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Jet Take off

August 22, 2000

A public radio commentary

I'm in the Chicago airport about to board a plane for Pittsburgh. To me, this is bit tense. Even though I'm an engineer, I'm a bit afraid to fly. For piece of mind, I've had learn exactly what happens when a jet takes off. And today I'm going to sit in the very back of a jet near its engines, and share with you what's happening.

Of course, that announcement gets me slightly more tense.

As I walk down the jetway, I first hear the sound of the compressor underneath that powers the plane right now. Its, of course, muted as I enter the fuselage.

As I buckle in, I watch for several things. First, I watch for the lights to flicker and the air conditioning to pause. That means the engines have been started with a blast of air from the terminal. There is only enough power to run either the air-conditioner or to start the engines. Then as the engines run they generate enough energy to power the air conditioning and lights, which come back on. Here they are.

Next, I can hear the pilots turn on the hydraulic pumps. They're preparing the brakes for take-off. Yes takeoff, if needed the pilots will halt the plane right in the middle of the runway.

We're now taxing to the runway, I can see the pilots adjust the flaps - this is the part of the wing that is extended for take off. These flaps give the jet more lift, letting it take off at a lower speed.

Now we've lined up on the runway, ready for take off - it'll take only thirty very quick seconds.

The pilot's revving the engines and we're moving. Now the jet has reached the speed Vee One, the maximum speed at which the pilots can stop the plane. If any error lights go on in the cockpit right now, the pilots will kick in the autobrake, which'll dramatically halt the plane.

Now, we've reached the speed Vee Two. We're still on the ground, but at this speed the plane cannot stop, we MUST take off.

I can hear the overhead compartments shake. I remind myself that they are lightweight plastic and have nothing to do with the structural integrity of the plane.

I can also hear a "bumping" sound, that's because the pilot is right on the centerline, and every seventy-five feet there a light that the plane rolls over.

Now, the nose of the plane has lifted, this is speed Vee R - R for rotation.

And we're in the air.

And you can hear the engines quiet down slightly, and I can hear the thump as the landing gear comes up.

Sit back and enjoy your flight. I don't think so, I'm already worrying about landing. Flying in a jet from Chicago to Pittsburgh, I'm Bill Hammack.

Copyright 2000 William S. Hammack Enterprises