Belfort AWOS, Maintenance Manual

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-23-
BELFORT
INSTRUMENT
Proprietary Information
5.6 W
IND
D
IRECTION
S
ENSOR
- A
NNUAL
M
AINTENANCE
V
ERIFICATION
The wind direction sensor verification procedure is a confidence test, which verifies that the
Belfort AWOS wind direction sensor has free rotation and balance and the sensor readings are
properly aligned with the airport north marker.
SAFETY PRECAUTIONS
1. Do not perform outdoor Belfort AWOS maintenance tasks during a thunderstorm.
2. Use extreme caution when lowering the tilt-over tower whenever ice or snow has accumulated
on the tower cross arm or the sensors. The extra weight may cause the tower to fall over
rapidly.
PARTS AND TOOLS REQUIRED
1. Belfort AWOS Hand Held Display Unit (HHDU)
2. 3 mm Allen wrench
3. Socket wrench and 13/16" socket
4. Large rubber band
VERIFICATION INSTRUCTIONS
1. At the DATU display terminal, issue a NOTAM advisory to alert users that the Belfort AWOS
system is being serviced prior to beginning this maintenance tasks. The NOTAM to be issued
is
"Belfort AWOS system being serviced, do not use current weather data outputs."
Verify that this NOTAM advisory is displayed on the operator screen prior to beginning this
maintenance tasks. Refer to the "Belfort AWOS Operator Manual" for instructions on how to
enter and delete NOTAMs.
2. Put the Belfort AWOS in “service mode” by toggling the “ALERT MESSAGE” toggle switch
located on the lower half of the hinged tower section six (6) times (See Table 1). This will
assure that pushing “REFRESH” on the HHDU will display instantaneous rather than averaged
wind direction, and true rather than magnetic information..
3. Remove tower-securing bolts and tilt the tower until the cross arm is at a comfortable working
height to access the wind direction sensor. Secure it in that position by tying the rope around
the base of the Belfort AWOS tower (refer to figure 2.a).
4. Power on the Belfort AWOS HHDU. The word “ALERT” must now be displayed across the
rectangular HHDU runway display. Push the “PAGE” button and the message “Belfort AWOS
being serviced” must appear.
5. The Alert messages are programmed in the same order as they appear in Table 1. If an alert
message other than message 6. is displayed, consult the list of alert messages in Table 1.
Toggle the tower switch an appropriate number of times until the “Belfort AWOS being
serviced” alert message is displayed. For example, if the alert message number 2 is displayed,
toggle the switch 4 times.
6. Position the wind vane so that it is vertical and parallel to the red pointer installed on the sensor
body. Secure the vane in that position by placing a rubber band around the tail of the direction
vane and the transmitter antenna as shown in figure 4. Erect the tower into the vertical position.
Confirm that the red pointer is aimed directly at the airport north marker. If the red pointer is
not properly aligned toward the airport north marker, adjust it as follows: