By Mark Mackay

METAL FATIGUE was quickly established as the cause of a helicopter crash in Perthshire that killed two men, a continuing fatal accident inquiry heard yesterday.

Pilot Robert Philip Ward (48) of Glasgow, and observer Edward Lapsley (56) of Tyne and Wear, died instantly when their Bell 206B Jet Ranger II plummeted to the ground near Coupar Angus on December 21, 2005.

The helicopter was flying from Cumbernauld to Aberdeen on a gas pipeline inspection for the National Grid when it crashed.

The helicopter’s tail rotor and gearbox were torn from their mountings in the accident, and eyewitnesses reported seeing the craft “fall apart” in mid-air.

An investigation by the Air Accident Investigations Branch has already concluded that the crash was caused by metal fatigue.

Allan Robinson of the AAIB gave evidence at Perth Sheriff Court yesterday as the circumstances were re-examined.

He told the inquiry that one cause of the accident could have been unsecured items falling from an open cabin and striking the helicopter’s tail rotor blade.

However, he said this was quickly discounted as all items from the cabin had been accounted for in or near the cabin wreckage.

“The tail-fin and stinger had been removed in the early stages of the accident and that had to be as a result of contact between the tail rotor and fin,” Mr Robinson said.

“The conundrum then was which of the components had moved.”

Mr Robinson said there had been no evidence of failure in the mounting bolts of the tail rotor, while conversely, metal fatigue had been found within the tail fin.

He revealed that as two upper bolts failed, the fin had moved, putting it into the arc of the tail rotor and causing contact.

The tail rotor then sheared through the tail fin, cutting off a section, together with the helicopter’s stinger.

One of the rotor blade tips was also removed.

“The fin movement was the primary event,” Mr Robinson said.

The inquiry before Sheriff Lindsay Foulis continues.