Piper PA-28-236 DAKOTA, Pilot Operating Handbook

Page: 107 / 367

SECTION 5 PIPER AIRCRAFT CORPORATION
PERFORMANCE PA-28-236, DAKOTA
REPORT: VB-910 ISSUED: JUNE 1, 1978
5-6 REVISED: NOVEMBER 22, 1982
values from the graph (Figure 5-31). Now, subtract the values
obtained from the field conditions from the values obtained from
the cruise conditions to find the true fuel, time and distance values
needed for the flight plan.
The values obtained by proper utilization of the graphs for the
descent segment of the example are shown below.
(1) Time to Descend
(8 min. minus 2 min.) 6 min.*
(2) Distance to Descend
(20 naut. miles minus
4.5 naut. miles) 15.5 naut. miles*
(3) Fuel to Descend
(2 gal. minus .5 gal.) 1.5 gal.*
(e) Cruise
Using the total distance to be traveled during the flight, subtract
the previously calculated distance to climb and distance to descend
to establish the total cruise distance. Refer to the appropriate Avco
Lycoming Operator’s Manual when selecting the cruise power
setting. The established pressure altitude and temperature values
and the selected cruise power should now be utilized to determine
the true airspeed from the appropriate Speed Power graph (Figure
5-19 or 5-21).
Calculate the cruise fuel flow for the cruise power setting
from the information provided by the Avco Lycoming Operator’s
Manual.
The cruise time is found by dividing the cruise distance by the
cruise speed and the cruise fuel is found by multiplying the cruise
fuel flow by the cruise time.
The cruise calculations established for the cruise segment of the
flight planning example are as follows:
(1) Total Distance 620 naut. miles
(2) Cruise Distance
(e)(l) minus (c)(4) minus (d)(2),
(620 naut. miles minus 13 naut.
miles minus 15.5 naut. miles) 592 naut. miles
*reference Figure 5-31