What happened
On June 21, 2016, a Beechcraft B-200C Super King Air, registration OB-2104-P, operated by Aerolínea del Caribe Perú S.A.C., was conducting a local flight instruction mission at Jorge Chávez International Airport. During the final approach to runway 15, the crew noted that the left main landing gear light failed to illuminate, indicating the gear was not down and locked.
Following established procedures, the crew attempted to reset the landing gear by retracting and extending it. They also attempted manual and emergency extension procedures with authorization from the tower. Despite these efforts, the left main gear remained unsecure. The crew proceeded with an emergency landing, coordinating to shut down engines and feather the propellers immediately upon touchdown to mitigate the impact of a potential gear collapse.
Upon contact with the runway, the left main gear retracted completely, causing the left wing to strike the pavement. This impact caused the aircraft to veer left and exit the active runway, coming to a stop near taxiway "B". The crew and onboard mechanic evacuated the aircraft without injuries.
The investigation
The investigation focused on the mechanical failure of the landing gear extension and retraction system. Investigators examined the aircraft's maintenance history, specifically noting that while recent Phase 1 and Phase 2 inspections were completed, the critical inspection of the torque tube was part of a Phase 3 inspection performed in 2014.
Technical analysis of the landing gear assembly revealed that the mechanical transmission chain—comprising an electric motor, a multi-segment torque tube, and a mechanical actuator—was compromised. Investigators found that a specific component, taper pin No. 13, was missing from one of the torque tube connection segments. Additionally, a self-locking nut and a washer were found to be absent or displaced at the connection point.
Findings
- The primary cause of the accident was the retraction of the left main landing gear during landing due to the absence of a taper pin, which prevented the electrical motor from effectively transmitting movement through the torque tube to secure the gear.
- A contributing factor was a deficient quality control process during a previous Phase 3 inspection, which failed to detect the improper installation of the self-locking nut and the subsequent loss of the taper pin.
- The aircraft sustained significant structural damage to the left wing, left main landing gear, left engine, and left propeller.