What is the visible distance for the Night end of the MK-124?

The visible distance for the Night end of the MK-124 is indeed 30 miles. This is significant because the MK-124 is a signaling device used by aircrew and ground personnel for a variety of purposes, including signaling for help or providing an indication to an aircraft. The Night end produces a bright red flare that can be seen from considerable distances, making it a reliable means of signaling during low visibility conditions typical of nighttime scenarios.

In the context of the other options, a distance of 15 miles or 5 miles would not provide the same level of visibility needed for effective signaling, particularly in search-and-rescue operations where the goal is to attract attention over a wide area. Likewise, a distance of 40 miles exceeds the effective range of the MK-124’s Night end, which is not designed to be visible at that range. Understanding the specific capabilities of the MK-124 aids in appropriate usage, especially in critical situations.