What happened
On the evening of October 5, 2004, at Prague/Ruzyně Airport (LKPR), a Fairchild SW4 aircraft, registration OY NPA, operating for North Flying, was taxiing toward a holding position near Runway 13. Due to scheduled maintenance, a portion of Runway 24 was closed, and the aircraft was instructed to taxi via Taxiway L, C, and Runway 24 to hold short of Runway 13.
While taxiing, the crew of OY NPA approached the intersection of Runway 13 and Runway 24. At approximately 19:19 UTC, the aircraft crossed the intersection and entered the active Runway 13. At that moment, a Fokker F27, registration HA-FAE, was on short final for landing, approximately 1 km from the threshold. Upon realizing the incursion, the pilot of OY NPA immediately attempted to vacate Runway 13 by crossing into the closed section of Runway 24. The aircraft eventually stopped after crossing red warning lights, but the incident constituted a serious runway incursion.
The investigation
The ÚZPLN investigation examined the crew's actions, air traffic control (ATC) instructions, and the airport's lighting and marking configuration. The investigation established that the ground controller (GEC) and Tower controller (TEC) had issued correct instructions to hold short of Runway 1 and that the phraseology used was in compliance with standard procedures.
Investigators found that at night, the edge lights for Runway 13 were difficult to discern from the pilot's perspective when approaching from the intersection. Furthermore, the crew had misinterpreted the red warning lights marking the closed portion of Runway 24 as stop bars, which influenced their decision-making regarding the holding position.
Findings
- The primary cause of the incursion was inadequate marking of the designated holding position and the use of red warning lights for the closed section of Runway 24, which led the crew to deviate from instructions.
- The configuration of the red warning lights, combined with active runway edge lights, caused the crew to misidentify the correct location to stop.
- Visual identification of the Runway 13 edge was significantly hindered by the nighttime conditions and the specific lighting layout at the intersection.
- The ATC instructions to hold short were issued timely and used correct phraseology.