Belfort AWOS User manual

BELFORT
INSTRUMENT Co.
800-937-2353 www.Belfortinstrument.com
Belfort ®
Automated Weather
Observing System
AWOS
Maintenance Manual
Proprietary
Prepared in Response
to the
FAA, Automated Weather Observing System (AWOS)
Requirements
Aug. 2014

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BELFORT INSTRUMENT Proprietary Information
Table of Contents
Maintenance Manual
Paragraph Description Page
1.0 Introduction....................................................................................................... 1
1.1 Purpose.............................................................................................................. 1
1.2 Scope................................................................................................................. 1
1.3 Level of Maintenance ....................................................................................... 1
1.4 Periodic Maintenance........................................................................................ 1
1.5 Warranty ........................................................................................................... 1
1.6 Warranty Support.............................................................................................. 2
2.0 Applicable Documents & List of Acronyms .................................................... 3
2.1 Applicable Documents...................................................................................... 3
2.2 List of Acronyms .............................................................................................. 3
3.0 Maintenance Program Overview ...................................................................... 5
4.0 Qualification Requirements for Maintenance Personnel.................................. 5
5.0 Preventative Maintenance and Calibration Procedures .................................... 6
5.1 DATU –Data Acquisition Terminal Unit Maintenance.................................... 7
5.1.1 DATU Tri-Annual Maintenance....................................................................... 7
5.1.2 DATU Annual Maintenance............................................................................. 9
5.2 DCP Annual Barometric Pressure Sensor Maintenance & Calibration ........... 11
5.3 Temperature, Humidity and Dew Point –Annual Maintenance & Verification
Procedures......................................................................................................... 17
5.4 6000 Visibility Sensor –Tri-Annual Maintenance Verification and Calibration
Procedure .......................................................................................................... 18
5.5 Wind Speed Sensor Annual Verification Procedure......................................... 22
5.6 Wind Direction Sensor Annual Maintenance Verification............................... 23
5.7 Lightning Protection System, Battery & Tower Tri-Annual Maintenance....... 26
5.8 The UHF Transceiver Annual Maintenance..................................................... 27
5.9 The VHF Unicom Radio Annual Maintenance ................................................ 27
5.10 Belfort AWOS System Component Failure...................................................... 28
6.0 Troubleshooting the System ............................................................................. 29
6.1 System Built–In Diagnostics and Troubleshooting ......................................... 29
6.2 Interpreting Diagnostic Messages .................................................................... 31
6.2.1 System Status Indicators ................................................................................... 31
6.2.2 Interpreting Sensor Status And Data Quality Indicators .................................. 34
7.0 Tools and Test Equipment Required ................................................................. 41
8.0 Key System Performance Parameters and Expected Sensor Outputs............... 42
9.0 Maintenance Data Recording and Forms.......................................................... 42
9.1 Belfort AWOS Comprehensive Facility Performance Adjustment Data Form 42
9.2 Belfort AWOS Technical Performance Record................................................ 42
9.3 FAA Form 6030-1............................................................................................. 42
10.0 Component Removal and Replacement Procedures......................................... 43
10.1 DCP Removal Procedures................................................................................. 43
10.2 Temperature, Humidity/Dew Point Sensor Removal Procedures..................... 45

