What happened
On 17 June 2020, an Aery on SkyRanger R60 unmanned aircraft system (UAS) was being deployed for emergency service operations near Maidenbower Pond in Crawley, West Sussex. The mission involved using a thermal camera to assist in a nighttime search for a missing person in an area characterized by trees and water. The weather conditions were favorable, with only a light breeze.
During the flight, a message appeared on the flight controller screen that the pilot did not immediately recognize. In an attempt to clear this notification from the interface, the pilot unintentionally interacted with the emergency cut-out function. This action caused all four electric motors to stop abruptly, resulting in the destroyed aircraft falling from a height of approximately 70 feet into the pond.
The investigation
Investigators analyzed data provided by the manufacturer, which confirmed that the emergency cut-out icon had been tapped three times within a three-second window, precisely as required to trigger the motor shutdown. The investigation also examined the pilot's training and experience. At the time of the incident, the pilot had a total of 6 hours and 15 minutes of flight time, with only 4 hours and 15 minutes specifically on the Aeryon SkyRanger R60. The pilot had not operated the aircraft for several months prior to the accident due to a lack of available equipment.
Furthermore, the investigation looked into the training protocols of the two neighboring police forces managing the UAS operations. While the pilot had completed the necessary manufacturer-designed course and internal assessments, the investigation noted that the pilot had not recognized the significance of the specific icon on the flight controller.
Findings
- The pilot failed to identify the meaning of the icon appearing on the flight controller screen.
- The accidental activation of the emergency cut-out function led to the immediate cessation of all motor power.
- The pilot's recent flight experience on this specific type was limited, having had no flight time on the aircraft in the 28 days preceding the accident.
- The investigation highlighted a broader concern regarding the potential for UAS pilots to lack a deep understanding of aircraft warnings and failures due to the relatively short training periods allowed for commercial UAS qualifications.