Air France A330 - Missing over Atantic

Zaitcev: From many discussions with Boeing drivers, I'm not sure your assertion that "this is not limited to Airbus" is 100% true.
(. . .)
Tech fails enough on its own, why build in odd-ball "failures" like that one Karlene points out? (Yeah, in my opinion if you hit TOGA and the aircraft does completely different things depending on the type of approach, that's broken).
I think I see the point, but I am inclined to think that if a designer attempts to build an airliner that flies in a more natural way, he's going to end with an airplane that places worse task load on its pilots routinely. Perhaps Boeing can find the golden middle. I'm just thinking what flying Tu-154 takes and then recall the crash near Khabarovsk a few years ago. There, nobody went to the toilet. Instead, the autopilot suddenly disconnected because the draw from wing tanks was too asymmetric, and the airplane spun in -- from cruise altitude. There you go: simple boosted controls with feedback and yet... Perhaps Airbus merely traded these types of crashes for the one in question.
 
Airbus Industries ?????

Ain't that the same con artists who built a plane that the verticle stab/rudder broke off of while being flown below VA ???

Ben.

And what common misconception do we have about maneuvering at or below VA??

http://www.flyingmag.com/myth-maneuvering-speed
 
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I read the WSJ article. What struck me was this:

excerpts:

... despite the fact that primary cockpit displays functioned normally, the crew failed to follow standard procedures to maintain or increase thrust and keep the aircraft's nose level, while trouble-shooting ...

The crew methodically tried to respond to the warnings, according to people familiar with the probe, but apparently had difficulty sorting out the warning messages, chimes and other cues while also keeping close track of essential displays showing engine power and aircraft trajectory.


So it seems that the software is designed so that when the plane gets iced up it throws so many cockpit distractions at pilots that they quit flying the plane.
 
What the report said,



This is a bit different than the airframe icing that most of us are more commonly familiar with. Still very early in the investigation, but this was my theory all along as I wrote up in my blog (snipit below) after the accident.

So what was is the proper procedure when your instruments ice up? I mean if the airframe wasn't iced up and was perfectly capable of flying, how could it possibly crash? Someone forgot to fly the plane.
 
So what was is the proper procedure when your instruments ice up? I mean if the airframe wasn't iced up and was perfectly capable of flying, how could it possibly crash? Someone forgot to fly the plane.

If you're in IMC and ALL your instruments are lying to you (or so confused you can't figure out which ones to trust), what's gonna happen?

What happens to you in a single if you have an electrical failure (killing your TC) and then your attitude gyro dies/lies due to a failed bearing? Or your AI is ok but then you have a static system problem and your airspeed and altimeter both start misbehaving? What happens is that you die, most likely.

I saw somewhere a reconstruction of the crash I mentioned earlier, where the crew thought they were thousands of feet in the air but were in reality dozens over the ocean. Trying to figure out what the true situation was was practically impossible. I believe the last words of one of the crew was "I see waves!" followed by the sound of impact.

So far I haven't seen anything in the reports that leads me to blame the airplane or the crew. Unlike many accident reports where I say "that would never happen to me", this one is more "damn I'm glad I wasn't flying that trip".
 
"So far I haven't seen anything in the reports that leads me to blame the airplane or the crew. Unlike many accident reports where I say "that would never happen to me", this one is more "damn I'm glad I wasn't flying that trip". "

Have you watched the NOVA video yet. If true then it was both plane and crew.
 
I don't know since I'm unfamiliar with the procedures on this particular aircraft. I assume there is some procedure(s) to follow, but diagnosing what the problem might have been quickly enough to know what procedure to follow likely was part of the problem in this case...

Airbus and every airline I've flown the Airbus at has an "Airspeed/Mach Unreliable" or similar checklist that is immediately available on cockpit checklist cards and/or a quick reaction checklist and/or has memory recall items. That should have been the first checklist they ran after making sure somebody was actually flying the aircraft (assuming the speculations are true.)

