NTSB · Safety Recommendation
Safety Recommendation A-25-039
Recommendation
TO THE FEDERAL AVIATION ADMINISTRATION: Require Bombardier to revise the maintenance procedures for the applicable Learjet models to include a check of the position of the aft landing gear trunnion pin and retaining bolt, following maintenance on the gear that requires removal of the aft trunnion, to ensure that the landing gear has been correctly attached to the airplane wing structure.
Safety Issue and Context
The National Transportation Safety Board (NTSB) is providing the following information to urge the Federal Aviation Administration (FAA) to immediately act on the safety recommendations in this report concerning the potential for incorrectly attached main landing gear on certain Learjet airplanes to separate from the wing structure during landing. We identified this issue during our ongoing investigation of a fatal runway excursion involving a Learjet 35A, N81VN, while landing at Scottsdale Airport (SDL), Scottsdale, Arizona, on February 10, 2025.
Response History
December 8, 2025 · Recipient Response · FAA
-From Bryan Bedford, Administrator: Learjet already released temporary revisions to the maintenance manuals to include warnings and notes to confirm that the aft trunnion pin is properly inserted and that the aft trunnion pin retaining bolt is installed through the switch striker, strut, and trunnion pin. We believe this additional maintenance information accomplishes the intent of this Safety Recommendation. The same SAIB for our response to SR A-25-38 will also recommend adoption of the temporary revisions of the maintenance manuals.
I anticipate providing an update to this safety recommendation by May 31, 2026.
October 29, 2025 · NTSB Correspondence · FAA
As a result of the NTSB’s preliminary findings in this investigation, we identified the following safety issues: • Misassembly of the aft trunnion pin on Learjet main landing gear is not readily detectable during routine maintenance or preflight inspection, risking gear separation on landing. • Learjet maintenance manuals do not provide procedural guidance to verify proper positioning and secure engagement of the aft trunnion pin and retaining bolt during main landing gear installation. Accordingly, the NTSB makes the following safety recommendations to the Federal Aviation Administration, the first of which is urgent:
• Require, as a condition of continued airworthiness, operators and owners of applicable Learjet models to comply with Bombardier Service Bulletins (SBs) A23/24/25-32-20, A28/29 32 21, A31 32 25, A35/36-32-29, A55-32-26, and A60 32 42. (A-25-38) (Urgent) • Require Bombardier to revise the maintenance procedures for the applicable Learjet models to include a check of the position of the aft landing gear trunnion pin and retaining bolt, following maintenance on the gear that requires removal of the aft trunnion, to ensure that the landing gear has been correctly attached to the airplane wing structure. (A-25-39)
From report AIR-25-07 "Ensure Learjet Main Landing Gear Are Securely Attached":
The NTSB is also concerned that Learjet maintenance manual procedures for installing the main landing gear do not contain a step to ensure that the aft trunnion pin is positioned correctly or that the retaining bolt is secured through it. 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; such misassembly may enter service undetected, increasing the risk of the main landing gear separating from the airplane during landing.
The manual should include steps to confirm, by direct visualization, that the aft trunnion pin is seated flush against the shim and bushing flange, to ensure the retaining bolt is correctly installed through the strut and trunnion pin, and to correct any discrepancies. Therefore, the NTSB concludes that revision of Learjet maintenance manual procedures for installation of the main landing gear to include an explicit procedural check that verifies correct engagement of the aft trunnion pin with its retaining bolt would ensure that the main landing gear is securely attached to the airframe.