During warm seasons in 1970 and 1971 operations shifted back to Bitburg while the runway was resurfaced at Spang. During this period the hardened NATO "Tab-V" shelters were constructed at both bases while operations around them continued. EB-66s were too large and remained parked around the ramp at the large hangar. End of runway alert aircraft F4s and EB-66's were under shelter for weather protection only. "V" or Victor Alert denoted nuclear forces from the British bombers Victor and Vulcan beginning with that letter. "E" Alert was for ECM.