The U.S. National Transportation Safety Board (NTSB) has issued urgent safety recommendations regarding CFM International’s Leap-1B engines, warning that a vibration-reduction feature could fill Boeing 737 Max cockpits with smoke during certain engine failures. The alert comes after two documented incidents involving bird strikes that activated the system.
Critical Safety Flaw Identified
The NTSB’s investigation focuses on the engine’s Load Reduction Device (LRD), designed to minimize damage during severe fan imbalances. However, when activated, the system can allow engine oil to contact hot components, creating smoke that enters the aircraft through bleed air vents. In one 2023 Southwest Airlines case, pilots reported “acrid white smoke” that obscured their instruments shortly after takeoff from New Orleans.
International Regulatory Action Sought
Beyond the 737 Max’s Leap-1B engines, the NTSB has asked global aviation regulators to examine similar risks in Leap-1A (Airbus A320neo) and Leap-1C (Comac C919) variants. While the FAA previously deemed the issue non-critical, the safety board maintains that without corrective action, the flaw could compromise flight safety during emergency situations.
Airlines and Manufacturers Respond
Boeing and CFM confirm they are developing a software update to limit smoke production during LRD activation. American and Southwest Airlines have already revised pilot procedures, instructing crews to shut down affected engines immediately. However, pilot unions argue the current guidance leaves insufficient time to assess situations properly, potentially creating new risks.
Controversy Over FAA Inaction
The FAA’s 2024 decision not to mandate immediate fixes has drawn scrutiny, particularly after an internal safety panel recommended precautionary measures. The rejected proposal would have required 737 Max pilots to take off with the left engine’s bleed air system disabled—a move that would prevent cockpit smoke intrusion but reduce engine performance.
Path Forward for 737 Max Operators
With Boeing updating flight manuals and CFM working on technical solutions, airlines now face operational decisions about implementing interim safety measures. The NTSB emphasizes that while no accidents resulted from previous smoke events, the potential for impaired crew performance during critical flight phases warrants urgent attention.
