What happened
On March 11, 2021, a Bell 206L-4 helicopter, registration PR-HIB, was performing a personnel transport mission for IBAMA in the district of Extrema, Porto Velho, Brazil. The flight was part of an environmental inspection operation. The aircraft had taken off from an informal landing site located at a local meat processing plant (frigorífico) to transport passengers to a monitoring point.
During the takeoff maneuver, the pilot executed a standard climb, accelerating at low altitude to reach translational lift before initiating an ascending turn to clear a nearby tree. During this maneuver, the aircraft struck low-voltage power lines. The crew heard a faint noise, which they initially mistook for a door opening, but no immediate flight parameter changes were noted. Upon landing at the subsequent destination, a post-flight inspection revealed damage to the windshield and the wire cutter.
The investigation
CENIPA investigators examined the operational procedures and the takeoff site. The investigation confirmed that the aircraft struck the lines, which caused a localized power outage in a nearby electric fence and resulted in a severed low-voltage wire. The crew, consisting of two pilots, one tactical operator, and three passengers, all escaped the incident without injury.
The investigation focused on the use of an unregistered landing site. While the pilots were fully qualified, licensed, and medically certified, the investigation found that the takeoff area had not been properly assessed for hazards. The pilot in command (PIC) had relied on the previous pilot's assessment of the site rather than performing a fresh risk evaluation. Furthermore, the investigation noted that the takeoff technique used—a standard climb—was inappropriate for an area with known obstacles, where a high-performance takeoff would have been more suitable.
Findings
- The aircraft collided with a low-voltage power line during the takeoff phase.
- The pilot failed to conduct an adequate risk assessment of the takeoff area, specifically regarding the presence of overhead obstacles.
- The crew did not identify the presence of utility poles and wires within the maneuver area.
- There was a lack of a standardized risk assessment methodology for operations in sites not registered with ANAC.
- The required mission briefing regarding the risks of operating in unregistered locations was not performed.
- The operational environment had become informal due to a lack of management oversight and adherence to established procedures.
Safety action
- It is recommended that ANAC reinforce its oversight of IBAMA operations to ensure that the inherent risks of such missions remain within the Acceptable Level of Safety Performance (ALOSP) defined in the operator's Safety Management System.