Probe into Serious Runway Incident at Helsinki on January 18, 2019, Urges Analysis of Landing Clearance -related Risks
At approximately 1715 h on Friday, January 18, 2019, a Turkish Airlines flight landed on runway 22L at Helsinki-Vantaa airport and was followed one-and-a half minutes later by a Norwegian Air International airplane landing on the same runway. Traffic situation was normal for the time of the day, and visibility was good.
Observing the Turkish airplane in the process of vacating the runway, the controller cleared the Norwegian flight to land. The controller also cleared two Scandinavian Airlines flights to cross active runway 22L behind the Turkish airplane and prior to the landing of the Norwegian flight.
The Turkish airplane had slowed down markedly during rollout, and by the time the Norwegian flight was coming overhead the threshold, it was entirely on the exit taxiway. The Norwegian pilots considered the runway clear and concentrated on landing the airplane safely. Since the controllers were unable to positively determine whether the Turkish airplane was stationary or in motion, they told the Norwegian flight to go around.
The instruction was transmitted at a very late stage of the landing. The pilots did not hear the message since it was masked by loud automated height callouts. Instead of executing a go-around, the airplane landed normally and vacated the runway along the same exit taxiway as the Turkish Airlines flight.
Air traffic control classified the event as a serious incident, however the incident did not result in any damage or injuries.
The Safety Investigation Authority Finland (SIAF) issues three safety recommendations with the aim of preventing similar occurrences.
The first recommendation is related to the so-called principle of reasonable assurance.
An airplane may be cleared to land on an occupied runway when there is reasonable assurance that the runway is clear no later than the point in time when the landing airplane crosses the threshold. This principle will be valid only if two conditions are met; that is, if the controller monitors the situation actively and calls a go-around sufficiently early, and if the pilot complies with the instruction, and these conditions did not exist in the Norwegian case, explains SIAF’s Executive Director, professor Veli-Pekka Nurmi.
SIAF recommends that the Finnish Transport and Communications Agency Traficom and air traffic service providers (ANS Finland) embark on a joint long-term risk analysis of potential hazards associated with landing clearances that are based on reasonable assurance. The results would be used to revamp the existing procedures by eliminating the possibilities of inconsistent interpretation resulting from the way the conditions are presented in the present documents.
The recommended action would also offer an opportunity to provide guidance for situations and circumstances where a landing clearance could be issued on the basis of reasonable assurance, or when the controller should resort to another option, adds Nurmi.
The SIAF also recommends that ANS Finland pays attention to the voice modulation (tone and pitch) of controllers in transmitting immediate-action instructions. These guidelines should be laid down in an unambiguous manner and included in the controllers’ training and site-specific familiarization syllabi.
The pilots of the landing airplane simply did not hear the go-around instruction that was masked by sounds from onboard systems, explains Chief Safety Investigator Janne Kotiranta.
In the third safety recommendation the SIAF proposes that Traficom and ANS Finland jointly see that the controllers’ actions are in compliance with the existing instructions and clarify the definition of a vacated runway in national documents if necessary.
The regulations pertaining to vacating of the runway after landing are interpreted inconsistently in the Finnish controller community. An underlying safety management principle is that actions shall not contradict rules and regulations, and all instructions and regulations must be consistent, emphasizes Kotiranta.
Chief Safety Investigator Janne Kotiranta, tel. +358 2951 50703
Executive Director professor Veli-Pekka Nurmi, tel. +358 2951 50701