Embedded Linux Watchdog Alarms
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Applicable alarms (43)
AIR_DATA_ABSOLUTE_PRESSURE_STATUS_UNAVAILABLEAIR_DATA_DIFFERENTIAL_PRESSURE_STATUS_UNAVAILABLEAIR_DATA_TEMPERATURE_STATUS_UNAVAILABLEC2_STATUS_UNAVAILABLECELL_MODEM_HEALTH_UNAVAILABLECELL_MODEM_B_HEALTH_UNAVAILABLECOMPUTE_B_STATUS_UNAVAILABLECOMPUTE_HARDWARE_METRICS_HEALTH_UNAVAILABLEGLOBAL_RESOURCE_MONITOR_STATUS_UNAVAILABLELOG_MANAGER_STATUS_UNAVAILABLENETWORK_AGENT_STATUS_SIDE_A_UNAVAILABLENETWORK_AGENT_STATUS_SIDE_B_UNAVAILABLENTRIP_CLIENT_SIDE_A_STATUS_UNAVAILABLENTRIP_CLIENT_SIDE_B_STATUS_UNAVAILABLEZIP_PROPULSION_COMMANDS_UNAVAILABLEGNC_STATUS_UNAVAILABLEGNSS_TASK_HEALTH_UNAVAILABLEIMU_HEALTH_UNAVAILABLENAV_IMU_MONITOR_UNAVAILABLEZIP_ANTENNA_STATUS_UNAVAILABLECLOCK_MANAGER_SIDE_A_HEALTH_UNAVAILABLECLOCK_MANAGER_SIDE_B_HEALTH_UNAVAILABLEFSYNC_SERVICE_HEALTH_UNAVAILABLEGMSL2_BRIDGE_STATUS_UNAVAILABLEGRPC_BRIDGE_STATUS_UNAVAILABLEIRQ_AFFINITY_SIDE_A_STATUS_UNAVAILABLEIRQ_AFFINITY_SIDE_B_STATUS_UNAVAILABLELINUX_EXCEPTION_SIDE_A_STATUS_UNAVAILABLELINUX_EXCEPTION_SIDE_B_STATUS_UNAVAILABLELINUX_RESOURCE_MANAGER_STATUS_UNAVAILABLELOCAL_TD_BODY_UNAVAILABLELOCAL_T_DROID_BODY_UNAVAILABLELOCAL_T_ECEF_UNAVAILABLELOCALIZATION_STATUS_UNAVAILABLEMOTOR_MANAGER_STATUS_UNAVAILABLENAV_STATE_FOR_CONTROLS_UNAVAILABLENAV_STATE_FOR_CONTROLS_STATUS_UNAVAILABLENAVIGATION_STATUS_UNAVAILABLESERVICE_RESTART_MONITOR_STATUS_UNAVAILABLEWINCH_GNC_EXECUTIVE_RESPONSE_UNAVAILABLEZIP_EXECUTIVE_SECONDARY_CONTROLLER_STATUS_UNAVAILABLEREMOTE_ZIP_LOG_MANAGER_STATUS_UNAVAILABLENAV_GPST_SYNC_UNAVAILABLE
Likely outcomes — click to expand
Based on 1,197,843 missions where this alarm fired in the last
90 days
(for AIR_DATA_ABSOLUTE_PRESSURE_STATUS_UNAVAILABLE) as of 2026-10-13
Grounding vs discrepancy (of 8,782 ZERP issues filed on these missions)
Top work orders
- EV2: Inspect Aircraft after Droid Left Behind (DLB) · MAINTENANCE_ACTION 501
- Inspect Droid after Droid Left Behind (DLB) · MAINTENANCE_ACTION 341
- EV3: Inspect Aircraft after Droid Left Behind (DLB) · MAINTENANCE_ACTION 333
- Reset Droid after DLB · REPAIR 285
- V4 Zipping Point: Inspect Zipping Point after Droid Left Behind (DLB) - Ranger · MAINTENANCE_ACTION 132
Frequently replaced parts
| Part | P/N | Removals |
|---|---|---|
| SERVO, ASSY, UNIVERSAL, P2 | 20398 | 1,810 |
| HOVER MOTOR ASSY, CCW MOTOR, ZIP, P2 | 19607 | 1,399 |
| ASSY, SPOOL AND LINE, DOCKING FIN | 48477 | 1,215 |
| TAIL, STBD, ZIP, P2 | 21840 | 1,166 |
| TAIL PORT, ZIP, P2 | 31280 | 1,109 |
Aggregated from fleet operations and refreshed daily. Individual outcomes may vary by site and configuration.
Background
Section titled “Background”This guide covers Exec watchdog alarms owned by P2 Embedded Linux On Call.
These alarms indicate that a required process, service, telemetry stream, or compute-side dependency stopped publishing within the watchdog timeout.
