Which of the following best illustrates standard phraseology to assign a SID for departure?

• A. <Callsign>, fly via <SID name>, climb/descend as assigned, maintain <altitude>.
• B. <Callsign>, fly via <SID name>, climb/descend as assigned, and descend to <altitude>.
• C. <Callsign>, depart via SID, turn left immediately, maintain altitude.
• D. <Callsign>, SID departure is authorized, proceed as directed.

Answer: (A)

Using standard phraseology to assign a SID means directing the aircraft to follow the published departure path and its altitude steps. Saying “fly via ” tells the crew to execute the SID from takeoff, following its route and initial climb as published. Adding “climb/descend as assigned” communicates that vertical changes should follow the SID’s published restrictions (or any altitude ATC assigns later), rather than making unsanctioned climbs or descents. Ending with “maintain ” gives a clear, explicit altitude to hold after the SID’s steps or after reaching a published constraint, preventing unintended altitude changes. This combination ensures the departure is executed exactly as designed and with clear vertical guidance.

Other options either introduce nonstandard actions (such as an immediate turn) or fail to provide the clear, standard route-and-altitude instruction required to assign a SID properly, or they state only that a SID is authorized without directing the exact SID and altitude behavior.