In what situation would a light gun signal be used?

A light gun signal is specifically employed in situations where radio communication is not possible, typically when pilots experience a loss of communication with air traffic control. This situation might arise due to technical failures, equipment damage, or other unforeseen circumstances that prevent the use of standard radio communication. The use of light gun signals ensures that pilots can still receive instructions for taxiing, takeoff, landing, or other operational needs, despite the lack of radio contact.

In contrast, the other options do not accurately describe scenarios where light gun signals are appropriate. Flight delays, for example, are typically managed through normal communication channels rather than visual signals. Ground speed communication between pilots generally relies on voice or data communication methods rather than visual signals. Adverse weather conditions might prompt certain types of communication, but light gun signals are not specifically designated for such situations unless accompanied by a loss of radio contact. Thus, the primary function of light gun signals is to facilitate essential communications when standard radio methods are unavailable.