 The CAB concluded that the somewhat cursory investigations performed by airline mechanics in these and other cases suggested that "the maintenance and airworthiness of the aircraft cannot be accepted as being normal in all respects," and recommended a reassessment of the airline's maintenance practices in the future.Pathological examination of the victims that had been recovered revealed "possibly disabling" levels of carbon monoxide in 14 of the 19 bodies.Investigators conducted a study to determine how high concentrations of the gas could have become present in the fuselage, and identified several possible ways it could have happened.