If the rumors and speculations from anonymous sources are correct about icing affecting the pitot/static instruments, I still don't see how this would affect attitude, heading, ground speed, or vertical speed which are all taken from the IRUs and displayed on both of the pilots Primary Flight Displays (PFDs) or Nav Displays (NDs). The airplane is still perfectly flyable but there would be a lot of distractions just like the B757 mentioned earlier that had the static ports taped shut for washing.
 
"So far I haven't seen anything in the reports that leads me to blame the airplane or the crew. Unlike many accident reports where I say "that would never happen to me", this one is more "damn I'm glad I wasn't flying that trip". "

Have you watched the NOVA video yet. If true then it was both plane and crew.

Mind you the NOVA video was made before the discovery of the CVR and FDR.
 
I'm not sure if you're referring to an Airbus or a Boeing... Boeing lost a few 737s due to tail issues as well....

That said, I don't approve of repairing FRP type structures. Once damaged they should be disposed of.

To be clear wrt to the 737 "tail issues" : the issue wasn't structural, per se, in the way the purported A300 series Va tail issues were. The issue was with a failure condition of the nested rudder servos -- the 737 introduced a new servo design that nested the secondary in the primary casing, and used and interference fit design versus a ring-sealed design -- and a particular flight regime.

When the failure condition would appear, the servo would command opposite deflection of the input (meaning left rudder inputs yield right rudder deflection), and do so in a manner that was difficult to diagnose in the cockpit. In Aliquippa and Colorado Springs, the aircraft were in a flight regime known as "crossover speed" (approx 160 KIAS IIRC), whereby the rudder maintained superior authority, while the aileron and elevator authority was degraded. Therefore, if the rudder blew over, unless you applied counter-intuitive inputs with the rudder, and you were at crossover speed, the plane would roll inverted in a nose-down attitude.

Boeing, like Airbus, does not lack in bad design decisions that have unfortunately cost lives. Both firms have resorted to nationalist hand-wringing to minimize culpability. The cultural differences in the way the firms design cockpit systems are ones that many American's find disagreeable. Some Asian and European regulators were hewing that Boeing should adopt more "Airbus-like" practices after the Chinese crash where the pilots asked themselves what "Pull-up" meant (EGPWS was barking in English, not Chinese)

Cheers,

-Andrew
 
Andrew, the Boeing rudder hardover theory, especially as applied to the COS incident, is very much unproven. The crossover speed issue is very much an issue, as you have pilots who are being trained to a particular performance capability (including simulator programming consistent with that capability), which (as it turns out) does not match what the aircraft can do.
 
Zaitcev: From many discussions with Boeing drivers, I'm not sure your assertion that "this is not limited to Airbus" is 100% true.

Yes there are complex systems that require some babysitting on the Boeings too, but...

I bet you'd be hard pressed to find a Boeing that would do one thing when TOGA was pressed on a "regular" approach, and do something completely counter-intuitive like drive along at high-power and "forget" to navigate when flying an RNP approach.

When the pilot is there to "serve" the needs of the technology, and not the other way around... That's a back-ass-ward design philosophy.

Tech fails enough on its own, why build in odd-ball "failures" like that one Karlene points out? (Yeah, in my opinion if you hit TOGA and the aircraft does completely different things depending on the type of approach, that's broken).

She didn't press TOGA (no such button on an Airbus). She pushed the throttles all the way forward to the TOGA detent. In a clean configuration as she stated (flap lever in 0), and the absence of other indications like windshear or GPWS all you get is TOGA thrust. PERIOD. Boeings will do the exact same thing!!

I find it a little disconcerting that she was surprised that the airplane did exactly what she told it to do and that is to accelerate.
 
Well, not so fast. There has to be an appropriately rated pilot at the controls at all times. For the long haul guys that have two Captains and two First officers, that isn't a problem. But for companies like United who use one Captain and two or three First Officers, that becomes an issue. To be appropriately rated, the First Officers need a PIC type rating.

I think the jury is still out, but I am pretty sure an SIC type rating will not suffice.

Greg, you are right. The US airlines started issuing SIC type ratings to the domestic fleets in order to comply with ICAO requirements so they could fly out of the country to places like Central and South America on short flights requiring only two pilots.

BTW, I got my B757/767 PIC type rating in the right seat.
 
