In 11 days of concentrated bombing, B-52s had completed 729 sorties and dropped 13,640 tonnes (15,000 tons) of bombs. The North Vietnamese claimed that almost 1,400 civilians were killed. The campaign was expensive, 16 B-52s were lost and nine others suffered heavy damaged, with 33 aircrew killed or missing in action. On the night of 26 December a B-52 was hit by a SAM wounding its tail gunner and knocking out four engines, the aircraft limped back to U-Tapao where it crash-landed killing four crewmen with the tail gunner and co-pilot surviving the crash.