Flight Performance and Planning
What you must know
Performance divides into take-off, climb, cruise, descent, landing, and mass-and-balance. Learn definitions: take-off distance to 35 ft, landing distance from 50 ft, accelerate-stop distance, and the effect of density altitude. Density altitude rises with altitude, temperature, and humidity and degrades all performance. Study climb gradients, service ceiling, and the effect of mass on climb and stall. For planning, know fuel calculation (taxi, trip, reserve, contingency, alternate, final reserve), and the difference between TAS, IAS, and ground speed with wind triangles. Mass and balance: datum, moment, CG position, forward and aft limits and their handling consequences.
Traps
Questions test whether a headwind or tailwind changes take-off ground roll vs air distance, and whether a higher altitude increases or decreases true airspeed for a given IAS. Another trap: reserve fuel is not usable for planning the trip, and forward CG increases stall speed and reduces cruise efficiency while aft CG reduces stability. Watch for unit conversions (lb to kg, ft to m) and pressure altitude vs density altitude confusion.
Worked example
A runway requires 800 m at sea level, ISA. At a density altitude of 4000 ft, performance degrades roughly 10–15% per 1000 ft of density altitude for normally aspirated aircraft. A conservative estimate: 800 m × 1.4 = 1120 m. Always use the AFM chart rather than a rule of thumb for the final decision.
Rule of thumb
Hot, high, humid, heavy - all reduce performance. Compute density altitude first, then read the chart.