What happened
On 23 June 2019, two aircraft were participating in a charity event at White Waltham Airfield, designed to provide air experience flights to disabled children. The event involved eight aircraft flying routes near the edge of London controlled airspace.
The pilot of a Fuji FA-200-180 Aero Subaru, registration G-HAMI, departed the airfield at approximately 0940 hrs. While following the briefed route, the pilot experienced a sudden bump, which they initially attributed to an air pocket.
Simultaneously, the pilot of a Cessna 172R Skyhawk, registration G-BXGV, departed at 0952 hrs. Due to a passenger becoming unsettled, the pilot decided to deviate from the planned route to shorten the flight. During this maneuver, the pilot observed a red aircraft above them, which then disappeared from view behind the high wing of the Cessna 172R Skyhawk.
Following the flight, the pilot of G-BXGV identified damage to the right wingtip. Investigation of the damage revealed that the tyre of G-HAMI had made contact with the wing. Both aircraft landed safely with no fatalities and no injuries to the crew or passengers.
The investigation
The AAIB investigation established that the pilot of G-XGV had been asked to conduct the flight briefing at very short notice because the regular safety manager was unavailable. This last-minute briefing lacked specific instructions regarding aircraft deconfliction or a coordinated communication plan.
Furthermore, the investigation found that the two aircraft were operating on different radio frequencies at the time of the incident, preventing any potential communication. While both aircraft had serviceable transponders, no secondary radar returns were recorded on the ground, and neither aircraft was equipped with Electronic Conspicuity (EC) technology. The investigation also noted that the airfield had not applied for an Airspace Coordination Notice (ACN) for the event.
Findings
- The collision occurred because no formal deconfliction or communication plan was established for the participating aircraft.
- The pilot of G-BXGV altered the flight path without a premeditated strategy to avoid other participants.
- Visual lookout was likely compromised by the pilots' engagement with their passengers and the physical obstruction caused by the high-wing and low-wing configurations of the two aircraft.
- The lack of Electronic Conspicuity (EC) devices and the absence of secondary radar returns contributed to the inability to detect the converging aircraft.
Safety action
- The host airfield has committed to performing formal risk assessments before future events and ensuring a standardized, comprehensive briefing is provided.
- The owner of G-BXGV has since installed an EC device integrated with navigation software.