Wednesday, February 03, 2010

What's Your Number?

I recently watched the movie "Up in the Air", a story about a corporate downsizer and his travels. The film follows his isolated life and philosophies along with the people that he meets along the way. In the movie, the main character, Ryan (played by George Clooney) runs into another frequent business traveler named Alex (played by Vera Farmiga). The question comes up; "What's your number? How many miles do you have?" They are of course, referring to the frequent flyer miles that are used for upgrades at various airports and hotels. To two well-traveled business people, that's kind of a personal question. Ryan reveals to Alex that he has a goal, a number in mind, of how many miles he wants to achieve. His goal - 10 Million Miles! It got me thinking about how many miles I have flown in my years as an airline pilot.

Before I could figure that out, I started thinking about the difference between nautical miles and statute miles. The average land-lubber uses statute miles, your car's odometer uses statute miles, and the speed limit signs on the road use statute miles per hour. Statute miles date back to the Roman Empire; 1,000 (left-right) paces by a Roman soldier equal one statute mile.

Ships and airplanes on the other hand, use "knots" as their unit of speed, one knot is equal to one nautical mile per hour. The origin of the word "knot" comes from ships. To measure the speed and distance of a ship, knots were tied into a "log line." This line was thrown overboard, an hourglass was tipped, and the knots were counted. When the sand ran out, the counting stopped, and a general speed was determined.

So why are nautical miles used in aviation rather than statute miles?
It's because pilots use nautical charts — similar to those originally designed for ships — based on longitude and latitude. The world is divided into 360 degrees, with 60 minutes to each degree. Each minute equals a nautical mile. So you might be asking, "What's the actual difference, speed and distance wise, between a nautical mile and a statute mile?" Well, one knot is equal to 1.15 MPH and one nautical mile is 5,280 feet, while one statute mile is 6,076 feet.

As an ironic side-note, the first airplane I flew was so slow that the airspeed indicator used MPH instead of knots, that way you at least felt like you were going faster.

After I did this little bit of research, it got me wondering, "Do the airlines use statute miles or nautical miles for their frequent flyer programs?" I checked a few different airline websites, after typing in different cities into the airlines mileage calculators, I compared it with the great circle mapper. You'll be happy to know that the airlines use statute miles, so you're gaining the higher number.

So how many miles have I flown? I didn't have the time to go through 16 years of flying and figure out the distance - we measure our time in the air by hours, not miles. I did however go through my 2009 calendar year and with the help of the great circle mapper, I calculated that with commuting, vacations, and of course trips that I actually flew; I flew a total of 370,667 nautical miles. If you were to convert that into statue miles (or frequent flyer miles), that's a grand total of 426,267 statute miles.

So, what's your number?