"So far I haven't seen anything in the reports that leads me to blame the airplane or the crew. Unlike many accident reports where I say "that would never happen to me", this one is more "damn I'm glad I wasn't flying that trip". "

Have you watched the NOVA video yet. If true then it was both plane and crew.
I woudn't believe anything NOVA puts out. They just got the FDR data this month, and it's WAY too early to start building up a dramatization of the "last moments".
 
Airbus and every airline I've flown the Airbus at has an "Airspeed/Mach Unreliable" or similar checklist that is immediately available on cockpit checklist cards and/or a quick reaction checklist and/or has memory recall items. That should have been the first checklist they ran after making sure somebody was actually flying the aircraft (assuming the speculations are true.)

If the rumors and speculations from anonymous sources are correct about icing affecting the pitot/static instruments, I still don't see how this would affect attitude, heading, ground speed, or vertical speed which are all taken from the IRUs and displayed on both of the pilots Primary Flight Displays (PFDs) or Nav Displays (NDs). The airplane is still perfectly flyable but there would be a lot of distractions just like the B757 mentioned earlier that had the static ports taped shut for washing.
VS is driven by IRUs instead of the static systems? Interesting, I didn't know that.

I'm not saying that having ONLY an unreliable airspeed is difficult to deal with. But I'm not sure what other errors they may have been seeing. It certainly sounds like they had multiple cascading failures, and the path for properly dealing with them in the correct sequence may not have been apparent.
 
I always smirked at all the Airbus bashing by old kudgels who distrust ball pens, home thermostats, automatic transmissions, and FBW controls in airplanes. However, here's a funny blog post by an A330 pilot that raises some questions (I only need 2 lines, but quoting a length to preserve the context):
What this tells me is that airliner type rating includes a few things that spam can drivers may fail to appreciate, but more importantly, that thing just flies in a different, counter-intuitive way. This is not specific to Airbus, but I am confident that carpers will take the opposite lesson from it.

(from http://karlenepetitt.blogspot.com/2011/03/go-around-but-what-if-youre-clean.html)

I also beleive that these type of statements do more to confuse people and perpetuate myth than truley explain things. So here are some Airbus basics.

There is no TOGA button on the Airbus. Just the forward detent for the thrust levers labeled TOGA. When you push the levers to TOGA, you get the maximum available thrust no matter what mode you are in. Surprise, Surprise!!

In order to get into the Go Around mode, you have to meet three specific criteria. 1: At least one Autopilot or Flight director must be on (other wise it behaves like any other stupid airplane). 2: The Flap Lever has to be out of the 0 detent( we must be getting ready to land). 3: At least one of theThrust Levers must be placed in the TOGA detent (gimme all the thrust you got).

When you get all three criteria met, the same things happens no matter what type of approach you are flying. 1: The airplane takes a snapshot of the track and gives inputs (Autopilot of Flight Director) to maintain that track GA TRK. 2: It gives input to pitch to the appropriate airspeed and at least a minimum climb rate. 3: It maintains this state until you give it another mode and/or you reach the missed approach altitude selected on the Flight Control Unit (FCU) on the glareshield (the MCP for the Boeing types). This altitude was already set according SOP. Pretty straight forward.

The normal practice was to select NAV once the aircraft was flying away from the ground and everything was under control. This allowed you to fly the programmed/published missed approach if you want to. Selecting NAV is an extremely complicated procedure so here it is. 1: Push the Heading/Track Selector on the FCU. 2: Check on your PFD that NAV is armed(white) and then engages (green) NAV.............
The author was complaining because somebody decided to move this step from 5 or 6 to step 2 in order to make sure that they stayed within RNP criteria. This isn't optimum IMO either but every airline does things a little differently.
 
VS is driven by IRUs instead of the static systems? Interesting, I didn't know that.

I'm not saying that having ONLY an unreliable airspeed is difficult to deal with. But I'm not sure what other errors they may have been seeing. It certainly sounds like they had multiple cascading failures, and the path for properly dealing with them in the correct sequence may not have been apparent.

TIM,

VS on the A319/320 is actually driven from the IRU and it's great because it is instintaneous. I assume it's the same on the 330.

