Regulations & Safety
NTSB Urges LEAP-1B Engine Fixes After Smoke Incidents
Safety alert issued for Boeing 737 MAX engines after bird strikes caused cockpit smoke via Load Reduction Device flaws. Software and design updates in progress.
Smoke Risk in LEAP-1B Engines: NTSB Issues Urgent Safety Recommendations
On June 18, 2025, the National Transportation Safety Board (NTSB) issued an urgent safety recommendation concerning CFM International LEAP-1B engines. These engines, a cornerstone of modern commercial aviation, are used on Boeing 737 MAX aircraft and have logged over 1.5 million flight hours. The recommendation follows two serious incidents in which smoke entered the cockpit and cabin after bird strikes triggered a safety mechanism known as the Load Reduction Device (LRD).
The NTSB’s findings point to a potentially systemic issue in the design of the LRD, which, though intended to reduce engine damage during emergencies, can inadvertently allow hot oil to leak into the aircraft’s ventilation system. This has raised red flags across the aviation industry, prompting calls for immediate action from aircraft manufacturers, engine developers, and international aviation regulators.
Given the widespread use of LEAP engines across Airbus A320neo, Boeing 737 MAX, and COMAC C919 aircraft, the implications of this safety concern are far-reaching. This article delves into the technical background, incident analysis, and the broader impact of the NTSB’s recommendations on aviation safety and operations.
Understanding the Load Reduction Device and Its Risks
The Intended Function of the Load Reduction Device (LRD)
The Load Reduction Device (LRD) is a mechanical safety feature built into the LEAP-1B engine. It is designed to activate automatically during severe engine imbalances, such as those caused by fan blade failures or bird strikes. When triggered, the LRD decouples the fan from the engine core to minimize vibrations that could otherwise damage the airframe or engine mounts.
This system is a product of lessons learned from over a billion flight hours on the CFM56 engine family. Its primary goal is to enhance safety without requiring pilot intervention, especially during critical phases of flight like takeoff and landing. However, despite its safety-driven design, the LRD has introduced a new and unanticipated hazard.
Investigations revealed that LRD activation can dislodge oil-supply tubes or fracture engine sump flanges. This allows engine oil to enter areas of high temperature, where it vaporizes and is then carried into the aircraft’s ventilation system via bleed air ports, resulting in smoke in the cockpit and cabin.
“What was once considered a fail-safe mechanism now presents a potentially serious hazard under specific but foreseeable conditions,”, NTSB report, June 2025.
Case Studies: Southwest Airlines Incidents
Two Southwest Airlines flights in 2023 serve as case studies for the LRD-related smoke hazard. In December, Flight 554 departed from New Orleans when a bird strike led to LRD activation. Within seconds, thick white smoke filled the cockpit, impairing the pilot’s visibility. The crew managed to return safely, but the NTSB noted that the 10–15 second delay in manually shutting off the engine bleed valve was a critical vulnerability.
Earlier that year, in March, a similar incident occurred on Flight 392 departing from Havana. A bird strike on the right engine led to LRD activation and subsequent vapor fog entering the passenger cabin. Passengers reported a chemical-like odor and visible haze. The crew declared an emergency and returned without injuries, but the incident reinforced concerns about the LRD’s unintended consequences.
Both incidents highlighted that while the LRD effectively mitigated engine damage, it introduced a new risk by enabling smoke to enter occupied areas of the aircraft. The NTSB emphasized that bird strikes are not rare, occurring roughly every 2,000 flights globally, and must be accounted for in engine safety systems.
Technical Analysis and Design Implications
The NTSB’s technical analysis found that oil leakage into the high-pressure compressor, where temperatures can exceed 500°F, results in rapid vaporization. This vapor is then distributed through the aircraft’s ventilation system, which draws bleed air from the engine. The system’s reliance on manual intervention to shut off the bleed valve poses a safety concern, particularly during high workload periods like takeoff.
CFM and Boeing have proposed a two-phase solution. The short-term fix involves a software update that automatically closes the bleed valve upon LRD activation. The long-term solution includes redesigning the oil-supply tube anchorage and sump sealing mechanisms to prevent displacement during LRD events.
These solutions aim to eliminate the delay in pilot response and reduce the likelihood of smoke entering the aircraft. However, implementation will require regulatory approval, certification, and fleet-wide retrofitting, which could be both time-consuming and costly.
Industry Response and Broader Implications
Regulatory and Manufacturer Actions
Following the NTSB’s urgent recommendation, the Federal Aviation Administration (FAA), European Union Aviation Safety Agency (EASA), and the Civil Aviation Administration of China (CAAC) have been asked to evaluate the risk across all LEAP engine variants, including the LEAP-1A and LEAP-1C used on Airbus and COMAC aircraft, respectively.
