What happened
On September 18, 2016, a Piper PA-28-140, registration HK-1791-G, was conducting a flight training mission from Perales Airport (SKIB) toward Benito Salas Airport (SKNV). The flight, operated by Aeroclub de Colombia, was being flown by a student pilot in the cruise phase of instruction.
While approaching the destination, the aircraft experienced a partial loss of power, which briefly recovered before transitioning into a total engine failure. Unable to reach the intended runway due to altitude and distance constraints, the pilot executed an emergency landing in an unprepared field characterized by hard earth and sparse vegetation in the Buziraco region of Huila. During the descent, the aircraft struck an electrical tension cable. The impact caused substantial damage to the airframe, including the failure of the landing gear, deformation of the engine firewall, and damage to the propeller. The student pilot sustained minor injuries and was able to evacuate the aircraft independently.
The investigation
The GRIAA investigation focused on the fuel system and maintenance history of the aircraft. Investigators examined the engine, propeller, and fuel tanks, discovering that a recent maintenance effort to seal a hole in the base of the left fuel tank had been performed using an outdated and non-approved procedure. Specifically, the use of slow-curing adhesives that were not endorsed by the manufacturer had compromised the integrity of the seal.
Furthermore, the investigation found that the fuel quantity indicators in the cockpit were unreliable due to the deteriorated condition of the signal transmitters located inside the tanks. This lack of precision led the pilot to rely on estimated fuel consumption rather than actual instrument readings.
Findings
- Fuel exhaustion caused by a leak through a hole in the base of the left fuel tank, which had been improperly repaired.
- Total loss of engine power resulting from the lack of fuel supply from the left tank.
- Deficient aeronautical maintenance practices regarding the aircraft's fuel system.
- Unreliable fuel quantity instrumentation due to deteriorated internal transmitters.
Safety action
- The flight school was advised to audit all maintenance processes performed or contracted to identify the functional condition of fuel system components.
- A recommendation was made to conduct an engineering study on the operational reliability of fuel system components, including a criticality analysis.
- The operator was advised to analyze historical fuel-related events over the previous five years to identify trends and implement mitigation measures.