L 3 Communications Avionics Systems TRC497 User Manual

SKY497

Installation Manual

CHAPTER 4

MAINTENANCE

4.1 INTRODUCTION

This chapter contains general flight-line maintenance and troubleshooting procedures for installations
interfaced to WX-1000/SKY497 display or an alternate display. Removal of components is on condition of
failure. Troubleshooting is intended to aid in isolating failures to a defective assembly. Each time the TRC,
directional antenna, or directional antenna cables (including connectors) are replaced, the TRC must be
calibrated to the directional antenna (refer to paragraph 4.4.1).

4.2 CONTINUED AIRWORTHINESS

No scheduled maintenance is required to ensure continued airworthiness.

4.3 PERIODIC MAINTENANCE

At regular inspection intervals, do the periodic maintenance procedures of paragraph 4.3.1 thru 4.3.3.

4.3.1 WX-1000/SKY497 Display

1. Check that indicator cable is properly mated and secured.

2. Check to ensure unit is properly placed and secured to the instrument panel.

CAUTION

Do not use cleaning solvents on the viewing face.

3. Check face-plate for cleanliness. Wipe the viewing face with a damp lint-free, static-free cloth. If
necessary, clean with a soft cloth moistened with a mild solution of soap and water. Take care to
prevent cleaning solution from running down inside the case.

4.3.2 TRC

1. Check that connectors are properly mated and secure.

2. Check to ensure that the hold-down knobs on the mounting tray are secured to the TRC.

4.3.3 Antenna

1. Check for dents, cracks, and punctures.

CAUTION

Do not paint the antennas.

Do not use cleaning solvents on the antennas.

2. Remove all dirt and grease from surface areas. Clean with a soft cloth moistened with mild soap and
water.

3. Visually inspect sealant around the antenna base. Reapply sealant if required.

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4.4 SERVICE MENU

The Service Menu is intended as an aid in installing, testing and troubleshooting the SKY497. Service
Menu items are to be used only for testing and troubleshooting an installation. The Service Menu is not
intended to be used by the pilot during normal system operation. When interfaced to an alternate display
the service menu functions must be performed by using an RS-232 terminal device, see appendix D for
operating instructions.

The Service Menu is accessed by holding soft-keys (1) and (2) (the left two buttons) depressed as the
system is turned on. Hold the buttons until the Service Menu is displayed. The Service Menu is shown in
figure 4-1.

Figure 4-1. Service Menu

The buttons perform the following operations:

• EXIT - causes the system to exit the Service Menu and run the power on self-test.

• SELECT - selects the highlighted item.

• PREV - steps to the previous item.

• NEXT - steps to the next item.

The Service Menu provides the following choices:

• Calibration

• System Log

• System Data

• Ground Test (Available only if squat switch input indicates aircraft is on the ground.)

The individual menu items are explained in the following paragraphs.

NOTE

Service Menu screens are shown for documentation purposes only. Each system
may be configured differently and live data will correspond to the sensors
installed in a particular aircraft..

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4.4.1 Calibration

NOTE

Ensure transponder is in standby while doing calibration.

Each time the TRC, directional antenna, or any of the directional antenna cables (including connectors)
have been repaired or replaced the TRC must be calibrated. Calibration is accessed by selecting that option
from the Service Menu (i.e., press SELECT with Calibration high-lighted). The initial calibration screen
(see figure 4-2) shows the current calibration value in degrees. Calibration can be performed with the
terminal device by using the Cal command.

NOTE

If the TRC has never been calibrated, the current calibration value will be displayed as 999.

Figure 4-2. Calibration Screen

Press YES to calibrate; press NO to return to the Service Menu. Soft-keys (3) and (4) are not used. During
the calibration procedure, the message “Re-Calibrating . . . ” will be displayed.

After a successful calibration, both old and new calibration values will be displayed (as shown in
figure 4-3). Press EXIT to return to the Service menu. Soft-keys (2), (3), and (4) are not used.

Figure 4-3. Successful Re-Calibration

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The calibration value (000-359) is derived from a variety of measurements. Specific values are meaningless
however, in a failed TRC, a varying spread may indicate problems with the directional antenna system
(antenna, cables, or connectors) or the TRC.

If the calibration failed, the message “Re-calibration Failed!” will be display (see figure 4-4).

Figure 4-4. Failed Calibration

Press YES to calibrate; press NO to return to the Service Menu. Soft-keys (3) and (4) are not used.

