Flight Performance and Planning
Performance fundamentals
Helicopter performance depends on density altitude, weight and wind. Density altitude rises with altitude, temperature and humidity, and it degrades both power available and rotor efficiency. Know the HIGE/HOGE distinction: in-ground-effect hover performance is better because the ground reduces induced downwash, and it is lost as the helicopter climbs above roughly one rotor diameter. Plan the takeoff and landing using the flight manual charts for your pressure altitude and temperature.
Weight and balance
Compute the empty weight, crew, fuel, payload and baggage, and check both maximum gross weight and the centre of gravity envelope. CG outside limits affects controllability and can be unsafe even when under weight. Fuel planning must include taxi/hover, trip, reserve and contingency; know the reserve required by the applicable rule.
Traps
Questions give a temperature and pressure altitude and expect you to interpolate a chart. Others mix up HIGE and HOGE, or present a load that is under max weight but outside the CG envelope. Watch for items where wind is a tailwind on approach - performance degrades and power margins shrink.
Worked example
If pressure altitude is 4,000 ft and OAT is 25 °C, density altitude is higher than 4,000 ft; use the higher figure when reading the performance chart, and expect reduced payload.