These systems were the subject of a comprehensive stall programme, involving some 3,500 stalls being performed by Hawker Siddeley before the matter was considered resolved by the Air Registration Board. The stall warning and recovery systems tended to over-react: of ten activations between the Trident entering service and June 1972, only half were genuine, although in the previous 6½ years there had been no false activations when an aircraft was actually in the air. When BEA Trident pilots were questioned informally by one captain, over half of the pilots said that they would disable the protection systems on activation rather than let them recover the aircraft to a safe attitude. Random checks carried out by the airline after the accident showed that this was not the case; 21 captains stated that they had witnessed their co-pilots react correctly to any stall warnings.