The National Transportation Safety Board warned that certain CFM engines installed in some Boeing 737 Max jets may feed smoke into the cockpit or cabin after a bird strike.

The recommendations were inspired by two incidents on Southwest Airlines flights, when engines malfunctioned after bird strikes and poured smoke into the cabins.

The NTSB has called on Boeing and engine-maker CFM to implement a software fix for Boeing 737 Max LEAP‑1B engines to prevent smoke from entering the cockpit.