"If the Gimli Glider or Flight 1549 had been on an Airbus, there would have been a lot of dead people"....

fyi- Flight 1549 was an Airbus A320. Perhaps you would like to rethink your conclusion?

Summary states:

Boeing planes allow pilots to take over from computers during emergency situations, Airbus planes do not.

According to this link [airbusdriver.net], the Airbus does, in fact, have a manual override mode.

Which would make the argument as presented a moot point.

Come on Slashdot, stop spreading FUD about european planes please.

Most airbus planes (including A330 and A340 models) can be flown under at least 3 different control modes aka. "flight control laws". This includes direct law, which basically makes the control fully assisted, two "alternate" laws, that reduce the envelope protection and .. the "direct" law which basically gives the pilot full control over the control surfaces without any limitation. Which TFA says is impossible.
See http://www.airbusdriver.net/airbus_fltlaws.htm

Extreme cases have been around a long time. The DeHavilland Mosquito was notoriously twitchy (on the other hand, this meant it was unbelievably manoeverable in a dogfight, superior to many fighters) and "flying wings" have existed for longer than the jet engine. Computer control merely makes these economic by having fewer do landscaping.

Yes, it is an annoying debate tactic [wikipedia.org] but weak and relatively easy to recognize. Diligent readers can recognize this though, and the glaring errors often come painfully to light in the discussions.

Anyway, the Airbus systems have multiple levels of computer massaging of the pilot's input, called different "flight laws." Read up about it here:

Airbus flight laws [airbusdriver.net]

In the most direct law, yes, the system will still not allow you to do things like rip the rudder off the airplane [wikipedia.org] (A300 was not FBW) or clearly overstress the aircraft and destroy the wings. This is a good thing -- of course, there is perhaps some imaginary situation where it would be better to destroy the aircraft to ameliorate some aspect of an impending crash, however, the vast majority (all ever recorded in an actual crash?) of inputs that can destroy aircraft are not intentional nor required. Also, the 'direct law' will allow a pilot to potentially overstress the aircraft in the event of computer failure or discordant input.

The role of conflicting pilot input is also well thought out (described in the link), and the airbus designers were aware of these (pseudo)philosophical objections to excessive computer control. I do not think there is much of a conflict among people familiar with the operation and implementation.

China Airlines Flight 140 was a route from Taipei, Taiwan to Nagoya, Japan. On April 26, 1994, the Airbus A300 on the route was due to land at Nagoya Airport. The Airbus A300 was completing a routine flight and approach, however just before landing, the First Officer pressed the Take Off/Go-Around button (also known as a TOGA) which raises the throttle position to the same as take offs and go-arounds.

Pilot Wang Lo-chi and copilot Chuang Meng-jung[1] attempted to correct the situation by manually reducing the throttles and pushing the yoke downwards. The autopilot then acted against these inputs (as it is programmed to do when the TOGA button is activated), causing the plane to have a very nose-high attitude. This nose-high attitude, combined with decreasing airspeed due to insufficient thrust, resulted in an aerodynamic stall of the aircraft
-- http://en.wikipedia.org/wiki/China_Airlines_Flight_140 [wikipedia.org]

That is completely true - the computer in the Airbus can not override the pilot. After the computers overrode the pilot's input at the Paris Air Show, causing the airplane to crash, Airbus added a mode called "direct law" that allows the pilot absolute control over the aircraft. There are several different flight control laws, depending on which of the three redundant flight computers are in operation, and in what mode:

Normal Law - computer prevents pilot from excessive pitch or bank, excessive speed, stall from insufficient speed, excessive load factor, and augments yaw (rudder) control.

Alternate Law - Aids in low and high speed stability, and excessive load factor, as well as yaw damping.

Abnormal Alternate Law - yaw damping and excessive load factor protection only

Direct Law - No protection, pilot can do anything they want

Disclaimer: I am a commercial pilot, but I am not an Airbus pilot. I have studied Airbus systems, and have about 10 hours of A320 (full motion) simulator time.

In order to get to the manual override mode in an Airbus (IIRC) you have to navigate through several screens on the flight control computer and disable everything via menus. In order to activate the manual override mode on a Boeing plane you just have to move the yoke. In an emergency situation where, for whatever reason, the automated flight controls aren't working or are working improperly the Boeing override implementation is vastly superior to that of the Airbus. Not to say that autopilots and fly-by-wire systems aren't useful, but they aren't infoulable and limiting the pilot's ability to respond to a situation just seems like a really bad idea.