4.4.2 System Log

The 20 most recent errors detected by the system self-test are saved in the System Log. For each error, the
corresponding error code and run-time of occurrence are saved. The system log, as shown in figure 4-5, is
displayed by selecting that option from the Service Menu (i.e., press SELECT with System Log high-
lighted). System Log can be accessed with a terminal device by using the Dump command.

NOTE

Tables 4-2 and 4-3 provide a list and description of each error code (see paragraph 4.6).

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Figure 4-5. System Log

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Installation Manual

The System Log displays the results in the following format:

### HHHHH:MM

where:

### = Error code.
HHHHH:MM = Run-time (in hours and minutes) at which error occurred.

The total elapsed run-time is displayed in the upper middle portion of the screen (System Time
HHHHH:MM).

A textual description of the highlighted error entry is displayed in the bottom portion of the screen.
If the System Log is empty, the following message is displayed:

NO FAULTS DETECTED

If, due to a failure of non-volatile memory, the System Log cannot be displayed, the following message is
displayed:

DATA NOT AVAILABLE

The buttons perform the following operations:

• EXIT - causes the system to return the Service Menu.

• NEXT - steps to the next entry.

• PREV - steps to the previous entry.

• Soft-key (4) is not used.

4.4.3 System Data

System Data screens (see figures 4-6 through 4-16) contain a record of setup information (software
identification and jumper configuration) and real-time sensor data. If you have problems with the SKY497,
verify the configuration screens match the wiring diagrams (see figures 2-2 and 2-3) and have this
information available when contacting BFGoodrich Avionics Systems Field Service Engineering. The field
service engineer must have adequate information to diagnose a problem. System Data screens are accessed
by selecting that option from the Service Menu (i.e., press SELECT with System Data high-lighted).

The System Data screen provides the following choices:

• Software Version

• Configuration

• Data Monitor

Figure 4-6. System Data

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The buttons perform the following operations:

• EXIT - returns to the Service Menu (figure 4-1).

• SELECT - selects the highlighted item.

• PREV - steps to the previous item.

• NEXT - steps to the next item.

4.4.3.1 Software Version. The software version screen (see figure 4-7) identifies:

• IOP Code Version

• IOP Boot Version

• STP Code Version

• STP Boot Version

Software version can be accessed with a terminal device by using the Version command.

Figure 4-7. Software Version

NOTE

The software version identified on the TRC equipment tag represents the system software
configuration (i.e., a collective designator for all software/firmware installed within the
unit).

Press EXIT to return to the System Data screen. Soft-keys (2), (3) and (4) are not used.

4.4.3.2 Configuration. The configuration display consists of 4 pages. Configuration data on pages 1, 3 and 4 must be verified and saved on all new installations or if changes in configuration jumper(s) occur. The buttons perform the following operations:

• EXIT - returns to the System Data Menu (figure 4-6).

• NEXT - steps to the next page.

• PREV - steps to the previous page.

• SAVE - saves configuration data for that page (not present if configuration jumpers

match configuration memory).

Configuration information can also be accessed with a terminal device by using the Config command.

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NOTES

1. Saved configuration data is read at power-up and compared with
configuration jumpers. If the saved configuration data has never been
saved (e.g., new installations) an ERROR 30 Check Configuration will
occur when the box comes out of standby. If the saved configuration data
does not match the current jumper(s) an error 30 will occur at power-up.
The conflicting jumper(s) will be highlighted on configuration screen(s).
(See figure 4-8.)

2. Configuration pages 1, 3 and 4 contain configuration jumper data. On
each page verify jumpers are correct and press SAVE to write the new
configuration into system memory. When done the SAVE button
disappears. Repeat this step for each page. Save command can be used if
using a terminal device.

Figure 4-8. Configuration - Page 1

Page 1 of 4 (see figure 4-8) displays:

• Heading Input Source (Hdg.: XYZ, STEP, 429, or NONE)

Configuration Jumpers P1-69 & P1-70 (OPEN or GND)

P1-69 P1-70
None OPEN OPEN
Synchro XYZ OPEN GND
Stepper GND OPEN
ARINC 429 Bus GND GND

• Heading Flag Sense (HIGH or LOW)

Configuration Jumper P1-68 (OPEN or GND)

P1-68

OPEN If LOW level input on HDG_FLG+ (P1-53) indicates

valid heading or no valid heading input is available.

