This is your flight attendant speaking. We are now beginning our descent into YCW, Collected Wisdom's private executive airport. So fasten your seatbelts, and could someone please retrieve the drink trolley from the cockpit?
THE QUESTION
Why do Canadian airport codes begin with Y? asks Keith Middleton of Paris, Ont. And why does Pearson International in Toronto have the cryptic YYZ when other major airports have codes that reflect their names, such as LAX (Los Angeles International)?
THE ANSWER
For this one, we hand the controls to aviation enthusiast Scott Walker of Toronto. "All airports around the world (with a few exceptions) have a three-letter code determined by the International Air Transport Association (IATA)," he writes.
Under this system, major Canadian airports begin with a Y, although there are a few other airports around the world that also start with a Y (such as YUM for Yuma International Airport). Some Canadian airports add letters from the city's name after the Y, such as YOW for Ottawa, YYC for Calgary and YVR for Vancouver (which really stands for Yes Very Rainy, Vancouverite Al Colodey says).
"The obvious choice for Pearson," Mr. Walker writes, "would have been YTO," but since Toronto has more than one airport, YTO is used for the area designation, while Pearson is called YYZ, Billy Bishop Toronto City Airport is YTZ and Toronto/Buttonville Municipal Airport is YKZ.
"Canadian airports are not the only ones with IATA codes that don't match the name," he adds. "Chicago's O'Hare airport, the fifth-busiest in the world, has the designation ORD. That's because it was known originally as ORcharD Field."
In the United States, CW has learned, many airports' letters date back to codes used for weather stations.
In the early days of aviation, according to a 1994 article in the journal of the Air Line Pilots Association, airlines simply copied a two-letter system used by the National Weather Service to identify cities around the United States that had weather stations. As airline service exploded in the 1930s, the article says, "towns without weather-station codes needed identification. Some bureaucrat had a brainstorm and the three-letter system was born, giving a seemingly endless 17,576 different combinations. To ease the transition, existing airports placed an X after the weather-station code." Thus, the Los Angeles tag became LAX.
THE QUESTION
"We are urged to brush our teeth with toothpastes that claim to reduce plaque, whiten teeth, preserve enamel and so on," writes W. Clements of Toronto. We are also urged to use mouthwash. Wouldn't the mouthwash wash away the toothpaste before it could do any good?"
THE ANSWER
Don't worry about it, says David Rose, a dentist in Thornbury, Ont.
"There is actually very little therapeutic benefit to mouthwash," he says, "and the only useful ingredient in toothpaste, which mostly acts as a lubricant, is fluoride. The only people telling us to use mouthwash are the mouthwash manufacturers. One should spit but not rinse after using fluoride toothpaste and let the good stuff hang around for a few minutes."
HELP WANTED
Why are Roman numerals used for the copyright year in movies and videos rather than standard numbers, as is the case with books or printed material? Patrick Tallon of Toronto wants to know.
Don Large of Kingston wonders how those huge taxes on airfares are calculated.
Why are the hands of a watch or clock always shown at 10 minutes after 10 in advertisements? asks Tim Hollick-Kenyon of North Vancouver.
Let's hear from you: If you have the answer to one of these questions (or a question of your own) send an e-mail to wisdom@globeandmail.com. Please include your location and a daytime phone number.