· Clearance limit, the end point of the clearance (usually, but not always, the destination airport)
· Route, the route that the flight is to follow as part of the clearance (often the route originally filed, although ATC may change this)
· Altitude, the initial altitude to be maintained by the flight, plus, in many cases, a time at which cruise altitude clearance may be expected
· Frequency, the frequency to which the pilot(s) should tune upon leaving the departure airport
· Transponder, the transponder code that must be set for the aircraft prior to departure and during the flight. T also stands for time, as in void time, if one is issued. A void time is an expiration time, meaning, the IFR clearance is voided if the aircraft is not airborne by the void time.
Consider the following example of an IFR clearance:
N12345 cleared to Las Vegas airport via the HOLTZ seven departure, Daggett transition, then as filed, climb and maintain five thousand, expect flight level three three zero one zero minutes after departure, departure frequency is one two four point five, squawk six five six two.
In this example, the clearance limit is Las Vegas Airport. The route is the HOLTZ7 Standard Instrument Departure, with a transition fix at the Daggett (DAG) VOR, and the rest of the route is as filed in the flight plan. The flight should climb to and maintain 5000 feet initially, and further clearance to FL330 may be expected (but is not guaranteed) ten minutes after departure. The frequency to which the crew should tune after departure is 124.50 MHz, and the transponder should be set to 6562 before departure. There is no void time in this example.