If technical difficulties arise with radio communications with the Control Tower, what alternative means may be used?

Utilizing light gun signals is the correct alternative means of communication when technical difficulties arise with radio communications with the Control Tower. Light gun signals are a standardized method used in aviation to convey commands visually. These signals consist of colored lights directed at aircraft and vehicles on the airfield, allowing for clear communication even in the absence of radio contact.

Ground-crew signals, hand signals, and vehicle horn signals may be used in some situations to convey information or instructions, but they are not standardized for all aircraft operations, making light gun signals a more reliable and universally understood method in airfield operations. Light gun signals can effectively communicate important information such as whether to stop, take off, or proceed, regardless of ambient noise or other factors that might impair verbal communication.