What happened
On September 1, 2015, a Robinson R44 II helicopter, registration TG-POD, performed an emergency landing in the vicinity of Aldea El Piol, within the municipality of San Sebastián, Huehuetenango, Guatemala. The aircraft was conducting a flight when the pilot was forced to descend toward a small road to avoid obstacles, including trees and cornfields. During the landing maneuver, the main rotor blades struck the ground, causing substantial damage to the rotor system, the cabin, and the tail boom. The pilot and passengers sustained no injuries.
The investigation
The DGAC/UIA investigation established that the aircraft was airworthy and maintained in accordance with Guatemalan regulations. The investigation focused on the sequence of events leading to the loss of engine power. It was determined that promotional flyers had been released inside the cabin and subsequently drifted into the engine's cooling system, causing the engine to overheat.
Furthermore, the investigation examined the refueling process, finding that the aircraft had been provided with the incorrect type of fuel. The investigation also noted that the pilot's decision-making was compromised by fatigue, as the pilot had been pressured to fly following an excessively long workday. Additionally, the investigation found that the pilot in command relinquished control of the aircraft during the critical phases of the emergency landing.
Findings
- The primary cause of the power loss was a combination of incorrect fuel grade being provided during refueling and engine overheating caused by debris (flyers) obstructing the cooling system.
- The pilot's ability to assess risks was impaired by fatigue.
- The lack of supervision during the refueling process allowed the use of improper fuel.
- The emergency landing area was constrained by obstacles, contributing to the loss of control during the final approach.
- The main rotor blades were destroyed upon direct impact with the terrain.