GND If HIGH level input on HDG_FLG+ (P1-53) indicates

valid heading.

• RS422 Interface (DR/Alt. 422: DR or 422)

Configuration Jumper P1-67 (OPEN or GND)

P1-67
Data Recorder OPEN
Alternate* GND

*Future Option

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NOTE

The RS422 Interface is used for factory testing and evaluation.

Figure 4-9. Configuration - Page 2

Page 2 of 4 (see figure 4-9) displays:

• Barometric Encoded Altitude (in Gray Code and Feet)

• Connector P1 Pin Assignments for Data Inputs

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Figure 4-10. Configuration - Page 3

WARNING

Verify displayed antenna position matches antenna location on the aircraft
(top or bottom). Failure to do so could give incorrect traffic bearing.

Installation Manual

Page 3 of 4 (see figure 4-10) displays:

• Antenna Position (Ant. Pos.: TOP or BOT)

Configuration Jumper P1-100 (OPEN or GND)

P1-100

Top OPEN
Bottom* GND

*See paragraph 2.3 (ANTENNA LOCATION)

• Antenna Type (NY164 or NY156)

Configuration Jumper P1-99 (OPEN or GND)

P1-99

NY164 OPEN

NY156 GND

• Airframe (Ant. Pos.: FIX or ROT)

Configuration Jumper P1-98 (OPEN or GND)

P1-98

Fixed Wing OPEN

Rotorcraft GND

SKY497

Figure 4-11. Configuration - Page 4

Page 4 of 4 (see figure 4-11) displays:

• Alternate Display Type (None Selected, ARINC 735 Type 1, or Illegal Display)

Configuration Jumpers P1-77, P1-78, P1-79 & P1-80 (OPEN or GND)

P1-77 P1-78 P1-79 P1-80
None OPEN OPEN OPEN OPEN
735 Type 1 OPEN OPEN OPEN GND

4.4.3.3 Data Monitor. The data monitor display consists of 5 pages. The buttons perform the following operations:

• EXIT - returns to the System Data Menu (figure 4-6).

• NEXT - steps to the next page.

• PREV - steps to the previous page.

• Soft-key (4) is not used.

The data monitor information can be accessed with a terminal device by using the Bar, Head, Rad and
Config commands.

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Figure 4-12. Data Monitor - Page 1

NOTE

Values displayed on the Data Monitor are continuously updated. The sensor
source (e.g., ARINC 429, Synchro XYZ, etc.) is latched at power-up. If it is
necessary to change a configuration, cycle power to ensure the correct
information is read into memory.

Page 1 of 5 (see figure 4-12) displays:

• Barometric Altitude

Source (Encoded Inputs, ARINC 429, or Simulated)
Altitude (in Feet)

• Heading Data

Source (Synchro XYZ, ARINC 429, None, or Simulated)
Heading (in Degrees)
Flag Line (Valid or Invalid)

1. When the system is set to GROUND TEST, the barometric altimeter is
simulated to 50,000 ft and the heading simulated to 0 degrees.

2. If an INVALID “Flag Line” is detected, the “Heading” will be flagged
INVALID.

NOTES

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Figure 4-13. Data Monitor - Page 2

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Page 2 of 5 (see figure 4-13) displays:

• Radio Altitude

Source (ARINC 429, None, or Simulated)
Altitude (in Feet)

NOTE

When the system is set to GROUND TEST, the radio altimeter simulated to 2,500 ft.

Figure 4-14. Data Monitor - Page 3

Page 3 of 5 (see figure 4-14) displays ARINC 429 Data:

• Transmit Data (Tx: None Selected or ARINC 735 Type 1*, Illegal)

*Alternate Display Device

• Received Data (Rx):

Status (Locked or Seeking)
Speed (High or Low)
Number of Parity Errors

• Label Data

Label Number & Function

164 RadAlt (Radar Altimeter)
203 BarAlt (Barometric Altimeter)

320 MagHead (Magnetic Heading)
Channel (1 or 2)
Value (Altitude in Feet; Heading in Degrees)

A “Failed” message will appear if the system fails an internal ARINC 429 communications test.

