What happened
On 16 April 2023, a Piper PA-28-161, registration G-RAAM, was performing a training flight at Blackbushe Airport. While on final approach to Runway 25, the pilot realized the aircraft may have struck an obstacle and immediately initiated a go-around. The subsequent landing was completed successfully. Upon inspection after landing, a twig was found attached to the left landing gear wheel. There were no injuries to the pilot or the passenger, and the aircraft sustained no damage.
The investigation
The AAIB investigation examined the approach path and the obstacle limitation surfaces (OLS) for the airfield. The investigation established that the approach to Runway 25 passes over Yateley Common, an area containing various woodland types. A recent survey conducted in March 2023 revealed that 19 trees were penetrating the approach OLS for Runway 25. Notably, some of these trees exceeded the OLS by more than 2 metres, with the tallest tree measured at 3.74 metres above the surface, located 200 metres from the runway threshold. For a light aircraft following a typical glide slope, this would leave only approximately 1 metre of vertical clearance.
It was also noted that while a 2017 survey had identified hazards, the airport had not followed up with the Hampshire County Council to verify if the previously identified trees had been removed. Furthermore, the 2023 survey, conducted using optical instruments from the runway thresholds, might not have captured all obstructions if they were obscured by foreground vegetation.
Findings
- The aircraft struck a tree or branch that was protruding above the permitted obstacle height.
- Trees were penetrating the Runway 25 approach obstacle limitation surface, with the most significant penetration reaching 3.74 metres above the OLS.
- The airport had not verified the removal of trees identified in previous years following discussions with the local council.
- The presence of these obstacles presented a risk to aircraft on the approach path.