What happened
On November 10, 2017, an AS350 B2 helicopter, registration PP-ENM, was conducting an aero-police operation in the Guassussê District, Orós, Ceará. The aircraft, operated by the Ceará Public Security and Social Defense Department, was engaged in a mission to monitor a vehicle traveling along a road. During the low-altitude flight, the main rotor blades struck a low-voltage power grid at an altitude of approximately 50 meters. Following the impact, the crew performed a successful precautionary landing to assess the aircraft's condition. While the aircraft sustained substantial damage to its main rotor blades and the power grid was damaged, all five occupants of the helicopter escaped without injury.
The investigation
CENIPA's investigation focused on the operational environment and the organizational framework of the CIOPAER unit. Investigators found that while the pilots were qualified and experienced, the mission was characterized by a lack of standardized procedures. The investigation established that there were no formal regulations within the organization defining a minimum altitude for police operations, such as vehicle tracking. Furthermore, the crew briefing conducted by the commander noted the presence of potential obstacles but failed to stipulate a specific minimum height for the flight. The investigation also noted that the crew had not received formal Crew Resource Management (CRM) training, and the organization's training program did not provide systematic CRM instruction.
Findings
- The crew's attention was focused on the vehicle being monitored, which led to a failure to observe the power lines.
- A lack of standardized minimum altitude limits for police operations contributed to the use of inappropriate operating parameters.
- Ineffective use of Crew Resource Management (CRM) resulted in poor task coordination and a failure to maintain situational awareness.
- The crew's focus on the ground target created a 'tunnel vision' effect, preventing the recognition of external hazards.
- The absence of formal organizational procedures allowed for the adoption of informal, unstandardized flight practices.