I know, I know, I'm an AC, I don't care, too lazy to log in. Fact of the matter is that whether you want a human or a computer in control is 100% conditional, and the best we can hope for is that the designers of the plane try to cover all the possible bases they know of. Whether it's better to put a human or a computer in control is moot... frankly I doubt there's a computer in existence currently that could have set a plane down in a river. By that same token, a computer never falls asleep, is never drunk, and unless it's programming is crap will never make any sort of "Beginner" or "stress" mistake. So the whole EU vs. America crap... Yeah... Thank you kdawson for turning this site into another digg or other crap news site.

I fly the Airbus. It has an alarm that sounds every time the autopilot is disengaged.

For the record, it was an Airbus A320 (a full FBW aircraft) that was flown into the Hudson [wikipedia.org].

i worked for and flew many times in the cockpit of an Unnamed Parcel Service'
and to me the phrase "battle tested" is quite valid. when a pilot barely has a
747-2 off the ground and is already reading car magazines, i get nervous. when
he tells me he is bored out of his mind because he has done over 1500 mid-air refuelings,
i can let go of the armrests and talk about that magazine with him. no offense
to civilian pilots, but the level of skill and experience those guys possess is unparralleled.

For anyone interested in details of the crashes:

Nagoya, Japan
http://aviation-safety.net/database/record.php?id=19940426-0 [aviation-safety.net]

Mulhouse-Habsheim, France
http://aviation-safety.net/database/record.php?id=19880626-0 [aviation-safety.net]

What you claim, is I think in extreme doubt. The airbus is 100% fly-by-wire. When everything is working correctly The airbus allows a pilot an envelope of operation. But it will not allow a pilot to stray outside that envelope. When sensor data is erroneous the envelope is erroneous.

To give you an understanding of this: at the altitude the airbus is flying their is a 25 knot windw between Stall and super-sonic, both of which are fatal if you happen to be in a thunderstorm. So the pilot has almost no controll. He can hardly turn the plane because that would require more thrust than the engines could provide and maintain the 25 knot range. If the instruments reading the air density, air speed and air pressure malfunction or the computer miscalcualtes the pilot is screwed.

My father, god rest his sole, was a lead designer on boeing flight systems and instrumental on it's philosophy. Interestingly he hated computers and loved world war 2. WWII was when designers got lots of feedback on how to design because they made so many errors and planes were pushed to their limits. They did so many post mortems that they learned the process of error free design.

Laugh if you will, but all those software design processes you were taught and all thoe iso compliance rules were not invented by computer scientists. They were borrowed from the airplane industry. There are methods to engineering that work and they learned these by error.

In any case, it was not until the 757 and 767 that boeing had the cahones to build al plane without fully mechanical controls from the cockpit. and even then they let the pilot over ride the computers. By the way there is not one computer. There are 3, and they vote. if one of them disagrees, the other two vote him off the island. They don't trust computers.

This however is changing. Even during my father's tenure they were envious of the weight savings that Airbus was getting with it's fly by wire approach. TO stay competative boeing has had to go that way too.

Quite so, for the non glider pilots out there an outlanding is a landing in a paddock or field away from an airfield.

Personally I have only outlanded twice in 300 flights, but it is a great confidence building exercise, that power pilots "Simulate" by flying over afield at 500ft, which is a waste of time.

"Only with Boeing is that possible, with airbus, regardless of the situation, the computer takes precedence."
"It's like the pilot that landed his plane in the river after losing an engine to birds."

In that instance, the plane WAS an Airbus. The summary saying that Airbus doesn't have control overrides is imply lying. It's not true. All Airbus aircraft allows pilots to override computer control. You're right though, if that flight HAD been controlled by computer, then it would have crashed - not because of computer error but because it's simply not possible to plan that scenario. Even if you could program a computer to look for water landings in such an instance, and give it detailed waterway charts, it couldn't know if there was a ferry there or not, possibly killing everyone on board AND everyone on the ferry. Its simply impossible to allow for all scenarios. This is where having the option of human override is good - and thats why all planes allow it.

