Flight Performance and Planning (Mass and Balance, Performance, Flight Planning)
Flight Performance and Planning
This domain tests mass and balance, take-off and landing performance, density altitude, fuel planning and navigation logs. The aim is to confirm the aircraft stays within certified mass and CG limits and that the planned flight has legal reserves.
Core rules
- Mass limits include MTOW, MLW, MZFW and maximum payload. Balance limits are expressed as a CG range at a given mass.
- Use mass, not volume, for fuel and payload. Include unusable fuel and crew as specified in the POH.
- Performance depends on pressure altitude, temperature, wind, runway slope, surface and aircraft configuration. Density altitude is pressure altitude corrected for temperature.
- Flight planning: route, altitude, TAS, wind, ground speed, time, fuel and reserves. Compare fuel required with fuel available.
Worked example
Empty aircraft 700 kg at arm 1.0 m; pilot 80 kg at 0.4 m; fuel 100 kg at 1.5 m; baggage 20 kg at 2.0 m. Moments: 700 + 32 + 150 + 40 = 922 kg·m. Total mass 900 kg. CG = 922 ÷ 900 = 1.024 m. If the limit is 0.95–1.25 m, the loading is within limits. The reasoning is that each item's moment is mass × arm and CG is total moment ÷ total mass.
Traps
Forgetting to convert fuel volume to mass, omitting unusable fuel, and using the wrong arm datum cost marks. Do not interpolate performance charts carelessly. A forward CG can increase take-off distance; an aft CG reduces stability.