In a recent comment reader ZuluDelta wrote:
I have noticed that the occasional aircraft reports that it is "with Juliet" or "Oscar, Tango, Papa, India, Uniform, Kilo" One checked in "with Whiskey"! Perhaps in some future blog, you could elaborate on what these secret codes are.
I almost think that with a name like ZuluDelta, this person might be kidding, but I always err on the side of treating a question as serious. Plus this is an easy one to answer, so it allows me to fill in a day on the blog without incurring the wrath of Texans by saying something inadvertently critical about one of their freeway ramps.
When an airport has a control tower, whether it's in Texas or not, there is almost always a published frequency that broadcasts a continuously repeating recorded message called the Automated Terminal Information Something. I think it's "Service," and I'm deliberately not looking it up to demonstrate how I don't care. We call it "the ATIS," pronounced Eh-Tiss. It might sound something like this:
This is Somewhere Airport Information Charlie, recorded at one nine three zero zulu. Wind three two zero at one four gusting two zero. Sky clear. Visibility fifteen miles. Altimeter three zero one four. IFR approach is a visual approach runway two zero. Active runways two zero and three five. Note One: Echo three taxiway is restricted to aircraft wingspan under 50 feet. Note Two: construction equipment operating west of runway 01/35. Vehicles will remain 400' from runway at all times. Inform Somewhere Tower on initial contact you have information Charlie.
The recording is often made by a human, just one of the controllers in the tower who checks the current conditions, presses a button on the machine and talks into the recorder. You can hear the regular hubbub of tower activity in the background, and there are stories about things audible on the ATIS that shouldn't be. Sometimes the conditions are coded in machine readable form and the ATIS is provided by a mechanical voice.
Either way, the ATIS is updated as required to keep up with changes in the information, usually at least once an hour. Every time it is changed, the information letter is incremented. So the first one in the morning is Alfa, then Bravo, then Charlie and so on through the radio alphabet. That way you need only listen long enough to hear the letter, called the identifier, to know if you have the latest information.
You tune the ATIS frequency and come in somewhere in the middle of that, drumming your pen impatiently on your kneeboard as they waddle through all the taxiway closure stuff when all you want to know is which approach plate to get out. You copy down the information and then call up the controller and "prove" that you have done your homework by specifying which ATIS information you have. If you don't say, or if you say but they weren't paying attention, they will ask you to "Confirm you have Quebec." If they've changed it between your picking it up and your calling them, sometimes they say "Information Romeo is now current. Inform when you have Romeo" and make you go listen again before they will talk to you.
Pilots and controllers get mileage out of making fun of the names of the letters. I've heard ATIS recordings that advertise "Information Echo-co-co-o" and I'm sure the story about the passenger named Mike or Charlie who asks "why did he ask if I was with you?" Here's a PilotsofAmerica forum thread on silly ATIS messages.
Here's an MP3 of an ATIS recording from
Ferihegy airport (
I think it's in the Czech Republic in Hungary). Here's
live ATIS from
Bankstown, Australia, if their tower is open when you click
it. This last one contains profanity, and it may or may not have
ever been actually broadcast but it perfectly demonstrates the
mechanical ATIS voice. And it's very funny if you don't mind
hearing a few words that shouldn't be
said on the radio.