What is a primary factor that contributes to the necessity for RVSM?

The necessity for Reduced Vertical Separation Minimum (RVSM) is primarily driven by the increased potential for altimeter errors that can occur at higher altitudes where air density is lower. As aircraft operate at altitudes above 29,000 feet, the atmosphere becomes less dense, and the performance of altimeters can be less reliable. This can lead to larger discrepancies in altitude reporting between aircraft, which poses safety risks in airspace with limited vertical separation.

RVSM allows for a reduction in the vertical separation between aircraft from 2,000 feet to 1,000 feet between 29,000 feet and 41,000 feet, effectively maximizing the use of available airspace and accommodating increasing air traffic. However, the successful implementation of RVSM relies on ensuring that altimeter errors are controlled and minimized, making the accuracy of altitude reporting a crucial aspect of the RVSM system.

Ensuring that all aircraft participating in RVSM operations have accurate altimeters is vital to prevent any potential mid-air conflicts, thus enhancing safety in high-density air traffic areas.