Would an Airplane on a Conveyor Crash in the Potomac?

Hi folks -- got an airplane-story trifecta here. The first two involve crashes, so if you're afraid of flying, maybe you should just skip to the end.

1. Air Florida Flight 90
First, saw this article in today's Washington Post (my local fishwrap): "A Crash's Improbable Impact" -- it's about the crash of Air Florida Flight 90, which occurred 25 years ago tomorrow.

Shortly after takeoff from Washington National Airport (now Ronald Reagan Washington National Airport), Flight 90 crashed into the 14th Street Bridge, killing 73 on-board and 4 motorists; 5 passengers survived after being pulled from the icy Potomac River (you may recall the images). One additional passenger, Arland D. Williams, drowned after passing a lifeline to other survivors.

It led to sweeping changes in airline safety procedures, cockpit culture and more -- check out the article. The democratization of the cockpit, and the demonstrated value in listening to all your team members, is especially interesting to me.

2. The Gimli Glider
In another, much cooler airline story with a happier ending, there's the Gimli Glider incident of 1983, when the crew of an Air Canada 767 with 61 passengers on board ran completely out of fuel.

As fate would have it, the captain of the flight had extensive experience piloting gliders, so he was able to set it down on a closed airport that had been converted into a race track.

What's also cool is, even after sustaining some damage (the nose landing gear didn't lock), the plane was repaired and is still in service. (Story link via Digg yesterday.)

3. Planes Spinning Their Wheels?
Finally, Salon's "Ask the Pilot" column today begs for mercy on the "Airplane on a conveyor belt" brain teaser that he brought up last week.

This one has been floating around on the Interwebs for a while. Depending on your point of view, it's a little counter-intuitive, but more importantly, the problem changes radically depending on the wording. It asks this:

If you put a jet plane on a conveyor belt [the exact wording of speed of the conveyor belt is what changes the question], will it take off?

The answer is "Yes", but I will get to that in a second.

I think I first saw it on Kottke.org at the beginning of 2006; it hit the Web in a big way after a Straight Dope article covered it, including  9 pages of discussion in their message boards.

As these things do, it disappeared out of view, re-emerging after NYT writer David Pogue blogged about it in December, which is where Salon's guy found it (boingboing also helped reinfect us with it).

Like I said, the plane takes off. Like many people, originally, I thought it wouldn't. The question should really be: Can a plane on a treadmill move forward? If it can move forward, it can get air moving over the wings, which would mean it would be able to get off the ground.

Since a plane gets its forward thrust from its engines (the wheels are just there to keep the plane from grinding a groove into the runway), it doesn't matter if the plane is taking off from a stationary runway, a treadmill, a sea of ball bearings, a frozen lake, water or anything else.

The thing that gets people is they immediately think of cars on dynometers (those big rollers when you go for an emissions test), or themselves on treadmills.

Anyway, even if people get bogged down into discussions of frictionless bearings and static coefficients of friction (which you can get plenty of in the Straight Dope discussion), it's more demonstrative of the importance of proper writing.

Thanks -- Joe

Tags: gimli glider, flight 90, straight dope, airplanes on conveyors