Fuel is sold in gallons, but all fuel computations in the aircraft reference pounds. This is
because it is important to know the total weight of the aircraft. Therefore, the conversion
from gallons to pounds is a necessary skill in aviation. To convert gallons of fuel to pounds,
the weight of a single gallon must be known. On a standard day, most aviation fuel weighs
between 6.5 and 6.9 pounds per one gallon. This ratio of 6.X to 1 is used in the formula:
TOTAL PO UNDS
1 GAL L O N
TOTAL GAL L O NS
Note that the outer scale on the CR-3 remains the FUEL scale, and the inner scale now
becomes the GALLONS scale.
It is important to remember that the 10 on the inner wheel represents 1-gallon. Since there
is no time involved in this type of problem, DO NOT use the rate index! Also remember that
there will always be more pounds than gallons.
Finding total fuel weight.
Given: Total gallons . . . . 525 gallons
Fuel weight. . . . 6.6 lbs per gallon
Total fuel weight.
Estimate the answer. Round the fuel weight up to 7 pounds per gallon. Round the
total gallons down to 500. 7 x 500 is 3500 (pounds).
Find 66 (6.6#) on the POUNDS (outer) scale and place it over 10 on the GALLONS
(inner) scale. (Figure 4.3-28)