ZIP_LOCAL_T_ECEF_UNAVAILABLE and ZIP_LOCAL_T_ECEF_TIMED_OUT
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Applicable alarms (2)
ZIP_LOCAL_T_ECEF_UNAVAILABLEZIP_LOCAL_T_ECEF_TIMED_OUT
Likely outcomes — click to expand
Based on 861,745 missions where this alarm fired in the last
90 days
(for ZIP_LOCAL_T_ECEF_UNAVAILABLE) as of 2026-10-13
Grounding vs discrepancy (of 5,566 ZERP issues filed on these missions)
Top work orders
- EV3: Inspect Aircraft after Droid Left Behind (DLB) · MAINTENANCE_ACTION 208
- Troubleshoot Hover Motor Resistance on Aircraft · INSPECTION 77
- EV2: Troubleshoot Electrical Contacts on Aircraft and Droid · INSPECTION 71
- Reset Droid Lid · TROUBLESHOOTING 57
- EV2: ZCO-2026-08-03 Lower Foam Wear Pad Retrofit (FRCO-286 / SB-2026-023) · UPGRADE_RETROFIT 35
Frequently replaced parts
| Part | P/N | Removals |
|---|---|---|
| SERVO, ASSY, UNIVERSAL, P2 | 20398 | 972 |
| CCW/CW HOVER MOTOR ASSY, ZIP, P2 | 19607 | 822 |
| ASSY, SPOOL AND LINE, DOCKING FIN, AIRCRAFT, P2 | 48477 | 754 |
| PRE-PREG TAIL ASSY STBD(RH), ZIP, P2 | 21840 | 624 |
| TAIL PORT, ZIP, P2 | 31280 | 594 |
Aggregated from fleet operations and refreshed daily. Individual outcomes may vary by site and configuration.
Background
Section titled “Background”ZIP_LOCAL_T_ECEF_UNAVAILABLE indicates that Exec is not receiving a fresh zip-local-to-ECEF pose from Zip Nav within the watchdog timeout. ZIP_LOCAL_T_ECEF_TIMED_OUT is the corresponding startup-timeout alarm. This guide covers both alarms.
This alarm is present nominally whenever the Zip is idle.
Use this guide when either alarm is associated with a mission failure. Do not treat an idle ZIP_LOCAL_T_ECEF_UNAVAILABLE alarm as the cause of a vehicle issue.
When the Aircraft is indoors, ZIP_LOCAL_T_ECEF_TIMED_OUT is expected and no action is needed.
Troubleshooting Steps
Section titled “Troubleshooting Steps”graph TD
check-zip-nav-operations-mode["<small><b>Step 1</b></small><br/>Telemetry: This widget should load a 2D plot of ..."]
check-whether-navigation-was-requested{"<small><b>Step 2</b></small><br/>Question: In the zip-nav-operations-mode plot..."}
alarm-was-expected["<small><b>Step 3</b></small><br/>Action: ZIP_LOCAL_T_ECEF_UNAVAILABLE and Z..."]
power-cycle-aircraft["<small><b>Step 4</b></small><br/>Action: Power cycle the Aircraft/procedure..."]
did-health-check-pass{"<small><b>Step 5</b></small><br/>Question: Did the health check pass and is the ..."}
the-aircraft-may-return-to-service("<small><b>Step 6</b></small><br/>Reference: The Aircraft may return to service.")
check-gnss-a-plot["<small><b>Step 7</b></small><br/>Telemetry: Use the gnss-a-raw-status template...."]
check-gnss-a{"<small><b>Step 8</b></small><br/>Question: Does the gnss-a-raw-status plot sho..."}
check-gnss-b-before-side-a-plot["<small><b>Step 9</b></small><br/>Telemetry: Before replacing the side A tail asse..."]
check-gnss-b-before-side-a{"<small><b>Step 10</b></small><br/>Question: Does the gnss-b-raw-status plot sho..."}
escalate-local-gnss-interference{{"<small><b>Step 11</b></small><br/>Escalation: Both GNSS A and GNSS B show degraded ..."}}
replace-side-a-tail-assembly["<small><b>Step 12</b></small><br/>Action: GNSS A is not receiving adequate sign..."]
check-compute-bridge-plot["<small><b>Step 13</b></small><br/>Telemetry: Use the gnss-b-a-data-bridge templa..."]
