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B KLN 94
Rev. 4, Jan/2003 10599I04.CDL Page 2-74
It is assumed that the operator’s manual for the various units connected to the KLN 94 (as well as
the manual for the KLN 94 itself), are available or that the installer is familiar with operating the
units.
2.4.3 INSTALLATION CHECK OUT
Before inserting the unit into the mounting rack, verify that at the rear connector of the mounting
rack, aircraft power is present on P942 pin 19, and that there is a ground on P941 pin 14 and
P942 pin 20. In installations using 28 V lighting, lighting bus voltage should be present between
P941 pins 24 and 14. In installations using 14 V lighting, lighting bus voltage should be present
between P941 pins 25 and 14. Verify that there are no voltages or grounds present on any other
pins of P941 and P942.
A.Verify that aircraft power is OFF or the unit circuit breaker is pulled. Making sure that the power
On/Off switch, located on the front panel of the KLN 94 is rotated the “off” position (power off),
plug the unit into the mounting rack and verify that the panel lighting works properly.
B.Energize the unit by rotating the power control switch to the “on” position.
C.Manipulate the controls as necessary to display the Set 1 Page on the right half of the screen.
On the Set 1 Page, enter the airport name or the present position (latitude and longitude) for the
installation location accurate to within 60 nautical miles. Display the Set 2 Page. Verify that the
date and time are correct to within 10 minutes and update if necessary.
D.At this point the aircraft will have to be moved to a location known to have reasonable GPS
signal coverage. This implies an outside location away from tall structures that could mask low
elevation satellites. (To speed up the next test it is helpful to turn unit power off then on again
once the system is away from structures).
E.Proceed to the AUX 1 page. The State shown on the display should change to Acquire (ACQ)
from INIT and after a period of not more than 5 minutes, (typically two minutes depending upon
the satellite coverage), the unit should display Latitude and Longitude values on the Nav 2 Page
that are correct for the installation location. If the unit has not been turned on for 6 months, the
unit will take up to 20 minutes to calculate a position.
F.Select the AUX 2 page, verify that no asterisks appear next to any satellite with an elevation
greater than 25°. Select 121.15 MHz on COMM 1. Transmit on COMM 1 for a period of 20
seconds and verify that no asterisks appear indicating satellites with an elevation of greater than
25°. Repeat for the following frequencies: 118.000, 120.925, 121.175, 121.200, 123.825,
127.100, 130.625, 131.250, 131.275 131.300 and 134.150 MHz. Repeat the above procedure for
all VHF COMM’s on board the aircraft.
If any of the above tests do not pass (any asterisks appear on satellites with greater than 25°
during the above tests), it will be necessary to identify the source of the interference. There are
two common sources of interference:
1.The 12th and 13th harmonics of the above mentioned frequencies can be radiated from the
VHF COMM at a level strong enough to be a problem to the GPS but still be well low enough to
meet TSO/JTSO requirements for the VHF COMM.