Page 650 - PPL-engelsk 2025
P. 650
Flight performance and planning
7.9.2.6 TAS at selected flight altitude
Before we can move on, we need to find the TAS at the selected flight altitude.
On this trip we are flying in OY-CTZ.
In the manual for
the C172 OY-CTZ
we find a table
with the aircraft's
performance data.
We can see that we are to fly with a TAS of approximately 100.
Our flight altitude of 2000 feet is in the column "Pressure Altitude".
We are to descend to 2300 Rpm, where a red line has been drawn.
We now have 3 columns we can go to:
o
- a column for 20 C below standard
- a column for standard temperature
o
- a column for 20 C above standard
o
The temperature is given as 25 C at MSL, which is 10⁰C more than standard. This
means that we need to have an average of the numbers in the middle column
o
and the column on the right with temp. at 20 C above standard (I assume you
o
are aware that the standard temperature at MSL is 15 C.
We then get:
- % BHP is between 58 and 55, so we set it to 56%
- KTAS is between 101 and 99, so it must be 100 Kt.
- GPH is between 6.7 and 6.5, so it must be 6.6 Gall/Hour
Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 650
