Fuel Grades and Capacities

This aeroplane is built in two fuel configurations, and the difference between them is nearly thirteen gallons of usable fuel. Getting the tank fit right — and knowing which two fuel grades are approved — is flight-planning work that starts on the ground with a colour.

At a glance

• Approved fuel, 100LL gradeblue
• Approved fuel, 100 grade (formerly 100/130)green
• Standard tanks, total capacity26 gallons
• Standard tanks, capacity each tank13 gallons
• Standard tanks, total usable24.5 gallons
• Long range tanks, total capacity39 gallons
• Long range tanks, capacity each tank19.5 gallons
• Long range tanks, total usable37.5 gallons

Two approved grades

What may go in the tanks

• 100LL grade aviation fuel — dyed blue.

• 100 grade aviation fuel, formerly designated 100/130 — dyed green.

The colour is the check you can actually perform on the ramp, which is why the handbook prints it alongside each grade. A sample drawn into the cup should be one of those two colours and nothing else.

Standard tanks against long range tanks

Both configurations use one tank in each wing, and both differ from each other only in tank size. The standard installation holds 13 gallons a side, 26 gallons in total, of which 24.5 gallons are usable. The long range installation holds 19.5 gallons a side, 39 gallons in total, of which 37.5 gallons are usable.

Note that the difference between total and usable is 1.5 gallons in both cases. Fitting bigger tanks buys extra usable fuel gallon for gallon; it does not change what is trapped at the bottom.

Topping up after refuelling

NOTE — The two tanks cross-feed into one another, so a second filling pass is needed after every refuelling if the full capacity is to be had.

This is a practical consequence of the two tanks being interconnected. Fill one side, walk round to fill the other, and by the time you come back the first tank has settled below the filler neck. Only a second pass gets you the capacity the table promises.

Check yourself

• Which two fuel grades are approved, and what colour is each dyed?

• How many usable gallons does the standard tank installation give, and how many the long range installation?

• How much fuel is unusable in each installation, and how does that quantity differ between the two?

• Why must the tanks be re-topped after refuelling?

Study aid — always fly your aircraft's current AFM/POH.