Included Exec watchdog alarms
Section titled “Included Exec watchdog alarms”- AIR_DATA_ABSOLUTE_PRESSURE_STATUS_UNAVAILABLE
- AIR_DATA_DIFFERENTIAL_PRESSURE_STATUS_UNAVAILABLE
- AIR_DATA_TEMPERATURE_STATUS_UNAVAILABLE
- C2_STATUS_UNAVAILABLE
- CELL_MODEM_HEALTH_UNAVAILABLE
- CELL_MODEM_B_HEALTH_UNAVAILABLE
- CLOCK_MANAGER_SIDE_A_HEALTH_UNAVAILABLE
- CLOCK_MANAGER_SIDE_B_HEALTH_UNAVAILABLE
- COMPUTE_B_STATUS_UNAVAILABLE
- COMPUTE_HARDWARE_METRICS_HEALTH_UNAVAILABLE
- FSYNC_SERVICE_HEALTH_UNAVAILABLE
- GLOBAL_RESOURCE_MONITOR_STATUS_UNAVAILABLE
- GMSL2_BRIDGE_STATUS_UNAVAILABLE
- GNC_STATUS_UNAVAILABLE
- GNSS_TASK_HEALTH_UNAVAILABLE
- GRPC_BRIDGE_STATUS_UNAVAILABLE
- IMU_HEALTH_UNAVAILABLE
- IRQ_AFFINITY_SIDE_A_STATUS_UNAVAILABLE
- IRQ_AFFINITY_SIDE_B_STATUS_UNAVAILABLE
- LINUX_EXCEPTION_SIDE_A_STATUS_UNAVAILABLE
- LINUX_EXCEPTION_SIDE_B_STATUS_UNAVAILABLE
- LINUX_RESOURCE_MANAGER_STATUS_UNAVAILABLE
- LOCAL_TD_BODY_UNAVAILABLE
- LOCAL_T_DROID_BODY_UNAVAILABLE
- LOCAL_T_ECEF_UNAVAILABLE
- LOCALIZATION_STATUS_UNAVAILABLE
- LOG_MANAGER_STATUS_UNAVAILABLE
- MOTOR_MANAGER_STATUS_UNAVAILABLE
- NAV_IMU_MONITOR_UNAVAILABLE
- NAV_STATE_FOR_CONTROLS_UNAVAILABLE
- NAV_STATE_FOR_CONTROLS_STATUS_UNAVAILABLE
- NAVIGATION_STATUS_UNAVAILABLE
- NETWORK_AGENT_STATUS_SIDE_A_UNAVAILABLE
- NETWORK_AGENT_STATUS_SIDE_B_UNAVAILABLE
- NTRIP_CLIENT_SIDE_A_STATUS_UNAVAILABLE
- NTRIP_CLIENT_SIDE_B_STATUS_UNAVAILABLE
- SERVICE_RESTART_MONITOR_STATUS_UNAVAILABLE
- WINCH_GNC_EXECUTIVE_RESPONSE_UNAVAILABLE
- ZIP_ANTENNA_STATUS_UNAVAILABLE
- ZIP_EXECUTIVE_SECONDARY_CONTROLLER_STATUS_UNAVAILABLE
- ZIP_PROPULSION_COMMANDS_UNAVAILABLE
- REMOTE_ZIP_LOG_MANAGER_STATUS_UNAVAILABLE
- NAV_GPST_SYNC_UNAVAILABLE
Troubleshooting Steps
Section titled “Troubleshooting Steps”graph TD
is-this-a-repeat-issue{"<small><b>Step 1</b></small><br/>Question: Is this a repeat issue? Check Fleetwr..."}
power-cycle-aircraft["<small><b>Step 2</b></small><br/>Action: Power cycle the aircraft. Reference: ..."]
did-the-watchdog-alarm-clear{"<small><b>Step 3</b></small><br/>Question: Did the watchdog alarm clear?"}
escalate-to-p2-embedded-linux-on-call{{"<small><b>Step 4</b></small><br/>Escalation: Escalate to P2 Embedded Linux On Call."}}
return-the-aircraft-to-service("<small><b>Step 5</b></small><br/>Reference: Return the Aircraft to service.")
is-this-a-repeat-issue -->|Yes| escalate-to-p2-embedded-linux-on-call
is-this-a-repeat-issue -->|No| power-cycle-aircraft
power-cycle-aircraft --> did-the-watchdog-alarm-clear
did-the-watchdog-alarm-clear -->|Yes| return-the-aircraft-to-service
did-the-watchdog-alarm-clear -->|No| escalate-to-p2-embedded-linux-on-call
style is-this-a-repeat-issue fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style power-cycle-aircraft fill:#dcfce7,stroke:#22c55e,color:#14532d
style did-the-watchdog-alarm-clear fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style escalate-to-p2-embedded-linux-on-call fill:#fef3c7,stroke:#f59e0b,color:#78350f
style return-the-aircraft-to-service fill:#f3e8ff,stroke:#a855f7,color:#581c87 Hover or focus a block to preview it. Select the block to keep the preview open.
1 question
Is this a repeat issue? Check Fleetwrangler and the Zerp Maintenance History to determine whether this is the second or a subsequent occurrence without a successful flight in between.
2 action
3 question
Did the watchdog alarm clear?
4 escalation
Escalate to P2 Embedded Linux On Call.
5 reference
Return the Aircraft to service.
Resolution note
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