Naked Science Forum
Non Life Sciences => Technology => Topic started by: Eric A. Taylor on 10/11/2009 14:31:27
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While flying from Portland to San Fransisco recently, just as the plane was pushed away from the gate and began to taxi to the runway the pilot came on to greet the passengers.
"Ladies and gentleman, I'd like to welcome you aboard Horizon flight 182B to San Fransisco. You will be the first passengers in the history of aviation to be flown on a plane controlled completely by computer. In fact no human pilot is even aboard. But please don't be afraid. Absolutely nothing can go wrong- go wrong- go wrong-....."
Airbus is already using computers to fly. The pilots, who in the past MADE the plane do what they wanted now "ask" the computer do make a control input. It works good as long as nothing goes wrong. During an airshow a few years ago Airbus wanted to show off one of their shiny new planes. The pilot was going to do a flyby so put the plane in landing mode. But as he added power to climb out the plane was still trying to land. Instead of climbing away safely the plane crashed.
A "missed approach", where for whatever reason the pilot decides to abort the landing (maybe the runway isn't clear (I once saw a kid on a Big Wheel riding down the middle of the runway while landing at a small airport) or the pilot has made a mistake in his approach, maybe the winds change) are not at all uncommon. An aircraft should be able to quickly abort a landing at any time, even after touchdown. This crash was due completely to computer failure. Weather a failure to properly program it or if the computer had a bug makes no difference. Personally I think humans are far more reliable than computers. Usually with a bad pilot you'll be able to ground them before they make a fatal error, like those idiots who missed the airport last week. Computers can be used to ASSIST the pilot, even warn the pilot if he or she is doing something dumb, but please allow the human full control.
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Many aircraft are equipped with auto take and land equipment and can also navigate between airports. They can go all the way handsfree already, and do so on occasions. The airports have also to be suitably equipped though. Auto landing is used frequently - you can usually tell because it makes a better job of it than a pilot - but it is essential in low visibility landing.
Fly-by-wire is the norm on modern aircraft and is essential on some of the latest military aircraft which are designed to be naturally unstable - it makes them more reactive but they cannot be flown by direct human manipulation of the control surfaces.
A recent design of the Harrier VTOL aircraft has been converted to computer aided control. It was very hard to fly and could be distracting when engaged in battle and need to control weapon systems too. They made it so (apparently) a child can fly it.
I don't have any problem with electronic control systems as an aid to flying or even of them being essential to fly an aircraft. The reliability is quite good these days - at least as good or better than the mechanical systems being controlled. But I would still like someone to have an overview where there can be unknown situations arising.
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It depends on the circumstances. If there is nobody on the plane but me (say the pilot had a heart attack)and I have the choice of trying to land it myself or letting the computer have a go I think I'd defer to the machine.
On the other hand, I might look for a parachute instead.
"Blue screen of death" anyone?
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Hahaha
If the programmers of the system were confident enough to sit next to me I would
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Not on your Nellie!
It is impossible to exhaustively test systems of that complexity. There will always be some set of conditions that were never tested where the system will fail because of some unhandled exception. Even remarkably simple systems are subject to this limitation.
It is essential to have a pilot who can override the system in exceptiional situations. The current problem is that there are so few exceptions that the pilots get bored out of their minds and tend to fall asleep!
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War planes such as F-22's are built to be manuverable. But what happens when the line between life and death for the pilot is the 1/2 G beyond what the plane is designed to do? If the pilot is shot down the plane will be destroyed anyway.
Passenger jets on the other hand are designed to fly in a comfortable manner. This does not include a lot of wild maneuvers. Most passengers become very upset if a pilot starts doing loops and rolls and high G yo-yos.
There are times, rarely, when the pilot may need to do a high G maneuver that could damage the airframe. Under Airbus rules the computer will simply not allow this. Your headed for a mountain and need to pull up really hard. All you need is 2 more G's and you can clear it but the computer says "nope sorry you might bend the wings" and splato. Big roiling clouds of black smoke. But the wings are unbent damn it!
