What is the typical fuel consumption of a 737 in MPG?

What is the typical fuel consumption of a Boeing 737 in MPG?

• Are you interested in MPG, or actually interested in things like emissions/mile or cost of fuel? Emissions between a gallon of gasoline and gallon of jet fuel are close but not equal, and the cost is very different. Aug 12, 2019 at 17:02
• Which size of 'Gallon' are you interested in - there are at least two common definitions in use Dec 27, 2023 at 12:30

The following table shows the long range cruise control data for a Boeing 737-800 (source: FCOMv1 Performance Inflight - All Engine PI.31.2):

Let us consider a typical cruise at FL370 with a weight of $$65 \, \mathrm{t}$$. The table tells us that the fuel flow per engine would be:

$$\mathrm{FF} = 1231 \, \mathrm{kg}/\mathrm{h}$$

We are interested in the fuel consumption per distance, not per time. The table tells us that we would fly at Mach $$0.793$$. At an altitude of $$37 \, 000 \, \mathrm{ft}$$ the speed of sound would be $$295 \, \mathrm{m}/\mathrm{s} \approx 574 \, \mathrm{kt}$$ assuming ISA (International Standard Atmosphere) conditions. This gives us the cruise TAS (true airspeed):

$$\mathrm{KTAS} = 455$$

The resulting fuel economy is then:

$$\frac{2 \times \mathrm{FF}}{\mathrm{KTAS}} = 5.41 \, \mathrm{kg}/\mathrm{NM}$$

You asked for MPG (miles per gallon), so we need to convert that mass of fuel into a volume. The density of jet fuel depends on temperature. Assuming you refer to the volume on the ground, let us assume $$\rho = 0.820 \, \mathrm{kg}/\mathrm{l}$$ for Jet-A. This gives:

$$1.51 \, \mathrm{gal}/\mathrm{mi} \; \Rightarrow \; 0.66 \, \mathrm{MPG}$$

All of this assumes no wind. If there is a $$50 \, \mathrm{kt}$$ headwind for example, the ground speed (GS) would reduce accordingly ($$\mathrm{GS} = \mathrm{TAS} - \mathrm{Headwind}$$). Using this instead of KTAS in the equations above gives:

$$50 \, \mathrm{kt} \; \mathrm{Headwind}: \; 0.59 \, \mathrm{MPG} \; ; \; \; 50 \, \mathrm{kt} \; \mathrm{Tailwind}: \; 0.73 \, \mathrm{MPG}$$

Note: This is for the entire aircraft. If you are interested in fuel economy per seat, multiply the MPG with the number of seats (189 is the exit limit for a 737-800).

It's not fixed, some of the variables are:

1. Which 737 family and variant
2. Flight (air) distance, which is affected by wind