What happened
On 5 May 2018, at Cumbernauld Airport, two Robinson R44 Raven helicopters were involved in a ground collision. The first aircraft, G-CTFL, was preparing for a training flight. Due to the presence of other aircraft and a nearby Cessna on the taxiway, the pilot of G-CTFL was unable to move forward or right. To avoid the downwash of nearby aircraft, the pilot lifted the helicopter into a hover and decided to taxi rearwards.
Unbeknownst to the pilot of G-CT andFL, a second Robinson R44, G-HYND, had recently landed on a grass area directly behind the first aircraft. The pilot of G-HYND had already begun the shutdown process, which included turning off the radio and removing his headset. As G-CTFL moved backward approximately 6 feet above the ground, one of the still-rotating rotor blades from G-HYND struck the engine housing of G-CTFL.
The impact startled the pilot of G-CTFL, leading to a loss of control. The aircraft experienced a rapid pitch change, striking the ground several times and bouncing across the pad. The helicopter eventually came to rest in a tail-down position near a parked Robinson R22. There were no fatalities and no injuries to the crew or passengers involved in either aircraft.
The investigation
Investigators reviewed CCTV footage, radio transmissions, and aircraft accident reports. The investigation established that the pilot of G-CTFL was unaware of the position of G-HYND because he had not heard any recent radio transmissions and had not performed a visual check of the area behind him. The pilot believed he was constrained from turning the tail toward the buildings due to the proximity of spectators, though CCTV showed the area was clear.
Regarding the second aircraft, the investigation found that the shutdown checklist for the Robinson R44 did not explicitly state when avionics should be deactivated. This led to the pilot of G-HYND turning off the radio and removing his headset while the rotors were still in motion, preventing him from warning the approaching aircraft.
Findings
- The collision occurred because the pilot of G-CTFL was unaware of the position of G-HYND.
- The pilot of G-CTFL did not perform a lookout turn to check the area behind the aircraft before reversing.
- The startle effect caused by the unexpected impact likely impaired the pilot's ability to maintain control of G-CTFL.
- The pilot of G-HYND had deactivated his radio and removed his headset during the shutdown process, which prevented him from communicating with the other pilot.