What happened
On August 9, 2022, an Airbus Helicopters AS350-B3, registration SE-JPI, was conducting a forest fire fighting mission near Sameiro, Guarda, Portugal. The aircraft, operated by Helibravo, was transporting a pilot and five GNR operatives from Seia to the Sameiro/Manteigas region.
Upon arriving at the operational site, the pilot identified a landing area that appeared suitable for disembarking the team. The pilot noted that the approach was performed within established speed and descent rate parameters, and the engine power appeared stable. However, during the final phase of the approach, specifically during the flare at approximately 5 to 6 meters above the ground, the pilot experienced a significant increase in the rate of descent.
In an attempt to mitigate the descent, the pilot applied collective pitch; however, this action did not reduce the descent rate and may have even worsened the situation. Fearing a catastrophic impact of the main rotor with the ground, the pilot pulled the cyclic back to adjust the aircraft's attitude. This resulted in the rear of the skids striking the ground violently. The impact triggered the Emergency Locator Transmitter (ELT) and caused significant damage to the aircraft's primary structure, specifically a fracture in the area where the tail boom joins the cabin.
The investigation
The GPIAAF investigation examined the aircraft's performance data, maintenance records, and environmental conditions. The investigation confirmed that the pilot held valid CPL(H) licenses and medical certificates, and that all flight time regulations were respected.
Analysis of the Vibration Engine Monitoring Unit (VEMD) showed that the engine was functioning correctly and that no engine exceedances or failures were recorded during the final 17 minutes of flight. The data indicated that the engine still had available power that could have been utilized. The investigation also noted that the aircraft was operating near its maximum takeoff weight on a hot day, which impacts performance.
Findings
- The aircraft was operating at a high gross weight, near its maximum takeoff limit, which reduces overall performance.
- The landing site was located in a leeward position relative to the mountain, which likely created turbulent air and downdrafts.
- The thermal load from the active forest fire, combined with the complex orography, contributed to an unstable atmosphere with significant vertical air movement.
- The pilot's decision to commit to the landing, combined with the high-risk environment, limited the options available to abort the approach when the descent rate increased.
- The primary cause of the incident was an inability to effectively control the aircraft during the final phase of the landing due to local environmental conditions.