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10.3 6000 Visibility Sensor Removal Procedures..................................................... 47
10.4 Wind Speed Sensor and Wind Cups Removal Instructions............................... 49
10.5 Wind Direction Sensor and Vane Removal Instructions.................................... 51
10.6 Power Supply Replacement Instructions............................................................ 53
10.7 Surge Suppressor Replacement Instructions...................................................... 54
11.0 Recommended Spare Parts................................................................................. 56
12.0 Customer Product Support and Website Assistance .......................................... 56
Tables
Table 1 Belfort AWOS Alert Messages........................................................................ 11
Table 2 Recommended Spare Components................................................................... 56
Table 3 Recommended Spare Hardware ....................................................................... 56
Figures & Illustrations
Figure 1 Typical Display Acquisition Terminal Unit Setup ........................................... 5
Figure 1a Advisor Main Screen ........................................................................................ 6
Figure 1b System Status Page........................................................................................... 7
Figure 2 Typical Belfort AWOS Tower Equipment Mounting Locations...................... 13
Figure 2a Securing the Tower for Maintenance................................................................ 14
Figure 3a Scatter Plate Attachment Detail........................................................................ 19
Figure 3b Tower with Visibility Scatter Plate Attached ................................................... 19
Figure 3c Installation of Opaque Filters on Transmitter Hood......................................... 20
Figure 4 Wind Direction Vane Alignment...................................................................... 24
Figure 5 Typical Battery Terminal Bruch....................................................................... 26
Figure 6 Belfort AWOS Alert Messages ........................................................................ 30
Figure 7 Advisor Current Status Page ............................................................................ 30
Figure 8 DCP Removal ................................................................................................... 44
Figure 9 Temperature/Humidity Sensor Removal .......................................................... 46
Figure 10 Visibility Sensor Removal................................................................................ 48
Figure 11 Wind Speed Sensor Removal............................................................................ 50
Figure 12 Wind Direction Sensor Removal...................................................................... 52
Figure 13 Power Supply and Surge Suppressor Mounting ............................................... 54
Appendix A Belfort AWOS Maintenance Forms
Appendix B Belfort AWOS Tri-Annual, Annual and Five-Year Maintenance Plan
Appendix C UHF Transceiver Specifications
Appendix D Standard Unicom Radio-ICOM A110 VHF Radio Specifications
Appendix E Belfort AWOS Commissioning / Annual Inspection Procedure & Data Record
Appendix F DCP Site Configuration Procedure
Appendix G Belfort AWOS Atomic Clock Verification Procedure

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1.0 Introduction
1.1 PURPOSE –This manual has been prepared to thoroughly describe the maintenance
requirements to be followed by the owner and factory qualified technician to assure a long-term
successful usage of a Belfort AWOS system.
1.2 SCOPE –This manual has been developed in accordance with the guidance and
requirements described in FAA Advisory Circular, AC No: 150/5220-16D and other referenced
documents. This manual is intended to provide the owner and maintenance technician with proper
maintenance procedures applicable to all FAA approved Belfort AWOS configurations. Owners
and maintenance technicians are encouraged to contact the Belfort product support group at 1-800-
937-2353 regarding questions concerning the applicability of any specific maintenance procedure.
1.3 LEVEL OF MAINTENANCE –All levels of maintenance must be performed by a technician
that meets the requirements indicated in section 4.0 of this manual. Site/user maintenance is
characterized by routine preventive periodic maintenance, calibration adjustments and quick
turnaround replacement of defective or unreliable Lowest Replaceable Unit (LRU) assemblies.
Examples include completion of tri-annual performance, annual performance
validation/maintenance checks and removal and replacement of a failed sensor component. This
manual provides site maintenance personnel with instructions for completion and documentation
of routine performance and maintenance checks and tasks, instructions for adjustment of out of
tolerance sensors, troubleshooting procedures to identify defective components, and instructions
for the removal and replacement of defective system components.
1.4 PERIODIC MAINTENANCE –Equipment/system components that require periodic
maintenance and maintenance frequencies are identified in this manual. Forms to be used to
document completion of maintenance tasks, system calibration and adjustments are provided in
Appendix A of this manual. These forms can also be downloaded from the Belfort Instrument Co.
website, http://www.belfortinstrument.com. In addition to providing documentation of
maintenance actions completed, the Facility Performances and Adjustment Data Forms provided
are intended to be used as checklists to assure that all required routine maintenance tasks are
completed. Tri-annual preventive maintenance tasks must be completed in a timely manner to
assure system accuracy, optimum performance and reliability of the system.
1.5 WARRANTY –The entire Belfort AWOS TM system is provided with a one-year warranty.
The warranty period starts with the date of delivery from the factory. The entire system has been
manufactured and will perform in accordance with the requirements of the FAA AC 150/5220-
16D. The dual-pressure sensor and visibility sensor will perform as a certified instruments in
accordance with requirements of the FAA AC 150/5220-16D. Any defect in design, materials, or
workmanship which may occur during proper and normal use during a period of 1 year from date
of installation or a maximum of 2 years from date of shipment will be corrected by repair or
replacement by the manufacturer FOB Belfort. An extended warranty or and service contract may
have been purchased. Maintenance personnel should check with the system owner to determine if
an extended warranty or service contract is applicable to the system installed at their site.

