Casualties unknown

2011-12-26: HELIO COURIER HT 295 (HC-B3Z20) — EC

EC

On December 26, 2011, a HELIO COURIER HT 295 (registration HC-B3Z20) was involved in an aviation accident near EC. Investigators recorded the probable cause as: The accident was caused by the failure of the right main landing gear axle resulting from material fatigue, exacerbated by the high structural stresses imposed by operating on irregular, unpaved runway surfaces. This summary draws on records from the Ecuadorian Civil Aviation Directorate (DGAC Ecuador).

Sourcesthe Ecuadorian Civil Aviation Directorate (DGAC Ecuador)Primary reportUpdated 1781086949Data APIEditorial standards

A fatigue-induced failure of a main landing gear axle caused a Helio Courier to veer off the runway at Nuevo Canuza, resulting in propeller damage but no injuries.

What happened

On December 26, 2011, a Helio Courier HT-295 was performing its second flight of the day on a route between Sucúa and Nuevo Canuza. The aircraft was carrying a pilot and five passengers, including three children.

Upon landing on runway 08 at Nuevo Canuza at 16:45 UTC, the aircraft began its landing roll. Approximately 175 meters after touchdown, the axle of the right main landing gear fractured. This caused the wheel to detach, which subsequently struck the propeller, bending one of the blades and breaking the brake line. The loss of the wheel caused the aircraft to veer sharply to the right, eventually coming to a halt transverse to the runway. Despite the impact and the sudden change in direction, there were no injuries to the pilot or the five passengers.

The investigation

The investigation focused on the mechanical failure of the landing gear and the maintenance history of the aircraft. Investigators examined the right main landing gear strut and identified that the wheel axle had sheared at its root. Physical examination of the fracture surface revealed clear evidence of material fatigue.

While the aircraft's maintenance records showed a recent 100-hour inspection completed on December 21, 2011, investigators noted that the manufacturer's maintenance program only requires a visual inspection of the landing gear. The investigation also found that the runway surface at Nuevo Canuza was uneven, containing puddles and mud, which subjects landing gear to higher structural stresses than prepared runways.

Findings

  • The primary cause of the accident was the fracture of the right main landing gear axle due to material fatigue.
  • The irregular and unpaved nature of the runway surface increased the mechanical stress on the landing gear components.
  • The existing maintenance program did not require specific non-destructive testing (NDT) or specialized inspections for the wheel axles, relying instead on visual checks.
  • Although not directly related to the excursion, investigators noted secondary maintenance deficiencies, including a deteriorated seatbelt in the rear of the cabin and an improperly secured fuselage panel.

Probable cause

The accident was caused by the failure of the right main landing gear axle resulting from material fatigue, exacerbated by the high structural stresses imposed by operating on irregular, unpaved runway surfaces.