Aviation Speak

Flight Level

In the United States, aircraft flying above 18,000 feet mean sea level travel at flight levels defined by pressure altitude rather than by local barometric pressure. Flight levels are written as the letters FL followed by three digits, so that FL180 corresponds to a pressure altitude of 18,000 feet, while FL240 corresponds to a pressure altitude of 24,000 feet. Flight levels are used at altitudes at and above 18,000 feet so that all aircraft at these altitudes are using the same altimeter setting - in this case 29.92 inches of mercury. The object is to allow aircraft traveling great distances at high speeds to continue on their way without constantly having to update the altimeter setting to local barometric pressure. But because pressure altitude - the altitude read off the altimeter when the number in the Kollsman window is set to 29.92 - is not always the same as true altitude, aircraft that are climbing to, or descending from, the flight levels to a lower altitude must update their altimeter settings as they pass through FL180. On the way up, pilots dial in 29.92. On the way down, local surface pressure readings are selected in order to get accurate altimeter readings in preparation for low-level flying, approach, and landing.

Ident

If you've ever received radar flight following, you've probably been asked to squawk a given transponder code and ident. When an air traffic controller asks you to ident, he or she is asking you to push the button labeled "Ident" on your transponder. You don't need to hold the button down or push it repeatedly. Just touching it once will do the job. This causes the radar return from your aircraft to brighten on the controller's screen, making it easier for him or her to identify you in a crowd. You should never engage the ident button unless you have been asked to do so by air traffic control.