On which frequency should an aircraft transmit a distress call initially?

When an aircraft is transmitting a distress call, the initial approach is to utilize the air-ground frequency in use at that time. This is crucial because it maximizes the chances of immediate response from nearby aircraft and ground stations that may be listening on that particular frequency. The air-ground frequency is meant for communication between pilots and air traffic control or other aircraft, making it the most effective means of alerting authorities to a distress situation.

By using the air-ground frequency, the distress call is likely to be heard by those who can provide the most timely assistance. This method also adheres to standard procedures for emergency communications, which prioritize the immediate context of the transmission for the best situational awareness and response coordination.

While other frequencies, such as designated emergency frequencies or routine communication channels, may be used for distress calls, the air-ground frequency currently in use offers the most direct line of communication given the current atmosphere and other aircraft operations.