Pilot’s Operating Handbook Section 5
EXTRA 500 Performance
2 Descent
Using the time-, fuel- and distance to descent charts, the
following results are obtained.
Time to Descent: 10:00 – 01:30 = 08:30 min:sec
Fuel to Descent: 14 – 3 = 11 l (19.7 lbs)
Distance to Descent: 43 – 10 = 33 NM
The distances shown on the descent chart are for zero wind. So
the decrease in distance due to wind shall be calculated as
follows:
9 min divided by 60 min = 0.15 multiplied by 10 kt = 1.5 NM.
Therefore the corrected distance to descent is: 33 NM minus
1.5 NM = 31.5 NM.
3 Cruise
The cruise charts will give the following result without respect
to head wind. The different values for different ISA conditions
may linearly interpolated. Using the ISA –2 °C we get:
ISA-20°C (figure 5-8, sheet 11):
Cruise speed: 191 kt
ISA (figure 5-8, sheet 11):
Cruise speed: 195 kt
For ISA -2°C subtract 2 / 20 times the difference between ISA
and ISA –20°C of the ISA value:
Cruise speed: 195 - 2 / 20 x (195 - 191)
= 195 – 0.4 = 194.6 kt
The cruise fuel flow is constant with the temperature: 85 l/hr
With a head wind of 10 kt, the ground speed becomes:
= 194.6 – 10 = 184.6 kt
26. January 2011
5-7
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