Investigation of serious incident on approach to Bergen airport Flesland, Norway, 20 January 2020 with DHC-8-300, LN-WFO

On approach to Flesland Airport on 20 January 2020, WF577 lost power on both engines after ice detached from the air inlet and entered the engine. The engines quickly restarted and the aircraft landed without problems. The most likely scenario is that the ice accumulated during flight because the aircraft inadvertently entered an area of severe icing with supercooled large droplets (SLD). The weather radar maps from the Meteorological Institute indicate that WF577 received a clearance after departure from Kvernberget which took the aircraft into an area with more icing than if the original flight plan had been followed. It has already been considered to establish a weather radar in Oslo TMA which will be integrated into the new "en route system" (iTEC). NSIA believes that this should also be considered for other areas in Norway, and especially in the north-west region. Being able to provide weather information in real time will make an important contribution to increased flight safety

The Norwegian Safety Investigation Authority recommends that the Norwegian Civil Aviation Authority implement a project in which Avinor, Norwegian Meteorological Institute and representatives from a suitable airline participate to assess possible solutions on presentation of updated (live) weather information that can be communicated to relevant flights.

On approach to Flesland Airport on 20 January 2020, WF577 lost power on both engines after ice detached from the air inlet and entered the engine. The engines quickly restarted and the aircraft landed without problems. The most likely scenario is that the ice accumulated during flight because the aircraft inadvertently entered an area of severe icing with supercooled large droplets (SLD). Although the DHC-8 300 is not certified to fly in such conditions, the pilots should be warned about the potentially serious consequences of ice accumulation in the air inlet.

The Norwegian Safety Investigation Authority recommends that Transport Canada (TC) assures that De Havilland includes a warning in the Airplane Flight Manual (AFM) in which users are informed that the engines may flame out if an aircraft inadvertently flies into severe icing conditions. Ice can build up in the air inlet and subsequently detach and enter the engine.

On approach to Flesland Airport on 20 January 2020, WF577 lost power on both engines after ice detached from the air inlet and entered the engine. The engines quickly restarted and the aircraft landed without problems. The investigation has identified an inconsistency between the definition of severe icing and meteorological forecasts. The definition of icing intensity contains no reference to atmospheric variables related to icing.

The Norwegian Safety Investigation Authority recommends that EASA clarifies the inadequate definitions as well as the existing inconsistency relating to icing problems and ensure that the results are harmonised with other international authorities.