What happened
On the evening of January 18, 2019, a serious runway incursion occurred on runway 22L at Helsinki-Vantaa Airport. The sequence began with the arrival of a Turkish Airlines Boeing 737-900 (TC-JYH), followed approximately 90 seconds later by a Norwegian Air International Boeing 737 MAX 8 (EI-FYA).
Prior to the arrival of the Turkish Airlines flight, air traffic control (ATC) had authorized two SAS flights to cross runway 22L via taxiway Y and taxiway ZD following the departure of the Turkish aircraft. As the Turkish Airlines flight slowed significantly on the runway and began turning onto taxiway ZJ, the controller observed the SAS aircraft crossing the active runway.
As the Norwegian Air International flight approached the runway threshold, the controller, uncertain if the Turkish Airlines aircraft had fully vacated the runway due to its extremely low speed, issued a go-around command. The command was issued twice within a single radio transmission. However, the crew of EI-FYA did not respond to the instruction. At the time of the command, the aircraft was at an altitude between 30 and 50 feet, and the cockpit's automated radio altitude call-out system was announcing height increments every 10 feet. Consequently, the crew continued a normal landing, eventually following the Turkish Airlines aircraft onto the same taxiway.
The investigation
The investigation examined the sequence of events, the effectiveness of the ATC commands, and the cockpit environment. Investigators analyzed radar data, radio communications, and the aircraft's automated systems. The investigation also reviewed the interpretation of runway vacancy procedures among Finnish air traffic controllers and the impact of cockpit audio environments on command reception.
Findings
- The primary cause of the missed command was that the go-around instruction was masked by the aircraft's automated radio altitude call-out system, which was announcing height values (50-40-30 feet) at the same time the controller spoke.
- The crew of EI-FYA was focused on the landing and visually confirmed the runway appeared clear, as the Turkish Airlines aircraft was already partially off the runway surface.
- There is a lack of uniformity in how runway vacancy instructions are interpreted within the Finnish air traffic control community, with some local practices deviating from international standard manuals.
- The low speed of the preceding aircraft (TC-JYH) created uncertainty for the controller regarding whether the runway was truly clear.