From the Flight Deck

Here's a spectacular view of a volcanic island hundreds of miles north of Iceland
while enRoute from Toronto to New Delhi when I flew the "big bus."



This article appeared in enRoute August 2003.
Notice the pilot going "above and beyond." We get a lot of
notice from passengers when we do this. Most pilots
will snag it as "dirty windscreens" in the log book.
(Click on article to enlarge)


This question is from my Ask Doug column. Even though it did not make the cut, it's a great question.

Hi Doug, I was on an Air Canada flight today from Vancouver to Toronto with a beautiful clear view over the Rockies, I saw a huge mountain was off in the distance and I wondered how far away it was, so my question is this... How far away is the horizon from a typical cruising altitude?

It's a very good question and I touched on the topic in my book: From the Flight Deck: Plane Talk and Sky Science (page 27).

The formula we use to determine how far our radios will receive/transmit is the exact same for distance seen. Based on the curvature of the earth, this "line of sight" formula is simple, but you'll need a calculator. Take the square root of your altitude in feet and multiply by 1.23 for a value in miles. (For metric units, it's the square root of your altitude in meters multiplied by 3.5, giving a value in kilometres). At a cruising altitude of 39,000 feet (the highest my Airbus 320 flies) will allow you to see 240 miles (386 km) on a clear day giving new meaning to a "room with a view."

Captain Doug