Aircraft Endurance Calculator

Calculate flight time remaining based on fuel quantity and consumption rate.

Estimated Endurance

00:00

Hours : Minutes (Excluding Reserve)

Safety Note: Fuel consumption varies based on power settings, mixture, and altitude. Always allow for a 45-minute VFR (or 45-minute IFR) reserve fuel margin according to aviation regulations.

Understanding Aircraft Endurance

Aircraft endurance is the total length of time an aircraft can remain in flight. Unlike range, which measures the distance an aircraft can travel, endurance focuses purely on time. This metric is critical for pilots, flight dispatchers, and aviation enthusiasts to ensure flight safety and compliance with fuel reserve regulations.

How to Calculate Flight Endurance

The basic formula for endurance is simple: divide the usable fuel by the fuel consumption rate. For example, if an aircraft has 40 gallons of usable fuel and burns 10 gallons per hour, its total endurance is 4 hours. However, in practical aviation, you must subtract the mandatory fuel reserves required by the FAA (Federal Aviation Administration) or your local aviation authority before calculating your safe flight time.

Factors Affecting Fuel Burn

It is important to remember that the fuel burn rate provided by the manufacturer in the Pilot's Operating Handbook (POH) is often an estimate. Real-world fuel consumption is affected by several variables:

  • Altitude: Thinner air at higher altitudes requires a leaner fuel mixture, which can improve efficiency.
  • Power Settings: Operating at 75% power will consume significantly more fuel than at 55% power.
  • Mixture Control: Proper leaning of the engine is essential to achieve the endurance figures calculated on the ground.
  • Weight and Balance: A heavier aircraft requires a higher angle of attack, increasing drag and fuel consumption.

Frequently Asked Questions

What is the difference between range and endurance?

Range is the distance an aircraft can fly (measured in miles or kilometers), while endurance is the time it can stay in the air (measured in hours and minutes). A strong tailwind increases range but does not change endurance.

How much reserve fuel is required?

Under FAA Part 91 regulations, VFR (Visual Flight Rules) flights during the day require enough fuel to fly to the destination plus 30 minutes. Night VFR requires 45 minutes of reserve. IFR flights generally require enough fuel to reach the destination, fly to the alternate, and then fly for 45 minutes at cruise speed.