NTSB Calls for Increased Attention to CFM LEAP Safety System

NTSB Calls for Increased Attention to CFM LEAP-1B Safety System

Concerns Over Cockpit Smoke Risk Prompt Regulatory Action

The National Transportation Safety Board (NTSB) has urged the Federal Aviation Administration (FAA) to enhance pilot awareness regarding a safety mechanism in CFM International’s LEAP-1B engines, following incidents where activation of the system resulted in smoke entering the cockpit. The board has also called for expedited regulatory approval and mandatory implementation of a software update intended to mitigate this risk.

In its final report released on June 18, the NTSB expressed concern that pilots operating Boeing 737 MAX aircraft may lack a full understanding of the load reduction device (LRD) and the implications of its activation. The LRD is engineered to separate the engine’s fan rotor from the remainder of the engine in cases of severe fan damage, such as from bird strikes, to prevent further structural failure. However, this separation can cause oil to enter the engine’s airflow, which in turn channels smoke and fumes into the bleed air system supplying the cockpit and cabin.

This issue gained urgency following two bird strike incidents involving Southwest Airlines 737-8 aircraft in March 2023 near Havana and December 2023 near New Orleans. Both events triggered the LRD and led to smoke infiltrating the cockpit. In response, Boeing updated its pilot instructions and revised the flight crew operations manual (FCOM) in 2024 to include procedures aimed at reducing smoke exposure.

Despite these revisions, the NTSB found that some pilots remain unaware of the incidents and the specific protocols, raising concerns about their readiness during critical flight phases such as takeoff and landing. The board emphasized the necessity of ensuring that pilots operating aircraft equipped with LEAP-1B engines are fully informed about the potential for smoke in the cockpit if the LRD activates during crucial moments of flight.

Industry Response and Future Safety Measures

To address the hazard, Boeing and CFM International are developing a software modification expected to be available by early 2026. This update will automatically close a valve designed to limit the ingress of smoke into the cockpit and cabin. The NTSB has issued an urgent recommendation for the FAA to mandate this software change across the entire 737 MAX fleet, which exclusively uses LEAP-1B engines, and to ensure comprehensive pilot briefings on the updated procedures.

The NTSB’s intensified scrutiny may increase regulatory pressure on CFM International and its airline customers. Industry analysts suggest that some carriers might consider alternative engine options to avoid operational disruptions, potentially influencing market competition. Rival manufacturers could capitalize on this by highlighting their engines’ durability and safety features, as demonstrated by General Electric’s recent GE9X dust-ingestion tests, reflecting a broader industry emphasis on engine reliability.

As the aviation industry confronts these challenges, the NTSB’s recommendations highlight the critical importance of clear communication, prompt regulatory intervention, and continuous technological innovation to uphold the safety and dependability of next-generation aircraft engines.