Drone Manufacturer: DJI
Drone Model: Pantom 4 RTK
Country: United Kingdom of Great Britain and Northern Ireland
Applies: Daytime Beyond Visual Line of Sight
Pilot Qualifications: Licensed or Certificated by Aviation Authority
Pilot Flight Experience: 98 Hours
Link to External Information About This submission: https://assets.publishing.service.gov.uk/media/609cf2d98fa8f56a39f36210/DJI_Phantom_4_RTK_UAS_reg_N-A_06-21.pdf
File Uploaded: dji_phantom_4_rtk_uas_reg_na_0621
The UAS, a DJI Phantom 4 RTK, was being operated in an automated flight mode to survey a railway track and surrounding infrastructure when one of the four propellers detached whilst in-flight. The aircraft rapidly descended from a height of 70 m (230 ft) where it struck the ground in the rear garden of a house. No persons were injured.
This investigation has reviewed the new UAS regulations introduced on 31 December 2020 concerning the safe overflight of people and data available to assist in risk assessments. Two Safety Recommendations are made to the UK CAA.
Loss of propeller. Analysis of the recorded flight log indicated that the left rear propeller had detached from the aircraft in flight. This resulted in a loss of control, with the aircraft descending rapidly and vertically to the ground.
After the propellers were fitted and before the accident flight, the aircraft had successfully completed two flights and flown for more than 30 minutes. This indicates that the propeller had probably been fitted correctly prior to flight and therefore either the propeller or its locking mechanism to the motor may have failed. The manufacturer did not confirm if it had carried out a detailed inspection of the aircraft and therefore it was not possible to determine the cause of the in-flight separation. However, the manufacturer stated that it had ‘currently not seen any recurring pattern of similar cases’.
In 2020, the AAIB was notified of nine accidents involving DJI Phantom 4s of which one was an accident on 1 December 2020 where the pilot of a RTK model attributed the accident to a possible propeller failure or in-flight loss of a propeller.