Man vs. Computer: The crash of Air France 447

[marmar]

(Bloomberg) The crash of Air France flight 447 in 2009 that killed 228 people casts the spotlight on pilots’ ability to execute split-second decisions and avert disaster in an era when computers have taken control of the cockpit.

Evidence gleaned from the Airbus A330’s last transmits shows the autopilot disengaged after speed readings became unreliable, forcing the two co-pilots in the cockpit to take over, just as the jet traversed a storm. Data from the final minutes indicate the aircraft went into a stall before crashing into the sea, four hours into its flight to Paris. The French investigators will publish a detailed report tomorrow.

The findings will likely fan the debate whether modern-day pilots, accustomed to simulators and automated flight controls, still possess the airmanship skills and training routine needed to overcome sudden adverse scenarios. The interaction between man and machine in the last two decades has moved toward computers flying the jet, with pilots more at the receiving end of electronic commands rather than the other way around.

“Automation is inevitable, yet the whole interface between pilot and automated systems must be rethought,” said Hans Weber, president of Tecop International Inc., an aviation consulting firm based in San Diego, who has given safety advice to the U.S. Federal Aviation Administration and companies including Airbus parent European Aeronautic, Defence & Space Co. .........(more)

The complete piece is at: http://www.bloomberg.com/news/2011-05-26/air-france-crash-pits-pilot-brains-against-computers-taking-over-cockpits.html

[hedgehog]

1. Here are my questions for any tech savvy folk here :

1. Was this a fly-by-wire craft, with a computer between the pilot and the actual controls?

2. If so, could the computer have read the false data inputs and over-ridden the pilots' attempts to save the plane? That is, the pilots tried to do A, but the computer said, you cant do A in this situation, we're doing B instead?

[nichomachus]

2. Here's one answer

The Airbus A330 jet that crashed on June 1, 2009, was a wide-body aircraft using so-called fly-by-wire technology that replaces traditional manual flight controls with an electronic interface. Airbus pioneered the system in civil aviation more than two decades ago on its A320 single-aisle jet, which remains the Toulouse, France-based company’s best-selling model to date.

From the link

[uponit7771]

12. delete

[marmar]

3. It is fly-by-wire, but I believe the pilot is supposed to have override capability....

...... they added that after an A320 crashed during an air show because the computer took over control of the plane from the pilot during a maneuver.

[av8rdave]

8. Another issue with the fly by wire:

(disclaimer: as of yet, I have stuck with Boeing and not bothered bidding and Airbus, so this is second hand from friends who fly them.)

Absent reliable speed indications, "control loading" is a valuable contextual clue as to what the airplane is doing speed - wise. In basic cable-and-bellcrank controlled airplanes, as airspeed increases, the controls become "stiffer" and harder to move - makes sense when you consider the air is moving faster over all those control surfaces connected to the controls. Conversely, low airspeed causes the controls to feel loose and sloppy, and larger inputs are required to get the desired results.

On most hydraulically powered flight control airplanes, the control system includes an artificial "feel" (or control loading) system to mimic that same sensation, since the air loads on the surfaces don't carry through hydraulic lines and pumps.

On the Airbus, the control stick is literally a computer joystick, which electrically sends inputs from the pilot to a flight control computer, which then outputs control commands to the hydraulic servos. There is no tactile feedback through the stick. Not much of an issue when all is working correctly, and Airbus pilots quickly adapt to flying without this feedback.

With a complete loss of airspeed/mach data, neither the pilot nor the flight control computer has anything to go on. Even a GPS groundspeed system doesn't provide usable data - all the wing and control surfaces care about is how many air molecules per second are passing over them. With no airspeed indication and no tactile feedback, it becomes impossible to know why attitude changes are occurring. On a dark, stormy night, things can quickly get out of hand.

[Sen. Walter Sobchak]

20. the plane crashed because the pilot was flying against the flight envelope protection

If you tell the computer you are landing the plane, you better mean it because it is going to land the plane. That crash and the subsequent Air Inter A320 crash were caused by pilots insufficiently experienced with the Airbus A320 doing stupid things. In both cases the aircraft performed exactly as designed and executed the maneuver instructed.

In the Air Inter crash the crew programmed an approach that flew the plane into the side of a mountain - the airplane performed exactly as instructed by the crew.

[mn9driver]

4. The A330 is fly-by-wire.

In this case it appears the pitot tubes froze up, causing the airspeed indications to go haywire. The real problem with this article is it seems to imply that all the pilots had to do was disconnect the automation and they could just fly it by hand with no problem, which isn't true.

