ZIP_WINCH_MOTOR_CONTROL_UNINITIALIZED
Viewing this guide for
Applicable alarms (1)
ZIP_WINCH_MOTOR_CONTROL_UNINITIALIZED
Likely outcomes — click to expand
Based on 0 missions where this alarm fired in the last 90 days as of 2026-10-13
Aggregated from fleet operations and refreshed daily. Individual outcomes may vary by site and configuration.
Background
Section titled “Background”This alarm occurs during startup when zip exec has not begun receiving status messages reported by the winch motor. It is common to see this alarm on startup, however if the alarm persists, it will block launch and prevent the zip exec from commanding takeoff.
Troubleshooting Steps
Section titled “Troubleshooting Steps”graph TD
enter-the-diagnostics-mode["<small><b>Step 1</b></small><br/>Action: Enter the Diagnostics Mode."]
can-the-aircraft-perform-a-droid-raise{"<small><b>Step 2</b></small><br/>Question: Can the Aircraft perform a Droid rais..."}
the-aircraft-may-return-to-service("<small><b>Step 3</b></small><br/>Reference: The Aircraft may return to service.")
are-the-winch-lights-on{"<small><b>Step 4</b></small><br/>Question: Are the winch lights ON?"}
look-at-distro-b-power-status-and-see-i["<small><b>Step 5</b></small><br/>Action: Look at /distro_b.power_status and ..."]
inspect-the-flex-harness-standoffs-on-t{"<small><b>Step 6</b></small><br/>Question: There are two root causes of a physic..."}
replace-the-docking-fin-winch-assembly["<small><b>Step 7</b></small><br/>Action: Replace the Docking Fin Winch Assembl..."]
replace-the-docking-fin-to-tail-node-fl["<small><b>Step 8</b></small><br/>Action: Replace the Docking fin to tail node ..."]
perform-a-droid-raise-and-lower-test-up["<small><b>Step 9</b></small><br/>Action: Perform a Droid raise and lower test ..."]
is-the-issue-resolved{"<small><b>Step 10</b></small><br/>Question: Is the issue resolved?"}
the-aircraft-may-return-to-service-2("<small><b>Step 11</b></small><br/>Reference: The Aircraft may return to service.")
escalate-to-the-owner-of-the-swapped-ha{{"<small><b>Step 12</b></small><br/>Escalation: Escalate to the owner of the swapped ..."}}
enter-the-diagnostics-mode --> can-the-aircraft-perform-a-droid-raise
can-the-aircraft-perform-a-droid-raise -->|Yes| the-aircraft-may-return-to-service
can-the-aircraft-perform-a-droid-raise -->|No| are-the-winch-lights-on
are-the-winch-lights-on -->|Winch lights are ON| inspect-the-flex-harness-standoffs-on-t
are-the-winch-lights-on -->|Winch lights are OFF| look-at-distro-b-power-status-and-see-i
inspect-the-flex-harness-standoffs-on-t -->|Yes| replace-the-docking-fin-winch-assembly
inspect-the-flex-harness-standoffs-on-t -->|No| replace-the-docking-fin-to-tail-node-fl
replace-the-docking-fin-winch-assembly --> perform-a-droid-raise-and-lower-test-up
replace-the-docking-fin-to-tail-node-fl --> perform-a-droid-raise-and-lower-test-up
perform-a-droid-raise-and-lower-test-up --> is-the-issue-resolved
is-the-issue-resolved -->|Yes| the-aircraft-may-return-to-service-2
is-the-issue-resolved -->|No| escalate-to-the-owner-of-the-swapped-ha
style enter-the-diagnostics-mode fill:#dcfce7,stroke:#22c55e,color:#14532d
style can-the-aircraft-perform-a-droid-raise fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style the-aircraft-may-return-to-service fill:#f3e8ff,stroke:#a855f7,color:#581c87
style are-the-winch-lights-on fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style look-at-distro-b-power-status-and-see-i fill:#dcfce7,stroke:#22c55e,color:#14532d
style inspect-the-flex-harness-standoffs-on-t fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style replace-the-docking-fin-winch-assembly fill:#dcfce7,stroke:#22c55e,color:#14532d
style replace-the-docking-fin-to-tail-node-fl fill:#dcfce7,stroke:#22c55e,color:#14532d
style perform-a-droid-raise-and-lower-test-up fill:#dcfce7,stroke:#22c55e,color:#14532d
style is-the-issue-resolved fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style the-aircraft-may-return-to-service-2 fill:#f3e8ff,stroke:#a855f7,color:#581c87
style escalate-to-the-owner-of-the-swapped-ha fill:#fef3c7,stroke:#f59e0b,color:#78350f Hover or focus a block to preview it. Select the block to keep the preview open.
