What happened
On November 9, 2016, at approximately 00:05 local time, a Boeing 737-476, registration HK5139, operated by Aercaribe S.A., experienced a serious incident during landing at El Dorado International Airport in Bogotá, Colombia. The aircraft was performing a cargo flight from Leticia to Bogotá.
During the approach to runway 13R, the crew executed an unstabilized approach characterized by frequent power adjustments and a descent rate between 450 and 1,000 feet per minute. The aircraft touched down on the left main gear at a speed of approximately 150 knots, which was 6 knots above the calculated reference speed (Vref) of 144 knots.
As the aircraft decelerated using brakes and reverse thrust, intense vibrations developed. This was followed by a sudden lateral movement where the aircraft veered approximately 170 degrees to the left before coming to a stop near taxiway K4. The four occupants—comprising the pilot, co-pilot, flight engineer, and a technician—evacuated the aircraft safely without injuries. Emergency services attended the scene to monitor the landing gear for potential fire hazards.
The investigation
The GRIAA investigation, supported by the NTSB and Boeing, analyzed flight data from the FDR and CVR. The investigation focused on the sequence of events following the touchdown and the physical state of the landing gear. Investigators examined the aircraft's maintenance records, which showed the plane was airworthy and compliant with all service bulletins.
Analysis of the FDR confirmed the unstabilized nature of the approach and the high-speed touchdown. Physical inspection of the aircraft revealed significant damage to the main landing gear, including the total destruction of wheels 3 and 4, damage to the rims, hydraulic lines, and electrical lines, as well as damage to the control surfaces due to the displacement caused by the vibration. The investigation also noted damage to the runway asphalt caused by the friction of the rims.
Findings
- The primary cause of the incident was a heavy landing at a speed exceeding Vref, which induced severe vibrations and triggered a failure in the shimmy damper.
- A contributing factor was the lack of sufficient safety management system alerts or inspections regarding the potential for component failure following heavy landings.
- The aircraft's landing gear experienced a significant misalignment, with the left wheels deviating approximately 55 degrees from the longitudinal axis.
- The investigation noted that the B737 model is susceptible to shimmy damper-related events during high-speed or heavy landings.