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Acceptance validation

Summary

Acceptance validation is the final gate between software commissioning and the maiden flight. It runs a structured battery of ground checks — mass budget, regulatory readiness, structural checks, electronics verification — to confirm that the build is within design specification before anything leaves the ground. A failed gate is information, not failure. Every deviation found on the ground costs minutes to fix. The same deviation found in the air costs the drone.

Concept

Gates vs checks

The acceptance validation distinguishes two types of verification:

Hard gates — the build must not proceed to maiden if these fail. Examples: AUW exceeds the EASA A2 limit, GPS fix cannot reach 8 satellites, motor directions are wrong. These are not warnings.

Soft checks — deviations should be logged and investigated but may not prevent the maiden under controlled conditions. Examples: OSD battery voltage reads 0.3V low vs. multimeter (investigate but probably a scale factor error, not a build defect).

The validation sequence runs hard gates first. If any hard gate fails, stop.

The maiden flight as a measurement event

The maiden flight is not a performance or a celebration. It is the first data collection event for this specific build. Blackbox records the gyro signal, RPM filter performance, and motor balance. Post-maiden visual inspection checks structural behaviour under load. Every deviation from expectation is information.

Reference

Acceptance gate sequence

Mass budget (hard gate)

  • Weigh bare frame (no payload, no battery): must be within 10g of target
  • Weigh with battery: must be below 807g (EASA A2 limit)
  • With 80g payload: must be below 887g

If AUW exceeds the A2 limit — do not fly in standard A2 operating conditions.

Regulatory readiness (hard gate)

  • Operator e-ID label on drone body
  • A2 CoC carried or not required for planned site
  • Airspace authorisation confirmed for planned site (aim.caa.cz)
  • Third-party insurance active
  • GPS Rescue return altitude set for local terrain

Structural checks

  • All 4 props: no cracks, chips, or looseness. Balanced.
  • All 4 arm T-locks: press each arm laterally — no play
  • All 6 sandwich bolts: present, hand-tight + 1/4 turn
  • All 4 CF rods: acoustic ping confirms ring tone
  • Motor mount passive covers: no direct contact with arm head

Electronics verification (bench, battery connected)

  • Battery voltage on OSD matches multimeter ±0.2V
  • GPS fix ≥ 8 satellites within 90 seconds (cold start outdoors)
  • All 4 motors spin in correct direction (Motors tab, props removed)
  • BiDShot RPM readout showing for all 4 motors
  • Blackbox enabled: device shows available flash space
  • RC link: all sticks show correct direction in Receiver tab
  • GPS Rescue manually tested at low altitude before operational use

Procedure

Acceptance validation run

  1. Mass gate. Weigh on calibrated scale. Record all-up weights (bare frame, with battery, with payload if fitted). Compare against gates above. If any gate fails: do not proceed to maiden. Investigate cause.

  2. Regulatory gate. Confirm e-ID on drone. Confirm airspace at planned maiden site. Confirm insurance. If any missing: do not proceed to maiden.

  3. Structural inspection. Physical inspection of all items in the structural checks list. Any prop defect: replace immediately. Any arm T-lock play: reseat tab and re-torque arm screws.

  4. Electronic bench verification. Battery connected, transmitter on first. Work through electronics verification list in order. Log any deviation.

  5. Pre-maiden briefing. If flying with observers:

  6. Confirm 20m safety perimeter will be maintained
  7. Identify two emergency landing zones

  8. Confirm communication method if GPS Rescue activates

  9. Ready for maiden. All hard gates passed, all deviations logged. Proceed to maiden-flight.

Rationale

Why structural checks run after electronics

If electronics verification reveals a hard gate failure (wrong motor direction, no GPS lock), the build returns to commissioning regardless of structural state. Doing structural checks first wastes time if electronics would fail anyway. Electronics verification is faster and more likely to find issues — run it first.

Connections

requires: - software-commissioning - electronics-installation related: - easa-open-category - preflight-checklist - lipo-batteries - failure-hierarchy leads_to: - maiden-flight