What happened
On 23 December 2017, a Cessna 172S JT-A, registration PR-PTS, departed Providenciales Airport in the Turks and Caicos Islands for a flight to Punta Cana, Dominican Republic. Shortly after the aircraft became airborne, witnesses in the control tower observed smoke emanating from the engine. The pilot immediately requested an emergency return to the airport.
As the aircraft attempted a left-hand turn to reposition for landing, the bank angle increased significantly. The nose then dropped, and the aircraft disappeared from view behind nearby buildings. The aircraft struck the ground north of the runway, outside the airport perimeter, near a petrol station. A severe post-impact fire consumed much of the wreckage. Both the pilot and the passenger sustained two fatalities, likely dying instantly upon impact.
The investigation
Investigators examined the wreckage and the engine's FADEC (Full-Authority Digital Engine Control) data. The engine, a Technify Motors turbocharged diesel, had been recently modified during its manufacture to include a cylinder head modification.
Analysis of the FADEC recordings revealed that during the takeoff climb, the manifold air pressure (MAP) dropped abruptly to near-ambient levels, which caused the engine power to plummet to approximately 50%. While the engine was still producing some power, the loss was substantial.
Engine manufacturer tests using a similar engine demonstrated that if the hose clamp securing the turbocharger compressor outlet hose is absent or improperly positioned, the hose can detach under full power, leading to a massive reduction in manifold pressure and smoky exhaust gases—exactly as observed during the accident.
Findings
- The aircraft suffered a significant loss of engine power due to a major leak in the engine air induction system.
- This leak was likely caused by either the detachment of an induction hose or the failure of one of the induction hoses.
- The single hose clamp that should have secured the turbocharger compressor outlet hose was not found in the wreckage.
- The pilot attempted to return to the airport following the power loss, but the aircraft entered a stall during the turn, leading to the crash.
- The loss of power was partial rather than total, and the available power was sufficient to maintain level flight or perform gentle turns, but the complexity of managing a partial power loss may have hindered effective decision-making.