Accident Overview
The aircraft, on a 20-minute flight from Lima-Jorge Chavez Airport to Jauja-Francisco Carlé, carried 142 passengers and 7 crew members. The approach and landing were conducted in good weather conditions.
Sequence of Events
Two seconds after the nose gear touched down on runway 31, the crew activated the reverse systems and felt strong vibrations and oscillations. The aircraft began to bounce and became uncontrollable. The right main gear collapsed, causing the aircraft to veer off the runway to the right. It lost its right engine and came to rest in a grassy area, where it burst into flames.
Damage and Evacuation
All 149 occupants evacuated safely. The aircraft was totally destroyed by fire.
Probable Cause
The official investigation determined the probable cause to be: Failure of the mechanical components of the shimmy damper system in each of the main landing gears which, being out of tolerance range, did not allow the correct damping of the vibrations and lateral oscillations of the wheels after touchdown, generating sequential shimmy events in both gears and causing their collapse.
Contributing factors included:
- Incorrect and probable absence of measurements on mechanical components of the 'cimmetic chain for shimmy damper operation', as indicated by the operator's PM AMM Task, which would have allowed timely detection and replacement of out-of-tolerance components.
- Service Letter 737-SL-32-057-E 'broken torsion link' does not provide for mandatory actions, only recommending maintenance practices to prevent fractures.
- Service Letter 737-SL-32-057-E 'fractures in lower torsion link' makes proper interpretation difficult, potentially inducing errors in selecting the corresponding AMM Task.