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Zipline Zipline Service Documentation

    HW_BRICK_UNDERVOLTAGE_CRITICAL

    published Last Updated: Oct 9, 2026 HW: all
    Applicable alarms (1)
    HW_BRICK_UNDERVOLTAGE_CRITICAL
    Likely outcomes (2,196 missions, 29 issues) — click to expand

    Based on 2,196 missions where this alarm fired in the last 90 days as of 2026-10-13

    Grounding vs discrepancy (of 29 ZERP issues filed on these missions)

    Grounding 13.8% (4 of 29 issues) Discrepancy 86.2% (25 of 29 issues)

    Frequently replaced parts

    Part P/N Removals
    BATTERY ASSY, ZIP, P2 27158 63
    TAIL ASM, STRBRD(RH), IM GNSS, ZIP, P2 0108359 20
    TAIL ASM, PORT(LH), OLD GEAR, ZIP, P2 0108336 20
    ASSY, SPOOL AND LINE, DOCKING FIN, AIRCRAFT, P2 48477 14
    BATTERY, DROID, P2 24544 12

    Frequently co-occurring alarms (% of the 2,196 missions above)

    SOFTWARE_CONFIGURATION_EVALUATION_INCOMPLETE 92% of missions STALE_CYCLE_METRICS_RECORD 22% of missions ANGLE_OF_ATTACK_INPUT_TIMED_OUT 17.4% of missions AMBIENT_TEMPERATURE_INPUT_TIMED_OUT 16.6% of missions RELATIVE_HUMIDITY_INPUT_TIMED_OUT 16.6% of missions

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

    Background

    Section titled “Background”

    This alarm occurs because at least one of the Aircraft battery bricks saw a critically low voltage, and the battery may be damaged.

    Troubleshooting Steps

    Section titled “Troubleshooting Steps”
    1 action
    Replace the Aircraft battery. See the UMM for steps.

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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 2
      Commit 6ca6807
    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
      Populate owner fields from migrated content
      Commit 6b6d45f
    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
      Replace 10 deactivated-Atlassian-user-prefix references with "To be determined"
      Commit de3ded4
    10. 2026-05-04 Gavin Edwards Bulk/mechanical change
      Batch 7: 47 new topics from full 4-gate pipeline
      Commit e5e26ab
    11. 2026-04-23 Gavin Edwards Bulk/mechanical change
      Replace all topics with 210 v3-generated baseline content
      Commit 9b61a6e
    12. 2026-04-15 Gavin Edwards Bulk/mechanical change
      Categorize 373 regenerated topics into subdirectories; drop 15 meta pages
      Commit 9bdc40f
    13. 2026-04-15 Gavin Edwards Bulk/mechanical change
      Replace topic corpus: 388 LLM-regenerated topics (round 1)
      Commit f950bfa
    14. 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 2)
    Commit 26c0b58
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