What happened
On July 30, 2003, at approximately 12:30 UTC, a heavy MI-8 MTV helicopter, registration UR-UHD, was performing an approach to the helicopter parking area at the Ferreira do Zêzere Municipal Aerodrome. The helicopter, operated by Aeronorte in support of the National Fire and Civil Protection Service, was approaching from the south to position a reserve bucket for firefighting operations.
As the helicopter flew at a low altitude over the area, the airflow generated by its large main rotor, combined with ground effect and a crosswind from the right, struck a parked Rand-Kar X-Air ultralight, registration CS-UJN. The force of the rotor wash pushed the ultralight across the apron and into a hangar, causing the aircraft to strike the ground and the building. The impact resulted in significant damage to the ultralight's engine, propeller, and the fabric covering of the fuselage, wings, and control surfaces. The hangar's gate and wall also sustained damage. There were no injuries to the helicopter crew or any other individuals.
The investigation
The GPIAAF investigation established that the helicopter crew was unable to establish two-way radio communication with the ground operator because the operator was occupied with a telephone call to the National Emergency Operations Center. Consequently, the crew was unaware of the ultralight's presence in the parking area. The investigation also noted that while the aerodrome was approved for both ultralight operations and heavy helicopter firefighting missions, it lacked specific regulatory procedures for managing simultaneous activities.
Findings
- The primary cause of the incident was the airflow generated by the main rotor of the MI-8 helicopter during its approach, which projected the ultralight into the hangar.
- The lack of established regulatory procedures for air traffic at the aerodrome acted as a contributing factor.
- The helicopter crew performed a low-altitude flyover of the ultralight parking area without visibility of the parked aircraft due to obstruction by a building.
- The ground operator's inability to communicate with the incoming aircraft prevented the warning of the parked ultralight's location.
Safety action
- The investigator recommended that the Director of the Ferreira do Zêzere Municipal Aerodrome establish specific operating procedures to restrict or condition helicopter approaches over the ultralight parking area.