Flight Performance and Planning: Mass, Balance, Performance, Flight Planning
Mass and balance
Know empty mass, basic empty mass, payload, zero-fuel mass, take-off mass and landing mass, and the maximum values for each. Compute moments (mass × arm) and centre of gravity position, then check the CG lies inside the forward and aft limits for take-off, in flight and landing. Forward CG increases stall speed and pitch authority demands; aft CG reduces static stability and can make stall recovery difficult.
Performance
Study take-off and landing distance factors: mass, density altitude, wind, runway slope and surface, and obstacle clearance. Know the difference between ground roll and total distance to 50 ft, and between pressure altitude, density altitude and indicated/true airspeed. Climb performance depends on excess power; service ceiling is where climb rate falls to a defined small value.
Flight planning
Prepare fuel: taxi, trip, reserve (final reserve plus alternate where required), and contingency. Compute true course from variation and deviation, then heading with wind correction. Estimate time en route and fuel burn from TAS and consumption.
Worked example
Aircraft mass 1 000 kg with arm 0.30 m, plus 100 kg at arm 1.50 m. Total moment = 300 + 150 = 450 kg·m; total mass = 1 100 kg; CG = 450 / 1 100 ≈ 0.41 m aft of datum. Check 0.41 m against the envelope.
Traps
Unit confusion (kg vs lb, litres vs gallons), forgetting the reserve in landing mass, and using pressure altitude where density altitude is required.