Force/Torque Anomaly Detected
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Applicable alarms (6)
FORCE_X_ANOMALY_DETECTEDFORCE_Y_ANOMALY_DETECTEDFORCE_Z_ANOMALY_DETECTEDTORQUE_X_ANOMALY_DETECTEDTORQUE_Y_ANOMALY_DETECTEDTORQUE_Z_ANOMALY_DETECTED
Likely outcomes — click to expand
Based on 184 missions where this alarm fired in the last
90 days
(for TORQUE_X_ANOMALY_DETECTED) as of 2026-10-13
Grounding vs discrepancy (of 120 ZERP issues filed on these missions)
Top work orders
- Perform Zero Hover Procedure (Calibration) · MAINTENANCE_ACTION 10
Frequently replaced parts
| Part | P/N | Removals |
|---|---|---|
| BATTERY ASSY, ZIP, P2 | 27158 | 72 |
| WING STBD, ZIP, P2 | 25266 | 63 |
| OUTBOARD WING ASSY PORT(LH), PRE-PREG, DEPOP, ZIP, P2 | 24762 | 63 |
| PRE-PREG TAIL ASSY STBD(RH), DEPOP, ZIP, P2 | 21840 | 60 |
| TAIL PORT DEPOP, ZIP, P2 | 31280 | 57 |
Frequently co-occurring alarms (% of the 184 missions above)
Aggregated from fleet operations and refreshed daily. Individual outcomes may vary by site and configuration.
Background
Section titled “Background”The controller detected force or torque behavior that does not match the aircraft model. Treat this as a likely physical aircraft issue.
These alarms are high-level model mismatches. The axis list below gives context for why the guide checks different hardware; follow the troubleshooting steps for the detailed inspection instructions:
FORCE_X: misparked propellers and fore/aft drag sources.FORCE_Y: left/right asymmetric drag sources and control-surface issues.FORCE_Z: hover propeller condition/parking, then gross body, wing, or tail damage.TORQUE_X: roll moment sources such as ailerons, outboard wings, and asymmetric propeller/drag issues.TORQUE_Y: pitch moment sources such as tail/ruddervator control surfaces, propeller parking, and fore/aft body drag.TORQUE_Z: yaw moment sources such as asymmetric drag and tail/ruddervator issues.
Troubleshooting Steps
Section titled “Troubleshooting Steps”graph TD
check-related-actuator-specific-alarms{"<small><b>Step 1</b></small><br/>Question: Are actuator-specific missing-feedbac..."}
resolve-related-actuator-specific-alarms["<small><b>Step 2</b></small><br/>Action: Resolve the actuator-specific alarm f..."]
check-high-drag-validator["<small><b>Step 3</b></small><br/>Telemetry: Load the failed maintenance validator..."]
did-the-high-drag-validator-fail{"<small><b>Step 4</b></small><br/>Question: Did the high drag validator fail?"}
perform-high-drag-inspection["<small><b>Step 5</b></small><br/>Action: Perform the High Drag Zip Inspection..."]
identify-anomaly-type{"<small><b>Step 6</b></small><br/>Question: Which force or torque anomaly was rai..."}
inspect-force-x["<small><b>Step 7</b></small><br/>Action: FORCE_X_ANOMALY_DETECTED is a fore/..."]
inspect-force-y["<small><b>Step 8</b></small><br/>Action: FORCE_Y_ANOMALY_DETECTED is a later..."]
inspect-force-z["<small><b>Step 9</b></small><br/>Action: FORCE_Z_ANOMALY_DETECTED is a verti..."]
inspect-torque-x["<small><b>Step 10</b></small><br/>Action: TORQUE_X_ANOMALY_DETECTED is a roll..."]
inspect-torque-y["<small><b>Step 11</b></small><br/>Action: TORQUE_Y_ANOMALY_DETECTED is a pitc..."]
