Flight Performance and Planning
This domain tests mass and balance, take-off and landing performance, climb and cruise planning, and fuel management. Expect chart reading, density-altitude calculations and questions on how weight, altitude, temperature, wind and runway condition change performance.
Mass and balance
- MTOW, MLW, MZFW and maximum fuel are limits, not targets. Basic empty mass plus payload plus fuel gives ramp mass.
- CG must remain within the forward and aft limits for the whole flight. Aft CG reduces static stability; forward CG increases stick force and can limit rotation.
Performance
- Take-off and landing distances increase with mass, altitude, temperature, tailwind, uphill slope, and soft or contaminated runway.
- Density altitude is pressure altitude corrected for temperature. Use it for performance, not indicated altitude.
- Climb rate falls with altitude; piston service ceiling is where best climb rate reaches 100 ft/min.
Fuel planning
- Trip fuel plus contingency, alternate, final reserve and taxi fuel. Do not plan to land with less than final reserve.
Worked example
Pressure altitude 5,000 ft, OAT 30 °C. ISA at 5,000 ft is 15 − (2 × 5) = 5 °C, so the deviation is +25 °C. Using the approximate 120 ft per °C rule, density altitude ≈ 5,000 + (25 × 120) = 8,000 ft. Performance should be read at 8,000 ft, not 5,000 ft.
Traps
- Using QNH instead of pressure altitude.
- Mixing kilograms and pounds.
- Ignoring taxi fuel or the wind component.
- Assuming a headwind improves landing distance by the same percentage as the groundspeed reduction.