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1.6 WARRANTY SUPPORT –For warranty support, contact Belfort Instrument Co. customer
support at 1-800-937-2353. When calling, please have the Belfort AWOS TM location and serial
number available.

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2.0 APPLICABLE DOCUMENTS &LIST OF ACRONYMS
2.1 APPLICABLE DOCUMENTS
This manual describes the periodic maintenance tasks to be performed on the Belfort Instrument
Co. AWOS system to comply with applicable sections of the following documents:
FAA AC No: 150/5220-16D Automated Weather Observing Systems (AWOS) For Non-
Federal Applications
FAA Order 6700.20 Non-Federal Navigational Aids and Air Traffic Control
Facilities
FAA Order 6560.13 Maintenance of Aviation Meteorological Systems and
Miscellaneous Aids
FAA Form 6030-1 Facility Maintenance Log
Belfort AWOS (VDD) Version located in Belfort AWOS site Maintenance Log
binder.
Description Document The VDD may also be located in the FRDF.
2.2 LIST OF ACRONYMS
AC
Alternating Current
AVG
Average
ALS
Ambient Light Sensor
AWOS
Automated Weather Observing System
BIT
Built-In-Test
CTAF
Common Traffic Advisory Frequency
DATU
Data Acquisition Terminal Unit
DC
Direct Current
DCP
Data Collection Processor
DDR
Digital Data Receiver
DMM
Digital Multi-meter
DSL
Digital Subscriber Line
DTMF
Dual-Tone Multi-Frequency
EEPROM
Electrically Erasable Programmable Read-Only Memory
FAA
Federal Aviation Administration
FBO
Facility Base Operator
FCC
Federal Communication Commission
FRDF
Facility Reference Data File
FRU
Field Replaceable Unit
FSDO
Flight Standards District Office
Hg
Mercury
HHDU
Hand Held Display Unit (Optional Maintenance Tool)
ICAO
International Civil Aviation Organization
ID
Identification
INOP
Inoperative
KT
Knots
LED
Light Emitting Diode

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LRU
Lowest Replaceable Unit
MCIF
Microphone Click Interface
MHz
Megahertz (million Hertz)
MOU
Memorandum of Understanding
MSL
Mean Sea Level
NAVAID
Navigational Aid
NIST
National Institute of Standards and Technology
NOTAM
Notice To Airmen
OMM
Operations and Maintenance Manual
RAF
Regional Airway Facilities
REL HUM
Relative Humidity
RIF
Radio Interface
RPM
Revolutions Per Minute
T1
T-carrier 1 (digital transmission line, 1.544 Mbps, 24 voice channels)
UHF
Ultra High Frequency
UNICOM
Universal Integrated Communications (System)
VAC
Volts Alternating Current
VDC
Volts Direct Current
VDD
Version Description Document (Belfort AWOS Configuration Baseline
Document)
VDU
Video Display Unit
VHF
Very High Frequency
VS
Visibility Sensor

