2 fatalities

1957-11-06: Curtiss C-46 Commando (N10425) — Aerovias Sud Americana — Guatemala City-La Aurora, Guatemala

Guatemala City-La Aurora, GuatemalaLanding (descent or approach)

On November 6, 1957, a Curtiss C-46 Commando (registration N10425) operated by Aerovias Sud Americana was involved in an aviation accident near Guatemala City-La Aurora, Guatemala during landing or approach. 2 people were killed. Investigators recorded the probable cause as: A fatigue fracture in the left engine crankshaft, caused by improper machining contours, led to engine failure and subsequent loss of flight capability. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 1 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781248901Data APIEditorial standards

A cargo flight departing from La Aurora Airport crashed into a residential area after returning to the airport for an engine inspection, causing multiple casualties.

What happened

A scheduled cargo flight departed from Runway 01 at La Aurora Airport at 11:18 local time, bound for St. Petersburg, Florida via Belize City. The aircraft, a cargo transport with a takeoff gross weight of 44,995 lbs and carrying 575 gallons of fuel, was operated by a crew of two with no passengers on board. Shortly after departure, at 11:25 local time, the flight crew notified the La Aurora Airport Control Tower that they intended to return to the airport to perform an engine check. The aircraft was cleared for an approach to Runway 19.

At approximately 11:35 local time, the aircraft crashed in a residential neighborhood located 3.3 miles northwest of the airport at an elevation of 5,029 feet. The impact and following fire destroyed the airframe. The accident resulted in two fatalities, involving one adult and one child on the ground. Additionally, both crew members and three individuals on the ground sustained serious injuries.

Findings

The investigation determined that the crash was caused by a failure of the left engine's crankshaft. Technical analysis revealed a large fatigue fracture originating in the splined section of the shaft. This crack was exacerbated by poor contouring and deep tool marks left during the machining process, which created a stress concentration point. While the steel composition met specifications, the structural integrity of the component failed due to this fatigue progression. Furthermore, the investigation noted that the aircraft was unable to maintain flight on a single engine following the secondary failure of the remaining engine.

Probable cause

A fatigue fracture in the left engine crankshaft, caused by improper machining contours, led to engine failure and subsequent loss of flight capability.