6.46 Fuel Planning

6.46.2 Derive, from an Aircraft Flight Manual, the fuel consumption rate for a given leg.

To derive the fuel consumption rate for a given leg, the pilot must use the performance data in the Aircraft Flight Manual (AFM) or Pilot’s Operating Handbook (POH).

The aim is to determine how much fuel the aircraft is expected to use per hour, and then apply that rate to the planned leg.

Step 1: Identify the planned operating conditions

From the flight plan for that leg, determine:

• planned cruising altitude
• planned power setting
• expected outside air temperature, if required
• planned mixture setting, if applicable

These factors affect fuel burn, so the AFM data must match the intended conditions as closely as possible.

Step 2: Refer to the AFM cruise performance section

In the AFM/POH, locate the cruise performance charts or tables. These usually show:

• power setting
• altitude
• true airspeed
• fuel flow or fuel consumption rate

Fuel consumption may be shown in:

• litres per hour
• US gallons per hour
• imperial gallons per hour
• pounds per hour