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3.0 MAINTENANCE PROGRAM OVERVIEW
Belfort AWOS maintenance consists of preventive and corrective maintenance activities.
Preventive maintenance consists of tri-annual and annual maintenance tasks required to keep the
Belfort AWOS system in peak operational condition. Corrective maintenance utilizes the Built-
In Test (BIT) features of the Belfort AWOS software to identify system faults and minimize
troubleshooting activities. For sensor troubleshooting, removal instructions and procedures refer
to section 6.0 of this manual. Refer to the Belfort AWOS Installation and Checkout manual for
installation instructions and checkout of replaced sensors and components.
A suite of system diagnostic self-tests is continuously running and automatically outputs system
status to a history file every time sensor information is transmitted from the DCP. If the self-test
detects a problem, the suspected sensor or function is identified in the system status log with an
error flag.
When routine maintenance tasks and adjustments are not adequate to correct system errors or
problems, defective components must be replaced. Site maintenance personnel must not attempt
to repair defective system LRU components.
Figure 1
Typical Display Acquisition Terminal Unit setup
4.0 QUALIFICATION REQUIREMENTS FOR MAINTENANCE PERSONNEL –Installation and
maintenance of the Belfort AWOS system must be performed by qualified personnel. FAA
Order 6700.20A contains the qualification requirements for maintenance personnel who
maintain Non-Federal facilities. Installation and maintenance personnel must meet the
requirements of FAA Order 6700.20A and have the special knowledge and skills needed to
install and maintain a Belfort AWOS facility. These skills can be obtained by completing the
“Belfort AWOS Installation and Maintenance Training Program” course and successfully

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passing the required FAA administered performance examination. The owner of the Belfort
AWOS system is responsible for assuring that only qualified personnel perform system
maintenance activities. Owners or maintenance technicians interested in scheduling this
Belfort training should contact the Belfort AWOS program manager at 1-800-937-2353 to
schedule this training.
5.0 PREVENTATIVE MAINTENANCE AND CALIBRATION PROCEDURES –Scheduled Belfort AWOS
calibration/verifications are performed tri-annually and annually as detailed in Appendix B.
Any defects observed or detected during these maintenance and calibration procedures and
tests must be described and recorded on the Facility Maintenance log, FAA Form 6030-1
and corrective actions initiated to resolve the issue as soon as possible.
As a standard practice, whenever maintenance personnel visit the outdoors Belfort AWOS site
location, regardless whether the visit is scheduled or unscheduled, a general walk-around
inspection of the Belfort AWOS tower and associated site grounds area must be performed. This
walk-around inspection should include the following observations at a minimum:
1) Visual inspection of the tower for obvious defects such as chipped paint, evidence of
corrosion on the tower or sensor enclosures or mounting structures, loose or broken hardware or
electrical connections, and any other unsafe conditions that could affect the reliability of the
system. Including an observation that the obstruction lighting is operational. Any defects
observed must be described and recorded on the Facility Maintenance log, FAA Form 6030-1 and
corrective actions initiated to resolve the issue as soon as possible.
2) A general inspection of the grounds area to assure that grounds maintenance is being
adequately performed and the area is neat and orderly.
3) The certified instruments Visibility Sensor and Altimeter must be verified as detailed
in Appendix B. The appropriate Belfort AWOS Maintenance Form from Appendix A must be
completed for each Maintenance event.
4) The non-certified instruments Wind Speed and Direction, Temperature and
Humidity/Dew-point Sensor must be verified as detailed in Appendix B. The appropriate Belfort
AWOS Maintenance Form from Appendix A must be completed for each Maintenance event.
The following scheduled preventive maintenance procedures must be completed at a minimum
for each of the LRU or system sensor assembly installed as identified in this section:

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5.1 DATU –DATA ACQUISITION TERMINAL UNIT MAINTENANCE
Any defects observed or detected during these tests must be described and recorded on the
Facility Maintenance log, FAA Form 6030-1.
5.1.1 DATU TRI-ANNUAL MAINTENANCE
1. Clean air filters with hand-held vacuum cleaner.
2. Clean cabinets with mild detergent and water (wring cloth dry).
3. Check the computer CPU Power Supply cooling fans to assure they are operating and listen
for any unusual noise such as; grinding or squealing, that would indicate the fan is not
functioning properly. The DATU computer is not a field repairable item. Therefore, if the fan
is not operating or is making unusual noise, contact Belfort to arrange for computer
replacement or factory repair.
3a. Check PC Clock for accurate time and Atomic Clock operation. If the time is not accurate,
then perform the Atomic clock verification procedure in Appendix G. Then reset the Windows
clock through the windows control panel to the correct time.
3b. Download and install any Windows Updates indicated by the Windows OS.
**The Belfort AWOS tower should be powered up with both AC and DC Circuit breakers
on. Some of the sensors take up to 5 minutes for their averaged values to be reported to the
DATU from the DCP.
4. The Belfort AWOS Tower transmits telemetry, system status, sensor status and data quality
status along with weather data. Advisor software captures the telemetry and displays it on the
Advisor Main screen. See Figure 1a below.

