UNRECOVERABLE_FAILURE
Applicable alarms (1)
Likely outcomes — click to expand
Based on 655,147 missions where this alarm fired in the last 90 days as of 2026-10-13
Grounding vs discrepancy (of 5,137 ZERP issues filed on these missions)
Top work orders
- EV2: Inspect Aircraft after Droid Left Behind (DLB) · MAINTENANCE_ACTION 484
- Inspect Droid after Droid Left Behind (DLB) · MAINTENANCE_ACTION 289
- EV2/EV3 Diagnostics Test Without Motors · INSPECTION 248
- Reset Droid after DLB · REPAIR 219
- EV3: Inspect Aircraft after Droid Left Behind (DLB) · MAINTENANCE_ACTION 157
Frequently replaced parts
| Part | P/N | Removals |
|---|---|---|
| SERVO, ASSY, UNIVERSAL, P2 | 20398 | 1,441 |
| HOVER MOTOR ASSY, CCW MOTOR, ZIP, P2 | 19607 | 1,101 |
| TAIL STBD, ZIP, P2 | 21840 | 887 |
| TAIL PORT DEPOP, ZIP, P2 | 31280 | 844 |
| WING PORT, ZIP, P2 | 24762 | 708 |
Aggregated from fleet operations and refreshed daily. Individual outcomes may vary by site and configuration.
Background
Section titled “Background”The navigation system provides information about the position, orientation, and velocity of the vehicle to the rest of the autonomy software. If the navigation system ever:
- Becomes unable to provide an accurate estimation of these parameters, or
- Would need to make a discontinuous \u201cjump\u201d in estimated position to correct large accumulated error,
Then an UNRECOVERABLE_FAILURE is declared.
If this alarm occurs in flight on compute B, it leads to a dock ASAP
If this alarm occurs in flight on compute A, it always leads to a paraland. The navigation system is required to operate correctly in order for other downstream paraland triggers to correctly protect the vehicle from e.g. terrain proximity or loss of attitude control. The loss of navigation requires immediate action.
Troubleshooting Steps
Section titled “Troubleshooting Steps”graph TD
is-the-aircraft-docked-or-is-this-alarm{"<small><b>Step 1</b></small><br/>Question: Is the Aircraft docked or is this ala..."}
restart-the-zip-executive-restart-zip-e{"<small><b>Step 2</b></small><br/>Question: Restart Zip Executive/procedures/r..."}
the-aircraft-may-return-to-service("<small><b>Step 3</b></small><br/>Reference: The Aircraft may return to service.")
power-cycle-the-aircraft-power-cycle-ai{"<small><b>Step 4</b></small><br/>Question: Power cycle the Aircraft Power Cycl..."}
the-aircraft-may-return-to-service-2("<small><b>Step 5</b></small><br/>Reference: The Aircraft may return to service.")
escalate-to-p2-navigation{{"<small><b>Step 6</b></small><br/>Escalation: Escalate to P2 Nav On Call."}}
escalate-to-p2-navigation-paraland{{"<small><b>Step 7</b></small><br/>Escalation: Escalate to P2 Nav On Call."}}
is-the-aircraft-docked-or-is-this-alarm -->|Aircraft is docked| restart-the-zip-executive-restart-zip-e
is-the-aircraft-docked-or-is-this-alarm -->|This alarm is reported as t...| escalate-to-p2-navigation-paraland
restart-the-zip-executive-restart-zip-e -->|Yes| the-aircraft-may-return-to-service
restart-the-zip-executive-restart-zip-e -->|No| power-cycle-the-aircraft-power-cycle-ai
power-cycle-the-aircraft-power-cycle-ai -->|YES| the-aircraft-may-return-to-service-2
power-cycle-the-aircraft-power-cycle-ai -->|NO| escalate-to-p2-navigation
style is-the-aircraft-docked-or-is-this-alarm fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style restart-the-zip-executive-restart-zip-e fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style the-aircraft-may-return-to-service fill:#f3e8ff,stroke:#a855f7,color:#581c87
style power-cycle-the-aircraft-power-cycle-ai fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style the-aircraft-may-return-to-service-2 fill:#f3e8ff,stroke:#a855f7,color:#581c87
style escalate-to-p2-navigation fill:#fef3c7,stroke:#f59e0b,color:#78350f
style escalate-to-p2-navigation-paraland fill:#fef3c7,stroke:#f59e0b,color:#78350f Hover or focus a block to preview it. Select the block to keep the preview open.
Resolution note
This plaintext block is ready to paste into the Resolution Note field on the ZERP issue you're working. The permalink below gives engineering review access to the full step-by-step timeline including any back-navigation; share it if the case needs a deeper look.
Permalink:
Session is too large to fit in a URL. Use Download session JSON to share the timeline out-of-band.
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