Recently an Airbus flew through a flock of birds. It ingested birds into both engines. The computer sencing the damage shut them both down. The computer did not have the ability to think "Now if I shut down BOTH engines we might crash." It was simply programed to prevent further damage by shutting them down. Would the plane have still crashed if the pilot could have gotten a restart, probably, but we will never know. Fortunately the pilot was able to ditch the plane in the river and no one was hurt. But what will happen next time if there is no safe place to land?
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It depends on the circumstances. If there is nobody on the plane but me (say the pilot had a heart attack)and I have the choice of trying to land it myself or letting the computer have a go I think I'd defer to the machine.
On the other hand, I might look for a parachute instead.
"Blue screen of death" anyone?
Are you sure? Planes are not really that hard to fly. The Mythbusters showed that a green novice could be talked down to a rough but safe landing, assuming the plane is in working order.
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Recently an Airbus flew through a flock of birds. It ingested birds into both engines. The computer sencing the damage shut them both down. The computer did not have the ability to think "Now if I shut down BOTH engines we might crash." It was simply programed to prevent further damage by shutting them down.
Bloody Hell! Are you really sure that is true? That's exactly the set of untested conditions that concerns me. If Airbus is relying on software to override the pilot, they are out of their minds. Believe me, I have attempted to manage software projects for forty years and I do know what I'm talking about.
If this is true I will make a point of never flying on an Airbus ever again.
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I think the situation is much more complicated and is subject of many claims and counter claims by Boeing and Airbus Industries. The general assertion is true, however, that Airbus have more automated systems that prevent pilots (or cockpit intruders) from causing an aircraft to exceed its design parameters. I also think this needs applying with more common sense and there have been accidents as a result. However, Airbus will point to a number of accidents that occurred on Boeings which Airbus would have survived as a result of their systems. I think there are pros and cons but we will see a convergence of the technological approaches with experience.
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It certainly makes sense to have systems that prevent the pilot from creating a situation that leads to a catastrophic failure of the airframe.
I'd be interested to know if Airbus system testing contemplated a situation where both engines were damaged by simultaneous bird strikes. I would assume there would be test cases for multiple engine failures.
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It depends on the circumstances. If there is nobody on the plane but me (say the pilot had a heart attack)and I have the choice of trying to land it myself or letting the computer have a go I think I'd defer to the machine.
On the other hand, I might look for a parachute instead.
"Blue screen of death" anyone?
Are you sure? Planes are not really that hard to fly. The Mythbusters showed that a green novice could be talked down to a rough but safe landing, assuming the plane is in working order.
I'm quite sure; you should see how fast I can kill flight simulator programs. I don't even drive a car.
I reckon a parachute is a fair bet- it's hard to miss the ground.
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I always reckoned you could tell when there was a serious problem: the autopilot ejected.
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If I peek into the cockpit of a plane and all I see is computer monitor and a mouse, I will do an immediate U-turn and get off the flight.
Mind you, "fly-by-wire" pretty much means that there are NO direct connections between any of the bells and whistles that you see in the cockpit and the actual controls that fly the plane. It's probably a heck of a lot more like Flight Simulator with a facade of knobs and dials than you care to imagine.
When someone convinces us that they have created an intelligent system that can replicate the actions of the fantastic pilot who ditched his plane in the Hudson and saved everyone on board, we might consider putting our faith in software. Until then, I would prefer to fly with a highly experienced human pilot who has total control of his/her aircraft.
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Recently an Airbus flew through a flock of birds. It ingested birds into both engines. The computer sencing the damage shut them both down. The computer did not have the ability to think "Now if I shut down BOTH engines we might crash." It was simply programed to prevent further damage by shutting them down.
Bloody Hell! Are you really sure that is true? That's exactly the set of untested conditions that concerns me. If Airbus is relying on software to override the pilot, they are out of their minds. Believe me, I have attempted to manage software projects for forty years and I do know what I'm talking about.
If this is true I will make a point of never flying on an Airbus ever again.
I don't know which model it was but one of the Airbus planes had a very bad design flaw. If the pilot put in enough rudder under some conditions the entire tail could be broken off. They "fixed" the problem, not by making the tail stronger but by entering a program that limits the amount of rudder the pilot can apply. Unfortunately you don't get to pick what type of aircraft you can fly on. You can ask the airline what model of aircraft will be used for that flight, but the only thing you can do is choose another flight.
