Incident Overview
On January 7, 2009, at 16:10 UTC, a Eurocopter EC 120 B Colibri, registration CS-HEX, operated by Heliportugal, was involved in an incident at Cascais Aerodrome (LPCS). The helicopter was on an operational flight with three persons on board (one crew and two passengers). No injuries were reported and the aircraft sustained no damage. Weather conditions were favorable for VFR flight, with visibility exceeding 10 km and wind from northeast at 15 to 19 knots.
Sequence of Events
The pilot held a valid CPL (H) license. The mission took place under favorable weather conditions, and no anomalies were reported with the helicopter or its equipment. The helicopter was fitted with skids. The aerodrome had no published air-taxiways.
Ground control authorized CS-HEX to taxi to taxiway (J) and hold position without entering the runway. During air-taxi, the helicopter was instructed to change to Tower frequency. The pilot landed the helicopter at the intersection of taxiway (W) and taxiway (J) to change frequency safely.
Initial instructions from Tower, "hold short of the runway," were given very quickly and not understood by the pilot. The Tower repeated the instructions, and the pilot read them back correctly. However, the pilot interpreted the Tower's instructions as authorization to approach the runway. Subsequently, the helicopter passed the runway holding position and entered the runway protection area. The Tower alerted the pilot, who promptly corrected the maneuver and moved back.
Probable Cause
The incident was due to the pilot's misinterpretation of the Tower's instructions.