Final answer:
The landing point size for a CH-47 with a long line during nighttime operations needs to be larger than the 100 feet daytime requirement, taking into account various factors like night-vision capability and environmental conditions.
Step-by-step explanation:
The size of the landing point required for a CH-47 helicopter with a long line during nighttime operations may vary based on a number of factors including operational requirements, the environment, and specific mission parameters. However, a common guideline suggests that the landing zone (LZ) for a CH-47 should be at least 100 feet in diameter during the day and larger at night, accommodating the extended length of the long line and allowing for additional safety margin. Special night-vision equipment, proficiency of the crew in night operations, weather conditions, and potential obstacles in the area are also critical considerations when determining the appropriate size for the landing point.