Helicopter collides with power lines during low-altitude flight in Brazil

Casualties unknown • NOVO PROGRESSO, PA, BR

An AS 350 B2 helicopter struck a power grid while performing a low-altitude maneuver to avoid birds, resulting in substantial aircraft damage.

What happened

On July 25, 2014, an AS 350 B2 helicopter, registration PR-HSC, was conducting an air observation mission for IBAMA. The flight originated from a base in Novo Progresso, Brazil, destined for the Castelo dos Sonhos District. Due to the presence of smoke and degraded visibility caused by fog and low clouds, the pilot elected to maintain an altitude of approximately 200ft.

While traversing a highway, the pilot observed a large flock of birds in the flight path and initiated a 360-degree right turn to avoid a collision. During this maneuver, the aircraft struck a power grid consisting of wires approximately 7m (21ft) above the ground. The impact broke the windshield and damaged the upper engine fairings and the main rotor starflex. The collision caused significant vibrations in the controls. The pilot managed to fly for approximately 1km before performing an emergency landing on the side of the highway. The aircraft sustained substantial damage, including a ruptured tail cone and damaged tail rotor drive shaft fairings.

The investigation

CENIPA's investigation focused on the pilot's decision-making and adherence to flight regulations. Investigators examined the meteorological conditions, noting that the region was experiencing high humidity and low cloud cover, which significantly reduced visibility. The investigation also reviewed the pilot's compliance with ICA 100-4, which establishes minimum heights for VFR helicopter operations. The analysis determined that the pilot's decision to fly below the prescribed minimum height to maintain visual contact with the terrain increased the risk of obstacle collision.

Findings

  • Failure to comply with minimum altitude regulations for VFR flight.
  • Inadequate flight planning and risk assessment regarding degraded meteorological conditions.
  • Flight indiscipline resulting from flying below the required height in an unfamiliar area with rough terrain.
  • Adverse weather conditions, specifically fog and low clouds, which influenced the pilot's low-altitude flight profile.
  • Improper decision-making regarding the assessment of inherent risks during the maneuver to avoid birds.

Probable cause

The accident was caused by the pilot's decision to fly below the regulatory minimum altitude to maintain visual conditions in degraded weather, which, combined with a low-altitude avoidance maneuver, led to a collision with power lines.

Frequently asked questions

What happened in the 2014-07-25 aircraft accident near NOVO PROGRESSO, PA, BR?

An AS 350 B2 helicopter struck a power grid while performing a low-altitude maneuver to avoid birds, resulting in substantial aircraft damage.

What aircraft was involved and where did it happen?

The accident on 2014-07-25 involved a aircraft, registration PRHSC, at NOVO PROGRESSO, PA, BR.

What was the probable cause of the accident?

The accident was caused by the pilot's decision to fly below the regulatory minimum altitude to maintain visual conditions in degraded weather, which, combined with a low-altitude avoidance maneuver, led to a collision with power lines.

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