I agree that sorting through multiple failures would be very distracting. But having one pilot fly the plane while the other works through them is pretty standard. Like you said, not enough information yet to draw real conclusions.
 
I woudn't believe anything NOVA puts out. They just got the FDR data this month, and it's WAY too early to start building up a dramatization of the "last moments".

Way too early!? That assertion with respect to the NOVA episode is "not even wrong." The show they did was nearly two years after the accident and no one by that time expected the FDR or CVR to ever be recovered. Are you saying there should be, say, no less than 5 years before anyone can say "well I guess we now have all the facts and it is OK now to start analyzing the data we do have?"

How long (without insisting on prescience) do you think NOVA should have waited before producing the show?

I'm also curious what "dramatization" you objected to in the show it appears you haven't seen? Which specific aspects do you object to, and why?

(Big hint: as these things go, and given what they had to work with, I thought the show was well done. Great introduction to accident analysis for its target audience, the lay public.)
 
Andrew, the Boeing rudder hardover theory, especially as applied to the COS incident, is very much unproven. The crossover speed issue is very much an issue, as you have pilots who are being trained to a particular performance capability (including simulator programming consistent with that capability), which (as it turns out) does not match what the aircraft can do.

With all due respect, and I mean that in the sincerest of terms, I disagree. All taken from http://www.ntsb.gov/publictn/1999/AAR9901.pdf, the final report of the NTSB.

Probable cause

The National Transportation Safety Board determines that the probable cause of the USAir flight 427 accident was a loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder PCU servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.

Enumerated findings, emphasis mine:

The USAir flight 427 flight crew was properly certificated and qualified, and had received the training and off-duty time prescribed by Federal regulations. No evidence indicated any preexisting medical or behavioral conditions that might have adversely affected the flight crew’s performance during the accident flight.

The USAir flight 427 accident airplane was equipped, maintained, and operated in accordance with applicable Federal regulations. The airplane was dispatched in accordance with FAA- and industry-approved practices.

All of USAir flight 427’s doors were closed and locked at impact.

USAir flight 427 did not experience an in-flight fire, bomb, explosion, or structural failure.

Neither a midair collision with other air traffic, a bird strike, clear air turbulence, nor other atmospheric phenomena were involved in the USAir flight 427 accident.

Asymmetrical engine thrust reverser deployment, asymmetrical spoiler/aileron activation, transient electronic signals causing uncommanded flight control movements, yaw damper malfunctions, and a rudder cable pull or break were not factors in the USAir flight 427 accident.

Although USAir flight 427 encountered turbulence from Delta flight 1083’s wake vortices, the wake vortex encounter alone would not have caused the continued heading change that occurred after 1903:00.

About 1903:00, USAir flight 427’s rudder deflected rapidly to the left and reached its left aerodynamic blowdown limit shortly thereafter.

Analysis of the human performance data shows that it is likely that the first officer made the first pilot control response to the upset event and manipulated the flight controls during the early stages of the accident sequence; although it is likely that both pilots manipulated the flight controls later in the accident sequence, it is unlikely that the pilots simultaneously manipulated the controls (possibly opposing each other) during the critical period in which the airplane yawed and rolled to the left.

Analysis of the human performance data (including operational factors) does not support a scenario in which the flight crew of USAir flight 427 applied and held a full left rudder input until ground impact more than 20 seconds later.

Analysis of the CVR, Safety Board computer simulation, and human performance data (including operational factors) from the USAir flight 427 accident shows that they are consistent with a rudder reversal most likely caused by a jam of the main rudder PCU servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.

The flight crew of USAir flight 427 could not be expected to have assessed the flight control problem and then devised and executed the appropriate recovery procedure for a rudder reversal under the circumstances of the flight.

The flight crew of USAir flight 427 recognized the initial upset in a timely manner and took immediate action to attempt a recovery, but did not successfully regain control of the airplane.

It is very unlikely that the loss of control in the United flight 585 accident was the result of an encounter with a mountain rotor.

Analysis of the CVR, computer simulation, and human performance data (including operational factors) from the United flight 585 accident shows that they are consistent with a rudder reversal most likely caused by a jam of the main rudder PCU servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.

