What happened
On September 3, 2009, at approximately 22:00 UTC, an EC120B helicopter, registration PR-JMM, was performing a night approach to the parking area (spot "C", patio 6) at Guarululos Airport (SBGR), Brazil. The flight, operated by Helibras, was transporting one pilot and two passengers from Heliponto América Business (SDKD).
During the final approach, the aircraft struck a 6-meter-tall prospecting tower positioned adjacent to the landing spot. The impact caused a noticeable jolt to the underside of the helicopter, but the pilot maintained control of the aircraft. Following the impact, the pilot proceeded to land at Heliponto Helicidade (SIBH). After disembarking the passengers, the pilot did not shut down the engine or perform a visual inspection of the airframe. It was only after the engine was stopped that the pilot noticed a dent in the tail cone.
The investigation
CENIPA's investigation focused on the circumstances leading to the collision and the subsequent handling of the aircraft. Investigators found that the weather at the time included moderate rain, a ceiling of 1,000 feet, and visibility between 3,500 and 4,000 meters, which likely hindered the pilot's ability to identify obstacles during the night approach.
The investigation also revealed that the prospecting tower was placed in an area incompatible with active aircraft maneuvering and was not properly marked or identified via NOTAM. Furthermore, the investigation highlighted that the pilot failed to report the occurrence to the aeronautical authorities as required by law and performed a subsequent flight the following day without a technical assessment of the aircraft's airworthiness. A technical analysis by the manufacturer later determined that the impact force had caused structural torsion at the junction of the tail boom and the central structure, necessitating a full replacement of the tail boom assembly.
Findings
- Inadequate obstacle marking: The positioning of the prospecting tower near an active maneuvering area was unsafe, and the lack of signaling or a NOTAM prevented the crew from identifying the hazard.
- Adverse weather conditions: Night operations combined with moderate rain and reduced visibility contributed to the difficulty in detecting the obstacle.
- Failure to inspect: The pilot did not perform a visual inspection of the aircraft immediately following the impact, which prevented the early identification of the damage.
- Regulatory non-compliance: The pilot failed to report the occurrence to the appropriate authorities and did not record the damage in the aircraft's logbook as required.