Cargo Aircraft Crash at La Aurora Airport (N10425)

Flight Details and Incident Overview A two-crew cargo aircraft departed La Aurora Airport on a scheduled flight to St. Petersburg, Florida, with a stop in Belize City. The flight operated under visual flight rules with a takeoff gross weight of 44,995 pounds, including 575 gallons of fuel. ## Crash Sequence Seven minutes after takeoff, the flight crew reported an engine issue and requested to return to the airport. The aircraft was cleared for an approach to Runway 19. Approximately ten minutes later, the aircraft crashed in a residential area 3.3 miles northwest of the airport at an elevation of 5,029 feet. ## Casualties and Damage The crash resulted in the deaths of one adult and one child on the ground. Three additional people on the ground and both crew members sustained serious injuries. The aircraft was destroyed by the impact and subsequent fire. ## Probable Cause and Technical Findings The official investigation determined the probable cause was a left engine crankshaft failure, followed by the aircraft's inability to maintain single-engine flight after the other engine failed. A National Bureau of Standards analysis revealed a large fatigue fracture in the crankshaft's splined section. The crack originated in a poorly contoured fillet with deep tool marks, which contributed to the failure. The fatigue crack extended approximately 600 degrees before a final overload fracture occurred. The investigation also noted that the drawing did not specify a minimum radius for the splines, and the steel's hardness indicated a tensile strength of about 200,000 psi.