NTSB Urges FAA Action on Bombardier Learjet Landing Gear Flaw

NTSB Calls for Urgent Action on Learjet Landing Gear After Fatal Accident

The National Transportation Safety Board (NTSB) has issued an urgent safety recommendation to the Federal Aviation Administration (FAA) concerning a critical flaw in the landing gear assembly of certain Bombardier Learjet models. This decisive action follows a comprehensive investigation into a fatal runway excursion in Scottsdale, Arizona, which highlighted a latent but severe safety risk. An urgent recommendation from the NTSB signifies a critical threat to life or property that requires immediate attention, compelling recipients to respond within 30 days. The gravity of the situation is underscored by the sheer number of aircraft involved, a total of 1,883 airplanes across 10 specific Learjet models currently in service.

The catalyst for this recommendation was a tragic accident on February 10, 2025, where a Learjet 35A experienced a catastrophic failure during its landing sequence. The aircraft’s left main landing gear separated upon touchdown, causing the jet to veer off the runway and collide with a parked aircraft. The incident resulted in the death of the captain and serious injuries to three other individuals. However, the NTSB’s investigation revealed that this was not an isolated event. A pattern of similar failures dating back decades pointed to a systemic issue with the landing gear’s design or, more specifically, its maintenance procedures. This history of incidents, combined with the fatal outcome in Scottsdale, has created a clear and present need for regulatory intervention to prevent future occurrences.

At the heart of the issue is a subtle but dangerous flaw in how the main landing gear is secured to the airframe. The investigation pinpointed a specific component, the aft trunnion pin and its retaining bolt, as the point of failure. The NTSB’s findings indicate that the current maintenance procedures allow for a critical misassembly that is nearly impossible to detect through standard pre-flight or even routine maintenance checks. This hidden vulnerability means that hundreds of aircraft could potentially be operating with insecurely attached landing gear, posing a significant and unacceptable risk to crew, passengers, and individuals on the ground.

Anatomy of a Failure: The Scottsdale Incident and a Hidden Flaw

The events of February 10, 2025, at Scottsdale Airport serve as a stark illustration of the potential consequences of this mechanical vulnerability. During the landing rollout, the Learjet 35A’s left main landing gear detached from the aircraft. This structural failure caused the jet to enter a “left-wing-low attitude” and veer uncontrollably off the runway. The excursion ended when the Learjet struck a parked Gulfstream G200 jet, resulting in significant damage to both aircraft. The separated landing gear was later found on an adjacent taxiway.

The human cost of this mechanical failure was severe. The captain of the Learjet was killed in the accident. The first officer and a passenger aboard the Learjet, as well as an occupant of the parked Gulfstream, all sustained serious injuries. Such outcomes transform a technical investigation into a pressing human safety issue, driving the urgency behind the NTSB’s recommendations. The investigation focused immediately on the separated landing gear, seeking to understand the precise cause of the detachment during what should have been a routine landing.

The Technical Flaw: A Bolt That Deceives

The NTSB’s investigation zeroed in on the aft landing gear trunnion pin and its retaining bolt. This assembly is a critical connection point that secures the entire landing gear structure to the aircraft’s wing. The board discovered that it is possible for a mechanic to inadvertently install the retaining bolt without it properly passing through the trunnion pin. In this state, the bolt appears to be correctly installed and secured, but it is not actually locking the pin in place. This leaves the landing gear insecurely attached to the airframe, held on by little more than friction and positioning.

This misassembly is particularly dangerous because it is not readily detectable. A visual inspection during a pre-flight walk-around would not reveal the improperly seated bolt. Furthermore, even during subsequent maintenance, the error can be easily missed without a specific verification step. This creates a latent failure condition that can persist through numerous flight cycles, waiting for the stresses of a landing to trigger a catastrophic separation. The NTSB’s findings highlight a critical gap in the maintenance process that has allowed this risk to go unaddressed.

