Australia CASA Instrument Proficiency Practice Exam

In Reduced Vertical Separation Minimum (RVSM) airspace, the maximum allowed altimeter divergence is 200 feet. This standard is crucial for maintaining safe vertical separation between aircraft operating at altitudes where only 1,000 feet of vertical separation is applied.

The reason for this specific limit is to ensure that even with varying altimeter settings and potential inaccuracies in altitude reporting systems, aircraft maintain a safe vertical distance between each other. In RVSM airspace, aircraft are often operating within + or - 200 feet of their assigned altitude to accommodate these discrepancies. Adherence to this standard is vital for safety and efficient air traffic management, particularly in congested airspace with high volumes of traffic.

The other figures, such as 50, 100, and 300 feet, do not reflect the established safety standards. A divergence of 50 feet would be overly conservative and unnecessary within RVSM parameters, whereas allowing a divergence of 300 feet could compromise safety by increasing the risk of collision. Thus, 200 feet is the established standard for altimeter divergence in RVSM airspace, striking a balance between safety and operational efficiency.