Which of the following are RVSM requirements?

• A. 1 autopilot; 1 altitude reporting system; 2 altitude reporting transponders (1 must be operational); 2 air data computers
• B. 2 autopilots; 2 altitude reporting transponders; 1 air data computer; 1 altitude reporting system
• C. 1 autopilot; 2 altitude reporting systems; 2 altitude reporting transponders (2 must be operational); 1 air data computer
• D. 1 autopilot; 1 altitude reporting system; 1 altitude reporting transponder (operational); 2 air data computers

Answer: (A)

RVSM relies on redundancy to keep altitude data accurate and reliably reported to air traffic control in the reduced vertical separation airspace. The essential idea is that there are multiple independent paths for both measuring altitude and transmitting it, so a single failure doesn’t leave the aircraft without reliable altitude information.

The best choice provides two independent air data computers, giving two separate sources for altitude-related data. It also includes two altitude-encoding transponders, with at least one still operational if a failure occurs, so ATC can always receive the aircraft’s altitude. A single autopilot/altitude-keeping system is paired with this redundancy in data and reporting paths, aligning with the requirement that altitude information and its transmission be safeguarded by multiple channels, even if the altitude-keeping control path isn’t duplicated in this specific configuration.

Options that reduce the redundancy—fewer air data computers, or only one transponder, or unnecessary duplication of autopilots—don’t meet the RVSM safety intent, which is about ensuring multiple independent sources for altitude data and reliable altitude reporting.