NTSB Issues Urgent Safety Recommendations for LEAP-1B Engines After Smoke Incidents

The National Transportation Safety Board (NTSB) has issued an urgent safety recommendation following two serious incidents involving CFM International LEAP-1B engines, which are used on Boeing 737 MAX aircraft. The advisory highlights the risk of smoke entering the cockpit or cabin when these engines are damaged, particularly after bird strikes.

The NTSB’s investigation stems from two 2023 events involving Southwest Airlines flights. In March, a flight departing Havana, Cuba, experienced vapor fog in the cabin after birds were ingested into the right engine. In December, a similar bird strike on departure from New Orleans led to thick, acrid smoke filling the flight deck, impairing the captain’s visibility. In both cases, crews returned safely without injuries.

The issue centers on the Load Reduction Device (LRD), a safety feature designed to reduce engine vibration after damage. The NTSB found that LRD activation can inadvertently damage the engine’s oil system, allowing hot oil smoke to enter the aircraft’s ventilation system.

In response, the NTSB has recommended that the Federal Aviation Administration (FAA) ensure all operators of affected aircraft inform flight crews about the hazard and update procedures accordingly.  Boeing has already revised flight manuals, and CFM International is developing a software update to mitigate the issue.

The NTSB also urged the European Union Aviation Safety Agency (EASA) and the Civil Aviation Administration of China (CAAC) to evaluate whether other LEAP engine variant, LEAP-1A and -1C, used on Airbus A320neo aircraft may be similarly vulnerable.