AAIB report – Evolve Dynamics Sky Mantis
RPAS are hard, not tough but difficult. Battery management is most of the job and any sign of damage should be taken seriously.
Having an unusual drone disconnects you from ready battery supplies from retailers all over the world. This has to be an operational consideration. I know of businesses that travel with no batteries at all on airliners to avoid the 100w hour faff, they then buy the batteries locally.
What a day it would be if manufacturers were made to adhere to a battery standard, size shape and connector.
The unmanned aircraft fell to the ground from a height of 20 m due to a loss of electrical power. This was caused by the separation of electrical connections due to thermal damage to the UA and battery connectors. Damage was also found to the batteries fitted during the three previous flights.
The manufacturer has updated the Sky Mantis Operating Manual to highlight the need to check the aircraft and battery connectors during pre-flight checks.
History of the flight
The Evolve Dynamics Sky Mantis UAS was being operated in support of emergency services that were tackling a building fire in St Albans. The UA had successfully completed two flights at the site and was about 13 minutes into its third flight when, from a height of about 20 m, it suddenly fell to the ground. The aircraft was destroyed (Figure 1). The operator had a 200 m cordon in place and was operating the aircraft overhead wasteland.
No persons were injured.
The UAS operator purchased the aircraft in 2020, which was supplied with five batteries. The operator’s procedures required that a weekly check flight was performed, which took place on the morning of the day of the accident. The aircraft’s battery was replaced prior to each flight on the day. These are referred to as ‘check flight’, ‘flight 1’, ‘flight 2’ and ‘accident flight’ batteries in this report. The pilot stated that he did not notice anything unusual during his checks of the aircraft between flights.
