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Zipline Zipline Service Documentation

    TAIL or propulsion motor _DISABLED alarm

    published Last Updated: Oct 9, 2026 HW: all
    Applicable alarms (6)
    HOVER_PORT_AFT_DISABLEDHOVER_PORT_FWD_DISABLEDHOVER_STBD_AFT_DISABLEDHOVER_STBD_FWD_DISABLEDTAIL_PORT_DISABLEDTAIL_STBD_DISABLED
    Likely outcomes (144 missions, 36 issues) — click to expand

    Based on 144 missions where this alarm fired in the last 90 days (for TAIL_STBD_DISABLED) as of 2026-10-13

    Grounding vs discrepancy (of 36 ZERP issues filed on these missions)

    Grounding 58.3% (21 of 36 issues) Discrepancy 41.7% (15 of 36 issues)

    Frequently replaced parts

    Part P/N Removals
    SERVO, ASSY, UNIVERSAL, P2 20398 22
    AFT MOTOR ASSY, ZIP, P2 23548 14
    BATTERY ASSY, ZIP, P2 27158 11
    COATED PCBA, TAIL NODE, ZIP, P2 29407 9
    CW/CCW HOVER MOTOR ASSY, ZIP, P2 19607 6

    Frequently co-occurring alarms (% of the 144 missions above)

    TAIL_PORT_DISABLED 98.6% of missions SOFTWARE_CONFIGURATION_EVALUATION_INCOMPLETE 66.7% of missions WING_PORT_DISABLED 47.9% of missions WING_STBD_DISABLED 47.9% of missions MIXED_DISABLED 43.1% of missions

    Aggregated from fleet operations and refreshed daily. Individual outcomes may vary by site and configuration.

    Background

    Section titled “Background”

    Either tail servo loses its calibration or propulsion motor set an unexpected alarm.

    Troubleshooting Steps

    Section titled “Troubleshooting Steps”
    1 escalation
    Escalate to P2 Firmware Motors On Call.

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    Topic history
    1. 2026-10-07 Susan Minne Bulk/mechanical change
      Replace individual guide ownership with system technical contacts
      Commit dca5a1a
    2. 2026-09-24 Susan Minne Bulk/mechanical change
      chore: backfill aircraft owner identities batch 4
      Commit d9b2270
    3. 2026-09-23 Susan Minne Bulk/mechanical change
      docs: remove obsolete Confluence metadata
      Commit 2d5374e
    4. 2026-09-13 Susan Minne Bulk/mechanical change
      feat: add MX approval metadata to topics
      Commit 406a785
    5. 2026-06-12 Susan Minne Bulk/mechanical change
      Update troubleshooting topics and escalation paths
      Commit 166da10
    6. 2026-05-28 Susan Minne Bulk/mechanical change
      Remove redundant topic applicability banners
      Commit e561ad0
    7. 2026-05-11 Susan Minne
      Reviewed and updated migrated topics
      Commit a50c961
    8. 2026-05-06 Gavin Edwards Bulk/mechanical change
      Remove redundant Engineer Owner table from topic body (#298)
      Commit 1619f07 PR #298
    9. 2026-05-06 Gavin Edwards Bulk/mechanical change
      Migrate Susan's missing topics from #292
      Commit f2f29d2
    10. 2026-05-04 Gavin Edwards Bulk/mechanical change
      Batch 8: 26 new topics — last from impact-ranked pool
      Commit ad9327f
    11. 2026-04-15 Gavin Edwards Bulk/mechanical change
      Replace topic corpus: 388 LLM-regenerated topics (round 1)
      Commit f950bfa
    12. 2026-04-14 Gavin Edwards Bulk/mechanical change
      Tag all 427 topics draft with DO NOT USE warning admonition
      Commit 1783498
    Baseline import
    Initial import into service_docs
    Imported by Gavin Edwards on 2026-04-10
    Import TG202615 aircraft topics (chunk 4 batch 1)
    Commit 968d51d
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