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Figure 4-15. Data Monitor - Page 4

Page 4 of 5 (see figure 4-15) displays switch status:

• Squat Switch (ON GND/FLYING)

Connector P1-88 (SQUAT) Input (OPEN or GND)

P1-88
Flying OPEN
On Ground GND

• Landing Gear (UP/DOWN)

Connector P1-87 (GEAR) Input (OPEN or GND)

P1-87
Gear Up OPEN

Gear Down GND

• GPWS (ACTIVE/INACTIVE)

Connector P1-33 (GPWS) Input (OPEN or GND)

P1-32
Inactive OPEN
Active GND

Figure 4-16. Data Monitor - Page 5

Page 5 of 5 (see figure 4-16) displays measurements of the following internal values:

• Voltage (+5 VDC, + 15 VDC, & -15 VDC)

• Processor Temperature (Degrees C)

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4.4.4. Ground Test

Ground Test initializes the system for on-the-ground testing. In this configuration, the barometric
altimeter is simulated to 50,000 ft, heading simulated to 0 degrees, and the radar altimeter simulated to
2,500 ft.

NOTE

Ground test is available only if the squat switch input indicates aircraft is on the ground.

Ground test (see figure 4-17) is accessed by selecting that option from the Service Menu (i.e., press
SELECT with Ground Test highlighted). To access ground test with a terminal device use the Ground
Test command.

Figure 4-17. Ground Test

If the system detects a heading fault, HDG will be displayed in the bottom center portion of the screen.

The buttons perform the following operations in this mode:

• EXIT - causes the system to return the System Data Menu (figure 4-6).

• Soft-key (2) toggles the system through the above (ABV), normal (NRM), and below (BLW)

altitude display modes. It is labeled to indicate current mode (i.e., ABV, NRM, or BLW).

• Soft-key (3) toggles the display range between 2 and 6 nm. It is labeled to indicate current

range (i.e., 2nm or 6nm).

• Soft-key (4) is not used.

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4.5 TROUBLESHOOTING

Table 4-1 is intended to assist trained electronic technicians to determine which assembly is inoperative.
Do the corrective action steps in the order described. Use the Service Menu (refer to paragraph 4.4) as an
aid in fault isolation. Information available from the service menu can help identify conditions that need to
be resolved. If interfaced to an alternate display service menu must be accessed via an RS-232 terminal
device, see Appendix D for operating instructions.

Table 4-1. Fault Isolation

SYMPTOM CORRECTIVE ACTION

Display remains dark after SKYWATCH is powered ON.

Display is distorted.
Incorrect response to buttons (soft-keys).

SKYWATCH will not enter service menu.

The self-test successfully completes without audio
annunciation.

SKYWATCH Failed.

Self-test does not execute. Aircraft is on the ground.

The display cannot be switched between SKYWATCH and
the WX-1000. Both systems are installed.

WX-1000 processor has been removed for service;
SKYWATCH fails to operate.

a. Check position of the WX-1000 maintenance switch

(NORMAL/OVERRIDE).
b. Reset circuit breaker if it is tripped.
c. Check aircraft power source.
d. Check connection to WX-1000 processor, if installed.
e. Check power input at TRC mating connector.

P8-A +28V (10.5-34V PWR)

P8-B +28V_RET (AIRCRAFT PWR RETURN)
f. Check cables connected to display.
g. Replace Display.

Check for interference from aircraft systems.
Check soft-key wiring inside display cable and WX-1000

processor cable (if installed).
a. Check soft-key wiring.

b. Verify alternate display pins (P1-77, P1-78, P1-79, or

P1-80) are not configured to ground. Service menu is
not accessible via softkeys when an alternate display is
configured.

c. If using an alternate display service menu must be

accessed via an RS-232 terminal device.

a. Check headphones/speaker and aircraft audio panel

switch settings.

b. Check cables connected to TRC.

Audio Alert Output:

P1-92 (AUDIO_H - 600-Ohm)
P1-91 (AUDIO_L - 150-Ohm)
P1-90 (AUDIO_C - Common)

a. Check system log (para 4.4.2) for errors. Error

messages are detailed in para 4.6.

b. Replace TRC.

a. If standby screen is displayed, check soft-key wiring
inside display cable and WX-1000 processor cable
(if installed).
b. Check connection between the TRC and the squat
switch sensor.

Squat Switch Input: P1-88

a. Check circuit breakers. Reset if tripped.
b. Check position of the WX-1000 maintenance switch

(SW2). It should be set to the NORMAL position.

c. Check wiring of the SKYWATCH/

mode switch (para 2.6.11/figure 2-2).

Check position of the WX-1000 maintenance switch
(NORMAL/OVERRIDE). When the WX-1000 has been
removed for service, it should be set to the OVERRIDE
position. This switch may be located in the avionics bay.

