What happened
On December 13, 2015, an AS 350 B2 helicopter, registration PT-HZL, was conducting an aeropolice patrol mission in the Coxilha Rica region of Santa Catarina. The crew, consisting of two pilots and two special equipment operators, had performed an unscheduled landing in a restricted area.
During the subsequent departure, the pilot executed a high-performance takeoff maneuver to avoid terrain obstacles. While attempting to transition from a vertical climb to forward flight, the aircraft struck rural low-voltage power lines at an altitude of approximately 25 to 35 meters. The impact caused structural damage to the main rotor blade, including a fracture on the lower surface. Despite the collision, the crew continued the flight for 18 minutes and successfully returned to their operational base in Lages. All four occupants remained uninjured.
The investigation
CENIPA's investigation focused on the decision-making process and the organizational environment of the Santa Catarina Military Police Aviation Battalion. Investigators examined the crew's qualifications, noting that while the pilot was fully qualified, the co-pilot lacked the specific technical rating for the AS 350 B2 and did not hold a Commercial Pilot License (PCH) required for public security missions.
The investigation also scrutinized the post-accident management. It was established that the aircraft was sent for repairs without notifying the investigating authority and subsequently returned to service without formal airworthiness approval from the national regulatory agency, ANAC. Furthermore, the investigation found that the takeoff maneuver was initiated before reaching the recommended safety altitude of 100 feet, leaving insufficient energy to clear the electrical wires.
Findings
- Improper Pilot Judgment: The pilot made the decision to interrupt the vertical climb and initiate forward movement before reaching the safe altitude required to clear obstacles.
- Inadequate Flight Planning: The mission lacked sufficient preparation for operating in a restricted environment characterized by high vegetation, hills, and power lines, and the crew failed to conduct an adequate briefing.
- Crew Coordination Failures: A lack of clear briefing regarding crew roles and the co-pilot's focus on the external environment—rather than monitoring engine parameters—contributed to the loss of available power during the maneuver.
- Organizational Culture: A weakened safety culture was identified, evidenced by the use of unqualified personnel for specific missions and the failure to follow established organizational and regulatory processes following the accident.