What happened
On 13 October 2012, a McDonnell Douglas MD-11F, registration N988AR, operated by Centurion Cargo, was performing a non-regular cargo flight from Miami International Airport (KMIA) to Viracopos Airport (SBKP). The flight crew, consisting of two pilots and a mechanic, was executing an IFR ILS approach for runway 15. At the time of landing, the wind was reported at 140 degrees, 20 knots, with gusts up to 29 knots.
Upon touchdown, the left main landing gear collapsed immediately. This caused the aircraft to skid along the runway for approximately 800 meters. The aircraft sustained substantial damage to the left engine, the left wing, and the left main gear assembly. The crew exited the aircraft without injuries, and airport firefighters successfully applied chemical agents to prevent any fire from developing.
The investigation
CENPIA investigators analyzed flight data from the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR). The data confirmed that the crew had followed all prescribed aircraft manuals and that the aircraft was properly configured for landing. The flight parameters, including approach speed and pitch, were within appropriate limits, and the landing was not classified as a hard landing.
Technical examinations of the failed landing gear components were conducted by the DCTA Laboratory of Materials and Boeing Laboratories in California. The investigation focused on the structural integrity of the left main gear cylinder. Investigators also reviewed the aircraft's history, noting that the right main landing gear had been replaced following a hard landing in Montevideo, Uruguay, in October 2009.
Findings
- The failure of the left main gear cylinder was caused by overload in the structure.
- Metallurgical analysis identified characteristics of a pre-crack at the point of origin, which likely functioned as a tension concentration point.
- It is hypothesized that traces of a pre-crack, resulting from a previous overload condition, may not have been identified during maintenance or periodic inspections following the 2009 incident in Uruguay.