What happened
On July 26, 2019, at approximately 21:40 UTC, a Neiva EMB-810C, registration PT-OBL, was performing a scheduled passenger flight from Marechal Thaumaturgo (SSMH) to Cruzeiro do Sul (SBCZ) in the state of Acre, Brazil. The aircraft was operated by Rio Acre Táxi Aéreo Ltda and was carrying a pilot and five passengers.
During the landing roll at Cruzeiro do Sul, the left main landing gear failed, causing the left wing to drop and the propeller to strike the runway. The impact caused the left engine to stop abruptly. The aircraft traveled approximately 100 meters before coming to a halt within the runway boundaries. There was no fire, and all six occupants escaped the aircraft without injury. The accident resulted in substantial damage to the aircraft, specifically affecting the left engine, propeller, and landing gear, as well as minor damage to the left wing, flap, and fuselage.
The investigation
CENIPA investigators examined the mechanical components of the landing gear assembly and the operational environment. The investigation focused on the failure of the retainer assembly pin (PN 6 and 67502-00) and the bolt (AN4-40A PN 401335). Laboratory analysis at the Department of Aerospace Science and Technology (DCTA) confirmed that both the pin and the bolt had suffered fractures due to overload.
Investigators also reviewed the maintenance history of PT-OBL, finding that the aircraft's airworthiness certificate was valid and all maintenance logs were up to date. The pilot was found to be fully qualified with valid instrument and multi-engine ratings. While the aircraft's landing gear had functioned normally during the preceding takeoff, the investigation looked into the impact of runway conditions at the departure airfield, Marechal Thaumaturgo (SSMH).
Findings
- The failure of the left main landing gear was caused by the fracture of the retainer assembly pin and the securing bolt due to overload.
- The fracture of these components allowed the landing gear strut to dislodge from its housing, causing the gear to shift backward during the landing roll.
- Poor runway infrastructure at the departure airfield (SSMH) acted as a contributing factor; the pilot reported significant jolts during takeoff due to numerous potholes in the pavement.
- The deterioration of the asphalt at SSMH had been previously identified in a prior safety recommendation, but the conditions remained hazardous at the time of the accident.