Final answer:
In RVSM airspace, flight crews must not exceed a deviation of more than 300 feet from their assigned altitudes during climbs or descents to maintain the required safety tolerances.
Step-by-step explanation:
During climbs or descents in Reduced Vertical Separation Minimum (RVSM) airspace, flight crews are required to adhere to strict altitude tolerances to maintain safety and efficiency of air traffic. The allowable tolerance for altitude deviation in RVSM airspace is to not overshoot or undershoot assigned altitudes by more than 300 feet (approximately 90 meters). Ensuring compliance with this requirement is critical, as RVSM airspace is designed with reduced vertical separation between aircraft, typically set at 1,000 feet vertically between flight levels at cruising altitudes. This reduced separation allows more aircraft to safely travel along the same airways, which increases airspace capacity and improves operational efficiency.