Flight Planning and Monitoring
Flight Planning and Monitoring is about producing a legal, safe plan before departure and then actively checking that the flight is tracking it - fuel, time and route.
Building the plan
Start with weather, NOTAMs, AIP routes, aircraft performance and mass and balance. Select destination and alternate, then compute trip fuel from the flight log (leg by leg, using wind-adjusted groundspeed), and add the standard reserves. A typical commercial breakdown is: taxi fuel, trip fuel, contingency fuel (commonly 5% of trip fuel, or a defined time), alternate fuel, final reserve (typically 30 minutes at holding speed at 1,500 ft above the aerodrome for commercial turbine operations - check the figure your GCAR applies), and any extra fuel the commander requires. Total fuel must also respect the tank capacity and the maximum landing mass at destination.
Filing
An ICAO flight plan must be filed in good time before estimated off-blocks time, with route, levels, speeds, alternates and equipment. Change of EOBT beyond the allowed window requires a fresh or amended plan; a flight plan may be cancelled once the flight is on the ground.
Monitoring in flight
Record fuel and time at each waypoint; compare with the log and revise ETA. A fuel check that shows more than a defined shortfall means a decision - reduce power, shorten the route, or divert early. Do not wait until the alternate is no longer reachable.
Worked example
Trip time 2 h 20 min at 40 L/h gives 93.3 L trip fuel. Contingency 5% = 4.7 L. Alternate 25 min = 16.7 L. Final reserve 30 min = 20 L. Taxi 5 L. Total required = 93.3 + 4.7 + 16.7 + 20 + 5 ≈ 140 L. Note that the final reserve is carried, planned and never spent as trip fuel.
Traps that cost marks
Omitting taxi fuel; computing contingency on the total rather than on trip fuel; treating the final reserve as usable; and using still-air times when wind is significant.