For UH-1 with rotor blade radius 50 ft, what are the day and night HLZ values?

For UH-1 with rotor blade radius 50 ft, what are the day and night HLZ values?

• A. 150/200
• B. 185/235
• C. 200/250
• D. 150/150

Answer: (A)

HLZ sizing for a UH-1 is tied to rotor blade radius, with day operations using a smaller zone and night operations requiring extra clearance due to reduced visibility. The standard rule multiplies the rotor radius by 3 for day and by 4 for night. With a rotor blade radius of 50 ft, that gives 3 × 50 = 150 ft for day and 4 × 50 = 200 ft for night. Hence the correct day/night HLZ values are 150/200. Other options would not follow this 3R/4R rule (or would imply equal day and night or different multipliers), so they don’t fit this size.

HLZ sizing for a UH-1 is tied to rotor blade radius, with day operations using a smaller zone and night operations requiring extra clearance due to reduced visibility. The standard rule multiplies the rotor radius by 3 for day and by 4 for night. With a rotor blade radius of 50 ft, that gives 3 × 50 = 150 ft for day and 4 × 50 = 200 ft for night. Hence the correct day/night HLZ values are 150/200. Other options would not follow this 3R/4R rule (or would imply equal day and night or different multipliers), so they don’t fit this size.