What happened
On September 15, 2013, a Piper PA-28-181, registration HK2078G, was conducting a flight instruction mission over the Guaymaral training zones in Cundinamarca, Colombia. The aircraft, operated by Escuela de Aviación de los Andes S.A., was carrying an instructor and a student pilot.
While performing maneuvers at approximately 10,200 feet, the aircraft experienced intense, uncontrollable vibrations accompanied by a loss of engine power. During the event, the oil cap opened and the dipstick was ejected from the engine. Faced with the deteriorating situation, the crew executed an emergency landing in an unprepared potato field. Both occupants exited the aircraft uninjured, and no fire occurred following the impact.
The landing caused significant damage to the aircraft, including the separation of the engine from its mount, a fractured nose gear, and damage to the right wing tip. One propeller blade was bent while the other suffered a fracture at the tip.
The investigation
The GRIAA investigation focused on the mechanical failure of the propeller and the maintenance history of the aircraft. Investigators reviewed the maintenance records for the Lycoming engine and the Sensenich propeller.
While the engine was found to be functioning normally, the investigation uncovered critical discrepancies in the Non-Destructive Testing (NDT) procedures performed on the propeller. Specifically, the investigation found that the maintenance workshop used the incorrect technical manual and documentation for the inspection. Instead of using the required Sensenich manual (SPRM 509), technicians applied a manual (SPM 100) and forms intended for McCauley propellers. This error meant the inspection was not performed according to the manufacturer's specific requirements for the Sensenich component.
Findings
- The primary cause of the incident was the in-flight separation of a propeller blade section due to ductile fatigue fracture.
- A major contributing factor was the improper application of inspection procedures, where NDT (Non-Destructive Testing) was conducted using documentation and manuals applicable to McCauley propellers rather than the Sensenich propeller installed on the aircraft.
- Inadequate supervision in the planning and execution of maintenance tasks allowed the use of incorrect technical references.