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Christmas Giveaway 2023: Question 11 - Fuel Minima


As part of your pre-flight preparations, it is essential to ensure that you have sufficient fuel and oil to complete your intended flight, as well as a safe margin for diversions or contingencies.

Part-NCO (Non-Commercial Operations) defines the legal fuel reserves required for a Part-21 Aircraft flying in VFR conditions, but what is the minimum fuel reserve for a day VFR flight that remains in sight of the departure aerodrome and is returning to that aerodrome?

  1. 30 Minutes
  2. 45 Minutes
  3. 15 Minutes
  4. 10 Minutes


As pilot-in-command (PIC), you must ensure sufficient fuel, oil, coolant or ballast (depending on the type of aircraft) is carried for the intended flight and that you have a safe margin for contingencies.

For Part-21 aeroplanes operating in accordance with Part-NCO, minimum fuel reserves above the amount needed to fly the intended route are also required for VFR flight as follows:

  • 10 mins - By day, if remaining within sight of the aerodrome and returning to that aerodrome
  • 30 mins - By day
  • 45 mins - At night

But what do we mean by the term minimum fuel? Under ICAO, the term minimum fuel describes a situation in which an aircraft's fuel supply has reached a state where the flight is committed to land at a specific aerodrome and no additional delay can be accepted.

Ensuring we have enough fuel to conduct a flight safely and legally starts on the ground. Accurate pre-flight planning and pre-flight checks are crucial in confirming that we have enough fuel on board to complete the flight, a safe margin for contingencies, and minimum fuel reserves on landing.

As the pilot in command, we should continually undertake checks in-flight so that we are constantly aware of our fuel state and to verify that our fuel planning assumptions are correct. It's essential as a pilot to understand the fuel burn for your aircraft at different cruise configurations, both to allow accurate pre-flight planning and to allow you to recalculate fuel requirements quickly in flight should it not be as originally planned. Always consult your POH/AFM for the specifics for your particular aircraft.

Regular FREDA checks, particularly during less demanding flight sections, will help you monitor your fuel consumption and fuel status and help you identify any planning errors or fuel issues early - giving you time to make an informed decision about the next steps. A flight PLOG can also be a great way to record your fuel status and management actions (such as changing tanks) for monitoring. You can download copies of our FREDA Checklist Postcard and PLOGs in the additional resources section.

What if I have miscalculated my fuel requirements?

If you find yourself low on fuel, the Civil Aviation Authority has issued guidance to help you alert Air Traffic Control of your situation so that you can determine whether you can proceed to your destination airfield safely. This involves three stages:

  • Request delay information from ATC if you believe you may need to land at your destination airfield with less than the final fuel reserve levels plus the fuel required to proceed to an alternate aerodrome. ATC can advise of any expected delays at your destination, and you can use this information to determine if a diversion is required.
  • Declare minimum fuel when you are committed to landing at an aerodrome and when any change to your existing clearance may result in landing with less than your required fuel reserve. Declaring minimum fuel differs from declaring an emergency, and ATC is not required to give you priority at this stage. After declaring minimum fuel, you should use the information ATC provides to decide whether to declare an emergency.
  • Declare a fuel emergency when your calculated usable fuel on landing at the nearest safe aerodrome is predicted to be less than the planned final fuel reserve.

You can find more information about protecting final reserve fuel and the process for declaring minimum fuel in CAA Safety Notice SN-2019/002.