During the Operation Antler trials, the British Government had given the AWTSC reassurances that safety measures were in place to prevent balloons from breaking loose. Despite this, two balloons broke free during a squall on 22 July 1959. One was subsequently recovered but the other was not. A board of inquiry was held, but an even more embarrassing incident occurred on the night of 23/24 September 1960, when seven of the eight balloons being readied for experiments broke free of their moorings during a thunderstorm. Five were recovered on the range on 27 September, but two were lost and drifted further afield, one being recovered near Cobar in New South Wales on 24 September and the other around Hungerford in New South Wales, which was not located until 1 October. Titterton wrote a critical letter to the AWRE. It was clear that the procedures to prevent balloon escapes had been inadequate and the self-destruction devices were unreliable.