What happened
On 30 April 2015, a Robin DR 400-180, registration F-GSBM, was performing a private cross-country flight from Lille, France, to Shoreham Airport. While the aircraft was descending on the base leg for Runway 20, its right wing leading edge struck a radio-controlled model glider known as a SAS Wildthing.
The collision occurred at an estimated altitude between 600 and 800 ft amsl. The pilot of the Robin DR 400-180 initially believed the impact was caused by a large bird, but onboard video footage later confirmed the contact with the unmanned aircraft. Despite the impact, the aircraft maintained normal handling and landed safely without zero fatalities or injuries to the crew or passengers.
The model glider pilot was operating the SAS Wildthing near Mill Hill, performing ridge-soaring maneuvers. The pilot reported that the light aircraft appeared suddenly from behind a hill. Due to the wind direction, the sound of the approaching aircraft was carried away from the glider pilot, leaving no opportunity for evasive action.
The investigation
The AAIB examined the flight paths, local regulations, and the visibility conditions at the time of the incident. The investigation established that the Robin DR 400-180 was flying within normal parameters for a standard circuit pattern. However, the pilot was unaware of the model glider activity occurring near the base leg.
Investigators looked into the local byelaws for the Mill Hill nature reserve, which permit model aircraft up to 4 kg. They also reviewed the airport's Aeronautical Information Publication (AIP) and website. While the AIP contained a warning regarding model aircraft, it did not specify the exact location or height of the activity. Furthermore, the airport's website circuit diagram did not highlight the model glider site.
Findings
- The primary cause of the collision was that neither pilot saw the other aircraft until it was too late to take avoiding action.
- The model glider pilot was unable to hear or see the approaching aircraft because it emerged from behind a hill and the wind was carrying the engine noise away from the glider site.
- The pilot of the Robin DR 400-180 was unaware of the model glider site's proximity to the Runway 20 approach.
- The model glider pilot had not requested permission from air traffic control, contrary to recommended guidance for flying in controlled airspace.
- The aircraft's right wing sustained scuffing and scraping damage, while the model glider suffered minor damage to its rudder and aileron.