Every plane has design flaws. The FAA will sometimes issue what's called an air directive. It's like a recall, except there are several levels. Anything from "fix at planes at next available inspection" to "ground the plane until item is fixed."
I know Boeing had a problem on one of there 737s. The 737 is the most popular airliner ever built. This problem could lead to a fire inside the wing that could rapidly spread to the cabin. Fortunately this item was resolved without loss of life. A fire broke out with an airplane on the ground and the crew was able to evacuate the plane in just 30 seconds.
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It certainly makes sense to have systems that prevent the pilot from creating a situation that leads to a catastrophic failure of the airframe.
I'd be interested to know if Airbus system testing contemplated a situation where both engines were damaged by simultaneous bird strikes. I would assume there would be test cases for multiple engine failures.
Engine failures in flight are extremely rare, multiple engine failures are almost unheard of. In almost every (if not every single) case of multiple engine failure the failures were caused by something that effects the entire airplane. Running out of fuel is probably the leading cause of engine failure in which case it matters little if you have one or 8 engines. Even a B-52 will suffer a failure of all 8 engines if it runs out of fuel. Probably the second most common cause is ingestion of stuff into jet engines. Flying through a flock of birds is not very common and even then it's rare to lose more than one engine. Modern jet engines need to pass a test where the engine needs to continue running after ingesting a bird. This is why I'm willing to bet the pilot might have gotten the engines restarted had he been given the chance. Finally volcanic ash is probably the leading cause of multi-engine failure after fuel starvation. Ash is not visible to radar and not visible to the eye at night.
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I had several years in predicting and troubleshooting failures, and I can tell you that, if a system has 100 failure conditions ¹, then it has 10,000 (100²) double-failure conditions, 1,000,000 (100³) triple-failure conditions, etc. A computer-controlled system would need to know what to do in all 10,000 (or 1,000,000 etc) situations, and someone would need to program it for that.
Right. And that assumes some piece of software didn't create the multiple failure condition in the first place! For example, if both engines are running the same version of management software, it is not inconceivable that there is some bizarre and untested "corner case" set of conditions that will make them shut down simultaneously. I'd be happier to fly on aircraft that had engines from two independent manufacturers.
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I would have thought that an aircraft running out of fuel was a fairly simple thing to insure against, my car has a dial that tells me how much fuel I have and how far it will take me do not aircraft have something similar ?
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I would have thought that an aircraft running out of fuel was a fairly simple thing to insure against, my car has a dial that tells me how much fuel I have and how far it will take me do not aircraft have something similar ?
It's probably not very simple to accurately measure the fuel in the many tanks in an aircraft. I'm not sure they even have float sensors like the ones found in cars. Also, they continually redistribute the remaining fuel between the tanks to maintain the aircraft's trim as the fuel is consumed.
If I'm correct, they rely heavily on the amount of fuel that was metered into the tanks when they were filled combined with the amount of fuel that is pumped to the engines as the fuel is consumed. One potential problem is that the actual amount of fuel loaded may not match the amount of fuel that gets plugged into the flight computer by the flight crew. If there is a human communication foul up, SURPRISE!
I was on a plane once when there was some confusion about how much fuel actually was in the tanks. The only way they could be sure was to unload all the fuel and refill it from scratch. It took quite a while, but I was happy to wait while they got it right.
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The human brain is often compared to a computer but this is not all that accurate. A computer is nothing more than an information storage and retrieval device. The human brain is much much more. When I was 15 years old my family took a trip to Washington State to visit Mt. St. Helens. This was 1985, 5 years after it erupted.
Because I'd just gotten my learner's permit (to drive) I did most of the driving from our home near San Fransisco. We had just crossed the Columbia River into Washington and I was driving along the river. My father and mother were in the back seat and my sister was up front with me driving. Dad was saying that I was like a computer, able to follow directions but I didn't have enough experience to make wise decisions on my own in case of emergency. Just as he said this things on the back dash started to fly passed his head.
