Investigation into helicopter crash which killed two people finds there are several 'possible causes'

Pilot Ian Macdonald, a 66-year-old from Burton in Lonsdale, died alongside his passenger Admarsu Birhan, a 16-year-old German exchange student, after the aircraft crashed into a tree and caught fire on June 20 last year.

The Air Accidents Investigation Branch (AAIB) said its investigation “was not able to reach a definitive conclusion” about what caused the crash.

But it found there could have been a mechanical failure, the pilot could have become incapacitated after suffering a medical issue or human error may have caused the collision.

According to the AAIB report, Mr Macdonald had agreed to take the teenager on his first helicopter flight, and they set off at 9.30am, from a site in Burton in Lonsdale.

The pilot went to land at the same site at 10.59am, but he turned left and began a “shallow climb”, before the helicopter yawed to the left, the nose dropped and it crashed into a tree.

A witness working close to the crash site claimed he heard a loud “bang or a pop”, before looking up to see the helicopter in a nose-down and heading towards the ground.

Investigators said issues with the tail rotor drive or pitch control could have caused the aircraft to yaw to the left before the crash.

According to the AAIB report, they “could not completely rule out a mechanical issue”, as the fire destroyed most of the helicopter and prevented them from conducting a full examination.

A post-mortem examination of the pilot’s body found evidence of heart disease which may have caused him to “become incapacitated”. But the report also stated “there was no evidence of an acute medical event” and he died after suffering a head injury.

The manufacturer of the Guimbal Cabri G2 helicopter said it can yaw and the pilot needs to immediately use the pedals to increase thrust.

Investigators said the pilot, who had been flying for over 20 years, may have failed to react in time and follow this procedure, but that is unlikely.

The AAIB report stated: “His instinctive pedal input would likely have been the correct one. Approximately half of his total flying experience was on the Cabri G2 and he was operating in a familiar environment.”

The helicopter also had dual controls, meaning the passenger could have inadvertently steered the aircraft of course. The AAIB said that “could not be ruled out as a potential explanation”.

It added: “The evidence recovered in this investigation was not sufficient to determine the cause of the accident.

“Based on the evidence available, the investigation concluded the cause was likely to be one or more of the following factors; a mechanical failure, an incorrect pilot response to unexpected environmental conditions, an inadvertent passenger input or restriction on the controls, or pilot partial or complete medical incapacitation.”