At what altitude does the high VOR service volume end?

The correct altitude where high VOR (VHF Omnidirectional Range) service volume ends is 60,000 feet. High VORs are designed to provide navigation guidance for aircraft operating at altitudes generally above 24,000 feet, with their service volume extending from the surface up to 60,000 feet. This range allows for effective navigation coverage for high-altitude operations, ensuring that pilots can maintain reliable VOR navigation even in the upper flight levels.

When considering the options, 45,000 feet is below the maximum operational limit for high VORs, making it unsuitable as a correct answer. Similarly, 18,000 feet is the lower limit where VOR service volumes are typically defined but does not pertain to the high VOR cutoff. Lastly, 14,500 feet does not correspond to the termination of high VOR coverage, as it still falls beneath the altitude where high VOR service is effective. Understanding these service volumes is vital for instrument-rated pilots to ensure they can rely on VOR navigation at the appropriate altitudes.