Which of the following is a CPDLC message example?

• A. Descend via
• B. Maintain present altitude
• C. Turn left heading 180
• D. Request weather update

Answer: (A)

CPDLC messages are the standardized, text-based communications used between pilots and air traffic control over the data link to convey clearances and requests. “Descend via” fits exactly as a CPDLC directive because it is a concise, predefined command that tells the pilot to descend according to the ATC-assigned altitude constraints. This kind of altitude-management instruction is a hallmark of CPDLC usage, designed to replace or supplement voice transmissions with clear, machine-encoded phrases.

The other phrases describe actions or requests that are typically given by voice or aren’t the canonical CPDLC command format for altitude changes, so they aren’t typical CPDLC examples in the same way.