Stormscope

display

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Table 4-1. Fault Isolation (Continued)

SYMPTOM CORRECTIVE ACTION

SKYWATCH paints itself as a target (e.g., TA). a. Verify suppression bus shielded cable is grounded

correctly at both ends.

b. Connect an oscilloscope to the suppression bus and

verify that the SKY497 suppression pulse (100 µs ±5 µs)
exceeds +15 V dc.

c. If less than +15 V dc, the suppression bus is

overloaded.
d. Check all equipment connected to the bus.
e. Repair/replace the offending device.

SKYWATCH TRC497 has been removed for service; the
WX-1000

Stormscope

fails to operate.

4.6 ERROR MESSAGES

SKYWATCH firmware is designed to generate error messages associated with a particular condition or
step in the program. The 20 most recent errors detected by the system are saved in the System Log (see
para 4.4.2). System Log can be accessed with a terminal device by using the Dump command. For your
convenience, in table 4-2, we have listed the error messages that have been associated with SKYWATCH
installations. Where appropriate, procedures that may assist in resolving installation problems are
provided. When a severe error occurs SKYWATCH will fail.

Check the adapter plug (see para 4.7). If the TRC497 is
removed for service, an adapter plug is required to permit
continued operation of the WX-1000.

Table 4-2. Installation Related Error Messages

ERROR NO. MESSAGE Remarks

ERROR 016 RF BITE a. Check directional antenna and associated cables.

b. Turn system power ON.
c. Calibrate directional antenna (para 4.4.1).

NOTE

Ensure transponder is in standby and DME is OFF while doing calibration.

d. Cycle power.
e. Run pilot initiated self-test.

ERROR 017 RF Amplitude a. Check directional antenna and associated cables.

b. Turn system power ON.
c. Calibrate directional antenna (para 4.4.1).

NOTE

Ensure transponder is in standby and DME is OFF while doing calibration.
d. Cycle power.
e. Run pilot initiated self-test.

ERROR 18 RF Angle a. Check directional antenna and associated cables.

b. Turn system power ON.
c. Calibrate directional antenna (para 4.4.1).

NOTE

Ensure transponder is in standby and DME is OFF while doing calibration.
d. Cycle power.

e. Run pilot initiated self-test.

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Table 4-2. Installation Related Error Messages (Continued)

ERROR NO. MESSAGE Remarks

ERROR 020 Barometric Altitude Input a. Check altimeter source. Is the unit turned on and been given enough

time to warm up.

When interfacing via an ARINC 429 serial data bus, at power-up
the TRC must adjust (auto-baud) to the speed of the incoming
data. Normally the TRC will lock-on after approximately 15
seconds.

b. Cycle power.
c. Ensure that barometric altitude is input from only one
source (Gray Code or ARINC 429, not both).
d. Encoded inputs can be checked from the system configuration screen
(para 4.4.3.2, Configuration - Page 2).
e. Using the Data Monitor, verify barometric source and altitude
(para 4.4.3.3).
f. Check wiring associated with altimeter source.

ERROR 021 Power Supply a. Using the Data Monitor, observe internal voltage measurements

(para 4.4.3.3, Data Monitor - Page 5).
b. Check aircraft power source.
c. Check power input at mating connector.

P8-A +28V (10.5-34V PWR)
P8-B +28V_RET (AIRCRAFT PWR RETURN)

ERROR 30 Check Configuration Configuration jumpers not saved or changed and need validated.

a. Using the Configuration menu, verify pages 1, 3 and 4 are correct

then save (para 4.4.3.2, Configuration).

b. Check wiring associated with configuration jumpers.

ERROR 152 HDG Invalid synchro XYZ input.

a. Check heading source.
b. Verify status of heading configuration jumpers (input source and flag
sense - para 4.4.3.2).
c. Using the Data Monitor, verify heading data (source, heading
& flag - para 4.4.3.3).
d. If the heading signals become valid, the system will recover
automatically.
e. Check wiring associated with compass heading.

ERROR 153 HDG Invalid heading reference (400 Hz).

a. Check heading source.
b. Verify status of heading configuration jumpers (input source and flag
sense - para 4.4.3.2).
c. Using the Data Monitor, verify heading data (source, heading
& flag - para 4.4.3.3).
d. If the reference signal becomes valid, the system will recover
automatically.
e. Check wiring associated with compass heading.

NOTE

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