How do we lose an airplane

[Savannahmann]

216. The Air France flight that crashed a few years ago.

The cause of that was catastrophic human error. The pitot tube froze in bad weather. The autopilot could not fly the plane without speed imput from the sensors. The autopilot threw up it's virtual hands and told the pilots "I'm out, you have to fly."

The pilots did the wrong thing. They did not fly the plane, they focused on the problem of the air speed information that was missing, and the autopilot. The copilot pulled back on the stick, causing the plane to go up, and then it stalled. Air was no longer flowing across the wings to provide lift.

The computer recognized a stall in progress and told the pilots over and over again. Stall, Stall, Stall the computer repeated the entire time the plane was falling, for almost five minutes, both pilots heard the warning bells and the computer chiding them with that word. Stall. But the copilot held the stick back until the plane hit the ocean. They were dropping at 12,000 feet per minute as they hit the water. Simple problem, compounded by human error.

I'm torn. I like technology, and think it is great. But, we become dependant on the technology. The pilot becomes accustomed to things working right. I can imagine the pilot thinking he's flown thousands of hours in this kind of plane and nothing has ever gone wrong. he becomes complacent, relaxed, comfortable. Then when the computer kicks out and says fly the plane human, the pilot has to start thinking immediately. They have to shift from all is well to holy crap what is going on in less than a second. The first question going through their minds is almost certainly what is wrong with the computer. Not what is wrong with the plane, but what is wrong with the computer.

Quantas flight 32 is a great example of that. The engine blew up, and the pilot did the right thing taking manual control immediately. Then he flew straight and level while they determined the problem and how bad it was. The co-pilot spent the next 55 minutes going through all the warnings on the computer one by one and acknowledging the problem, or authorizing a computer work around, that didn't work.

They worked the problem for 55 minutes while flying a plane that had suffered a catastrophic engine explosion. They flew for 55 minutes with a hole in the wing leaking fuel while they acknowledged what they knew a minute after the explosion. The god damned engine blew up and we need to land the plane as soon as possible or we are all going to die.

They could not start anything else until they had acknowledged the computers long list of problems. Then they still had to do what they could have been doing 55 minutes ago. Easing the controls around while they found out how badly the plane was hurt and how much control they had.

On the ground, the crew found to thier dismay that the engine cut off was not working, due to the damage to the wing. So they could not shut down one of the engines. The chief engineer at Quantas suggested squirting water into the engine to make it fail. Engines are designed to work in that very situation. After an hour of firetrucks pumping water into the engine to no avail, they decided to try firefighting foam. That extinguished the engine, making it safe for the firefighters to approach the plane and deal with the fuel leak.

Taca Airlines flight 110 exposed the problem of plane engines not working like they are supposed to when throttled back, and the engines were redesigned for that problem. There was no way on earth that a firehose would make it to the combustion chamber and extinguish the flame even at idle. The engine is designed to spit the water out long before it gets to the flame.

Computer assisted controls sound like a good idea, but I have believed for a long time that true piloting skills are lost every hour the computer is controlling the aircraft. You can't help but get complacent, comfortable. Then when an emergency happens, you spend too long trying to figure out what the computer is doing before you start to think about the plane. Precious seconds are lost while you are asking the normal question. What the hell is going on?