There were many windsurfers playing in the water and I was zipping along about 45 or 50 MPH. Suddenly a small group of people climbed the river bank and started to cross the road. The people stopped to let me pass (it was far too late for me to stop safely). But they had a large dog that was not on a leash and the dog stopped right in front of me. There was a gravel parking lot on the right but a motor home was in the way. My choices were quite limited. Swerve left and run down the people, swerve right and crash into the motor home or continue strait and kill the dog (and wreck the car). I stomped the breaks thinking how sad I was going to be for killing someone's dog. Then the motor home pulled forward just enough. I don't remember thinking anything. I just acted. I took my foot off the break and severed to the right. I clearly remember the dog pulling his head back as I went by. I missed him by inches. I looked in the mirror as I drove away and saw the people hugging their dog. I just smiled. If a computer had been driving I think there would have been dog guts all over southern Washington.
No computer can look at something like this and make a decision, then change it's mind when things change. Also, during the Apollo 11 moon landing they had some trouble with the computer being overloaded. When a computer get's overloaded it shuts down entirely and does nothing. A human brain can filter information and continue with dealing with an emergency.
By far the leading cause of plane crashes is pilot error. We should do things to reduce pilot load and try to eliminate errors but to take the human out of the cockpit is a bad idea.
No computer can be programed ahead of time to deal with all possible emergencies, mainly because in any system all possible emergencies are very nearly infinite! I hate this term 1 a 1 google or a googleplex are all equally close to infinite. Let's say all possible emergencies are probably around a googleplex. Only a thinking person can deal with situations never before encountered.
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I would have thought that an aircraft running out of fuel was a fairly simple thing to insure against, my car has a dial that tells me how much fuel I have and how far it will take me do not aircraft have something similar ?
Yes indeed. Pilots don't always pay enough attention to it though. Also pilots are taught not to trust such systems. They are trained to check the fuel physically, looking into the tank or rapping it to see where the level is. They also check to ensure there is no water in the fuel and that it has the proper type of fuel. FAA regulations require that a plane carry enough fuel not only to reach it's destination but to fly to an alternate airport incase the target airport becomes unavailable. After 9/11 all US airspace was closed. Planes en route from else where had to fly to other countries. Some friends from Ireland were forced to land in Canada instead. But even good pilots make mistakes. And there are a fair number of bad pilots. Sometimes in combat you may lose fuel as well.
In the 1950's a DC-4 (a four engine piston powered liner) flying from Hawaii to San Fransisco broke a drive shaft in one of it's engines. The pilots were unable to feather the prop so it just windmilled causing a lot of extra drag. The extra drag caused the plane to run short of fuel and they were forced to ditch in the sea. Everyone was unhurt and the pilot did such a good job of ditching that the cabin was not breached. The navy had to shell the plane so it would sink! They made a really bad movie about it staring John Wayne, later the comedy Airplane was based partly on The High and the Mighty.
Had the High and the Mighty been made in the 70's it would have stared Cheech and Chong I think.
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One day the Americans will lose a city due to their Imperial/SI units confusion while testing nuclear warheads then maybe they will adopt the metric system.
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Whilst I have great sympathy with the idea that a pilot should have a final override because there are circumstances where a good pilot will always make better decisions than computer software, it is worth looking at these stats:
http://www.planecrashinfo.com/cause.htm
They show pilot error to be the main cause of serious accidents. One danger is that introduction of sophisticated systems will further de-skill the pilot's job, reduce the training he may get and reduce the need for as good a qualification to get the job. In the example above I wonder whether if a pilot who had not been a glider enthusiast would have coped as well. Airbus Industrie's argument is that they reduce the chance of getting into situations where the pilot has to make such decisions. I don't think there are enough comparable statistics to judge at the moment.
As a matter of interest I worked on some of the early fly-by-wire systems (chip designs). Fly-by-Wire systems really just replaced direct mechanical linkages with electronic systems. There were quite a few people who did not think this wise too as there were people who did not like control lines replacing with hydraulics. Of course these systems do not remove decision making from the pilot, but they did remove a degree of physical feedback - though actually many later aircraft give artificial physical feedback.
I think the concept in a modern aircraft is to allow the pilot to fly the plane simply and not have to try to manage too many functions simultaneously. The pilot who landed on the Hudson River did really well - if a wing had dipped a bit it could have flipped the plane over. By the way, it was an Airbus A320 with the computer doing a lot to manage the attitude of the craft.
