The first Beaufort operation took place on the night of 15/16 April, when nine Beauforts laid mines in the Schillig Roads (north of Wilhelmshaven). One Beaufort failed to return. A second unit, 42 Squadron began to re-equip with Beauforts, starting in April. The Beaufort still had teething problems and after some Beauforts were lost in mysterious circumstances, a Court of Enquiry in June 1940 concluded that the Taurus engines were still unreliable and both operational squadrons were grounded until the engines could be modified.