What happened
On 29 June 2020, a DJI Inspire 2 was being operated for private use in a semi-rural area near Eton Wick, Windsor. The pilot was monitoring the aircraft during its landing sequence in wind conditions estimated at approximately 18 to 19 mph. During this procedure, the pilot observed what appeared to be a propeller fragmenting, after which the drone lost control and descended rapidly.
The aircraft struck a car that was parked on a private residential driveway. The impact caused the DJI Inspire 2 to disintegrate and resulted in damage to the bodywork of the third-party vehicle. Following the incident, the pilot exchanged details with the car owner and removed the wreckage and the damaged battery from the scene.
Earlier that same day, the pilot had been approached by another drone operator working at Windsor Racecourse. That operator had expressed concern regarding the proximity of the private flight to the public during racing events, prompting the pilot to relocate to the area where the accident eventually occurred.
The investigation
The AAIB investigation was constrained by a lack of physical evidence. The pilot reported that the aircraft had been disposed of immediately following the accident, meaning the wreckage could not be examined. Furthermore, the flight controller provided no useful data for analysis. While the pilot suggested the propeller may have struck an object, the lack of access to the drone's logs or debris prevented a definitive technical assessment.
Findings
- The aircraft experienced a sudden loss of control during its landing phase.
- The pilot observed a propeller appearing to come apart prior to the descent.
- The exact cause of the mechanical failure could not be determined due to the unavailability of the wreckage and flight data.
Safety action
- Because drone batteries store significant amounts of energy, they require careful handling if damaged. To prevent thermal runaway, which can lead to intense heat, flames, and toxic gases, damaged batteries should be transported and stored in specialized, commercially available protective pouches or cases.