What happened
On January 23, 2018, a Robinson R44 II helicopter, registration PP-HLI, crashed into the sea near Pina Beach in Recife, Brazil. The aircraft was performing a local flight for a television channel to capture aerial imagery of the metropolitan area. Approximately fifteen minutes after departing from Guararapes - Gilberto Freyre International Airport, the aircraft entered a downward trajectory and struck the water. The impact destroyed the aircraft, and the pilot and two passengers sustained fatal injuries.
The investigation
CENIPA, with participation from the NTSB, examined the wreckage and the maintenance history of the aircraft. The investigation focused on the main rotor blades (S/N 6128 and S/N 6131). Investigators discovered that an unauthorized filler material had been injected into the blades. Laboratory analysis revealed that this material was not a standard factory component and was likely applied to mask a void. The presence of corrosion on the metal surfaces beneath this filler indicated that the material was applied after the skin had already begun to separate from the end cap, which allowed moisture to enter and accelerate the degradation of the original adhesive.
Findings
- The primary cause of the accident was a structural failure of the main rotor blades.
- The upper skin of the red blade (S/N 6128) peeled away due to the separation of the skin from the blade core.
- An unapproved repair attempt using a non-standard filler material acted as a wedge, forcing the skin away from the end cap and accelerating the debonding process.
- The application of the filler material likely occurred between the aircraft's last 100-hour inspection and its last annual inspection, shortly before the accident.