What phraseology is typically used to instruct an aircraft to ascend?

• A. “Descend and maintain”
• B. “Ascent and reach”
• C. “Climb and maintain” followed by altitude
• D. “Increase altitude”

Answer: (C)

The phraseology "Climb and maintain" followed by an altitude is standard in air traffic control communications when instructing an aircraft to ascend. This command is clear and concise, providing the pilot with a direct course of action that specifies not only to climb but also to maintain a specific altitude once it is reached.

Using "climb and maintain" conveys the expectation for the aircraft to increase its altitude up to the specified level, which pilots are trained to recognize and respond to promptly. It ensures there is no ambiguity about what is being instructed, which is crucial for maintaining safety in the airspace.

The other options do not meet the established communication protocols or may introduce confusion. "Descend and maintain" is the opposite of an ascent directive; "ascent and reach" is not a recognized phrase in aviation, potentially leading to misunderstandings; and "increase altitude" lacks the specificity regarding the altitude to be maintained afterwards. Therefore, "climb and maintain" is the appropriate format that aligns with aviation standards for instructing aircraft to ascend.