What happened
On March 29, 2015, a Robinson R44 II helicopter, registration TG-POD, was performing a flight from Barillas toward Acul, Guatemala. During the flight, the pilot encountered degraded environmental conditions characterized by low clouds and fog, which are common in the mountainous terrain of the region. Due to the lack of visibility, the pilot was forced to perform a controlled descent to an emergency landing site in the Aldea Las Majadas area, within the municipality of Aguacatán.
The landing site was a steep slope with an inclination of approximately 25 degrees, containing several felled tree trunks. During the landing maneuver, the tail rotor blades struck one of these obstacles, causing the blades to fracture at the root. The impact also resulted in significant damage to the 90-degree gearbox and the tail boom. Despite the impact, the aircraft remained upright on its right skid, and the pilot and passenger sustained no injuries.
The investigation
The DGAC/UIA investigation focused on the aircraft's maintenance, the environmental conditions, and the pilot's decision-making. Investigators confirmed that the helicopter was properly maintained and compliant with all Guatemalan aviation regulations. The investigation also noted that the pilot had not filed a flight plan for the specific leg of the flight on the day of the accident, and there was no record of the aircraft's movement in air traffic control logs for that day.
Technical analysis of the wreckage showed that the tail rotor blades were destroyed by direct contact with a tree trunk. The damage to the tail boom and gearbox was consistent with the engine being under power at the moment of the tail rotor strike. Furthermore, the investigation examined the performance limitations of the aircraft at high density altitudes, noting that the landing occurred at an elevation of approximately 9,620 feet, with a density altitude of roughly 12,900 feet.
Findings
- The pilot's inadequate assessment of flight risks due to a lack of up-to-date meteorological information for the intended route.
- The decision to continue operations despite degraded environmental conditions.
- The pilot's failure to properly account for the aircraft's performance limitations at high density altitude, which significantly reduces engine power and affects hovering capabilities during approach and landing.
- The presence of obstacles (felled trees) on the emergency landing slope that contributed to the tail rotor strike.
- Inadequate knowledge of the specific terrain and landing area performance requirements.