WASHINGTON, June 18 (Reuters) - The National

Transportation Safety Board issued an urgent safety

recommendation Wednesday to address the possibility of smoke

entering the cockpit or cabin of Boeing 737 MAX airplanes

equipped with CFM International LEAP-1B engines.

The NTSB also recommended evaluating the potential for the

same issue with LEAP-1A and -1C engines. The recommendation

comes after two incidents involving a Southwest Airlines

Boeing 737 MAX in 2023. The NTSB wants the Federal Aviation

Administration to ensure that operators inform flight crews of

airplanes equipped with the affected engines.

Southwest ( LUV ) said it is reviewing the recommendations and that

it has mitigation procedures currently in place. Southwest ( LUV )

notified its flight crews about the effects of certain bird

strikes following two events that occurred in 2023, reiterating

the importance of following established safety procedures.

CFM LEAP engines are used on variants of Airbus A320neo

and Boeing 737 MAX. CFM, the world's largest engine maker by

units sold, is co-owned by GE Aerospace and Safran

.

The FAA said it and Boeing ( BA ) agreed with the NTSB

recommendations, and it alerted operators that smoke could enter

the flight deck following the activation of the Load Reduction

Device (LRD) in the engines, as a result of a bird strike.

"We advised operators to evaluate their procedures and

crew training to ensure they address this potential issue," the

FAA said. "When the engine manufacturer develops a permanent

mitigation, we will require operators to implement it within an

appropriate timeframe."

Boeing ( BA ), GE and Airbus did not immediately comment.

The NTSB asked the European Union Aviation Safety Agency

and the Civil Aviation Administration of China to determine if

other variants of the CFM LEAP engine are also susceptible to

smoke in the cabin or cockpit when an LRD activates.

In November,

the FAA said it would not require immediate

action after convening a review board to consider concerns

about Boeing 737 MAX engines after two bird strike incidents

involving the CFM LEAP-1B.

The FAA had been considering recommendations for new

takeoff procedures to close the airflow to one or both engines

to address the potential impact of a bird strike and prevent

smoke from entering the cockpit.

In 2024, the NTSB opened an investigation into the

Southwest ( LUV ) left engine bird strike and subsequent smoke in

cockpit event that occurred near New Orleans in December 2023.

The other incident occurred in a Southwest ( LUV ) March 2023

flight that had departed Havana and in which a bird strike led

to smoke filling the passenger cabin.

In February, 2024, Boeing ( BA ) published a bulletin to inform

flight crews of potential flight deck and cabin effects

associated with severe engine damage.