Boeing has revised its Flight Crew Operations Manual (FCOM) and Quick Reference Handbook (QRH) to include new procedures for managing LRD-related smoke events. These revisions instruct pilots to immediately close the engine bleed valve and initiate emergency descent protocols if necessary.
Training simulators are being updated to include LRD-specific scenarios, and operators are being urged to brief flight crews on the new procedures. The NTSB stressed that awareness and preparedness are crucial, especially given that many pilots were previously unaware of the LRD’s potential to cause smoke ingress.
Economic and Operational Impact
Retrofitting the existing fleet of over 1,200 Boeing 737 MAX aircraft with the proposed software update is estimated to cost $150,000 per engine, amounting to approximately $360 million. Additional downtime during modifications could cost airlines an estimated $1.2 million per day in lost utilization.
Despite these costs, industry analysts suggest that proactive compliance with the NTSB’s recommendations may help mitigate reputational damage for both Boeing and CFM. The joint venture between GE Aerospace and Safran Aircraft Engines has committed to implementing the changes and supporting operators throughout the transition.
Beyond financial implications, the issue underscores the importance of comprehensive risk modeling in engine design. As aircraft systems become more complex, ensuring that safety features do not introduce new hazards is a critical challenge for manufacturers and regulators alike.
Future Directions and Safety Innovations
The LEAP engine’s LRD issue offers valuable lessons for future engine development. One potential area of innovation is the integration of real-time oil leak detection systems, which could provide early warnings before smoke enters the aircraft.
The incident also highlights the need for harmonized global regulations. As the aviation industry becomes increasingly interconnected, ensuring consistent safety standards across regions is essential. The International Civil Aviation Organization (ICAO) may play a key role in standardizing LRD-related procedures.
Looking ahead, resolving the LRD issue could set a new benchmark for fail-safe design in next-generation propulsion systems, including those powered by sustainable aviation fuels or hydrogen. The aviation industry must balance innovation with rigorous safety validation to maintain public trust and operational reliability.
Conclusion: A Turning Point in Engine Safety
The NTSB’s urgent recommendation concerning LEAP-1B engines marks a pivotal moment in aviation safety. While the LRD was designed to protect aircraft from structural damage, its unintended consequence, smoke ingress, revealed a critical vulnerability. The incidents involving Southwest Airlines flights underscore the importance of continuous monitoring, evaluation, and adaptation in aerospace engineering.
As regulatory agencies, manufacturers, and operators work together to address the issue, the aviation industry is reminded that even the most well-intentioned safety features require thorough testing under all plausible scenarios. The resolution of the LRD flaw will not only restore confidence in the LEAP engine family but also inform the design of future propulsion systems.
FAQ
What is the Load Reduction Device (LRD)?
The LRD is a mechanical safety feature in LEAP engines that decouples the fan from the engine core during severe imbalances to reduce vibration and prevent structural damage.
Why is smoke entering the cockpit and cabin?
When the LRD activates, it can dislodge oil-supply tubes, allowing oil to enter hot engine areas and vaporize. This vapor can then be circulated into the cockpit and cabin via the bleed air system.
What actions are being taken to resolve the issue?
Boeing and CFM are developing a software update to automatically close bleed valves upon LRD activation and are redesigning certain engine components. Regulatory agencies are evaluating similar risks in other LEAP engine variants.
Sources: NTSB Press Release, NTSB Investigation Report, NTSB Docket DCA24LA330
Photo Credit: NTSB
Regulations & Safety
FAA Proposes Supersonic Noise Standard to Repeal 1970s Ban
The FAA announced noise-based certification standards for supersonic overland flight on June 30, 2026, targeting final rules by mid-2027.
The Federal Aviation Administration (FAA) has proposed a new noise-based certification standard for supersonic aircraft, initiating the formal regulatory process to repeal the 1970s ban on commercial supersonic flight over United States territory.
Announced on June 30, 2026, by U.S. Transportation Secretary Sean P. Duffy and FAA Administrator Bryan Bedford, the rulemaking aims to establish acceptable noise thresholds for overland flights. The proposal provides aerospace Manufacturers with the regulatory framework required to finalize next-generation supersonic designs that utilize quiet boom and “Mach cutoff” technologies.
Regulatory framework and timeline
The initial proposal focuses on noise-based certification standards during cruise flight. According to the FAA press release, the agency plans to introduce a second rule covering landing and takeoff noise standards later in 2026. The FAA has set a target date of mid-2027 to finalize both sets of rules.
