AN RAAF plane carrying Prime Minister John Howard and Defence Force chief Major-General Peter Cosgrove from Perth to Sydney was forced to turn back to Perth last night.

A Defence Force spokesman said the RAAF Challenger plane was diverted because of a hydraulic leak.

An Air Transport Safety Bureau spokesman said a hydraulic leak could affect a plane’s landing gear or brakes.

Planes suspected to have mechanical difficulties are routinely diverted to the nearest airport.

A staff member travelling with Mr Howard said the incident happened about 4.40pm when the plane was about an hour into its flight. “The PM was on a plane with General Cosgrove,” the staff member said.

“About an hour out of Perth, on its way back to Sydney, the pilot said they were turning back.

“He only did it as a precautionary measure. We arrived back in Perth safely.”

Mr Howard and General Cosgrove were travelling to Sydney after announcing new counter-terrorist measures in Perth as he and other political leaders welcomed 150 Special Air Service Personnel back to Australia after a 12-month tour of duty in Afghanistan.

John Howard will be spending Christmas and New Year in Sydney.