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Figure 1a
Advisor Main Screen
Advisor software also captures this status and compares it to the last status received and if there
is a difference in any of the data, writes all the data to the Advisor Status Log and to the Advisor
Current Status Page. See Figure 1b below.
Figure 1b
System Status Page
The System Status Page is updated when the page is accessed. To reread the status, the
technician must select the Return Button then access the System Status page again for
updated status.
At any time the maintenance technician can view the most recently received Status Information
displayed in a user-friendly format. The maintenance technician can also view the Status Change
History for past or recurrent problems. View the Status Pages past history by selecting Status
Pages from the History menu entry on the Advisor main menu. Refer to the Belfort AWOS
"Operator Instruction Manual” for complete user instructions for operating the Advisor software.
5. Document any error flags on the Tri-annual or Annual “Facility Performance and Adjustment”
data form.

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6. Check the Advisor Status Log Page for any past or recurrent problems that have not been
addressed as current.
7. If doing a Tri-Annual or Annual performance test, document any unexplained recurrent error
flags on the Tri-annual or Annual “Facility Performance and Adjustment” data form. All
actions taken to correct errors identified will need to be documented and addressed on the FAA
Form 6030-1.
5.1.2 DATU ANNUAL MAINTENANCE –In addition to completing scheduled tri-annual maintenance
tasks, DATUannual maintenance consists of verifying operation of the Atomic Clock and defragmenting
the DATU computer hard drive and verification of the installed Belfort AWOS software configuration. It
is not necessary to stop the Belfort AWOS application during disk defragment.
To verify the Belfort AWOS Atomic clock, follow the Verification Procedure in Appendix G.
Follow the steps below to defragment the computer hard drive:
1. Minimize the Advisor Window and any other running Belfort AWOS programs
2. Empty the Recycle bin.
3. Click on the “Start” button
4. Click on “My Computer”
5. Right click on “Local Disk, “C:”
6. Select “Properties”
7. Select the “Tools: tab
8. Select and click on the “Disk Cleanup”button to perform that function.
9. Click on the “Defragment Now” button
10. Note the “% Free Space”
If “% Free Space is less than 15% or < 3G ,” notify Belfort Instrument Company for support.
11. Click the “Defragment” button
12. Once the defragmenting process is complete you may exit all windows opened in the above listed
steps.
13. Maximize the Advisor window and any other previously minimized Belfort AWOS programs
Follow the steps below to check the version status of the installed Belfort AWOS software:
1. Belfort AWOS Advisor:
a) Select "Help" from the Advisor Menu.
b) Select "About" from the submenu.
c) The version number is located on the bottom of the window.
d) Record the software version on the Annual Configuration Validation Performance and
Maintenance Record.
2. Belfort AWOS Phone:
a) Right click on the Belfort AWOS Phone icon located in the system tray.
b) Select “Configure”from the popup menu.
c) The version number is located on the top of the window.
d) Record the software version on the Annual Configuration Validation Performance and
Maintenance Record.

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3. Belfort AWOS Voice:
a) Select “Help”from the Belfort AWOS Voice main menu.
b) Select “About Belfort AWOS Voice”from the submenu.
c) The version number is located at the top of the window.
d) Record the software version on the Annual Configuration Validation Performance and
Maintenance Record.
4. Contact the Belfort Factory Customer Service for the current released versions information and the
software if needed.
5. If the current installed versions of software are not the current released FAA approved versions of
software, then the system should be updated with the newest released versions.
6. Add an entry in the Facility Maintenance Log on Form 6030-1 for each software version
upgraded or any changes made to the PC.

