Peru

It was determined that the crew of the fire truck entered the active runway 16L without prior permission from air traffic controller. This chain of events was caused by the lack of joint planning, poor coordination and the non-use of ICAO-standardized communication and phraseology.

Progressive loss of engine power due to the malfunction of the combustion system from the beginning of the takeoff, which significantly compromised the aircraft's performance in flight, as it was unable to maintain the proper speed and altitude to return to the airport, entering into a sudden loss of lift and the subsequent collision with ground.

Runway Excursion due to loss of directional control of the aircraft after landing by disengaging the propeller stops for aerodynamic braking at a higher than established speed, which generated an uncontrollable leftward turning moment of the trajectory, due to asymmetric thrust of the propellers.
The following contributing factors were identified:
- Performing a landing on an Unstabilised Approach, not executing the established Go-Around procedure.
- Performing a failed landing due to asymmetric thrust of the propellers, not applying the procedure established in the Operator's QRH to shut down the failed engine.
- Probable failure of the KTA Fuel Regulator of the Automatic Engine Rotation Frequency and Power Regulation System, which blocked the reduction of the power of the N°2 engine to established operating regimes for the approach and landing.

Double engine failure in flight due to fuel starvation, forcing the crew to attempt an emergency landing in trees.
The following contributing factors were identified:
- Recurrent failures on the ground and in flight of the aircraft fuel quantity indicators, a situation that was maintained because the Maintenance Programme did not include an inspection and calibration of the fuel quantity gauges.
- Initiating the flight with a fuel indication system inoperative.
- Complacency on part of the crew who decided to continue the flight by having an aerodrome nearby after the first engine failure.

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:
- 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 for the timely detection and replacement of out-of-tolerance components, ensuring their integrity and correct operation.
- The Service Letter 737-SL-32-057-E 'broken torsion link', does not provide for mandatory actions, it only recommends maintenance practices to prevent fractures in mechanical components of the 'cimmetic chain for shimmy damper operation'.
- Service Letter 737-SL-32-057-E 'fractures in lower torsion link', makes a proper interpretation difficult; that could induce errors to choose the corresponding AMM Task and determine its scope.

The accident was the consequence of a loss of situational awareness of the pilots, by not making a continuous surveillance during the VFR flight in good weather conditions, not determining timely the corrections of direction or altitude, which finally led them to fail to fly over the ground of the new route adopted in flight, generating a probable aerodynamic loss at the limit of the performance of the aircraft, occurring a CFIT accident.
Contributing factors:
- Limited or poor use of the available GPS Terrain Proximity Warning system.
- Poor or erroneous appreciation of the weather conditions at the beginning of the flight, which led them to vary the route to fly over terrain with higher elevation.
- Limited appreciation of terrain height on the new route in relation to the selected cruising altitude.

Unstable approach and inadequate landing technique for high altitude fields, which resulted in increased landing speed, the start of the flare manoeuvre at higher altitude, and low descent speed, which made the OB-2040-P aircraft make soft contact with the runway, causing inefficiency in operation of the shimmy damper, which did not prevent uncontrolled oscillation of the shock absorbers.
Contributing factors:
- Lack of instruction and training in simulators that include techniques and maneuvers of landing at high altitude fields, with emphasis on speed control at landing.
- Lack of a performance analysis process, through the use of flight recorders or other installed data recording equipment and flight parameters, by the operating company, to enable supervision, control and corrective measures in the operational use of its aircraft.