Take-Off Room

Q: I was on a flight from Amsterdam to Manchester. While accelerating for takeoff we stopped suddenly on the runway due to conflict with a plane ahead. After a few minutes we restarted the takeoff from the point where we’d stopped. I can’t help wondering how much of the runway we’d used up in the first attempt. How did the pilot know we had enough runway left?

Well, it’s not like the crew figures “Yeah, this is probably enough room,” and gives it a go. Runway length must always allow for two things: 1. successful climb (the data includes off-airport obstructions) assuming an engine failure at the most critical point of takeoff, and, 2., sufficient distance to stop following an aborted takeoff initiated at this same moment. This length will be variable depending on weight, temperature, wind, atmospheric pressure, etc.

If it seemed your crew was able to calculate rather quickly, it’s because the info can be processed by the folks backstage (dispatchers and flight planners) and relayed to the pilots via computer in a matter of seconds. Alternately, it’s available in the tables and graphs in the on-board performance manuals.

Airplanes will typically used the full length of a runway, but once in a while this isn’t entirely practical or necessary. So-called “intersection departures” are not uncommon, and aren’t necessarily a case of bad judgment. Amsterdam to Manchester is a very short distance, so I doubt your flight was heavily loaded, and the runways at Schiphol are long. Not the usual procedure, but neither was it unprecedented.

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This article is part of a collection that originally appeared on Salon.com. Patrick Smith, 38, is an erstwhile airline pilot, retired punk rocker and air travel columnist. His book, Ask the Pilot (Riverhead) was voted “Best Travel Book of 2004” by Amazon.com. Patrick has traveled to more than 55 countries and always asks for a window seat. He lives near Boston.