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5.2 DCP –Annual Barometric Pressure Maintenance & Calibration
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. Portable pressure standard with current NIST traceable calibration certification.
2. Notebook computer running ACBSTXCOM and RS232 cable
3. Belfort AWOS hand held display
4. Socket wrench and 13/16" socket
5. Eight (8) foot step ladder 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. Instructions for issuing and deleting NOTAMs are
provided in the "Belfort AWOS Operator Manual".
2. At the tower, toggle the “ALERT MESSAGE” toggle switch located on the lower half of the
hinged tower section (refer to figure 2.a) six (6) times (See Table 1).
Belfort AWOS Alert Messages
1. Contact FBO for an important message.
2. Wind speed sensor INOP.
3. Wind direction sensor INOP.
4. Temperature and/or humidity sensor INOP.
5. Barometric pressure sensor INOP.
6. Belfort AWOS being serviced. Do not use readings.
7. Belfort AWOS not maintained. Do not use readings.
8. Private Belfort AWOS weather station. Do not use.
9. Landing area warning
0. No Alerts
Table 1.
Belfort AWOS Alert Messages
3. Remove tower-securing bolts and lower the tower until the DCP is at a comfortable working
height so that the portable pressure standard on an upper step of the ladder is at the same

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height as the DCP. Secure the tower in that position by tying the rope to the base of the
Belfort AWOS tower. Figure 2.a illustrates the height locations where the various Belfort
AWOS sensors and other system components are located on the tower. Figure 2.b illustrates
the tower as typically secured for maintenance.

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Figure 2.
Typical Belfort AWOS Tower Equipment Mounting Locations

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Figure 2a
Securing the Tower for Maintenance

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4. Power on the Belfort AWOS HHDU. The word “ALERT” should be displayed across the
HHDU runway display. Push the “PAGE” button and the message “Belfort AWOS being
serviced” must appear. For the VHF output and the Phone output, the affected instrument
will be reported as “inoperable”. On the Advisor Screen, the indicated Alert will be reported
on the front page of the display.
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. You
will need to 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. Check and clear the altimeter pressure ports of any blockage or insect infestation. If blockage
is found, slide a wooden tongue depressor between the plates to clear the debris. Visually
check the tubes from the pressure ports to the tower, look for any indications of crimping or
degradation. Replace if necessary.
7. Verify accuracy of pressure sensor data - Place the portable pressure standard on the ladder
at the same height (± 6 inches) as the DCP. Turn the standard on and allow it to stabilize for
five (5) minutes. Check for low battery indication (a decimal point will appear between each
digit of the displayed pressure when the battery is low).
8. If the system has a visibility sensor, there will be a serial RS232 cable from the visibility
sensor connected to another RS232 cable which is connected to the back of the DCP.
Disconnect these two RS232 cables. Connect the cable connected to the DCP to the test
notebook computer RS232 serial communication port. If there is no visibility sensor
installed, connect the portable notebook computer (with ACBSTXCOM installed) to the
DCP through the serial communication cable that extends to the bottom of the tower.
9. If the system has a battery backup, turn off the DC circuit breaker so battery backup is
disabled. Start the ACBSTXCOM program. After 10 seconds, turn the AC circuit breaker
in the Belfort AWOS power box off and then on again to force a reset. Immediately type
“m” <enter> to put the DCP in monitor mode. Enter the password.
10. Type “T10” <enter> to display the measured pressure from the 2 sensors. If the measured
pressure of either of the sensors differs from the standard by more than 0.05 in Hg, it indicates
that the sensor is not suitable for calibration. The DCP must be replaced before continuing
further with this procedure. DO NOT ATTEMPT TO CALIBRATE A PRESSURE
SENSOR THAT DIFFERS FROM THE STANDARD BY MORE THAN 0.05 in Hg.
Follow the Belfort AWOS System Component Failure Instructions in Section 5.10.
11. If either sensor differs from the standard by more than .02 in Hg, or the sensors differ from
each other by more than .02 in Hg, review the previous year’s maintenance log for the Belfort
AWOS Comprehensive Facility Performance and Adjustment Record and any Annual
Configuration Validation Performance and Maintenance Records. If the Annual Drift value
is greater than +-.02 in Hg then the sensors are suspected to be faulty and the DCP needs to
be returned to Belfort for Factory Service. If the Annual Drift value is less than +- .02 inHg,
the sensors can be adjusted. Document the Drift Value on the appropriate test record sheet.
12. To adjust the sensors, unbolt the DCP from the tower allowing access to the tube connectors
on the back of the DCP. Remove the tubes from the back of the DCP and blow through
tubes, checking for any obstructions. After assuring the tubes are clear and reconnecting
them to the DCP (either tube to either connector is OK), start the pressure sensor calibration
process by typing “U P ~” and press <enter>. The DCP will prompt you for a password.