The flight crew of United flight 585 recognized the initial upset in a timely manner and took immediate action to attempt a recovery, but did not successfully regain control of the airplane.

The flight crew of United flight 585 could not be expected to have assessed the flight control problem and then devised and executed the appropriate recovery procedure for a rudder reversal under the circumstances of the flight.

Training and piloting techniques developed as a result of the USAir flight 427 accident show that it is possible to counteract an uncommanded deflection of the rudder in most regions of the flight envelope: such training was not yet developed and available to the crews of USAir flight 427 or United flight 585.

During the Eastwind flight 517 incident, the rudder reversed, moving to its right blowdown limit when the captain commanded left rudder, consistent with a jam of the main rudder PCU servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.

It is possible that, in the main rudder PCUs from the USAir flight 427, United flight 585, and Eastwind flight 517 airplanes (as a result of some combination of tight clearances within the servo valve, thermal effects, particulate matter in the hydraulic fluid or other unknown factors) the servo valve secondary slide could jam to the servo valve housing at a position offset from its neutral position, without leaving any obvious physical evidence, and combined with a rudder pedal input, could have caused the rudder to move opposite to the direction commanded by a rudder pedal input.

The upsets of USAir flight 427, United flight 585, and Eastwind flight 517 were most likely caused by the movement of the rudder surfaces to their blowdown limits in a direction opposite to that commanded by the pilots. The rudder surfaces most likely moved as a result of jams of the secondary slides to the servo valve housings offset from their neutral position and overtravel of the primary slides.

When completed, the rudder system design changes to the Boeing 737 should preclude the rudder reversal failure mode that most likely occurred in the USAir flight 427 and United flight 585 accidents and the Eastwind flight 517 incident.

Rudder design changes to Boeing 737-NG series airplanes and the proposed retrofit of the remainder of the Boeing 737 fleet do not eliminate the possibility of other potential failure modes and malfunctions in the Boeing 737 rudder system that could lead to a loss of control.

The dual-concentric servo valve used in all Boeing 737 main rudder PCUs is not reliably redundant.

A reliably redundant rudder actuation system is needed for the Boeing 737, despite significant improvements made in the system’s design.

The results of this investigation have disclosed that the Boeing 737 rudder system design certificated by the FAA is not reliably redundant.

Transport-category airplanes should be shown to be capable of continued safe flight and landing after a jammed flight control in any position, unless the jam can be shown to be extremely improbable.

Pilots would be more likely to recover successfully from an uncommanded rudder reversal if they were provided the necessary knowledge, procedures, and training to counter such an event.

A neutral rudder pedal position is not a valid indicator that a rudder reversal in the Boeing 737 has been relieved.

The training being provided to many Boeing 737 flight crews on the procedures for recovering from a jammed or restricted rudder (including a rudder reversal) is inadequate.

The continued use by air carriers of airspeeds below the existing block maneuvering speed schedule presents an unacceptable hazard, and the existing block maneuvering speed for the flaps 1 configuration provides an inadequate margin of controllability in the event of a rudder hardover.

The FDR upgrade modifications required by the FAA for existing airplanes are inadequate because they do not require the FDR to be modified to record yaw damper command voltage, yaw damper and standby rudder on/off discrete indications, pitch trim, thrust reverser position, leading and trailing edge flap position, and pilot flight control input forces for control wheel, control column, and rudder pedals.

Based on the rudder-related anomalies discussed in this report, FDR documentation of yaw damper command voltage, yaw damper and standby rudder on/off discrete indications, and pilot flight control input forces for control wheel, control column, and rudder pedals is especially important in the case of the 737, and these parameters should be sampled on 737 airplanes at frequent intervals to provide optimal documentation.

The FAA’s failure to require timely and aggressive action regarding enhanced FDR recording capabilities, especially on Boeing 737 airplanes, has significantly hampered investigators in the prompt identification of potentially critical safety-of-flight conditions and in the development of recommendations to prevent future catastrophic accidents.

