Flight Performance & Planning — PPL(A)

Aircraft performance is based on density altitude, not indicated altitude. Density altitude is the pressure altitude corrected for non-standard temperature. High density altitude means thinner air — longer take-off rolls, reduced climb rate, and reduced engine power.

• High temperature, high altitude, high humidity = high density altitude = poor performance.
• Performance charts in the POH use pressure altitude and temperature as inputs.
• Pressure altitude: set 1013.25 on altimeter and read altitude indicated.
• A hot summer day at a high-elevation airfield can dramatically increase take-off distance — check the charts.

Before any flight, the aircraft must be within its certificated maximum take-off weight (MTOW) and within the CG (centre of gravity) envelope. Being out of limits is illegal and dangerous — an aft CG reduces longitudinal stability and can make the aircraft uncontrollable.

• Mass × arm = moment.
• Total moment ÷ total mass = CG position.
• CG must fall within the forward and aft limits specified in the POH for all phases of flight (including fuel burn).
• Check CG at take-off weight AND at landing weight (after fuel burn).
• Unusable fuel is part of the empty weight — never subtract it from the calculation.

UK VFR fuel requirements (SERA): sufficient fuel to fly to destination, then to the first alternate, then for a fixed final reserve. The final reserve for day VFR in a piston aeroplane is 30 minutes at normal cruise power.

• Trip fuel: fuel from departure to destination.
• Contingency fuel: 5% of trip fuel or 5 minutes, whichever is greater (for planned routes).
• Alternate fuel: fuel from destination to alternate (required if destination forecast below minima).
• Final reserve: 30 minutes at holding speed/normal cruise for VFR piston day.
• Additional fuel: any extra the commander decides is prudent.
• Taxi fuel: fuel for start-up and taxi — include in planning if significant.

• File a VFR flight plan via NATS or equivalent for any flight leaving UK FIR or entering controlled airspace that requires a flight plan.
• File SARTIME (Search and Rescue time) when landing at a non-ATZ aerodrome or making a remote landing — cancel it promptly on arrival.
• Weather minima check: confirm forecast at departure, route, and destination are within VFR limits for your route altitude.
• NOTAMs: check for TFRs, closed runways, MATZ/RMZ activations, and changes to airspace.
• Fuel check: dip tanks or check sight gauges AND cross-reference with fuel log from last uplift.