However, if computers had control, then many other flights which have crashed killing all on board would have been avoided. Plane crashes are virtually always either a) mechanical error or damage (such as the Hudson landing), b) weather/micro-burst related (such as Air France), or c) pilot error - either making the wrong decision, misinterpreting the information the computer was giving them, or blatantly ignoring the advice of the computer and resulting in a plane crash. There are very few incidents (if any) where computer control of an aircraft has led to its crash.

You seem to have bought into the summary, thinking that Airbus planes don't allow manual control. I assure you, thats not the case, as seen in the Airbus A320 on the Hudson River landing. It is unfortunate though, that in computer vs human scenarios, the vast majority of the time humans make the mistakes, not the computers. As discussed in many places here the Buffalo flight where the computer started diving and the human overrode it - people will say he's an idiot but the fact is the pilots flying all planes are just as capable of making similar mistakes, no matter how good their training. Computers can't make such a mistake, unless programmed incorrectly.

If you read any of the ACARS data that has been released you would see that you claim is false. The autopilot disengaged, and when the ADIRU faulted, the plain went into ALTERNATE law which does not offer the same envelope protection as normal, because the computer knows that its own inputs can't be trusted. Fly by wire has got nothing to do with it. When it knows the envelope data is erroneous it downgrades its protection. This has got nothing to do with what a Boeing plane will let you do versus Airbus.

Anyway it will take the black boxes to confirm what happened. Anything before that is pure speculation.

Not quite sure. Airbus airplanes have three distinct FBW modes, called "laws." Depending on how you count, there are three or more of them. In Normal Law, it is as you say. The airplane won't let you go into a mach tuck, won't let you stall out by going too slow, won't let you apply the rudder too hard, has strong yaw dampering, etc.

When things go wrong, the control laws are designed to degrade gracefully. To my knowledge, the airbus does not give pilots the choice of flight laws, which is what you are complaining about. If multiple systems fail, the system goes into "alternate law" which provides speed safety and yaw dampering only. Note that in alternate law, any changes that the computer requests can be overriden by the pilot. If ADR systems fail, the speed safety, rudder travel limiter, etc. are also disabled. This means that the plane is being flown pretty much in "direct law" but with yaw dampering.

Additionally, in alternate law, if the plane enters an unusual attitude, flight laws degrade further.

If additional failures occur, the plane reverts to "direct law" which is supposed to be an equivalent to mechanical control over the airplane. In direct law, some manual/mechanical backup systems are actually used.

If all FBW systems fail, there are limited mechanical backups to the rudder and elevators.

Sourse: http://www.airbusdriver.net/airbus_fltlaws.htm [airbusdriver.net]

That's a great article by William Langewiesche. Note that he makes the point that Flight 1549 was able to make a smooth engines-out landing in the Hudson because the flight control computers were helping all the way to the water. The computers kept the aircraft just above stall (which is very tough with no engine power) and allowed a slow descent and a slow landing speed (which are competing goals for an aircraft).

I seem to recall that the plane was in 'try-to-land mode' and saw the crew's attempts to power up as a mistake to be ignored as it determinedly and successfully put itself on the ground. I don't know if or at what point the mode was changed to 'go-around'. This isn't what it says in the above report though. Hmmm. Am I misremembering, remembering a false rumour or is it that vast conspiracy again? Stupid low grade modern tinfoil.

58-year-old flight captain Marc Dubois, who joined Air France in 1988, had approximately 11,000 flight hours, with 1,700 hours on an Airbus A330

The autopilot disengaged at 23:10, 4 minutes before the last automated messages indicating failing cabin pressure were sent by the plane.

But the plane that landed in the Hudson was an Airbus A320, something that people seem to keep on ignoring. Not only a fly by wire design, but also the first (and only?) commercial plane controlled with a sidestick instead of the classic control column ( http://images.google.com/images?hl=en&safe=on&q=airbus+a320+cockpit [google.com] ). So, if the computer was fighting the pilot (which is not true) how did the pilot manage to land the plane?

Here is 1: http://en.wikipedia.org/wiki/Bashkirian_Airlines_Flight_2937 [wikipedia.org].

Basically, the on-board computers gave the correct advice, but one of the pilots "disregarded the TCAS instruction to climb and instead began to descend, as instructed by the [air traffic] controller, thus both planes were now descending."

