What is a requirement for aircraft under Reduced Vertical Separation Minimum (RVSM)?

In the context of Reduced Vertical Separation Minimum (RVSM), a critical requirement is that aircraft must be equipped with two independent altitude measurement systems. This is essential for ensuring safety and accuracy in altitude reporting, particularly when aircraft are operating at high altitudes where RVSM allows for reduced vertical separation between aircraft.

The implementation of RVSM allows aircraft to fly at altitudes of 29,000 feet to 41,000 feet with a vertical separation of only 1,000 feet instead of the traditional 2,000 feet. To maintain flight safety in such close proximity, the redundancy provided by two independent altitude measurement systems is crucial. It ensures that if one system fails or provides incorrect data, the second system can serve as a backup, thereby giving pilots and air traffic controllers reliable altitude information.

This requirement aligns with safety regulations and standards set by aviation authorities to mitigate the risks associated with altitude discrepancies in high-density airspace.