On 1 April 2011, a Southwest Boeing 737-300 climbing through FL340 experienced a sudden loss of pressurisation as a section of fuselage crown skin ruptured. A successful emergency descent was made with a diversion to Yuma, where the aircraft landed half an hour later. Investigation found that the cause of the failure was an undetected manufacturing fault in the 15 year-old aircraft. One member of the cabin crew and an off duty staff member who tried to assist him became temporarily unconscious after disregarding training predicated on the time of useful consciousness after sudden depressurisation.