sentences:  The F-100s received by the squadron were aircraft being withdrawn from the 20th Tactical Fighter Wing at RAF Wethersfield and the 48th TFW at RAF Lakenheath, England.RAF Wethersfield was being closed for flight operations and the 20th TFW being re-equipped with the new General Dynamics F-111 Aardvark at their new base, RAF Upper Heyford.The 48th TFW – a permanent resident at RAF Lakenheath after moving aircraft and personnel from Chaumont AB in France – was also preparing for the arrival of the F-111, but had to initially convert to F-4D Phantom IIs before their ultimate F-111 version – the F-111F – came available during 1977.