ASN Wikibase Occurrence # 243746
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| Date: | Saturday 2 May 2020 |
| Time: | 14:30 UTC |
| Type: | Believer UAS |
| Owner/operator: | Private |
| Registration: | Unregistered |
| MSN: | 3 |
| Fatalities: | Fatalities: 0 / Occupants: 0 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | Solent Airport, Hampshire -
 United Kingdom
|
| Phase: | Take off |
| Nature: | Test |
| Departure airport: | Lee-On-Solent Airfield (EGHF) |
| Lee-On-Solent Airfield (EGHF) | |
| Investigating agency: | AAIB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The flight was part of a test programme prior to the start of commercial operations to the Isle of Wight. The accident UAS was considerably smaller than the production aircraft but it was representative in terms of the avionics and communications. It crashed shortly after taking off because the safety pilot switched the radio control transmitter off before the automatic flight control system was engaged. Several safety actions have been undertaken by the operator because of this accident.
=AAIB Analysis=
The launch was conducted with the UAS in manual mode, which meant that the safety pilot had full control of the aircraft. The safety pilot believed that the instruction to turn the transmitter off had been issued, but this was incorrect. When the transmitter was turned off, the fail-safe logic operated as designed, and there was insufficient time to regain control before the aircraft crashed.
The operator reviewed their operating philosophy and modified the control system so that takeoffs are performed with the aircraft in automatic mode with the safety pilot correcting the flightpath as necessary. Whilst not a direct cause of this accident, they also reviewed the fail-safe logic to ensure that the settings are automatically configured by the mode the aircraft is in eg if the aircraft is in automatic mode the transmitter failsafe is disabled. Prior to this improvement, the transmitter fail-safe had to be manually turned off, which required human intervention and was open to error.
=AAIB Conclusion=
The safety pilot erroneously turned the transmitter off before the automatic control system was activated and before the instruction to turn the transmitter off had been issued. The operator believed that the accident was unavoidable after the radio control transmitter was turned off because there was insufficient time to switch it back on and regain control of the UAS.
=Damage sustained to airframe=
Per the AAIB Report "Destroyed".
=Safety actions taken by the operator=
● Operations were reviewed to minimise the period where a UAS is under manual control. The UAS is now launched in a revised automatic mode where the safety pilot can apply control inputs to correct the flight path if appropriate. The safety pilot can also disable the automatic flight control system and take full control of the UAS in the event of an emergency.
● The fail-safe logic has been reviewed and modified so that settings are automatically configured depending on the status of the UAS.
● The operator has reviewed their fatigue risk management strategy and is introducing limitations with respect to permissible crew working times and a requirement for crew members to consider their well-being and declare themselves fit for operation during every flight briefing. The operator is updating their operations manual accordingly.
Accident investigation:
 |
|
Sources:
1. AAIB Final Report: https://assets.publishing.service.gov.uk/media/5f5a039bd3bf7f7232e7e654/Believer_UAS_registration_na_10-20.pdf
2. AAIB Annual Safety Review 2020 p.140: https://assets.publishing.service.gov.uk/media/60d2e72ed3bf7f4bd4662d67/Annual_Safety_Review_2020.pdf .
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 08-Oct-2020 18:56 | harro | Added |
| 27-Jun-2021 00:18 | Dr. John Smith | Updated [Time, Registration, Operator, Departure airport, Destination airport, Source, Narrative, Category] |
| 27-Jun-2021 00:23 | Dr. John Smith | Updated [Source, Narrative] |
| 27-Jun-2021 00:24 | Dr. John Smith | Updated [Source] |
Corrections or additions? ... Edit this accident description
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