What happened
On March 5, 2021, a Pilatus PC-12/47E, registration HB-FRP, was performing a positioning flight from Buochs to Payerne. During the taxi phase, the pilot activated the signaling system to manage the crossing of a cantonal road via Taxiway D. The pilot proceeded at approximately 20 km/ and observed the aircraft's signal change from red to green.
As the aircraft approached the intersection, a car traveling at approximately 75 km/h from the direction of Ennetbürgen entered the crossing. The driver noticed the red traffic light only moments before passing the intersection and was unable to stop in time. The right side of the vehicle struck the rotating propeller tips of the PC-12/47E. The pilot immediately brought the aircraft to a halt, and no injuries were reported for the pilot or the driver.
The investigation
SUST examined video recordings of the collision, signal system logs, and statements from the pilot and the driver. The investigation confirmed that the signaling system, which includes lights for both aircraft and road traffic, was functioning as designed. The investigation also reviewed the physical layout of the intersection, noting that while some airport crossings are secured with barriers, this specific intersection relies solely on light signals and warning signs.
Findings
- The primary cause of the collision was that the driver perceived the red traffic light too late to perform an effective braking maneuver.
- A contributing factor was the inadequate protection of the intersection, as the crossing lacks physical barriers to prevent unauthorized vehicle entry.
- The driver was traveling at a speed of approximately 75 km/h, while the permitted limit for that section of the road is 80 km/h.
- The aircraft propeller sustained damage to five blade tips, and the vehicle sustained damage to its right side.
Safety action
SUST issued a safety recommendation (No. 576) stating that the Nidwalden Office of Mobility, in coordination with relevant cantonal and federal authorities, should implement measures to reduce the risk of collisions between road users and aircraft at the intersections of Taxiways C and D with the cantonal road.