1 action
Enter the Diagnostics Mode.
2 question
Can the Aircraft perform a Droid raise and lower three (3) times?
3 reference
The Aircraft may return to service.
4 question
Are the winch lights ON?
5 action
Look at
Check for any loose connectors.
/distro_b.power_status and see if any alarms are present.Check for any loose connectors.
6 question
There are two root causes of a physical comms issue on the winch:
- The standoffs on the winch PCBA can get damaged and tear out.
- The flex harness going to the winch is damaged.
Inspect the flex harness standoffs on the winch PCBA. Look for signs of the standoff being pulled out of the board, such as cracked solder or a very obvious tear out. Is damage present?
- The standoffs on the winch PCBA can get damaged and tear out.
- The flex harness going to the winch is damaged.
Inspect the flex harness standoffs on the winch PCBA. Look for signs of the standoff being pulled out of the board, such as cracked solder or a very obvious tear out. Is damage present?
7 action
Replace the Docking Fin Winch Assembly:
1. Link the issue as “Caused by” [Root Cause] [EV2] Winch pem nut standoff tears off and causes comms issues and assign to Johnny Sun.
2. Swap the winch motor following UMM Winch Assembly - Remove and Install.
3. Send the damaged motor to the Aviary addressed to Johnny Sun.
1. Link the issue as “Caused by” [Root Cause] [EV2] Winch pem nut standoff tears off and causes comms issues and assign to Johnny Sun.
2. Swap the winch motor following UMM Winch Assembly - Remove and Install.
3. Send the damaged motor to the Aviary addressed to Johnny Sun.
8 action
Replace the Docking fin to tail node flex harness:
1. Link the issue as “Caused by” [Root Cause] Winch Flex - Trace Cracking and assign to Kunal Verma.
2. Swap the flex following UMM Remove and Install PCB Harness and Standard Practices.
3. Send the damaged flex to the Aviary addressed to Kunal Verma.
1. Link the issue as “Caused by” [Root Cause] Winch Flex - Trace Cracking and assign to Kunal Verma.
2. Swap the flex following UMM Remove and Install PCB Harness and Standard Practices.
3. Send the damaged flex to the Aviary addressed to Kunal Verma.
9 action
Perform a Droid raise and lower test up to three (3) times.
10 question
Is the issue resolved?
11 reference
The Aircraft may return to service.
12 escalation
Escalate to the owner of the swapped hardware:
- Winch: Powertrain (P2 Firmware Motors On Call)
- Winch flex: Avionics (P2 Avionics Hardware On Call)
- Winch: Powertrain (P2 Firmware Motors On Call)
- Winch flex: Avionics (P2 Avionics Hardware On Call)
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.
Inspect the Winch
Section titled “Inspect the Winch”There are two root causes of a physical comms issue on the winch:
- The standoffs on the winch PCBA can get damaged and tear out.
- The flex harness going to the winch is damaged.
Follow the steps below to determine which one is damaged.
Did this guide help you get unblocked?
Open suggestions
There are no open suggestions.
Open pull requests
There are no open pull requests.