Boeing reported that this minimum tolerance PCU servo valve operated normally for each test condition designed to simulate a hydraulic system overheat, with one or both hydraulic systems circulating fluid through the servo valve before insertion of the heated fluid and at Boeing’s estimated normal operating temperatures within the vertical fin (conditions similar to those used in the Safety Board’s simulated hydraulic system failure tests). Boeing conducted additional tests in which hot hydraulic fluid was injected directly into the minimum tolerance servo valve. Hydraulic fluid was not circulated through the servo valve before insertion of the heated hydraulic fluid (conditions similar to those used in the Board’s extreme temperature differential tests). In some tests under these two conditions, the minimum tolerance servo valve’s secondary slide jammed to the servo valve housing (and remained jammed as long as the force on the input crank was maintained). The smallest temperature differential between the inlet hydraulic fluid and the servo valve housing at which the minimum tolerance PCU jammed was 145° F

After the Safety Board’s October 1996 thermal tests, Boeing engineers began an independent detailed examination of the test data. Their review of the data indicated that the PCU servo valve responded slowly and erratically to the input commands when the secondary slide was jammed to the housing by the thermal shock and an input was applied to the external input arm. Boeing subsequently conducted tests using a new-production PCU that had been modified to simulate a jam of the secondary slide to the servo valve housing at various positions and then to simulate the application of a full rudder input to the PCU. These tests revealed that, when the secondary slide was jammed to the servo valve housing at certain positions, the primary slide could travel beyond its intended stop position because of bending or twisting of the PCU’s internal input linkages (compliance). This deflection allowed the primary slide to move to a position at which the PCU commanded the rudder in the direction opposite of the intended command (reversal). Specifically, the tests revealed that, when the secondary slide was jammed at positions greater than 50 percent off neutral toward the extend or retract position and a full-rate command was applied to the PCU, the rudder would move opposite to the commanded position

Given the NTSB factual report, how do you hold that the "rudder hardover theory, especially as applied to the COS incident, is very much unproven"?

Cheers,

-Andrew
 
To be clear wrt to the 737 "tail issues" : the issue wasn't structural, per se, in the way the purported A300 series Va tail issues were. The issue was with a failure condition of the nested rudder servos -- the 737 introduced a new servo design that nested the secondary in the primary casing, and used and interference fit design versus a ring-sealed design -- and a particular flight regime.

Understood, but you have to look at it from another perspective, both had issues with the tail that killed everyone onboard. That's all you average CNN/Fox News watcher gets. To the average passenger, there is no difference between Airbus and Boeing.
 
Over the past ten years I have become less and less willing to fly commercial - to the point of not going a couple of times recently...
I either fly myself or drive... Both of which are statistically more dangerous than commercial flight...
The issue for me is the increasing reliance on computer technology to control the commercial aircraft...
I have a brand new boat where the high tech ECM controlled Cummins diesel is in the shop with just 130 running hours... In the middle of the Gulf of Mexico it developed a corrupted fuel management map and barely got us back to shore...
I have a pair of brand new, high dollar diesel trucks... Both have had computer issues that required going to the dealer, including one being towed...
Then there are the crashes like air france we are discussing, and the wonderful Airbus at the Paris Airshow that ignored the full throttle (toga) command from the pilot because of faulty programming...
And then the Boeing where the hydraulic servo spool jammed the rudder circuit and took the plane down... I have hydraulic equipment, back hoes, excavators, etc. and we have had jammed spools putting the machine down for the rest of the day (but at least not killing me)... It does take your breath away when you gently roll your wrist for a small movement and instead get a pedal-to-the-metal move with the excavating bucket crashing into the side of the trench, just missing the guys...

The corrupted string of code in your CPU - which has total control of the aircraft - is not fixable and is likely to fight you every inch of the way / to the ground!
So, unless there is no other choice, I choose to fly my old mechanical airplane - or drive my CPU dependent diesel truck - which may leave me on the side of the road but at least it won't put me in the bottom of a smoking crater...

denny-o
 
I am from the old school too.....

Give me a carb, two coils,a distributor and a metal throttle cable..... If I have fuel in the tanks and spark to the plugs by gosh I am getting home...... Computer controlled stuff is PFM when it works... it is downright deadly when is don't....:yikes::yikes::yikes: IMHO.

