Originally Posted by
polax52
My understanding is that a Mayday call is made when you have a fixed amount of fuel remaining as defined in the Company operating manual e.g. 2000kg's.
My understanding is that a Mayday, Mayday, Mayday Fuel call is made if you will not have the full reserve fuel left from landing at the nearest suitable airport. Therefore, if there is a suitable airport closer to you than destination and you can see that you will have 1 minute less than reserve fuel at destination, you don't declare a Mayday but land at the nearer suitable airport.
From ICAO Amendment 36 to ICAO Annex 6 Part I:4.3.7.2.3 The pilot-in-command shall declare a situation of fuel emergency by broadcasting MAYDAY, MAYDAY, MAYDAY, FUEL, when the calculated usable fuel predicted to be available upon landing at the nearest aerodrome where a safe landing
can be made is less than the planned final reserve fuel.