Rotor failure caused helicopter crash

The wreckage is moved for further investigation

An initial report suggests mechanical failure caused a police helicopter to crash in to the roof of a house in Cardiff.

A leaked report from the Air Accidents Investigation Branch (AAIB) says the helicopter was tracking a vehicle when the tail rotor drive - which stops the aircraft from spinning - failed.

An amateur video caught the helicopter in flight

Initial findings by the crash investigators, following an examination of the wreckage at RAF St Athan, say the helicopter then rotated before crashing into the roof of the house.

A family and three aircrew escaped unhurt after the aircraft - which was following a stolen car - plummeted on to the two-storey semi on Good Friday.

Air accident investigators have been moving the remains of the twin-engined squirrel helicopter from south Wales to a base at Farnborough, where they will build up a picture of exactly what went wrong.

Investigator Margaret Dean

The French-built twin-engined Squirrel has a good safety record. The Civil Aviation Authority says 62 others are in service across Britain with nearly 600 in service across the world.

"We are carrying out a full investigation into all aspects of the accident," said Margaret Dean of AAIB.

"Once we've completed that investigation, we will produce a report which will be in the public domain."

Video footage of the last air-borne moments of the helicopter shot by a resident, will also be studied as part of the major inquiry which could take months.

Damage to the house is being assessed

South Wales Police also says the aircraft had a good safety record.

Since it began flying in 1995, it has completed 2,073 hours of operational police duties without serious incident.

In the past year alone, it has been responsible for 200 arrests and the recovery of over £200,000 worth of property.

Diane Patterson: Very lucky

Around 60 residents who had been evacuated from their homes have now been allowed to return.

But the occupants of the damaged property - Diane and Colin Patterson and their three sons - have been told their house remains structurally unstable.

They are staying in temporary accommodation while the damage is assessed.