 But a 1961 study by the Federal Aviation Administration found that airlines suffering financially tended to experience a drop in safety standards, and by 1960 several of the extant supplementals were in poor fiscal health.The years of battling protean regulations and competing for a fluctuating supply of contracts had whittled the once-abundant non-skeds down to a few dozen companies, many of which barely limped along despite their updated classification.On 19 September 1960, a World Airways Douglas DC-6A took off from Guam carrying military personnel and their families, 80 of whom were killed when the plane crashed shortly thereafter.