Cessna Skyhawk 172N Pilot Operating Handbook page 76

SECTION 5
CESSNA
PERFORMANCE
MODEL 172N
of fuel. The corresponding distance during the climb is 9 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 100/0 for each lOoC above standard temperature, due to
the lower rate of climb. In this case, assuming a temperature 16°C above
standard, the correction would be:
16°C
lOoC )( 10%
=
16% Increase
With this factor included, the fuel estimate would be calculated as follows:
Fuel to climb, standard temperature
1.3
Increase due to non-standard temperature
(1.3
x
16%) 0.2
Corrected fuel to climb
1.5Gallons
Using a similar procedure for the distance to climb results in
10
nautical
miles.
The resultant cruise distance is:
Total distance
460
Climb distance
-10
Cruise distance
450 Nautical Miles
With an expected 10 knot headwind, the ground speed for cruise is
predicted to be:
114
-10
104 Knots
Therefore, the time required for the cruise portion of the trip is:
~
Nautical Miles - 43 H
104 Knots - . ours
The fuel required for cruise is:
4.3 hours
x
7.1 gallons/hour = 30.5 Gallons
5-6
1 July 1978