Boeing has begun assembly of the first of four C-17 Globemaster 3s to be leased to Britain's Royal Air Force. The aircraft will be identical to the 135 C-17s on firm order from the U.S. Air Force. First delivery to the RAF is scheduled for spring 2001. A final contract for the aircraft is being negotiated and a signed deal is expected in September. The RAF will use the four aircraft to meet near-term strategic mobility requirements. The USAF will provide aircrew training and maintenance support.