Suspect Tail Surface Mechanism Issue
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Background
Section titled “Background”Use this guide when a tail control surface needs hardware inspection for suspected sticky, binding, range-limited, or linkage-related behavior.
Possible causes include:
- Hardstop damage or misalignment
- Mechanical binding in the hinge or linkage
- Torque tube disconnection (EV3)
- Interference with surrounding structure
Generally, there are four classes of hardware failures:
- Friction: retry the test, either the EOL test or the pre-flight check. If it fails again, replace the tail. The removed-part flow references the UMM rework procedure.
- Over range: the motor can move beyond the expected range, which generally indicates a failure in the linkage between the torque tube and the motor. Replace the servo/linkage as an off-tail maintenance action.
- Under range: the motor cannot reach full range or deflection and is likely binding or seeing high friction. Retry the test, either the EOL test or the pre-flight check. If it fails again, replace the tail.
- Comms issues: intermittent comms can be caused by servo motor electrical failure, M5 connector or harness damage, or flex harness damage. Replace the tail and/or harness, as required.
Hardware-related tail servo issues should drive immediate tail replacement in the field to restore the aircraft. Test and repair the removed tail at the hub with proper equipment, then return it to inventory as a serviceable spare.
Troubleshooting Steps
Section titled “Troubleshooting Steps”graph TD
are-you-troubleshooting-an-ev2-or-ev3{"<small><b>Step 1</b></small><br/>Question: Are you troubleshooting an EV2 or EV3..."}
ev2-visually-inspect-the-tail["<small><b>Step 2</b></small><br/>Action: Do a visual inspection of the tail wh..."]
ev2-is-linkage-damaged-or-disconnected{"<small><b>Step 3</b></small><br/>Question: Is the linkage damaged or disconnecte..."}
ev2-was-the-linkage-plastic{"<small><b>Step 4</b></small><br/>Question: Was the linkage plastic?"}
ev2-where-was-the-pin-missing{"<small><b>Step 5</b></small><br/>Question: Was the pin missing at the servo side..."}
ev2-link-rcca-servo-side["<small><b>Step 6</b></small><br/>Action: Link the discrepancy to RCCA ticket ..."]
ev2-link-rcca-torque-tube-side["<small><b>Step 7</b></small><br/>Action: Link the discrepancy to RCCA ticket ..."]
ev2-raise-tail-discrepancy-linkage["<small><b>Step 8</b></small><br/>Action: Raise a discrepancy against the tail ..."]
ev2-manually-actuate-control-surface{"<small><b>Step 9</b></small><br/>Question: Manually actuate the control surface...."}
ev2-link-rcca-friction["<small><b>Step 10</b></small><br/>Action: Remove the tail and replace it to res..."]
ev2-raise-tail-discrepancy-friction["<small><b>Step 11</b></small><br/>Action: Raise a discrepancy against the tail ..."]
ev2-raise-tail-discrepancy-no-obvious-damage["<small><b>Step 12</b></small><br/>Action: Raise a discrepancy against the tail ..."]
ev3-remove-and-replace-the-tail["<small><b>Step 13</b></small><br/>Action: Remove the tail from the aircraft and..."]
ev3-raise-tail-discrepancy["<small><b>Step 14</b></small><br/>Action: Raise a discrepancy against the tail ..."]
are-you-troubleshooting-an-ev2-or-ev3 -->|EV2| ev2-visually-inspect-the-tail
are-you-troubleshooting-an-ev2-or-ev3 -->|EV3| ev3-remove-and-replace-the-tail
ev2-visually-inspect-the-tail --> ev2-is-linkage-damaged-or-disconnected
ev2-is-linkage-damaged-or-disconnected -->|Yes| ev2-was-the-linkage-plastic
ev2-is-linkage-damaged-or-disconnected -->|No| ev2-manually-actuate-control-surface
ev2-was-the-linkage-plastic -->|Yes| ev2-where-was-the-pin-missing
ev2-was-the-linkage-plastic -->|No| ev2-raise-tail-discrepancy-linkage
ev2-where-was-the-pin-missing -->|Servo side| ev2-link-rcca-servo-side
ev2-where-was-the-pin-missing -->|Torque tube side| ev2-link-rcca-torque-tube-side
ev2-link-rcca-servo-side --> ev2-raise-tail-discrepancy-linkage
ev2-link-rcca-torque-tube-side --> ev2-raise-tail-discrepancy-linkage
ev2-manually-actuate-control-surface -->|Yes| ev2-link-rcca-friction
ev2-manually-actuate-control-surface -->|No| ev2-raise-tail-discrepancy-no-obvious-damage
ev2-link-rcca-friction --> ev2-raise-tail-discrepancy-friction
ev3-remove-and-replace-the-tail --> ev3-raise-tail-discrepancy
style are-you-troubleshooting-an-ev2-or-ev3 fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style ev2-visually-inspect-the-tail fill:#dcfce7,stroke:#22c55e,color:#14532d
style ev2-is-linkage-damaged-or-disconnected fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style ev2-was-the-linkage-plastic fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style ev2-where-was-the-pin-missing fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style ev2-link-rcca-servo-side fill:#dcfce7,stroke:#22c55e,color:#14532d
style ev2-link-rcca-torque-tube-side fill:#dcfce7,stroke:#22c55e,color:#14532d
style ev2-raise-tail-discrepancy-linkage fill:#dcfce7,stroke:#22c55e,color:#14532d
style ev2-manually-actuate-control-surface fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style ev2-link-rcca-friction fill:#dcfce7,stroke:#22c55e,color:#14532d
style ev2-raise-tail-discrepancy-friction fill:#dcfce7,stroke:#22c55e,color:#14532d
style ev2-raise-tail-discrepancy-no-obvious-damage fill:#dcfce7,stroke:#22c55e,color:#14532d
style ev3-remove-and-replace-the-tail fill:#dcfce7,stroke:#22c55e,color:#14532d
style ev3-raise-tail-discrepancy fill:#dcfce7,stroke:#22c55e,color:#14532d Hover or focus a block to preview it. Select the block to keep the preview open.
1 question
Are you troubleshooting an EV2 or EV3 aircraft?
2 action
Do a visual inspection of the tail while it is installed on the aircraft. Use a flashlight to look at the control servo linkage while manually moving the control surface up and down.
3 question
Is the linkage damaged or disconnected, including missing pin(s)?
4 question
Was the linkage plastic?
5 question
Was the pin missing at the servo side or the torque tube side?
6 action
Link the discrepancy to RCCA ticket ISS-24506. Replace the tail to restore the aircraft.
7 action
Link the discrepancy to RCCA ticket ISS-13876. Replace the tail to restore the aircraft.
8 action
Raise a discrepancy against the tail titled "Tail Linkage Issue". Then follow the Removed Tail Flowchart.
9 question
Manually actuate the control surface. Does it feel like there is a lot of friction?
10 action
Remove the tail and replace it to restore the aircraft. Link the discrepancy to RCCA ticket ISS-70537. Send the damaged tail to mx holding for structure repair rework following UMM 51.6.4.e Repair Tail Control Surface Friction or Binding.
11 action
Raise a discrepancy against the tail in ZerpMX. Then follow the Removed Tail Flowchart.
12 action
Raise a discrepancy against the tail in ZerpMX and follow the Removed Tail Flowchart for removed-part testing and disposition.
13 action
Remove the tail from the aircraft and install a serviceable replacement tail to restore the aircraft.
14 action
Raise a discrepancy against the tail in ZerpMX. Then follow the Removed Tail Flowchart.
Resolution note
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