A flight shall not be commenced unless, taking into account both the meteorological conditions and any delays that are expected in flight, the aircraft carries sufficient fuel and oil to ensure that it can safely complete the flight. In addition, a reserve shall be carried to provide for contingencies. When a destination alternate aerodrome not is required the following have to be fulfilled:
Either to fly to the aerodrome the flight is planned, and thereafter for a period of 2 HRs in normal cruise consumption.
Or to fly to and execute an approach, and a missed approach, at the aerodrome to which the flight is planned, and thereafter:
• to fly for 30 MIN at holding speed at 450m (1500ft) above the aerodrome to which the flight is planned under standard temperature conditions, and
• to have an additional amount of fuel sufficient to provide for the increased consumption on the occurrence of any of the potential contingencies specified by the operator to the satisfaction of the State of the Operator.
Source: ICAO Annex 6