Worries about the plane flared up again after a door plug blew off a Max operated by Alaska Airlines, leading regulators to cap Boeing’s production at 38 jets per month. The NTSB plans to meet next Tuesday to discuss what investigators found about that incident.

The NTSB issued an “urgent safety recommendation” related to the engine on the 737 MAX after two incidents where smoke entered the cabin.

US safety investigators called for urgent actions to be taken in response to an engine issue on Boeing Co. 737 Max aircraft that can lead to smoke in the cockpit or cabin.