J.P. Instruments EDM 960 Twin Primary Installation Manual User Manual
Page 34
FAA Approved Installation Manual for the EDM-960 system Report No 909
Primary Engine Data Management System Page 34 of 46 Rev D
Date 2-6-2014
37.1.2 K factor
The K factor is shown on the fuel flow transducer as a four-digit number, which is the number of pulses generated per
gallon of fuel flow. Before installing the transducer, write down the K factor here _________. To enter the number,
move the decimal point three places to the left. For example if the K factor on the fuel flow transducer is 29,123, enter
29.12 in the K factor parameter.
If the K factor is increased, the indicated fuel flow will decrease, and vice-versa. When the K factor is changed during a
trip, calculations of fuel used, fuel remaining and time to empty are not retroactively recalculated.
37.1.2.1.1 Fine Tuning the K factor
The K factor shown on the fuel flow transducer does not take into account your aircraft’s particular installation. Fuel
hose diameters and lengths, elbows, fittings and routing can cause the true K factor to be different from that shown on
the fuel flow transducer.
You must use the following procedure to fine tune the K factor.
1. Make at least three flights of about two to three hours each. Note the actual fuel used (as determined by topping
the tanks) and the EDM-960 calculation of the fuel used for each flight USD.
Flight
Fuel USED shown by EDM
(total tank - REM)
Actual fuel used by topping
tanks
1
2
3
Total
2. Total
the EDM-960 calculated fuel used and the actual fuel used.
3. Record the current K factor here
____________________ and in the table below.
4. Calculate the New K factor as follows:
New K factor = (EDM fuel used) x (Current K factor)
(actual fuel used)
New K factor = (
) x (
)
(
)
Every time you fine tune the K factor, change it by only half of the amount calculated above, and record the
measurements here:
Date
EDM fuel
used
actual fuel
used
Current
K factor
New K factor
=
x
/
Pilot’s initials