Piper Cherokee Archer II Pilot Operating Handbook page 63

PIPER AIRCRAFT CORPORAnON
PA-28-18I, CHEROKEE ARCHER 11
SECTION 5
PERFORMANCE
(d) Descent
The descent data will be detemlined prior to the cruise data to provide the descent distance
for establishing the total cruise distance.
Utilizing the cruise pressure altitude and OAT we determine the basic time, distance and
fuel for descent (Figure 5-29). TI,ese figures must be adjusted for the field pressure altitude and
temperature at the destination airport. To find the necessary adjustment values, use the existing
pressure altitude and temperature conditions at the destination airport as variables to find the
time, distance and fuel values from the graph (Figure 5-29). Now, subtract the values obtained
from the field conditions from the values obtained from the cruise conditions to find the true
time, distance and fuel values needed for the flight plan.
6.5 min.·
13 nau tical miles·
.7 gal.·
The values obtained by proper utilization of the graphs for the descent segment
example are shown below.
(I) Time to Descend (17 min. minus 10.5 min.)
(2) Distance to Descend (35 minus 22 nautical miles)
(3)
Fuel to Descend (1.7 gal. minus I gaL)
of our
( (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.
20 gal.
2.64 hrs.
314 nau tical miles
290 nautical miles
65% rated power
IIOKTSTAS··
7.6 GPH
The cruise calculations established for the cruise segment of our flight planning example are
as follows:
(I)
Tot;y Distance
(2)
Cruise Distance
(e)(I) minus (c)(4) minus (d)(2), (314 minus II minus 13)
(3) Cruise Power
(4) Cruise Speed
(5) Cruise Fuel
(6) Cruise Time
(e)(2) divided by
(e)(~),
(290 nautical miles divided by 110 KTS)
(7)
Cruise Fuel
(e)(5) multiplied by (e)(6),(7.6 GPH multiplied by 2.64 las.)
c
·reference Figure 5-29
··reference Figure 5-21
ISSUED: JUNE 18,1976
REPORT: VB-790
5-5
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