Problem
• Noise interference from other
GPS signal levels
drop when avionics
are turned on.
• Improper antenna installation or
The GPS signal
levels are very low.
• Antenna shaded from satellites.
• RF interference at 1575.42 MHz
• The PTT input is not being
The 400W Series
unit does not
transmit.
• No transmit power to the COM.
• The input voltage is too low.
• Wrong type of headsets, or level
The sidetone level is
too low or too high.
• Incompatible resolver or
OBS Resolver won't
calibrate.
• 400W Series unit resolver input
OBS indication on
400W Series unit
does not agree with
• Resolver has not been
OBS setting.
• ARINC 429 input port speed not
400W Series unit is
not receiving
heading from
compass system
(ARINC 429
• Wiring connections are
heading input used)
• 400W Series unit does not have
Autopilot is not
getting GPSS/Roll
Steering data from
• 400W Series unit ARINC 429
the 400W Series
400W Series
Instructions for Continued Airworthiness Bell 206B
Possible Cause
avionics.
coax routing.
from VHF COM.
pulled low.
needs adjustment.
improper connection.
not calibrated correctly.
calibrated.
correct
incorrect.
a position or flight plan entered.
output not configured correctly.
Solution
• Turn all avionics off, then turn on each
piece one at a time to isolate the
source of the interference. Route
GPS cable and locate GPS antenna
away from sources of interference.
• Check GPS antenna installation,
connections, and cable routing. The
GPS antenna must be mounted on
the top of the aircraft.
• Make sure the aircraft is clear of
hangars, buildings, trees, etc.
• Move GPS antenna further from the
COM antenna. Add a 1575.42 MHz
notch filter in COM coax. Fix or
replace the COM. Disconnect the
ELT antenna coax to check for
possible re-radiation.
• Check that the PTT (mic key) input is
pulled low for transmit.
• Make sure power input is connected to
the COM 25-pin connector P4002 11
and 12 and ground to P4002 21 and
22.
• Increase input supply voltage to
>12VDC. (>24VDC for 430AW
models)
• If necessary, adjust the sidetone level.
Sidetone adjustment is found on the
COM Setup page.
• Check the resolver specifications and
wiring.
• Check wiring and calibration.
•
Check ARINC 429 input port speed
setting for port that device is
connected to and verify that the
speed is correct for that device.
•
Check wiring.
•
Acquire GPS position and enter a
flight plan.
•
Check ARINC 429 output port setting
for port that autopilot is connected to.
190-01226-04 Rev. 2
Page 9 of 22
Imprimer la page