What happened
On March 28, 2017, a Boeing 737-3M8, registration OB-2036-P, operated by Peruvian Air Line S.A.C., was performing a scheduled flight from Lima to Jauja. Upon landing on Runway 31 at Francisco Carlé Airport, the aircraft experienced intense vibrations and oscillations shortly after touchdown. During the rollout, the right main landing gear collapsed, causing the aircraft to veer off the runway.
As the aircraft exited the paved surface, it entered a drainage ditch. The impact caused the number two engine to detach from its pylon, resulting in a significant fuel spill. The spilled fuel ignited, and the resulting fire consumed the aircraft. While the crew and 142 passengers successfully evacuated via the left-side emergency slides, the aircraft was destroyed by fire.
The investigation
The investigation conducted by the CIAA focused on the mechanical state of the landing gear and the sequence of the structural failure. Investigators examined the components of the shimmy damper system and the maintenance records of the aircraft. The inquiry also reviewed the operational conditions at the time of landing, noting that maintenance work was being performed on the runway, which had restricted operations to the right side of the pavement.
Findings
- The primary cause of the accident was the failure of the mechanical components within the shimmy damper (SD) system on both main landing gears. These components were found to be outside of required tolerances, which prevented the proper damping of lateral oscillations.
- This mechanical failure triggered sequential "shimmy" events in both landing gears, leading to their structural collapse during the landing roll.
- Maintenance inspections may have been insufficient or absent regarding the specific kinematic chain of the shimmu damper components, which would have allowed for the detection of out-of-tolerance parts.
- The existing Boeing Service Letter (737-SL-32-057-E) regarding lower torsion link fractures provided only recommendations rather than mandatory actions, and its complexity may have hindered proper interpretation of required maintenance tasks.