What is the function of DRDF in aviation?

The function of the Directional Radio Direction Finder (DRDF) in aviation is primarily to determine the bearings of radio transmissions. This capability is crucial for navigation and situational awareness, as it allows pilots and air traffic controllers to locate various radio frequencies and signals accurately. By establishing the direction from which a radio signal is coming, the DRDF enables pilots to pinpoint their location relative to navigational aids, such as VOR stations, enhancing their ability to navigate effectively and maintain safety in the airspace.

The other options do not align with the primary function of DRDF. For instance, while flight plans are transmitted through other communication systems, their submission is not the role of the DRDF. Similarly, controlling aircraft speed involves different mechanisms and systems rather than relying on direction-finding capabilities. Offering weather updates is managed through specific meteorological services and tools designed for such purposes, thus not falling under the function of the DRDF either.