law. See my previous. Also the way the 330 flight control computers are configured is a little different to the smaller fbw.. Better IMHO
Again let's give the relatively experienced pilots on that day have the benefit of any doubt until the report is out.. Maybe then would be the time to analyse why things went so badly wrong.

Gretchenfarge

A few of us had a discussion along similar lines in the Safety Forum about a year ago. However, those threads seemed to have disappeared into cyberspace due to inactivity.

The whole purpose of the FD, autopilot, etc is to releave the burden on the pilot by allowing the computer to do those tasks. You take the software away and the industry will quickly find itself back in the days of a four crew flight deck.

On the other hand, byzantine failures can never be entirely eliminated. Sooner or later a flight crew is going to be surprised. As you note, manual flying may or may not be of any help because by the time it gets kicked back to the pilot it may already be too late.

My own opinion is that what the industry needs is not a new set of facts but a new perspective. Sometimes, in rare instances, no one is to blame. Everybody did their jobs as well as could be expected and it really was just an accident. The insurance industry likes to call these "acts of God".

In other words, I don't think there is an effective way to address the problem. It just doesn't exist. Recognizing that might be cold comfort to the pilots and passengers whose bad luck it was to be on such an ill-fated flight, but at least it would cut down of the A$$ covering and lengthy bulletins.

MountainBear

To a certain extent I agree. There is no way we can cover all situations, with software or 4 in the cockpit.
This should however not lead to (cheap) complacency, to cover the engineers or the companies not having to spend what is their most cherished good: money. This for improvement.

Now I do not ask for impossible improvement, you know, the kind of asymptotic research that brings infinitively small increase of safety. All I ask for is to implement in some models what others have done more intelligently or effectively.

It is not to pretend what might have saved AF447, but the discussion about Airbus autopilot-off authority is quite old. Just as the debate about the 777 speed brake function. Both designs are definitely weaker than the one of the competition. But no manufacturer wants to change anything. First due to cost, then due to eventual law suits. Safety comes third .......

The same applies to training. We all KNOW that it has become very theoretical, in sims and online. Hands on costs and is therefore reduced. Everybody would like more, but the beancounters stand in between and they are omnipotent today. Cost and time are again more importatn than safety.

More training and a better system design MIGHT have saved AF447 or not. That will be the question remaining unanswered, but it will constantly hang over the heads of those who might have helped to prevent it and didn't due to reasons mentioned above.

I for myself will not stop pointing at possible improvements, even if some lobbyists or freaks don't like it.

I can't agree with any of that, Mountainbear.

Not good enough. This is not NASA testflying; this is mass transportation. It's supposed to be safe enough not to worry too much about things that go wrong that kill everybody because the pilots can't control the aeroplane. While some would argue that double-engine failures are a possibility, they have designed-in failure rates (well above the on-wing time, of course).

You cannot say the same about, for example, QF 72, where a defect caused the aeroplane to be uncontrollable. Why did that defect have that effect? Because somebody didn't build in a error checking circuit. That is not an accident. That's a stuffup and all efforts should be made to fix it, including pumping out bulletins.

You're basically making excuses for technology that has got ahead of itself.

If that requires lots of bulletins, then so be it until they fix it. To suggest that we just accept the crash "recognizing that might be cold comfort to the pilots and passengers whose bad luck it was to be on such an ill-fated flight, but at least it would cut down of the A$$ covering and lengthy bulletins", is, quite frankly, pretty poor.

Jet Jockey A4,

I would say in relation to aircraft it's pretty unambiguously "poussée" for engine power / thrust.

A quick look in TLF (Trésor de la Langue Française) and Dictionnaire de l'Académie française will show a reference to an aéronautique/astronautique definition when looking in pousée that is not present under puissance.

Also, a good French <-> English reference for specialist terms can be found at FranceTerme here. Enter the French or English search term in the box, select the appropriate field (e.g. Aéronautique / Aérodynamique) and hit rechercher.