check-compute-bridge{"<small><b>Step 14</b></small><br/>Question: Does the gnss-b-a-data-bridge plot ..."}
escalate-compute-b-issue{{"<small><b>Step 15</b></small><br/>Escalation: The telemetry indicates a Compute B i..."}}
check-gnss-b-plot["<small><b>Step 16</b></small><br/>Telemetry: Use the gnss-b-raw-status template...."]
check-gnss-b{"<small><b>Step 17</b></small><br/>Question: Does the gnss-b-raw-status plot sho..."}
replace-side-b-tail-assembly["<small><b>Step 18</b></small><br/>Action: GNSS B is not receiving adequate sign..."]
check-imu-plot["<small><b>Step 19</b></small><br/>Telemetry: Use the nav-has-imu-data template. ..."]
check-imu{"<small><b>Step 20</b></small><br/>Question: Is HAS_PIM_FOR_EVERY_EPOCH false ..."}
escalate-imu{{"<small><b>Step 21</b></small><br/>Escalation: The problem is with the IMU. Escalate..."}}
escalate-to-p2-nav{{"<small><b>Step 22</b></small><br/>Escalation: Escalate to P2 Nav On Call."}}
check-zip-nav-operations-mode --> check-whether-navigation-was-requested
check-whether-navigation-was-requested -->|No, neither signal was ACTIVE| alarm-was-expected
check-whether-navigation-was-requested -->|Yes, at least one signal wa...| power-cycle-aircraft
power-cycle-aircraft --> did-health-check-pass
did-health-check-pass -->|Yes, the health check passe...| the-aircraft-may-return-to-service
did-health-check-pass -->|No, the health check failed...| check-gnss-a-plot
check-gnss-a-plot --> check-gnss-a
check-gnss-a -->|Yes, at least one of those ...| check-gnss-b-before-side-a-plot
check-gnss-a -->|No, none of those condition...| check-compute-bridge-plot
check-gnss-b-before-side-a-plot --> check-gnss-b-before-side-a
check-gnss-b-before-side-a -->|Yes, at least one of those ...| escalate-local-gnss-interference
check-gnss-b-before-side-a -->|No, none of those condition...| replace-side-a-tail-assembly
check-compute-bridge-plot --> check-compute-bridge
check-compute-bridge -->|Yes, both plots are healthy| check-gnss-b-plot
check-compute-bridge -->|No, the timestamps are not ...| escalate-compute-b-issue
check-gnss-b-plot --> check-gnss-b
check-gnss-b -->|Yes, at least one of those ...| replace-side-b-tail-assembly
check-gnss-b -->|No, none of those condition...| check-imu-plot
check-imu-plot --> check-imu
check-imu -->|Yes, HAS_PIM_FOR_EVERY_EPOC...| escalate-imu
check-imu -->|No, HAS_PIM_FOR_EVERY_EPOCH...| escalate-to-p2-nav
style check-whether-navigation-was-requested fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style alarm-was-expected fill:#dcfce7,stroke:#22c55e,color:#14532d
style power-cycle-aircraft fill:#dcfce7,stroke:#22c55e,color:#14532d
style did-health-check-pass fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style the-aircraft-may-return-to-service fill:#f3e8ff,stroke:#a855f7,color:#581c87
style check-gnss-a fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style check-gnss-b-before-side-a fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style escalate-local-gnss-interference fill:#fef3c7,stroke:#f59e0b,color:#78350f
style replace-side-a-tail-assembly fill:#dcfce7,stroke:#22c55e,color:#14532d
style check-compute-bridge fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style escalate-compute-b-issue fill:#fef3c7,stroke:#f59e0b,color:#78350f
style check-gnss-b fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style replace-side-b-tail-assembly fill:#dcfce7,stroke:#22c55e,color:#14532d
style check-imu fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style escalate-imu fill:#fef3c7,stroke:#f59e0b,color:#78350f
style escalate-to-p2-nav fill:#fef3c7,stroke:#f59e0b,color:#78350f Hover or focus a block to preview it. Select the block to keep the preview open.
3 action
ZIP_LOCAL_T_ECEF_UNAVAILABLE and ZIP_LOCAL_T_ECEF_TIMED_OUT are expected when the vehicle is inactive. They are not the cause of the vehicle issue. Identify and troubleshoot the alarm or failure that prevented the mission. 4 action
Power cycle the Aircraft, then run a health check.
5 question
Did the health check pass and is the alarm clear?
6 reference
The Aircraft may return to service.
