 Eight Chinook HC Mk3s were ordered in 1995 as dedicated special forces helicopters , which were intended to be low @-@ cost variants of the US Army 's MH @-@ 47E . The Mk3s include improved range , night vision sensors and navigation capability . The eight aircraft were to cost £ 259 million and the forecast in @-@ service date was November 1998 . Although delivered in 2001 , the Mk3 could not receive airworthiness certificates as it was not possible to certify the avionics software . 
