@Linkat,
Linkat - the thing to do in such an emergency is to grab the pilot's headset and keep repeating "mayday, mayday" until you hear a reply. Frequency is whatever frequency the headset is tuned into. Many passengers have had to do this and were directed to safe landings by step-by-step instructions from air traffic controllers - no expertise needed, just keep plane in straight and level flight unless directed to do something different.