MOTOR_FREEWHEELING_PERMANENTLY
Applicable alarms (2)
Likely outcomes — click to expand
Based on 81 missions where this alarm fired in the last
90 days
(for MOTOR_FREEWHEELING_PERMANENTLY) as of 2026-10-13
Grounding vs discrepancy (of 99 ZERP issues filed on these missions)
Top work orders
- Perform Software Update on Aircraft · MAINTENANCE_ACTION 19
- EV3: Inspect Aircraft after Droid Left Behind (DLB) · MAINTENANCE_ACTION 15
- EV2: Inspect Aircraft after Droid Left Behind (DLB) · MAINTENANCE_ACTION 11
Frequently replaced parts
| Part | P/N | Removals |
|---|---|---|
| AFT MOTOR ASSY, ZIP, P2 | 23548 | 56 |
| ASSY, SPOOL AND LINE, DOCKING FIN, AIRCRAFT, P2 | 48477 | 55 |
| PARALAND ASSY, DROID, P2 | 18427 | 42 |
| MIXED MOTOR ASSY, ZIP, P2 | 25263 | 35 |
| CCW HOVER MOTOR ASSY, ZIP, P2 | 19607 | 33 |
Frequently co-occurring alarms (% of the 81 missions above)
Aggregated from fleet operations and refreshed daily. Individual outcomes may vary by site and configuration.
Background
Section titled “Background”This alarm can be raised by any motor in the Aircraft. The root cause could be, but isn’t necessarily in, any of the following:
- Battery
- Bus Bars
- Power Distribution Board
- Flexes
- Motors
Feedback on the occurrence of these issues will be used to provide diagnostic indicators for the common underlying issues.
Troubleshooting Steps
Section titled “Troubleshooting Steps”graph TD
is-the-motor-a-winch-motor-and-the-off{"<small><b>Step 1</b></small><br/>Question: Is the motor a winch motor and the o..."}
follow-the-relevant-steps-in-maintenanc("<small><b>Step 2</b></small><br/>Reference: Follow the relevant steps in MAINTEN...")
while-there-are-a-number-of-reasons-for("<small><b>Step 3</b></small><br/>Reference: While there are a number of reasons f...")
escalate-to-p2-firmware-motors-on-call{{"<small><b>Step 4</b></small><br/>Escalation: Escalate to P2 Firmware Motors On Cal..."}}
is-the-motor-a-winch-motor-and-the-off -->|Yes| follow-the-relevant-steps-in-maintenanc
is-the-motor-a-winch-motor-and-the-off -->|No| while-there-are-a-number-of-reasons-for
while-there-are-a-number-of-reasons-for --> escalate-to-p2-firmware-motors-on-call
style is-the-motor-a-winch-motor-and-the-off fill:#dbeafe,stroke:#3b82f6,color:#1e3a5f
style follow-the-relevant-steps-in-maintenanc fill:#f3e8ff,stroke:#a855f7,color:#581c87
style while-there-are-a-number-of-reasons-for fill:#f3e8ff,stroke:#a855f7,color:#581c87
style escalate-to-p2-firmware-motors-on-call fill:#fef3c7,stroke:#f59e0b,color:#78350f Hover or focus a block to preview it. Select the block to keep the preview open.
off_nominal FREE_SPINNING also set?NOTE: There are many ways motors can get to this state, and even if there was a guide with hundreds of steps describing all the permutations of signals to look for, there will still be blind spots if the troubleshooter does not understand the underlying system. It is definitely possible to teach individuals most of the background information about the motor systems to be effective troubleshooters who can troubleshoot the more simple issues and identify and escalate when things are trickier, but that will require in-person shadowing time to gain hands-on experience.
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.
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