AIM Text
Pilots on IFR flight plans should communicate with the control tower on the appropriate ground control or clearance delivery frequency prior to starting engines, to receive engine start time, taxi, and/or clearance information.
Source: FAA Aeronautical Information Manual · current edition · paragraph 5-2-4.
The short answer
This AIM section is FAA advisory guidance on taxi clearance for IFR flights. It directs pilots on IFR flight plans to communicate with the control tower on the appropriate ground control or clearance delivery frequency before starting engines, to receive engine start time, taxi, and/or clearance information. It supports orderly IFR departure ground movement and clearance delivery procedures.
Research Notes
Common Questions
When should an IFR pilot call for taxi clearance?
The AIM advises pilots on IFR flight plans to communicate with the control tower on the appropriate ground control or clearance delivery frequency prior to starting engines, in order to receive engine start time, taxi, and/or clearance information.
Which frequency do I use for taxi and clearance?
Per the AIM, pilots should use the appropriate ground control or clearance delivery frequency of the control tower. That same initial contact is used to obtain engine start time, taxi instructions, and/or clearance information before engine start.
What information does the taxi contact provide?
The AIM states this contact lets the pilot receive engine start time, taxi, and/or clearance information. Making that call before starting engines lets ATC sequence the IFR departure on the ground.