The controller was later assassinated by someone who had lost wife and children in the accident.

He was given the adulation because water landings are notoriously difficult to pull off, with the number of successful ditches so low that the procedures are still essentially educated guesswork. A random swell that catches a wingtip or engine nacelle can cause a plane to flip or to break open. Hit too steeply -- something that again can change with a swell -- and the plane may decelerate fast enough that injuries or death occur.

All planes come with a checklist for ditching in the water. Few pilots come away from actually using them unscathed.

That's a falsehood. The crash was caused by multiple pilot errors (failure to heed his instruments; failure to apply power in time - jets do not react instantly, turbo-fans are particularly slow to do so). I've blogged a bit more about the AF296, Airbus tree crash [wordpress.com], including links to a previous /. discussion.

Basically, you're repeating a myth.

Huh. Funny that the Wikipedia article on Fuel dumping [wikipedia.org] even shows a picture of a "Fuel dumping point of an Airbus A340-311"...

Here's another quote from that article:
"Longer-range twin jets such as the Boeing 767 and 777 and the Airbus A300, A310, and A330 may or may not have fuel dump systems, depending upon how the aircraft was ordered, since on some aircraft they are a customer option. Three- and four-engine jets like the Lockheed L-1011, McDonnell Douglas DC-10 / MD-11, Boeing 747 and Airbus A340 usually have difficulty meeting the requirements of FAR 25.119 near maximum structural takeoff weight, so most of those have jettison systems. A Boeing 757 has no fuel dump capability as its maximum landing weight is similar to the maximum take-off weight."

Get your facts straight, Mr. Boeing-Name-Tag.

Being a commercial pilot is a very precarious, insecure profession. You can lose your job at any time through no fault of your own. E.g. fail a medical or, more commonly, become unemployed (airlines operate on very narrow margins, and so are extremely vulnerable to external changes like fuel prices; also, there are simply lots of pilots out there).

Fiat ???

Troll.

As a former real-time flight control software developer, I can say that letting the pilot fly the plan is the only possible choice.

There are circumstances that where it is impossible for the programmers and requirements writers to have guess could occur and program for every possible situation. Autopilots have "modes" and once in a mode, they do their best to do whatever that mode's purpose is regardless of the pilot inputs.

Humans tend to forget modes and just grab the yoke or throttles under unusual circumstances to fly the plane and forget what mode they are in. We know this. Why some companies decided to ignore this is a different question. Computers are almost always more fuel efficient than humans and the cost of fuel is 3x the cost of the aircraft over the lifespan.

As a flight software developer, I know that I'm not in the plane. The guys in the cockpit have their lives and the lives of everyone else aboard. They want to do the best job they can, especially during an emergency. I want my software to all them to do it. It is like the old breakfast/committed joke. I'm the chicken providing eggs, but the pilot is like the pig providing ham. He is committed, while I care just a little.

BTW, the Hudson river crash was an Airbus A320, so pilots can manipulate the aircraft "mode" to perform their intention. They just have to think "mode" for what they are trying to accomplish.

I agree, however the thunderheads in this scenario were over 50,000ft. If I recall correctly, most commercial jets fly at around 30,000ft. I don't know if the A330 can climb fast enough to have gotten over the clouds or even operate at that altitude.

http://shippai.jst.go.jp/en/Detail?fn=0&id=CA1000621 [jst.go.jp]

Many contributing causes for that crash.

A very badly informed comment though - it's actually so wrong it isn't even wrong.

Boeing use both fly by wire and composites. The B777 is full fly by wire, just like the Airbus (The B777 is a great aircraft - very reliable, with no fatal crashes to date - only one has crashed - no one was seriously hurt - due to fuel contamination). The B787, which is Boeing's next model, is almost *entirely* composite - it's the first airliner to be primarily composite construction. It is due to enter service in 2010 (and has suffered some delays). Oh, and it's fly by wire too, naturally.

Composites are also much stronger than aluminium - it is no accident that high performance gliders have been made from composites since the 1970s - you can't make gliders with such a slender wing as something like any open class glider - huge long 25 meter plus wingspans, with very little chord - with aluminium. The best aluminium gliders were the designs by Richard Schreider in the late 1960s - he brought aluminium to its limits in the design of high performance gliders. Composites also have other advantages - you can make much more efficient shapes with them too.