7 telemetry
Use the
gnss-a-raw-status template. The incident URL from the previous telemetry step is reused automatically, preserving the exact incident window. Check /compute_a.debug.gpsins.update_flags.flags.HAS_ALL_SIGNALS_ON_STARTUP and /compute_a.gnss.observation_epochs.observations[<em>].signals[</em>].cn0. Paste the Baraza incident log URL above to load the plot for that exact time range.
8 question
Does the
-
- Empty
- All
gnss-a-raw-status plot show:-
HAS_ALL_SIGNALS_ON_STARTUP frequently stuck at false?- Empty
cn0 channels?- All
cn0 channels below 40 dB-Hz? 9 telemetry
Before replacing the side A tail assembly, use the
gnss-b-raw-status template. The incident URL is reused automatically, preserving the exact incident window. Check the GNSS B signals. Paste the Baraza incident log URL above to load the plot for that exact time range.
10 question
Does the
-
- Empty
- All
gnss-b-raw-status plot show:-
HAS_ALL_SIGNALS_ON_STARTUP_SECONDARY frequently stuck at false?- Empty
cn0 channels?- All
cn0 channels below 40 dB-Hz? 11 escalation
Both GNSS A and GNSS B show degraded signals, which suggests local interference. Escalate to P2 Nav On Call.
12 action
GNSS A is not receiving adequate signals while GNSS B is healthy. Create a work order to replace the side A tail assembly.
EV2: Use this template: https://zerp.flyzipline.com/maintenance/work-order-templates/24
For side A (this step), STARBOARD tail must be specified to be replaced.
EV3 Use this template: https://zerp.flyzipline.com/maintenance/work-order-templates/672
For Side A (this step), PORT tail must be specified to be replaced.
EV2: Use this template: https://zerp.flyzipline.com/maintenance/work-order-templates/24
For side A (this step), STARBOARD tail must be specified to be replaced.
EV3 Use this template: https://zerp.flyzipline.com/maintenance/work-order-templates/672
For Side A (this step), PORT tail must be specified to be replaced.
13 telemetry
Use the
gnss-b-a-data-bridge template. The incident URL from the previous telemetry step is reused automatically, preserving the exact incident window. Compare the Compute B and Compute A plots during the incident. Paste the Baraza incident log URL above to load the plot for that exact time range.
14 question
Does the
gnss-b-a-data-bridge plot show steadily incrementing timestamps on both plots? 15 escalation
The telemetry indicates a Compute B issue. Escalate to P2 Embedded Linux On Call.
16 telemetry
Use the
gnss-b-raw-status template. The incident URL from the previous telemetry step is reused automatically, preserving the exact incident window. Check /compute_a.debug.gpsins.update_flags.flags.HAS_ALL_SIGNALS_ON_STARTUP_SECONDARY and /compute_b.gnss.observation_epochs.observations[<em>].signals[</em>].cn0. Paste the Baraza incident log URL above to load the plot for that exact time range.
17 question
Does the
-
- Empty
- All
gnss-b-raw-status plot show:-
HAS_ALL_SIGNALS_ON_STARTUP_SECONDARY frequently stuck at false?- Empty
cn0 channels?- All
cn0 channels below 40 dB-Hz? 18 action
GNSS B is not receiving adequate signals while GNSS A is healthy. Create a work order to replace the side B tail assembly.
EV2: Use this template: https://zerp.flyzipline.com/maintenance/work-order-templates/24
For side B (this step), PORT tail must be specified to be replaced.
EV3 Use this template: https://zerp.flyzipline.com/maintenance/work-order-templates/672
For Side B (this step), STARBOARD tail must be specified to be replaced.
EV2: Use this template: https://zerp.flyzipline.com/maintenance/work-order-templates/24
For side B (this step), PORT tail must be specified to be replaced.
EV3 Use this template: https://zerp.flyzipline.com/maintenance/work-order-templates/672
For Side B (this step), STARBOARD tail must be specified to be replaced.
19 telemetry
Use the
nav-has-imu-data template. The incident URL from the previous telemetry step is reused automatically, preserving the exact incident window. Check /compute_a.debug.gpsins.update_flags.flags.HAS_PIM_FOR_EVERY_EPOCH. Paste the Baraza incident log URL above to load the plot for that exact time range.
20 question
Is
HAS_PIM_FOR_EVERY_EPOCH false in the nav-has-imu-data plot during the incident? 21 escalation
The problem is with the IMU. Escalate to P2 Embedded Linux On Call.
Resolution note
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