The UK Ministry of Defence has advanced a project to convert eight grounded Boeing CH-47 Chinook HC3 transport helicopters for delayed use by the Royal Air Force from late this decade.

"An initial contract was placed with Boeing on 1 August," says armed forces minister Bob Ainsworth. "On current plans we expect to see the aircraft delivered by the end of 2009."

Originally scheduled to enter service in the late 1990s, but delivered from 2001, the Chinook HC3s were placed into storage after trials work concluded that their unique hybrid digital/analogue avionics configuration could not be certificated. Plans to prepare the aircraft for battlefield support use were finally confirmed earlier this year, under a £235 million ($480 million) initiative also covering the acquisition from Denmark of six AgustaWestland EH101 Merlin HC3As.

The MoD says the first phase of its so-called reversion deal with Boeing is worth £6.3 million, and will cover "aircraft characterisation" work, flight trials activities and the purchase of long-lead items for the Chinooks’ subsequent modification. Qinetiq will support the modification and test process.

A follow-on contract is expected to be signed before year-end, with this to conclude design activities and cover modification work to take place during 2009, the MoD says. Focused on the installation of a secondary structure to support replacement avionics and display equipment, the project was earlier this year projected as valuing around £50-60 million.