"About half the army's new 3 billion pound (4.7 billion euro, dollar) fleet of Apache attack helicopters will have to be mothballed for up to four years because pilots cannot be trained in time to fly them," the Financial Times said.

Although the helicopters themselves are on schedule, a 1 billion pound private finance initiative to train the pilots was running three years behind, the FT said, quoting a damning National Audit Office report.

"Because of limited capability, the Apache will not have the capacity for secure voice communications with the UK's Gazelle, Lynx, Sea King and Puma helicopters," the report blasted, according to The Daily Telegraph.

"Nor will it be able to exchange data securely with most of the UK's military aircraft, or battlefield helicopters, or with UK ground forces," the report said, according to the same source.

It will not be able to fly in icy conditions until December 2006, more than 18 months after the in-service date, the right-wing daily added.

Problems with the Apache's Hellfire anti-tank missiles, which can damage the tail rotor when fired, were discovered by the US military two years ago but no practical solution has been found, said the FT.

The British version has also found problems with its other missile system, which can damage flight control surfaces when fired, the business daily added.

SPACE.WIRE