What happened
On November 4, 2013, a Beechcraft BE-58, registration PT-DRM, operated by Uirapuru Táxi Aéreo Ltda., was performing a transport flight from Recife (SBRF) to Maceió (SBMO). Following takeoff from Recife, the pilot commanded the landing gear to retract; however, the gear remained in the up position. Despite attempts to extend the gear using the aircraft's emergency system, the mechanism failed to deploy.
Because the company's maintenance base was located in Fortaleza, the pilot decided to proceed to Fortaleza (SBFZ). Upon arrival at SBFZ, the crew made further attempts to deploy the gear using both normal and emergency systems, but the gear remained retracted. The pilot declared an emergency and executed the emergency checklist for a belly landing. The aircraft touched down on runway 13, traveling approximately 900 meters along the runway before coming to a complete stop. All four occupants—one pilot and three passengers—remained uninjured, though the aircraft sustained minor damage.
The investigation
CENIPA investigators examined the aircraft's landing gear actuator assembly, known as the Gear Box, which is responsible for both electric retraction during normal flight and mechanical extension during emergencies. The investigation revealed that the Gear Box was physically jammed, preventing the manual emergency actuator from moving the gear struts to the extended position.
Upon disassembling the Gear Box, investigators found that the teeth of the worm gear shaft were misaligned with the teeth of the crescent actuator. This misalignment was linked to damage found in the electric motor of the Gear Box. Evidence suggested that a voltage surge (overvoltage) occurred when the motor was activated to retract the gear after takeoff from Recife, damaging the motor and causing the mechanical misalignment that subsequently locked the system.