Garmin GNC 420AW, Installation Manual

Page: 122 / 236

Page 5-38 400W Series Installation Manual
Rev. G 190-00356-02
5.6 Flight Checks
All system functions that cannot be adequately tested on the ground will require a flight test. Even if all
functions can be verified on the ground, a flight test is recommended as final installation verification.
Verify system operation as described in the following sections.
NOTE
The analog deviation (LEFT/RIGHT and UP/DOWN), TO/FROM, and FLAG (lateral
and vertical) outputs to a CDI or HSI should be verified in flight with potential sources of
electrical noise such as autopilot, flaps, gear, heater blowers, etc. operating. Lateral
deviation and flags may be checked with either GPS or VOR/ILS, and vertical deviation
and flags must be checked with Glideslope. Verify that the flags are hidden at the correct
times, and that the flag is in view at the correct times.
5.6.1 GPS Flight Check
1. Verify that GPS position is not lost during normal aircraft maneuvering (e.g. bank angles of up to
30 degrees and pitch angles associated with take-off, departures, approaches, landing and missed
approaches as applicable). If GPS position is lost, a “LOSS OF GPS NAVIGATION” message
will be displayed.
2. Enter and activate a flight plan on the 400W Series unit. Fly the flight plan and verify that the
display of flight plan data is consistent with the CDI indication (deviation, TO/FROM…) in the
pilot’s primary field of view.
5.6.2 VHF COM Flight Check (GNC 420W and GNS 430W)
After the installation is complete, a flight test is recommended to ensure satisfactory performance. To
check the communications transceiver, maintain an appropriate altitude and contact a ground station
facility at a range of at least 50 nautical miles. Contact a ground station in close proximity. Press the
COM volume knob to select manual squelch and listen for any unusual electrical noise, which would
increase the squelch threshold. If possible, verify the communications capability on both the high low
and mid bands of the VHF COM band. It may be required by the governing regulatory agency to verify
operation of the COM transmitter and receiver at the extents of a ground facility’s service volume (e.g.,
FAA AC 23-8A).
5.6.3 VOR Flight Check (GNS 430W)
1. Tune a local VOR station within 50 miles.
2. Verify the audio ident and voice quality and verify that no objectionable electrical interference
such as magneto noise is present.
3. Verify the Morse code decoder IDs the station (95% probability).
4. Fly to and from the station.
5. Verify NAV flag, TO/FROM flag, and CDI are operational.
6. Record accuracy in System Log (see manual).
It may be required by the governing regulatory agency to verify operation of the VOR receiver at the
extents of a ground facility’s service volume (e.g., FAA AC 23-8A).