U.S. Transportation Secretary Sean P. Duffy characterized the initiative as a move to safely enable the next quantum leap in aviation technology. FAA Administrator Bryan Bedford noted that advances in aerospace engineering, materials science, and noise reduction will eliminate the traditional sonic boom.
“This means we can ultimately repeal the ban from the 1970s on supersonic flight over U.S. territory while minimizing noise impacts to residents in communities along the route and near airports,” Bedford stated.
The White House Office of Science and Technology Policy (OSTP) is also involved in the initiative. OSTP Director Michael Kratsios stated that the updated rules will strengthen the industrial base and ensure the future of aviation is built in America.
Technological foundations and industry response
The June 30 announcement follows a series of preparatory steps by both regulators and the aerospace industry. On January 27, 2026, the FAA unveiled a new agency structure that included the creation of the Office of Advanced Aviation Technologies, a division specifically tasked with overseeing the integration of supersonic aircraft into U.S. airspace.
The technical basis for the new noise thresholds draws on data from the NASA and Lockheed Martin X-59 quiet supersonic research aircraft. The X-59 completed its First-Flight on October 28, 2025. The aircraft was explicitly designed to reduce sonic booms to a gentle thump, providing regulators with the acoustic data necessary to establish new overland flight standards.
Commercial developers have responded positively to the regulatory clarity. Boom Supersonic CEO Blake Scholl confirmed that the FAA rulemaking includes provisions for the “Boomless Cruise” or Mach cutoff approach. Boom has been demonstrating this operational concept with its Boom XB-1 test aircraft. Scholl described the FAA announcement as a major step toward the supersonic renaissance.
AirPro News analysis
We view the establishment of a definitive noise standard as the single most significant regulatory hurdle for the revival of commercial supersonic travel. For the past several years, manufacturers have been developing quiet supersonic technologies without a finalized target for acceptable noise levels. By defining the Certification standards, the FAA is shifting the primary challenge for companies like Boom Supersonic from regulatory uncertainty to engineering execution. The mid-2027 target for finalizing both cruise and terminal area noise rules sets a tight timeline, but it aligns with the development schedules of the next-generation supersonic aircraft currently in testing.
Sources: Federal Aviation Administration
Photo Credit: Boom Supersonic
Regulations & Safety
Pilatus PC-6 Crash in France Kills 11 on Skydiving Flight
A Pilatus PC-6 crashed near Nancy-Essey aerodrome on June 28, 2026, killing all 11 aboard in France’s deadliest skydiving accident in 30 years.
This is a developing story. Information may change as official details are released.
This article summarizes reporting by the Associated Press, Reuters, and CBS News, alongside official statements from the Bureau d’Enquêtes et d’Analyses pour la Sécurité de l’Aviation Civile (BEA).
Eleven people sustained fatal injuries on June 28, 2026, when a Pilatus PC-6/B2-H4 Turbo Porter Commercial-Aircraft crashed shortly after takeoff during a skydiving flight in northeastern France.
The Accident occurred at approximately 09:00 UTC (11:00 local time) near the Nancy-Essey aerodrome (ENC/LFSN). According to French Transport Minister Philippe Tabarot, the event represents the deadliest general aviation accident involving skydiving operations in France in approximately 30 years. The Bureau d’Enquêtes et d’Analyses pour la Sécurité de l’Aviation Civile (BEA) has deployed four Investigations to the site to determine the circumstances of the crash.
Aircraft departure and impact
The aircraft, registered in Germany as D-FIPS and reportedly owned by Classic Wings GmbH, departed Nancy-Essey for a tandem skydiving excursion. Less than one minute after takeoff, the aircraft banked left and descended almost vertically, impacting a grassy area in the town of Tomblaine, approximately 300 meters from the runway.
The Meurthe-et-Moselle Prefecture confirmed that all 11 occupants died in the crash. The victims included one pilot, five skydiving instructors, and five students. Thierry Pechey, president of the Meurthe-et-Moselle branch of the Order of Independent Nurses, told CBS News that the students were local nursing colleagues participating in a first-time jump.
Local officials noted the aircraft crashed near a residential neighborhood and shopping center. Yves Séguy, Prefect of the Meurthe-et-Moselle department, told the Associated Press that the accident could have caused collateral casualties had the impact occurred just a few dozen meters away. No injuries on the ground were reported.
Safety investigation and witness reports
The BEA is leading the Safety investigation, working in coordination with the Paris Criminal Investigation Department and the Air Transport Gendarmerie Brigade (GTA). The official cause of the accident remains under investigation.
