Textron Cessna 172R, Pilot Operating Handbook

Page: 156 / 500

SECTION
5
PERFORMANCE
CESSNA
MODEL 172R
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
6000 feet requires 1.4 gallons of fuel. The corresponding distance
during the climb is 10
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 (28°C
- 12°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
Increase
due
to
non-standard
temperature
(1.4
X
16%)
Corrected fuel to climb
1.4
0.2
1.6 Gallons
Using a similar procedure for the distance to
climb results in
12
nautical miles. (10
nm using chart
+
1.2 nm
to correct
for higher
than standard temperature
= 11.2 nm.
Rounded
up
to 12 nm.)
5-6
Revision 7
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