Which of the following is required equipment for RVSM airspace?

In RVSM (Reduced Vertical Separation Minimum) airspace, specific equipment is mandated to ensure safe operations at reduced vertical separations of 1,000 feet between aircraft operating at altitudes from 29,000 feet to 41,000 feet. The correct answer highlights the requirement for an autopilot, which is crucial for maintaining stable flight and precise altitude control in RVSM airspace.

The autopilot allows aircraft to stay within strict altimeter settings and vertical separation requirements, thus reducing the likelihood of altitude deviations that could lead to potential conflicts between aircraft. It helps maintain the aircraft's flight path and eases the workload on the pilots, especially during long flights at high altitudes.

While other equipment such as flight recorders, ground proximity warning systems, and traffic collision avoidance systems are important for overall flight safety and are often found on modern aircraft, they are not specifically mandated for operations in RVSM airspace like the autopilot is. Each aircraft must be equipped with a functioning autopilot to be eligible to fly in this special airspace, ensuring compliance with the necessary safety standards and regulations.