While the BEA has not confirmed any mechanical faults, Reuters reported that witnesses on the ground heard the aircraft engine noise stop suddenly before the descent. Hervé Féron, the mayor of Tomblaine, stated that the aircraft fell in an unexplained manner during its initial ascent.
French Interior Minister Laurent Nunez noted that families of the victims were present at the aerodrome and witnessed the accident, resulting in significant psychological trauma.
AirPro News analysis
We note that this accident follows another fatal skydiving flight earlier in June 2026 in Missouri, which resulted in 12 fatalities. While the two events involve different operators, aircraft types, and regulatory jurisdictions, the proximity of these high-fatality accidents will likely bring renewed regulatory scrutiny to general aviation skydiving operations globally. The Pilatus PC-6 involved in the Tomblaine accident was 35 years old, a common age for utility turboprops in the skydiving sector, where aircraft are subjected to high-cycle operations characterized by rapid ascents and descents. The BEA preliminary report will be critical in establishing the sequence of events following takeoff.
Sources: Bureau d’Enquêtes et d’Analyses pour la Sécurité de l’Aviation Civile (BEA), Associated Press
Photo Credit: ALEXANDRE MARCHI – L’EST REPUBLICAIN – MAXPPP
Regulations & Safety
Light-Sport Aircraft Strikes CITIC Tower in Beijing
A Sunward SA 60L Aurora struck Beijing’s 528-meter CITIC Tower on June 26, 2026, breaching restricted airspace.
This is a developing story. Information may change as official details are released.
This article summarizes reporting by CNN by Steven Jiang, with additional reporting from Reuters, Forbes, the South China Morning Post, the Financial Times, and the Associated Press.
A domestically produced light-sport aircraft struck the upper floors of the CITIC Tower in Beijing’s Central Business District on June 26, 2026, triggering mass evacuations and a heavy police response in one of the world’s most tightly controlled airspaces.
According to CNN, the aircraft impacted the 528-meter (1,732-foot) skyscraper shortly before 10:00 UTC (6:00 PM local time), scattering debris onto the streets below. The incident represents a highly unusual breach of the restricted flight zones over central Beijing, which are strictly enforced to protect nearby government leadership compounds.
Flight trajectory and aircraft identification
The aircraft involved has been identified by the South China Morning Post as a Sunward SA 60L Aurora, a two-seat light-sport aircraft, bearing registration B-12PP. The exact number of occupants on board at the time of the crash has not been officially confirmed.
The Associated Press reported that the flight originated from an Airports approximately 50 kilometers (27 nautical miles) east of the Chinese capital at around 5:30 PM local time. Flight tracking data indicates the aircraft deviated from its standard operating area before entering the restricted airspace over the city center.
Ian Petchenik, a spokesman for Flightradar24, told Forbes that the aircraft type is typically utilized for pilot Training in the region east of Beijing. He noted that no possibilities regarding the nature of the flight can be ruled out at this stage of the Investigation.
Evacuations and official response
The collision prompted immediate evacuations of the 109-story CITIC Tower, also known as China Zun. Occupants reported fleeing the building rapidly, with one evacuee telling the South China Morning Post they left without personal belongings. Unverified eyewitness accounts provided to Reuters described the impact noise as louder than fireworks.
The Beijing Municipal Public Security Bureau quickly cordoned off the surrounding Central Business District. CNN noted that Chinese state media has not yet reported on the event, and images or videos of the crash are being actively removed from domestic social media platforms.
Official casualty figures remain pending, and the condition of the pilot or any potential passengers is currently unconfirmed. The Civil Aviation Administration of China (CAAC) and local authorities have not issued a formal statement regarding the cause of the crash, which remains under investigation.
Beijing airspace security context
The airspace over central Beijing is subject to stringent Regulations. The Financial Times highlighted that commercial flights routinely execute wide detours to avoid the city center, primarily to secure the Zhongnanhai compound, which houses the central government leadership just kilometers from the crash site.
This event follows recent regulatory actions by Beijing authorities to further tighten airspace controls. Last month, officials implemented new restrictions that effectively banned the sale and operation of consumer Drones within the capital, as reported by the Associated Press.
AirPro News analysis
We note that unauthorized incursions into central Beijing’s airspace by crewed aircraft are exceptionally rare due to the severe security protocols in place. The investigation by the CAAC will likely focus on whether the deviation from the training area was the result of mechanical failure, pilot incapacitation, navigational error, or an intentional act. The immediate censorship of the event on Chinese social media aligns with standard operational procedures by state authorities during high-profile domestic incidents, which may delay the public release of preliminary investigation findings.
Sources: CNN
Photo Credit: X
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