ERROR_SERVO_TAIL_STBD_FWD_RESISTANCE
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Applicable alarms (1)
ERROR_SERVO_TAIL_STBD_FWD_RESISTANCE
Likely outcomes — click to expand
Based on 20 missions where this alarm fired in the last 90 days as of 2026-10-13
Grounding vs discrepancy (of 1 ZERP issues filed on these missions)
Frequently co-occurring alarms (% of the 20 missions above)
Aggregated from fleet operations and refreshed daily. Individual outcomes may vary by site and configuration.
Background
Section titled “Background”This alarm occurs when high resistance is detected in the tail starboard servo’s DC power path during preflight.
Troubleshooting Steps
Section titled “Troubleshooting Steps”graph TD
is-the-servos-m5-connector-to-the-tail{"<small><b>Step 1</b></small><br/>Question: Is the servo’s M5 connector to the ta..."}
hand-tighten-m5-connector-and-apply-new["<small><b>Step 2</b></small><br/>Action: Hand tighten M5 connector and apply n..."]
swap-the-tail-node-update-the-ticket-wi["<small><b>Step 3</b></small><br/>Action: Swap the tail node. Update the ticket..."]
perform-preflight-check-does-the-alarm{"<small><b>Step 4</b></small><br/>Question: Perform preflight check. Does the ala..."}
did-you-already-swap-the-tail-node-in-s{"<small><b>Step 5</b></small><br/>Question: Did you already swap the tail node in..."}
now-swap-the-tail-that-contains-the-fai["<small><b>Step 6</b></small><br/>Action: Now swap the tail that contains the f..."]
swap-the-tail-node-update-the-ticket-2["<small><b>Step 7</b></small><br/>Action: Swap the tail node. Update the ticket..."]
after-performing-the-required-swap-redo{"<small><b>Step 8</b></small><br/>Question: After performing the required swap, r..."}
if-you-have-not-already-swapped-the-tai["<small><b>Step 9</b></small><br/>Action: If you have not already swapped the t..."]
aircraft-can-be-cleared-for-service-red["<small><b>Step 10</b></small><br/>Action: Aircraft can be cleared for service."]
aircraft-can-be-cleared-for-service-ste["<small><b>Step 11</b></small><br/>Action: Aircraft can be cleared for service."]
is-the-servos-m5-connector-to-the-tail -->|Yes| hand-tighten-m5-connector-and-apply-new
is-the-servos-m5-connector-to-the-tail -->|No| swap-the-tail-node-update-the-ticket-wi
hand-tighten-m5-connector-and-apply-new --> perform-preflight-check-does-the-alarm
swap-the-tail-node-update-the-ticket-wi --> perform-preflight-check-does-the-alarm
perform-preflight-check-does-the-alarm -->|Yes| did-you-already-swap-the-tail-node-in-s
perform-preflight-check-does-the-alarm -->|No| aircraft-can-be-cleared-for-service-ste
did-you-already-swap-the-tail-node-in-s -->|Yes| now-swap-the-tail-that-contains-the-fai
did-you-already-swap-the-tail-node-in-s -->|No| swap-the-tail-node-update-the-ticket-2
now-swap-the-tail-that-contains-the-fai --> after-performing-the-required-swap-redo
swap-the-tail-node-update-the-ticket-2 --> after-performing-the-required-swap-redo
after-performing-the-required-swap-redo -->|Yes| if-you-have-not-already-swapped-the-tai
after-performing-the-required-swap-redo -->|No| aircraft-can-be-cleared-for-service-red
style is-the-servos-m5-connector-to-the-tail fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style hand-tighten-m5-connector-and-apply-new fill:#dcfce7,stroke:#22c55e,color:#14532d
style swap-the-tail-node-update-the-ticket-wi fill:#dcfce7,stroke:#22c55e,color:#14532d
style perform-preflight-check-does-the-alarm fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style did-you-already-swap-the-tail-node-in-s fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style now-swap-the-tail-that-contains-the-fai fill:#dcfce7,stroke:#22c55e,color:#14532d
style swap-the-tail-node-update-the-ticket-2 fill:#dcfce7,stroke:#22c55e,color:#14532d
style after-performing-the-required-swap-redo fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style if-you-have-not-already-swapped-the-tai fill:#dcfce7,stroke:#22c55e,color:#14532d
style aircraft-can-be-cleared-for-service-red fill:#dcfce7,stroke:#22c55e,color:#14532d
style aircraft-can-be-cleared-for-service-ste fill:#dcfce7,stroke:#22c55e,color:#14532d Hover or focus a block to preview it. Select the block to keep the preview open.
1 question
Is the servo’s M5 connector to the tail node loose? Check for broken torque stripe on the M5 connector.
2 action
Hand tighten M5 connector and apply new torque stripe. Proceed to step 2.
3 action
Swap the tail node. Update the ticket with findings and actions performed. For swap instructions refer to:
- UMM Remove Tail Node
- UMM Install Tail Node
Send the removed tail node back to the Aviary (ATTN: Kunal Verma) with a label indicating the ticket number.
- UMM Remove Tail Node
- UMM Install Tail Node
Send the removed tail node back to the Aviary (ATTN: Kunal Verma) with a label indicating the ticket number.
4 question
Perform preflight check. Does the alarm reappear?
5 question
Did you already swap the tail node in step 1?
6 action
Now swap the tail that contains the failing servo. Update the ticket with findings and actions performed. For swap instructions refer to:
- UMM Remove Tail Assembly
- UMM Install Tail Assembly
Send the removed tail back to the Aviary (ATTN: Kunal Verma) with a label indicating the ticket number.
- UMM Remove Tail Assembly
- UMM Install Tail Assembly
Send the removed tail back to the Aviary (ATTN: Kunal Verma) with a label indicating the ticket number.
7 action
Swap the tail node. Update the ticket with findings and actions performed. For swap instructions refer to:
- UMM Remove Tail Node
- UMM Install Tail Node
Send the removed tail node back to the Aviary (ATTN: Kunal Verma) with a label indicating the ticket number.
- UMM Remove Tail Node
- UMM Install Tail Node
Send the removed tail node back to the Aviary (ATTN: Kunal Verma) with a label indicating the ticket number.
8 question
After performing the required swap, redo the preflight check. Does the alarm reappear?
9 action
If you have not already swapped the tail:
- Now swap the tail that contains the failing servo, and redo preflight check. If the alarm reappears, escalate to P2 Zip Hardware On Call and await engineering response. If the alarm does not reappear, aircraft can be cleared for service.
If you have already swapped the tail:
- This is likely a new issue. Escalate to P2 Zip Hardware On Call and await engineering response.
For tail swap instructions refer to:
- UMM Remove Tail Assembly
- UMM Install Tail Assembly
- Now swap the tail that contains the failing servo, and redo preflight check. If the alarm reappears, escalate to P2 Zip Hardware On Call and await engineering response. If the alarm does not reappear, aircraft can be cleared for service.
If you have already swapped the tail:
- This is likely a new issue. Escalate to P2 Zip Hardware On Call and await engineering response.
For tail swap instructions refer to:
- UMM Remove Tail Assembly
- UMM Install Tail Assembly
10 action
Aircraft can be cleared for service.
11 action
Aircraft can be cleared for service.
Resolution note
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