More accurately, there are very few people on Slashdot who have any fracking clue how a fly-by-wire system works. It's evident from the comments; just like everything else, people go spouting off and making claims about what they think things are like based on just a tiny bit of knowledge and their own prejudices, rather than looking at the facts and finding out what things actually are.

(Full disclosure: My day job is developing and testing a new FBW system, and I took an entire course dedicated to this in college.)

FBW systems are not the autopilot. They are not autonomous AIs, they do not make their own decisions, they do not just arbitrarily "decide" to go do something against the pilots' wishes. FBW systems are, in essence, little more than simple feedback control loops, similar to the familiar PDI controllers we all remember from control theory classes. All they do is compare the current state (pitch/yaw/roll angle and rate) with the one commanded through the stick, and try to make the two match by moving the control surfaces. The biggest difference is the presence of limiters which will prevent the aircraft from exceeding certain parameters (usually G load and angle of attack). That's it. That's all there is to a fly-by-wire system. It's just a controller.

In fact, let's compare a "traditional" manual system with a (simplified) FBW one from the pilot's perspective. In a traditional system, the stick/yoke in the cockpit is directly mechanically connected to the control surfaces through pushrods, bellcranks, cables, pulleys, etc. A given deflection of the stick will always result in the same deflection of the surface. For our purposes, we'll assume it's roughly linear, so Dsurface = K * Dstick. Now, let's look at the airplane as a whole. A given deflection of a control surface will not always achieve the same result--at low speeds, you need more deflection for a given response than you do at high speed. The net effect is that, at low speeds, the pilot needs to make large deflections of the stick make a given maneuver. At high speeds, he only needs to move the stick a little bit. It's kind of like your car--the steering gets more sensitive the faster you go; you wouldn't use the same inputs on the freeway as you do in a parking lot. Matching the desired response with the control input is the pilot's job--he's the feedback loop connecting control surfaces with the desired flight path.

A FBW system, on the other hand, doesn't have mechanical connections between stick and surface. Instead, the stick uses force or deflection sensors to read the pilot's input. That input is fed to the FCC, which then sends signals to the actuators on the control surfaces. Instead of commanding a given control surface deflection, the pilot's input will usually command something else, eg. roll rate or G load. Rather than varying according to speed and aircraft position, this will be constant--in other words, the command for 20 deg/sec will be the same at really low speeds as it will at high speeds. Basically, the pilot is telling the aircraft "do this", and the FCC figures out how to achieve that by moving the surfaces.

A FBW system will also often have limiters, which prevent the aircraft from exceeding certain parameters. Most common are angle-of-attack and G limiters. Angle of attack (AOA) is the relative angle of the aircraft to the oncoming air. Imagine sticking your hand out the window of your car, palm downwards. As you slowly rotate your hand so your palm faces forwards, notice that your hand wants to go up--you're making lift, and the angle of your palm to the airflow is your hand's AOA. Notice, though, that once you rotate too far, you stop generating lift--that's a stall. On a wing, the amount of lift generated is roughly linearly proportional to AOA, at least up to a point. Past that critical AOA, the air stops flowing smoothly over the top of the wing and gets all jumbled, causing a loss of lift. That's what a stall is.

> I don't agree with a lot of the discussions Airbus has made over the years:
> - Low strength materials in key areas

possibly true. But boeing is following airbus to using more composite materials. they even advertize 787 for beeing ahead of airbus in this area.

> - No warning alarm when auto-pilot is disengaged

Not true, Airbus plays 'Cavalry Charge' alert for autopilot disconnect

> - Less manual control in case of system failure

FUD. Regardless, both boeing and bus pilots fly so little manually these days that system failure dropping the pilot to manual flying has become a huge risk scenario in itself.

It has been suggested that AF447 suffered a airspeed indicator failure. Imagine being dropped from autopilot to manual while the airplane is alerting "stall" and "overspeed" at random times while flying in turbulence in a tropical storm cloud.. technically the airplane is still flyable using the manual controls, but you will have big trouble feeling the speed and direction of your plane. That is if manage not to panic from all the alerts shakiness of the plane...

google for "Aeroperu Flight 603" which happened on Boeing 757 when airspeed indication failed.