inspect-torque-z["<small><b>Step 12</b></small><br/>Action: TORQUE_Z_ANOMALY_DETECTED is a yaw ..."]
physical-issue-found{"<small><b>Step 13</b></small><br/>Question: Did any inspection identify a physica..."}
resolve-physical-issue["<small><b>Step 14</b></small><br/>Action: Raise a discrepancy and send the zip ..."]
escalate-zip-controls{{"<small><b>Step 15</b></small><br/>Escalation: If all inspections pass and no physic..."}}
check-related-actuator-specific-alarms -->|Yes| resolve-related-actuator-specific-alarms
check-related-actuator-specific-alarms -->|No| check-high-drag-validator
resolve-related-actuator-specific-alarms --> check-high-drag-validator
check-high-drag-validator --> did-the-high-drag-validator-fail
did-the-high-drag-validator-fail -->|Yes| perform-high-drag-inspection
did-the-high-drag-validator-fail -->|No| identify-anomaly-type
perform-high-drag-inspection --> identify-anomaly-type
identify-anomaly-type -->|FORCE_X_ANOMALY_DETECTED| inspect-force-x
identify-anomaly-type -->|FORCE_Y_ANOMALY_DETECTED| inspect-force-y
identify-anomaly-type -->|FORCE_Z_ANOMALY_DETECTED| inspect-force-z
identify-anomaly-type -->|TORQUE_X_ANOMALY_DETECTED| inspect-torque-x
identify-anomaly-type -->|TORQUE_Y_ANOMALY_DETECTED| inspect-torque-y
identify-anomaly-type -->|TORQUE_Z_ANOMALY_DETECTED| inspect-torque-z
inspect-force-x --> physical-issue-found
inspect-force-y --> physical-issue-found
inspect-force-z --> physical-issue-found
inspect-torque-x --> physical-issue-found
inspect-torque-y --> physical-issue-found
inspect-torque-z --> physical-issue-found
physical-issue-found -->|Yes| resolve-physical-issue
physical-issue-found -->|No| escalate-zip-controls
style check-related-actuator-specific-alarms fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style resolve-related-actuator-specific-alarms fill:#dcfce7,stroke:#22c55e,color:#14532d
style did-the-high-drag-validator-fail fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style perform-high-drag-inspection fill:#dcfce7,stroke:#22c55e,color:#14532d
style identify-anomaly-type fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style inspect-force-x fill:#dcfce7,stroke:#22c55e,color:#14532d
style inspect-force-y fill:#dcfce7,stroke:#22c55e,color:#14532d
style inspect-force-z fill:#dcfce7,stroke:#22c55e,color:#14532d
style inspect-torque-x fill:#dcfce7,stroke:#22c55e,color:#14532d
style inspect-torque-y fill:#dcfce7,stroke:#22c55e,color:#14532d
style inspect-torque-z fill:#dcfce7,stroke:#22c55e,color:#14532d
style physical-issue-found fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style resolve-physical-issue fill:#dcfce7,stroke:#22c55e,color:#14532d
style escalate-zip-controls fill:#fef3c7,stroke:#f59e0b,color:#78350f Hover or focus a block to preview it. Select the block to keep the preview open.
3 telemetry
Load the failed maintenance validator results for the affected mission. Look for the fixed-wing high drag maintenance validator,
high_drag_fixed_wing_maintenance/fixed_wing_drag_and_torque. Enter the mission identifier above to load failed maintenance validator results.
4 question
Did the high drag validator fail?
5 action
Perform the High Drag Zip Inspection. Replace any off-nominal components or perform any maintenance actions as indicated in the inspection template.
If no issues are found, proceed to the next step of the guide.
If no issues are found, proceed to the next step of the guide.
6 question
Which force or torque anomaly was raised in the alarm report?
