London CNN Business  — 

Discount carrier Norwegian Air will stop flying routes between Ireland and North America in the wake of the grounding of the Boeing 737 Max aircraft.

The decision, effective September 15, was taken after the airline concluded the routes were “no longer commercially viable,” the company said in a press release.

Norwegian cited the global grounding of the Boeing 737 MAX and uncertainty over when it would return to service as a key factor.

The 737 Max was pulled out of service after two crashes killed 346 people, costing Boeing billions of dollars and causing problems for airlines around the globe.

Norwegian is seeking compensation from Boeing over lost flight time affecting its fleet of 18 of the planes.

The carrier said that six routes from the Irish cities of Dublin, Cork and Shannon to the United States and Canada will be discontinued.

“Since March, we have tirelessly sought to minimize the impact on our customers by hiring replacement aircraft to operate services between Ireland and North America,” said company executive Matthew Wood.

“However, as the return to service date for the 737 MAX remains uncertain, this solution is unsustainable.”

Customers with existing bookings will be rerouted onto other services and full refunds will be offered if they no longer want to travel.

The airline is working to ensure the impact on staff is minimal.

“We are proactively engaging with our pilots and cabin crew at our Dublin base, including their respective unions, to ensure that redundancies remain a last resort,” said Wood.

CEO Bjorn Kjos stepped down in July.

Norwegian has made a name for itself by offering discounted flights within Europe and to the United States, Asia, and Latin America.

However the company’s future has been called into question after a rapid expansion left it in debt. In January, it sought to raise 3 billion Norwegian kroner ($352 million) to shore up finances.

Chief executive Bjoern Kjos stepped down in July, 17 years after founding the company that he still partially owns.

Kjos will continue working as an adviser to the airline’s chairman, focusing on industry alliances and building on a recent agreement with rival EasyJet (ESYJY).