Cessna 172R, 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