During an emergency, which frequency should the aircraft remain on?

The recommended frequency for an aircraft to remain on during an emergency is the initial contact frequency unless there’s a valid reason to change. This is because the initial contact frequency is where air traffic control (ATC) has been monitoring the flight and is best able to assist with the emergency situation. Staying on this frequency ensures that the communication line remains open with those who are already familiar with the flight's situation.

This practice is built on the idea that ATC is already aware of the aircraft's last known position and intentions, allowing for a quicker response to any emergencies. Additionally, air traffic controllers are trained to prioritize emergency traffic that is already established on their frequency, which can facilitate a rapid and effective response during critical situations.

In contrast, other frequencies, including emergency frequency 121.5, are meant for distress calls but do not ensure that the pilot is in contact with the controller who is already managing their flight. Changing to a frequency with less traffic may not guarantee communication with ATC or other useful air traffic, and while a VHF frequency is important for communication in general, it doesn't necessarily provide optimal assistance in an emergency scenario compared to the established contact frequency.