What happened
On February 4, 2015, a Maule MXT-7-180, registration PT-OPO, was conducting a private flight from Ivinhema, MS, to Cascavel, PR. The flight included a pilot and two passengers. Due to unfavorable weather conditions for visual flight, the crew performed an intermediate landing at the Fazenda Santa Ada Aerodrome in Mato Grosso do Sul to wait for improved conditions.
After departing again at 19:25 UTC, approximately 25 minutes into the flight, the pilot noticed smoke and a significant drop in engine oil pressure accompanied by an oil leak. The pilot promptly shut down the engine and executed an emergency landing in a cultivated area near Assis Chateaubriand, Paraná. All three occupants remained uninjured, and the aircraft sustained no damage.
The investigation
The investigation focused on the mechanical failure that led to the engine shutdown. Investigators determined that the oil leak was caused by the rupture of a lubrication system hose (part number 624000-6-0354).
However, the investigation faced significant challenges regarding evidence preservation. The aircraft operator removed the aircraft from the landing site without authorization from the investigating authority. Furthermore, the operator performed repairs on the engine, including the replacement of the failed hose, before the initial investigation actions could be completed or before the National Civil Aviation Agency (ANAC) could oversee the process. Because the damaged component was replaced prior to inspection, investigators were unable to conduct laboratory testing to determine the specific cause of the hose rupture.