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Enter the site password (the password is case sensitive). Next, hold the CTRL key down and
type “V” then enter the 5 digit target pressure from the portable pressure standard (Example
30.235) and press <enter>. The automatic calibration routine will make any required
adjustments to the pressure sensor parameters and the DCP will report “calibration
complete”. At the end of the routine, press the “esc” key to return to the main configuration
menu.
13. Verify that the pressure sensors are calibrated by repeating step 10. If the sensors still differ
from each other or the standard by more than .02 in Hg. first, repeat step 12.
14. If the sensors cannot be adjusted to within spec, then the sensors are faulty and the DCP
needs to be returned to Belfort for Factory service. Follow the Belfort AWOS System
Component Failure Instructions in Section 5.10.
15. Type “c” and enter the new date of calibration, then type “CR”.
16. Press the “Esc” key. This will cause the data to be saved in the EEPROM.
17. Exit ACBSTXCOM by typing “x” then press <enter>.
18. Reattach the DCP to the tower with the 4 screws removed in step 11 above.
19. Disconnect the RS232 cable from the notebook computer and reconnect the RS232 data
communication cable to the visibility sensor (if present). Apply Dow Corning #4 liberally
to the connection to protect against moisture. .
20. Remove and reapply power to the DCP to restore normal operation.
21. If additional maintenance tasks are to be performed, skip to next maintenance task. If
maintenance tasks are complete, toggle the “ALERT MESSAGE” switch 4 times to return
the unit to service.
22. Observe system output and verify that the system is reporting data as expected.
23. Switch the DC circuit breaker back on if battery backup is present.
24. Untie the rope and SLOWLY erect the tower to the vertical position and secure it by
installing and tighten-up (DO NOT OVER TIGHTEN) the three (3) tower-securing bolts.
NOTE: Be careful to avoid pinching the wires on the inside of the hinged Tower Section
when raising the tower.
24. If all maintenance tasks are complete, issue another NOTAM advising users that
“maintenance activities were completed, system has been returned to normal
operation.” The expiration date and time of this NOTAM should coincide with the same
expiration date and time of the previous advisory NOTAM that was issued to put the system
in the maintenance mode. Verify that this NOTAM advisory is correctly displayed on the
operator screen. Refer to the "Belfort AWOS Operator Manual" for instructions on how to
enter and delete NOTAMs.

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5.3 TEMPERATURE,HUMIDITY AND DEW POINT-ANNUAL MAINTENANCE &VERIFICATION
PROCEDURES
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. Kestrel Model 3000 Wind Instrument or equivalent
2. Belfort AWOS hand held display
The Temperature and Dew Point Verification Test is a confidence test, which verifies that the
Belfort AWOS air temperature and humidity readings compare reasonably with readings taken by
a calibrated Kestrel Model 3000 Wind Instrument.
VERIFICATION INSTRUCTIONS
1. Turn on the HHDU. Stand near the base of the Belfort AWOS tower, facing into the wind.
Observe the Belfort AWOS wind indicator vane to ascertain wind direction. Turn on the
Kestrel Model 3000, select average mode, and hold the Kestrel Model 3000 at eye level,
square to the wind and record the temperature and relative humidity. If the wind speed is
below 2 mph, wave the Kestrel Model 3000 back and forth several times to assure air
temperature is being measured and not case temperature. Press refresh on the HHDU to get
the most recent Belfort AWOS data. The temperature and humidity readings should agree
within 20%.
2. If either temperature or relative humidity does not agree within 20%, the sensor should be
replaced. Follow the Belfort AWOS System Component Failure Instructions in Section
5.10.