SECTION 5
CESSNA
PERFORMANCE
MODEL 172S NAV III
FUEL REQUIRED
The total fuel requirement for the flight may be estimated using the
performance information in Figure 5-7 and Figure 5-8. For this
sample problem, Figure 5-7 shows that a climb from 2000 feet to
8000 feet requires 2.2 gallons of fuel. The corresponding distance
during the climb is 15 nautical miles. These values are for a
standard temperature and are sufficiently accurate for most flight
planning purposes. However, a further correction for the effect of
temperature may be made as noted on the climb chart. The
approximate effect of a non-standard temperature is to increase the
time, fuel, and distance by 10% for each 10°C above standard
temperature, due to the lower rate of climb. In this case, assuming
a temperature 16°C above standard (16°C - 0°C), the correction
would be:
16°C X 10% = 16% Increase
10°C
With this factor included, the fuel estimate would be calculated as
follows:
Fuel to climb, standard temperature
2.2
Increase due to non-standard temperature
0.4
(2.2 X 16%)
Corrected fuel to climb
2.6 Gallons
Using a similar procedure for the distance to climb results in 18
nautical miles. (15 nm using chart + 2.4 nm to correct for higher
than standard temperature = 17.4 nm. Rounded up to 18 nm.)
The resultant cruise distance is:
Total distance
360
Climb distance
-18
Cruise distance
342 nm
(Continued Next Page)
5-6 U.S.
172SPHAUS-00