Recognizing an airspeed indication problem is tricky; especially if you're in the dark and getting slapped around by weather. You have to override all of your instincts about what you THINK the airplane is doing and disregard one of the main instruments that help you figure things out.

Additionally, the engine thrust levers do not move during normal operation on this airplane. If you're massively distracted by the autopilot clicking off and the nose pitching up while airspeed appears to be INCREASING, you won't notice that the thrust computer has commanded the engines to idle. Then, when the airplane starts to buffet you think that it's an overspeed when in fact the airplane is stalling and getting ready to fall out of the sky due to LACK of airspeed.

This is an ugly, ugly situation. I fly airbuses and this scenario is hard to deal with, even when it is an expected training maneuver in the simulator. You have to disregard EVERYTHING, take POSITIVE action to get manual control of the engines and then set the aircraft pitch, set the thrust at a level you know will keep you flying, and try really hard not to look at all the haywire indications that tell you you're doing the wrong thing.

[zappaman]

6. Thank you for the information

Very helpful in understanding what happened.

[Puglover]

7. Hey I haven't seen you in a zillion years!

I used to be Jeff the Crew Coordinator but thankfully when the job went to Atlanta I got to go the way of the dinosaurs. :)

FYI There is a WONDERFUL Nova special out there on 447. They pretty much explained things exactly as you have. The pilots essentially had nothing to go by. And yes, it sounds even to my layman's ears, very very ugly.

PS I hope the new company is treating you well!

[mn9driver]

15. It HAS been a long time!

All us northies are still trying to get used to the cultural differences; some are good, others, um, not so much :eyes:

Hope you are well!

[RamboLiberal]

14. Thanks for the explanation - I was hoping one of our DU

multi-engine pilots would visit one of the threads on this accident.

[shireen]

16. +1

thanks for the insights. Good to hear from a pilot that's flown the aircraft.

[uponit7771]

13. 3...where was the sensor redundency on such a gating control? It's cheap and easy to have 2

[Blue_Tires]

5. Ironically, some loose cannons in the industry

had been pushing toward a future with one or no pilots, since everything is so automated now...

[ProgressiveProfessor]

9. Its not the fly by wire, it is if the airplane can over ride the pilot

In extreme situations, you have to design the airplane to listen to its sensors or the people in the cockpit. Purportedly with Boeing coming from a military focus, the pilot can always over ride the airplane flight computers. Not so much with Airbus. The problem is sometimes the sensors are right, other times the pilots.

As a holder of a commercial pilot certificate, I tend to bet on the ATP rated crew.

[Sen. Walter Sobchak]

21. computers don't crash airplanes, panicking pilots crash airplanes

Had the Bombardier Q400 been equipped with Airbus style flight envelope protection the Continental Buffalo crash would have been impossible, if the Airbus A300 had the flight envelope protection found in modern Airbus aircraft the crash of American Airlines 587 would have been impossible. That is why Airbus gives the computer the final word. The same goes for dozens of other accidents when the crew forced the aircraft into suicidal maneuvers that either resulted in structural failure (AA587) or an uncontrolled spiral into the ground. (CO3047)

[hedgehog]

10. My thanks to all of you for taking the time to explain this.

I suspected that the fly-by-wire might cause some problems, but I hadn't thought of the lack of accurate feedback.

Now I'm wondering if the computer actually fed incorrect pseudo-feedback to the controls!

[Odin2005]

11. My TomTom can't get me to the right place...

...and yet we already want computers making decisions for us?

[shireen]

17. reminds me of that awful fly-by-wire Airbus crash in 1988.

Not the same situation, but it's still chilling.

http://www.youtube.com/watch?v=SCwYAzqvcrQ

:(

[mn9driver]

18. Interesting thing about that crash:

It happened during an airshow flight demonstration with 130 passengers on board. Because it settled into the trees in completely controlled flight commanded by the flight control computers, instead of in a full stall (which is what any human pilot would have done in order to try not to hit the ground), only 3 died, in spite of the horrible post crash fire.

The crash was caused by several factors not involving the flight controls, having to do with engine power response, pilot error, etc. But the Flight Control Computers on that airplane are why 127 people walked away from it.

[petronius]

19. Interesting! I never bothered to read up on it after seeing the video;

just assumed from the fireball that everyone had died. I also assumed, given the air show aspect, that it wasn't actually full of people...