Final answer:
In RVSM airspace, the maximum allowed deviation from assigned altitudes during climbs or descents is 150 feet to maintain safety and efficiency in air travel.
Step-by-step explanation:
During climbs or descents in RVSM airspace, flight crews shall not overshoot or undershoot assigned altitudes by more than 150 ft. RVSM stands for Reduced Vertical Separation Minimum and it refers to the reduction of the standard vertical separation required between aircraft flying between FL290 (Flight Level 290 or approximately 29,000 feet) and FL410 (approximately 41,000 feet). The standard vertical separation minimum in this airspace is 1,000 feet, and adherence to altitude assignments is crucial to maintaining the safety and efficiency of air travel.