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Graham - I agree. Finding the right balance between experience and automation is the challenge. BTW, did you see in the news recently that a flight bound for Minneapolis overshot its destination by a about a hundred and fifty miles? The air traffic controllers could not get the crew to respond on radio. They were about to scramble fighter jets to intercept it when they finally managed to contact the crew! Precisely what they were up to is still a matter of conjecture.
I don't know much about avionics. Do you happen to know if there is a trend to consolidate all the fly-by-wire controls into a single computerized system, or are they deliberately implemented as discrete control systems? These days I would think it's entirely possible to control an entire aircraft from a single computer so that it's no longer quite "fly-by-wire", more "fly-by-software". This would look like a weight, power and complexity advantage, but I also think it would be extremely dangerous.
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I am no expert on avionics either even though I worked on a small part in the past. All avionics systems have multiple redundancy and a lot of effort goes into ensuring there are as few as possible common components whose failure would be critical. This extends to software, so not only are there multiple computers with "voting rights", but also the critical software is written by teams operating independently. In passenger aircraft, safety will trump weight, and electronic systems are generally not heavy. The fly-by-wire technology reduced the weight of copper wire considerably as all the data goes via a serial bus (multiple and separately routed for redundancy).
I didn't know about the Minneapolis flight. It's hard to know how they could do that because everyone has GPS now even if flying manually. 150 miles is not far though - they may have mistakenly thought they had much further to go and had their attention drawn to an in-flight snack :-) I guess that they should have been monitoring ATC though.
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Thanks for the reassuring information!
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When I used to come home from Hamburg in the eighties the computer used to bring the plane to about 10M above the long LHR runway then what seemed to be an interminable time later the pilot would wake up "oh yes we are supposed to be stopping here" and switch it off and we would come down with a bump.
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When I used to come home from Hamburg in the eighties the computer used to bring the plane to about 10M above the long LHR runway then what seemed to be an intermingle time later the pilot would wake up "oh yes we are supposed to be stopping here" and switch it off and we would come down with a bump.
Yes. I've noticed something like that quite often. I think it might be something to do with "ground effect". A plane tends to float on a cushion of air the closer it gets to the ground. Sometimes it seems as if they really have to force them on to the runway. Other times they seem to be able to land so gently you don't even notice they have landed. Any pilots out there?
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Syphrum, are you saying that you think the pilot decided to disengage auto landing because the hold-off period was too long? I would suppose he could do this but the only reason I can think of would be because he felt that it would delay his getting the aircraft to its parking bay because it would involve a longer period of taxiing back. LHR runways are quite long. You get two effects approaching the ground, ground effect and wind shear (plus residual turbulence from previous aircraft). Normally landings are into wind and, because the wind drops as you get nearer the ground, the aircraft's airspeed falls as you descend, which helps to counter ground effect and lets the aircraft get down gently. I related a personal incident in another post where I had to land downwind and where it can be hard to get on the ground in the usual way. Flying the aircraft on to the ground can be more bumpy and it can be hard to stop the craft wanting to get airborne again :-). It is a technique used though and is especially recommended if damage to an aircraft has rendered knowledge of the stalling speed unreliable.
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When I used to come home from Hamburg in the eighties the computer used to bring the plane to about 10M above the long LHR runway then what seemed to be an intermingle time later the pilot would wake up "oh yes we are supposed to be stopping here" and switch it off and we would come down with a bump.
Yes. I've noticed something like that quite often. I think it might be something to do with "ground effect". A plane tends to float on a cushion of air the closer it gets to the ground. Sometimes it seems as if they really have to force them on to the runway. Other times they seem to be able to land so gently you don't even notice they have landed. Any pilots out there?
When a tricycle landing gear aircraft lands (as opposed to a tail-dragger, where the third wheel is at the tail of the aircraft), the aircraft has to be stalled to get it on the ground and the skill in making a smooth landing is to get it to stall just as the gear touches the ground, so that it doesn't simply drop on to the ground.