7 action
FORCE_X_ANOMALY_DETECTED is a fore/aft force mismatch.Perform the following inspections:
1. Inspect hover propeller condition and installation per UMM 60.3.2.a Inspect Hover Propeller - General.
2. Inspect upper/lower foam fitment, foam tape seams, nose cone fitment, and panels or surfaces that protrude into the airflow. Use UMM 53.1.5.a Inspect Upper Foam - General, 53.1.6.a Inspect Lower Foam - General, and 53.1.4 Foam Aerodynamic Requirements.
8 action
FORCE_Y_ANOMALY_DETECTED is a lateral force mismatch.Perform the following inspections:
1. Inspect ailerons and ruddervators for missing, damaged, stuck, or otherwise abnormal control surfaces. Use UMM 57.2.2.d Inspect Control Surface (Aileron) and 85.1.3.c Inspect Control Surface (Ruddervator).
2. Inspect outboard wings and the tail assembly for one-sided damage, missing material, deformation, or surfaces protruding into airflow. Use UMM 57.2.2.b Inspect Outboard Wing - General and 85.1.3.a Inspect Tail - General.
3. Compare upper/lower foam fitment, nose cone alignment, foam tape seams, and panel fitment from side to side. Use UMM 53.1.4 Foam Aerodynamic Requirements.
9 action
FORCE_Z_ANOMALY_DETECTED is a vertical force mismatch.Perform the following inspections:
1. Inspect hover propeller condition and installation per UMM 60.3.2.a Inspect Hover Propeller - General.
2. Inspect body foam, outboard wings, and tail for gross damage, missing material, deformation, or surfaces that are no longer attached. Use UMM 53.1.2 Foam Damage Limits, 57.2.1 Outboard Wing Damage Limitations, and 85.1.1 Tail Allowable Damage Limitations.
10 action
TORQUE_X_ANOMALY_DETECTED is a roll moment mismatch.Perform the following inspections:
1. Inspect ailerons per UMM 57.2.2.d Inspect Control Surface (Aileron).
2. Run the wing diagnostic test or the normal post-maintenance wing check for the aircraft configuration. If a wing is removed, follow the Removed Wing Flowchart.
3. Inspect outboard wings per UMM 57.2.2.c Inspect Outboard Wing - Detailed. Compare any damage against UMM 57.2.1 Outboard Wing Damage Limitations.
4. Compare left/right foam, wing, and tail surfaces for asymmetric drag.
11 action
TORQUE_Y_ANOMALY_DETECTED is a pitch moment mismatch.Perform the following inspections:
1. Inspect ruddervators per UMM 85.1.3.c Inspect Control Surface (Ruddervator).
2. Ensure the ruddervator servos are not miswired (connections intended for port may be wired into starboard and vice versa).
3. Inspect the tail assembly per UMM 85.1.3.b Inspect Tail - Detailed. Compare any damage against UMM 85.1.1 Tail Allowable Damage Limitations.
4. Inspect upper/lower foam, nose cone, and foam tape for fore/aft drag sources using UMM 53.1.4 Foam Aerodynamic Requirements.
12 action
TORQUE_Z_ANOMALY_DETECTED is a yaw moment mismatch.Perform the following inspections:
1. Inspect ruddervators per UMM 85.1.3.c Inspect Control Surface (Ruddervator).
2. Compare the left and right sides for body foam fitment, loose or missing foam tape, nose cone fitment, wing damage, tail damage, missing material, or any surface protruding into the flow. Use UMM 53.1.4 Foam Aerodynamic Requirements, 57.2.2.b Inspect Outboard Wing - General, and 85.1.3.a Inspect Tail - General.
13 question
Did any inspection identify a physical issue that requires UMM corrective action, replacement, or a discrepancy?
14 action
Raise a discrepancy and send the zip to maintenance in order to repair, replace, or calibrate the affected hardware using the referenced UMM procedure.
15 escalation
If all inspections pass and no physical issue is found, escalate to P2 Zip Controls On Call. Include the alarm axis, notes from any inspections that were performed, and any diagnostic or pre-flight results.
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:
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