In the absence of a required verification step, a mechanic could inadvertently install the retaining bolt without it passing through the trunnion pin, leaving the gear insecurely attached to the airframe. The misassembly is not readily detectable during routine maintenance or preflight inspections.

A Pattern of Failures and a Call for Mandatory Action

While the Scottsdale accident was the immediate trigger, the NTSB’s investigation quickly uncovered a disturbing history of similar incidents. This pattern demonstrates that the vulnerability in the Learjet’s landing gear assembly is a long-standing issue, not a new phenomenon. By looking into past events, the board identified at least three prior occurrences where a Learjet’s main landing gear disconnected from the airframe due to the same failure of the retaining bolt and trunnion pin assembly.

These historical cases span several years and different aircraft models within the Learjet family. On October 4, 1995, a Learjet 25B experienced a left main landing gear collapse in Oklahoma City. A few years later, on February 4, 2001, another Learjet 25B suffered a gear separation after touchdown in Fort Pierce, Florida. A third documented incident occurred on March 28, 2008, when a Learjet VU-35A operated by the Brazilian Air Force had its left main landing gear collapse in Recife, Brazil. This documented history proves that the potential for misassembly has existed for decades, making the need for a permanent solution all the more critical.

The NTSB’s Two-Pronged Recommendation

In response to its findings, the NTSB has issued two specific recommendations. The first and most urgent is for the FAA to mandate compliance with service bulletins issued by Bombardier. Following the Scottsdale accident, Bombardier released a service bulletin requesting a one-time inspection of the landing gear on all affected models. However, the response has been alarmingly low; according to Bombardier, only 12 percent of the 1,883 airplanes have been inspected. By calling for an FAA mandate, likely in the form of an Airworthiness Directive (AD), the NTSB is seeking to make these inspections compulsory, ensuring the entire fleet is checked.

The second recommendation targets the root cause of the problem: the maintenance procedure itself. The NTSB has asked the FAA to require Bombardier to revise its procedures to include a specific post-maintenance visual check. This new step would require mechanics to visually verify the correct position of the aft trunnion pin and retaining bolt after installation, eliminating the ambiguity that allows for the current misassembly. This procedural fix is designed to prevent the error from occurring in the first place, providing a long-term solution to the safety vulnerability.

Conclusion: From Investigation to Prevention

The NTSB’s urgent recommendations regarding the Bombardier Learjet fleet represent a critical step in the aviation safety cycle. The investigation into the tragic Scottsdale accident successfully identified not only a mechanical point of failure but also a procedural gap that allowed a hidden danger to persist across more than 1,800 aircraft. By uncovering a history of similar incidents, the board has demonstrated a systemic risk that requires a robust and mandatory solution. The focus now shifts to the FAA and Bombardier to implement these changes swiftly.

This case serves as a powerful reminder that aviation safety is an ongoing process of learning and adaptation. The subtle, hard-to-detect nature of the landing gear flaw underscores the importance of designing maintenance procedures that are not only effective but also include clear verification steps to prevent human error. The implementation of a mandatory inspection and a revised maintenance protocol will be crucial in ensuring that this specific type of accident does not happen again, protecting flight crews, passengers, and the public from a known and preventable risk.

FAQ

Question: What is the specific problem with the Learjet landing gear?
Answer: The NTSB found that the retaining bolt for the aft trunnion pin on the main landing gear can be installed incorrectly without being obvious. This leaves the gear insecurely attached to the airframe, creating a risk of it separating during landing.

Question: How many aircraft are affected by this recommendation?
Answer: The recommendation affects 1,883 airplanes currently in service across 10 different Private-Jets models.

Question: Why is the NTSB’s recommendation considered “urgent”?
Answer: The NTSB issues urgent recommendations to address immediate and critical safety issues that pose a threat to lives or property. Given the fatal accident in Scottsdale and the large number of potentially affected aircraft, the agency determined that immediate action was necessary.

Sources

• NTSB Issues Urgent Recommendation on Learjet Landing Gear