What is the maximum altitude difference allowed between PFD 1 and PFD 2 in RVSM?

In a Reduced Vertical Separation Minimum (RVSM) environment, the regulations stipulate a maximum altitude difference between the primary flight displays (PFD) for both pilots to ensure safe vertical separation from other aircraft. The correct maximum allowable altitude difference between PFD 1 and PFD 2 is 200 feet.

The significance of this limit is rooted in the need for precise altitude reporting and maintenance, as errors beyond this threshold could compromise the safety and separation standards established in RVSM airspace. Assuming both PFDs are functioning properly, staying within this limit allows for effective monitoring and timely corrections, ensuring that the aircraft maintains proper altitude throughout its flight.

The other options reflect lesser altitude differences, which are not in alignment with RVSM regulations. Should the altitude discrepancy exceed 200 feet, it would necessitate corrective action from the flight crew, potentially including notifying air traffic control of the situation.