The aircraft has to come down the glideslope at a speed safely above the stall speed, so that there's no risk of it crashing short of the runway, but this means that once over the runway it has to shed the excess speed. To do this, the nose-up attitude of the aircraft is increased (called the flare), which increases its effective cross section, which in turn increases its induced drag and slows it down. However, increasing the nose-up pitch also increases the Angle of Attack (AoA) over the wings, which increases lift, which tends to keep the aircraft in the air.
The actual stall speed depends upon both the speed of the aircraft and its weight and although the landing weight of the aircraft can be calculated quite accurately, based upon fuel level sensors and loading records, getting it perfectly right, so that the stall occurs just at the touchdown point, requires a very high sensing rate, whether it be by an autopilot/Flight Control System or the pilot's backside. Another factor that complicates the issue is that runways are not perfectly flat or level and there may be quite an appreciable slope to the runway. While it's relatively easy to land 'uphill', landing 'downhill' is more problematic because the runway is dropping away beneath you, so getting the stall just right is even harder.
The effect of a tailwind, if is relatively steady, is mostly just to increase the ground speed, but this then means you'll be further down the runway when you touch down and have got to slow down from a higher speed, so it's likely that a pilot will be more inclined to just get the aircraft on the ground and stopped before he runs out of runway than making the smoothest of landings.
Most land based aircraft cannot be flown into the ground without sustaining some degree of damage - have a look at this MD-80 that failed to flare:
http://www.youtube.com/watch?v=x9deMKE-iek (http://www.youtube.com/watch?v=x9deMKE-iek)
Not only does the tail fail off (because it carries the engines, which are very heavy) but the gear nearly collapses and it's also possible to see the fuselage flex, and nearly buckle.
However, aircraft that land on aircraft carriers are just flown onto the 'deck' as there's no room for a flare. These aircraft have to be specifically strengthened to do so though, both in regard to their landing gear and their structure, as not only do they have to cope with the high vertical speed at touchdown but also the rapid deceleration once they've caught the wire.
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Just a thought.
All aircraft are flown by computers; in practically all cases the computer concerened is between the pilots' ears.
The difference is that in one case the software has been in development for rather longer than the other. The problems highlighted earlier are not due to the use of computers- just that the computers were not programed properly.
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Lee, there is flying into the ground and flying into the ground. Good grief, in the video the pilot made no attempt to reduce is descent slope at all. Perhaps he was an ex-navy pilot thinking he was hitting the deck of a carrier. There is a compromise that can be reached without such disasterous results. It can be done quite safely. Carrier pilots do it because they have to hit the deck in a particular region to catch the arrester system and, also, the deck is likely to be going up and down just to make it harder.
In fact this site suggests that (gently) flying the aircraft into the ground is commonly used. You level out close to the ground and cut the engine, but the implication is there is no need to wait for a stall to drop you down.
http://www.auf.asn.au/groundschool/umodule12.html
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Thanks guys! These are very informative posts.
BTW, here's some of Captain Sullenberger's take on it
http://cityroom.blogs.nytimes.com/2009/11/15/sullenberger-takes-issue-with-new-book/
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One day the Americans will lose a city due to their Imperial/SI units confusion while testing nuclear warheads then maybe they will adopt the metric system.
There is currently a ban on nuclear weapons testing so it's not even being done anymore so you can relax. I have a friend who's a cop. He pulled over a guy for speeding and he told her he got confused between MPH and KPH. Unfortunately for him, If this were true he was speeding thought he was going much faster than he was. A kilometer is much shorter than a mile (.61 mile to 1 kilometer) so 61 MPH is 100 KPH.
I'm used to miles and feet but I'd prefer using metric. It's just a mater of getting used to the new system. They are now teaching metric to kids in school so maybe the switch will take place in the next generation.
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Lee, there is flying into the ground and flying into the ground. Good grief, in the video the pilot made no attempt to reduce is descent slope at all. Perhaps he was an ex-navy pilot thinking he was hitting the deck of a carrier. There is a compromise that can be reached without such disasterous results. It can be done quite safely. Carrier pilots do it because they have to hit the deck in a particular region to catch the arrester system and, also, the deck is likely to be going up and down just to make it harder.
