The other side is telling its version of the Carnahan plane crash story – and it is saying a critical airplane part did not fail and cause the crash. Parts manufacturer Parker Hanifan is being sued by the survivors of Mel Carnahan and his son Randy – who died in the crash. Carnahan family experts say one of the plane’s vacuum pumps failed, giving improper instrument readings. Their lawsuit is being heard in Kansas City. Parker Hanifan’s expert, an engineering professor from Ohio, says they did not fail. A federal investigation says both pumps were probably working when the plane crashed.