Start with the route
Confirm departure, destination, route structure, altitude constraints, terrain, airspace, navigation capability, and suitable diversion points. The route establishes the distances and conditions used by every later calculation.
Apply wind before calculating time
Wind changes heading and groundspeed. Use the appropriate wind for altitude and time, determine the wind-correction angle, and then calculate groundspeed. A common error is using true airspeed directly as groundspeed.
Fuel = Time × Fuel flow
Build fuel by phase
Separate taxi, takeoff and climb, cruise, descent, approach, alternate, reserve, and additional operational fuel. This makes the plan easier to audit and shows which assumption causes a change.
Cross-check reasonableness
Compare the calculated time and fuel with experience, published performance, forecast wind, and the previous leg. Large changes need an explanation. A plan should remain understandable even when computed electronically.
Plan the alternative before it is needed
Evaluate alternates for weather, runway suitability, approach capability, services, terrain, and fuel. A named alternate that cannot support the aircraft or expected conditions is not a practical escape plan.