Ben.
www.haaspowerair.com
 
Over the past ten years I have become less and less willing to fly commercial - to the point of not going a couple of times So, unless there is no other choice, I choose to fly my old mechanical airplane - or drive my CPU dependent diesel truck - which may leave me on the side of the road but at least it won't put me in the bottom of a smoking crater...

denny-o

Except, statistically, your old mechanical airplane is way more likely to put you in the bottom of a smoking crater than that new fangled jet.
 
I woudn't believe anything NOVA puts out. They just got the FDR data this month, and it's WAY too early to start building up a dramatization of the "last moments".

So thats a no on watching the video? I now the recorders will show a more detailed picture, however, I think there was already enough info for a really good indication of what happened.
 
I am from the old school too.....

Give me a carb, two coils,a distributor and a metal throttle cable..... If I have fuel in the tanks and spark to the plugs by gosh I am getting home...... Computer controlled stuff is PFM when it works... it is downright deadly when is don't....:yikes::yikes::yikes: IMHO.

Ben.
www.haaspowerair.com

I'm with both of you on this one. When computer-control works, Im sure it's wonderful, but when it doesn't work :mad2: is about all ya can do. Of course mechanical controls can fail (and do), but at least there is feedback from the senses to indicate a problem rather than a computer...
And yes, statistics are all well and good, but they're only statistics. (Fig Newtons are fruit and cake:D)
 
Very interesting. The pundits were all over the news this morning blaming the crew. Normally, I try to be devil's advocate and argue against the "conventional wisdom" in these things, just as a brake against rushing to a conclusion.

But I'm having a hard time trying to understand the nose up inputs, and the incredibly high angle of attack recorded. What I'd really like to compare that data with would be the aircraft attitude displayed on the PFD and ISIS, but I'm not sure that's recorded.
 
My heart goes out to the crew who tried to deal with this emergency.

This just doesn't pass the smell test to me. We have ATP rated pilots with a lot of experience trying to get a plane under control for over three minutes. How many ATPs raise the nose to exit a stall? What were they seeing? What was the software showing? We are taught to TRUST our instruments and I'm confident they were doing that.
The tail was found a good distance from the aircraft. Makes one wonder if it was attached when they got to the surface.

Best,

Dave

From the transcript:
The airplane’s angle of attack increased progressively beyond 10 degrees and the plane started to climb. The PF made nose-down control inputs and alternately left and right roll inputs. The vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied between 12 degrees right and 10 degrees left. The speed displayed on the left side increased sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees. From 2 h 10 min 50, the PNF tried several times to call the Captain back.At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed. The PF continued to make nose-up inputs. The airplane’s altitude reached its maximum of about 38,000 ft, its pitch attitude and angle of attack being 16 degrees.Note: The inconsistency between the speeds displayed on the left side and on the ISIS lasted a little less than one minute.
 
As I said already in this thread, total fly by wire gives me the shiverin fits...

Now, the reports leaking out suggest the airplane was in a flat spin all the way down, some 3.5 minutes... So, if we (I) assume that, it raises interesting questions...

Did it remain in a flat spin all the way down because it was out of CG to the rear?
If so, how did it get that way?

One hunch is that the CG datum is measured by strain sensors on the landing gear during loading and reported to the loading crew by some form of read out... If the flight computer program is involved in producing the readout, then !?!
Or if the airplane is loaded by the crew weighing the cargo and using a nomogram for loading and CG, screwed up...

OK, so IF (just speculating here) invalid data was produced for loading, leading to an aft CG, and IF invalid data was later reported to the computer in flight when the sensors iced up, then perhaps the computer came to erroneous conclusions and rejected the pilot inputs for 3.5 minutes! Like trying to reason with a 3 year old who doesn't want to go to bed...

Anyway, a flat spin all the way down is most likely due to one of two causes: (in my mind)
1. The CG being so far aft that once the aircraft (at altitude and near the coffin corner) noses up, stalls, and drops a wing, the spin becomes aerodynamically locked in...