In fact this site suggests that (gently) flying the aircraft into the ground is commonly used. You level out close to the ground and cut the engine, but the implication is there is no need to wait for a stall to drop you down.
http://www.auf.asn.au/groundschool/umodule12.html
When you level out (from a nose-high attitude) close to the ground you reduce the lift produced by the wings so that they can no longer support the weight of the aircraft.
The most important thing though, is that once you've got the aircraft on the ground you want to ensure that it has insufficient speed to take-off again i.e. the wings have insufficient lift and the aircraft is effectively stalled. So yes, just as you can drop an aircraft onto the runway, albeit from a very low height, you can put a tricycle aircraft down while its wings are still generating enough lift to fly as long as you can lose that lift by putting the nose down (which is one of the greatest benefits of tricycle landing gear over tail draggers; if you bring a tail landing gear aircraft down on its mains, and then drop the tail, you increase the AoA over the wings, which increases lift and which may cause the aircraft to take-off again. This will only be temporary though, as increasing the AoA by bringing the tail down also increases the drag, which means that once the aircraft is back in the air it rapidly loses speed and finally stalls, but probably from an unsafe height).
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Exactly right Lee. I remember a few times when, despite a tricycle undercarriage, the aircraft I flew, err, bounced a bit! When this happens you can get quite a change to the AoA in a rather uncontrolled manner. Fortunately it tended to eventually settle down but tends to worry onlookers a bit :-) I got better though. It takes a while to be able to judge how high you are off the ground, though not quite as bad as in the video you posted; he must have thought the ground was another 100 feet below him.
I gave up flying long ago although my wife has bought me (for my last birthday) an hour flying a Phantom - regrettably only in a simulator though. I have yet to take it up. I am told by an ex-airforce pilot that I probably won't get far without a lot of help. Still, it should be fun. It was either that of a 737, so no choice really.
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I've no idea what happened with that MD-80 and can only assume some sort of failure prevented prevented the flare. It did look a bit like a carrier landing though.
Re your landing 'moment'; well, they say that any landing you can walk away from is good, but be thankful that you weren't flying a B-52. Controlling lift, via speed, in these motorised swept-wing gliders at touch-down is crucial because of their quadracycle landing gear. If you try to touch down on the front gear first, and then bring the tail down, the increase of AoA across the wings, which are set at +six degrees incidence at the roots, generates a lot more lift with the result that the nose of the aicraft balloons up, perhaps to 50-60 degrees, and with the tail dragging along the ground. Pretty quickly though, the extra induced drag stops and stalls it, at which point it comes crashing down again, usually resulting in a complete write-off, even assuming no fire.
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When I used to come home from Hamburg in the eighties the computer used to bring the plane to about 10(metres?) above the long LHR runway then what seemed to be an interminable time later the pilot would wake up "oh yes we are supposed to be stopping here" and switch it off and we would come down with a bump.
When talking to some commercial airline pilots in the past, I was told that the plane's manufacturers recommend pilots drop the plane down fairly hard on the runway - although no doubt plenty of experienced pilots pride themselves on smooth landings. From what I understand, the hard landing is safer particularly if there's crosswinds or other such complications.
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This sort of question comes up increasingly with technology taking over traditional expertise.
You could ask the similar: "Would you trust a machine over a surgeon to perform major surgery on you?"
"Would you want to travel in a fully computer-controlled car on the public highway?"
The debate also rages on in various aspects of medical diagnostics where machines with sophisticated software perform blood tests etc in the GPs surgery instead of sending samples away to a lab. The results come back far quicker, and in the main are probably more reliable - but over time you end up with fewer and fewer people who understand the test and its limitations... and an organisation which abruptly becomes paralysed when the wonder-machine breaks down.
I suspect that in many cases where computer-control is deployed, the machine is at least as good as the average professional it replaces (in terms of narrow well-defined conditions like straight-and-level flight, it probably outperforms all humans). Of course that means it's worse than the 'best' professionals. But then the 'best' professionals probably started out as average professionals, who then learned from experience as their career progressed. Computers don't normally learn from experience.
If we fully replace professionals with computers, although we may make short-term gains, there is a grave danger we will cease learning and advancing the skill.
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Latest on the flight that flew past its destination
http://news.yahoo.com/s/ap/us_flight_overflown