What happened
On March 17, 2017, a Bell 206B helicopter, registration PT-YHH, operated by Icaraí Turismo Air Taxi Ltd., crashed in the Estação neighborhood of Araucária, Paraná. The flight departed from the JIHAD DEHAINI Heliport for a verification service flight carrying the pilot and three passengers.
During the initial climb, while the aircraft was at approximately 300 feet AGL, the pilot initiated a left turn to reach a target altitude of 500 feet AGL. At this moment, the pilot noticed a 5% drop in rotor RPM. Although the pilot attempted to recover the RPM by reducing the collective lever, a subsequent attempt to apply power caused both the rotor (NR) and the power turbine (N2) to decrease rapidly. This triggered the low RPM warning. The pilot, believing there was insufficient altitude to perform an autorotation, attempted to maintain flight, but the aircraft lost altitude and struck the ground. The impact resulted in serious injuries for all four occupants and substantial damage to the aircraft.
The investigation
CENIPA's investigation focused on the sudden loss of engine performance and the operational conditions of the flight. Investigators examined the aircraft's maintenance logs, which showed the airframe and engine were up to date, though the aircraft was found to be operating above its maximum weight limits due to inadequate density altitude calculations during flight planning.
Technical analysis of the fuel system revealed particles of contamination within the fuel filter and the fuel nozzle last chance filter. While laboratory tests could not provide an absolute identification, there was a high probability that the contaminants were polyacrylamide (PAM), likely introduced during the cleaning or maintenance of the operator's fuel storage tanks using acid descalers. The investigation also noted that the company's operational manuals and standard operating procedures were outdated.
Findings
- Fuel contamination from the operator's storage tanks contributed to the engine power loss.
- The aircraft was operating overweight because the pilot failed to account for density altitude in the weight and balance calculations.
- The pilot's decision-making was a factor, as he chose to continue the flight after the initial RPM drop rather than executing the manufacturer-recommended emergency procedures.
- Organizational deficiencies within the operator, including inadequate management oversight, outdated manuals, and a lack of formal safety surveys, weakened the overall safety culture.
- The pilot's judgment was compromised by an attempt to avoid an autorotation due to perceived altitude constraints.