2. Or, the CG is within the controllable range and once in a spin the computer simply refuses, and continues to refuse, the full throttle, opposite rudder, and down elevator commands which I am sure the pilots attempted over and over.
( "I'm sorry Dave, I can't do that.")

All in all, a horrifying situation that gives me sweats to think about...

Now, I was out today doing some balked take offs and some critical engine cuts... This is statistically vastly more dangerous than flying in a commercial jet, yet I was happy the whole time...
Happy, not because I am oblivious to the risk level, but happy because if I crash it is I that blew it - and not because the computer refused to open the carburetor or refused to move the elevator...

denny-o
 
Was the crew in IMC the entire time?

It was night over the ocean. Unless the cockpit was dark enough and the pilot's eyes so dark adapted that the stars were brightly visible it was IMC. Even if stars were visible, a few lights on the water (ships, islands, and/or reflections of stars) the visual illusions would be tough to avoid.

As to the cockpit displays, it's quite possible that the pitch attitude was fairly nose down even though the AoA was high. In addition, at that altitude there's likely not a lot of separation between "stall speed" and overspeed with associated mach induced loss of control and I'm wondering if the PF confused the stall warning with an overspeed warning.

I'm also curious about the statement that the elevator trim moved to full up during the event and the reason for that happening. It might simply be the result of the PF applying nose up stick but I'm not sure how trim is managed when the control system is in alternate law. Whatever the reason, it sure seems like full nose up trim would contribute to the problem.
 
But... But... You CAN'T stall an AIRBUS!!! It's fly-by-wire! The computers will prevent it! :rolleyes:

Yeah, I know. I am having a hard time reconciling what I think I know about the system. If the inputs to the computer were FUBAR'd, maybe it didn't know it was stalling. But with the SAS vanes providing AOA, I just don't know.
 
Yeah, I know. I am having a hard time reconciling what I think I know about the system. If the inputs to the computer were FUBAR'd, maybe it didn't know it was stalling. But with the SAS vanes providing AOA, I just don't know.
In alternate law does the system provide AoA based stall protection?

The report also mentioned that the AoA is considered invalid if the airspeed is below 60 Kt, would a problem in the airspeed sensing disable AoA?
 
From the transcript:
The airplane’s angle of attack increased progressively beyond 10 degrees and the plane started to climb. The PF made nose-down control inputs and alternately left and right roll inputs.

So far, unusual, but nothing out of bounds. I wonder why the roll inputs.

The vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied between 12 degrees right and 10 degrees left.

Up or down, I wonder? But still, not out of bounds.

The speed displayed on the left side increased sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees.

That would have been down from a Cruise Mach of about .80. I guess the 7,000 fpm was up.

From 2 h 10 min 50, the PNF tried several times to call the Captain back.

If the Captain was not in the cockpit, more than likely he was on his rest break. Nothing to see here, really.

At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs.

I wonder why. That is really counter intuitive.

The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase.

This baffles me. Shouldn't get that warning until somewhere around 13-15 degrees AOA.

The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.

This also baffles me. Why was it trimmed into the high AOA.

Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed.

Does that mean there was an inconsistancy with recorded speeds? Why was that?

The PF continued to make nose-up inputs. The airplane’s altitude reached its maximum of about 38,000 ft,

I wonder what their assigned altitude was.

its pitch attitude and angle of attack being 16 degrees.

That is definitely a stalling AOA.

All in all, more questions than answers at this point.
 
In alternate law does the system provide AoA based stall protection?

The report also mentioned that the AoA is considered invalid if the airspeed is below 60 Kt, would a problem in the airspeed sensing disable AoA?

I was about to edit my post.

In alternate law, if I recall correctly, yes it does. It has been over 14 years. However, if it went all the way to direct law, or whatever the direct mode is called, there are no automatic stall protections. The airplane can be stalled in Direct law.

Makes me wonder if it degraded all the way to Direct. Very conceivable, in my mind if the computers could not make sense of the inputs they were receiving.

And to answer the question about the 60 knots and the AoA, I think it is entirely plausible that if the computers sensed an unreasonably low speed the AoA inputs could have been ignored.
 
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