22 September 2020, Blog #545
With a pilot and three passengers on board a Cessna 208B Grand Caravan was scheduled to operate a (private) flight between Flaminio Suárez Camacho airport in Guaymaral, Bogotá and the Santiago Vila airport, Flandes Tolima, both in Colombia.
The aircraft wreckage, shortly after the accident (Source; baaa-acro.com © unknown) Early in the morning (06.10 lt - local time) the pilot arrived at the hangar and completed the necessary preparations for the flight, including the preflight inspection of the aircraft and ordering fuel for the flight. A total of 30 gallons were added to the aircraft, total block fuel was 1100 pounds. The flight was estimated to last about 20 minutes.
After the passengers had boarded, the pilot gave a safety briefing to the passengers. ATC was contacted upon completion of the necessary checklists and taxi clearance was issued to runway 29. Once at the holding point for runway 29 the required engine checks were completed without any abnormal indications.
Parts of the landing gears that broke off on touchdown in the field (© GRIAA)
At 06.52 lt the take-off was initiated and an uneventful take-off run followed, the aircraft rotated and started to climb. When at approximately 200 feet height an explosion was heard, the engine noise changed considerably and a loss of power was immediately apparent. This was confirmed by a check of the aircraft instruments, the aircraft engine, a Pratt & Whitney Canada PT6A-114A turboprop, had failed. A field left of the aircraft seemed appropriate as an emergency landing location, the pilot lowered the nose to maintain an airspeed of 70 knots, while keeping the flaps at the take-off setting of "Flaps 2". The pilot then attempted to control the engine with the use of the "emergency power lever, without success. ATC was informed of the loss of power and that an emergency landing was imminent.
Close-up of the wreckage (© GRIAA)
Just before landing the landing gear impacted a house, causing a loss of airspeed. The pilot kept control of the aircraft and touched down in the field which caused the landing gear to be ripped off the aircraft and settle on the cargo pod under the fuselage, which gave away under the impact forces. The aircraft slid for some distance on the lower fuselage structure before coming to a stop. Local residents aided in the evacuation of the occupants, some of them with serious injuries.
There was no post-crash fire, the aircraft was substantially damaged.
Damage caused by the aircraft landing gear when it hit a house, j ust before the emergency landing (© GRIAA)
The GRIAA (Grupo de Investigación de Accidentes - Columbian Accident Investigation Group) was alerted and an investigation was launched. After an extensive investigation the following probable cause was identified;
"The emergency landing a field was the result of an engine failure, caused by the fracture of three blades of the high-pressure compressor rotor. This caused severe damage to the hot section, power turbine and exhaust."
Engine damage that was found during the accident investigation (© GRIAA)
The following Contributing Factors were identified;
Failure of the operator to comply with FAA AD No. 2014-17-08R1, which mandated the replacement of high-pressure compressor rotor blades.
Failure of the maintenance provider to detect the condition of the high-pressure compressor rotor blades during routine borescope inspections.
Insufficient verification of the maintenance processed contracted out by the operator.
Four safety recommendations were also made in the investigation report published by the GRIAA. The investigation report (in Spanish) can be accessed by clicking on the .pdf file below.