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Zipline Zipline Service Documentation

    LOCK_MECH_STUCK

    published Last Updated: Oct 9, 2026 HW: all
    Applicable alarms (1)
    LOCK_MECH_STUCK
    Likely outcomes (54 missions, 89 issues) — click to expand

    Based on 54 missions where this alarm fired in the last 90 days as of 2026-10-13

    Grounding vs discrepancy (of 89 ZERP issues filed on these missions)

    Grounding 5.6% (5 of 89 issues) Discrepancy 94.4% (84 of 89 issues)

    Top work orders

    • Lock Mech Inspection · INSPECTION 29
    • EV2/EV3 Perform Preflight Without Motors · INSPECTION 17
    • EV2/EV3 Diagnostics Test Without Motors · INSPECTION 13
    • Reset Droid after DLB · REPAIR 12
    • EV2: Replace Lock Mechanism on Aircraft Docking Fin/Winch Assembly · MAINTENANCE_ACTION 12

    Frequently replaced parts

    Part P/N Removals
    DOCKING FIN WINCH ASSY, ZIP, P2 24084 110
    LOCK MECH ASSY, PRE-EV2, ZIP, P2 30166 65
    ASSY, SPOOL AND LINE, DOCKING FIN 48477 34
    DOCKING FIN WINCH LRU, AIRCRAFT, P2 48561 27
    WINCH, ASSY, ZIP, P2 24078 24

    Frequently co-occurring alarms (% of the 54 missions above)

    WINCH_MOTOR_DISABLED 31.5% of missions SQUIB_PORT_DEPLOYED 31.5% of missions DROID_LEFT_BEHIND 31.5% of missions WINCH_CUTTER_DEPLOYED 31.5% of missions

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

    Background

    Section titled “Background”

    This alarm can occur whenever there is an attempt to latch. It indicates that the lock mechanism or Droid side stabilizer hardware is degraded, causing slow or incomplete latching.

    Troubleshooting Steps

    Section titled “Troubleshooting Steps”
    1 action
    The Aircraft will need to be removed for maintenance. Follow the troubleshooting steps in: Lock Mechanism -- Cam Hang Validator / Failure to Unlock / Failure to Lock.

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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 3
      Commit 8ff7b9b
    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. 2026-05-28 Susan Minne Bulk/mechanical change
      Remove redundant topic applicability banners
      Commit e561ad0
    6. 2026-05-11 Susan Minne Bulk/mechanical change
      Update troubleshooting topics and links
      Commit 0aa9df2
    7. 2026-05-09 Susan Minne Bulk/mechanical change
      Fix high-confidence internal documentation links
      Commit a6593fc
    8. 2026-05-06 Gavin Edwards Bulk/mechanical change
      Remove redundant Engineer Owner table from topic body (#298)
      Commit 1619f07 PR #298
    9. 2026-05-05 Gavin Edwards Bulk/mechanical change
      Prompt v2.2 + recover 107 demoted/false-abort topics
      Commit f7f27fe
    10. 2026-04-15 Gavin Edwards Bulk/mechanical change
      Replace topic corpus: 388 LLM-regenerated topics (round 1)
      Commit f950bfa
    11. 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 2 batch 3)
    Commit e12ebe5
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