Design evaluation of the fractured main landing gear of a BAE Jetstream SX-SKY aircraft

The purpose of this paper is to study the main landing gear (MLG) mechanism configuration.

Mechanism kinematics and dynamics, stress analysis and sizing of the MLG structural members, and fatigue issues related with the mechanism operation. Spreadsheet solutions were incorporated to this survey to analyze the most conceivable loading situations, and important factors of the mechanism design for an initial evaluation of safety implications.

MLG design approach along with conservative fatigue design factors lies in the area of accepted limits in commercial aircraft industry.

MLG loading associated with landing as well as those associated with ground maneuvers (steering, braking and taxiing) contribute significantly to fatigue damage, along with the stresses induced by manufacturing processes and assembly. The application of FEA methods for the design of the landing gear does not always guarantee a successful approach to the problem solution, if precise analytical solutions are not available in advance.

From the investigation of this incident of fractured struts of the MLG it is confirmed that the reduction in Pintle Housing diameter on the upper part has contributed to the avoidance of damaging the fuel tank above the MLG that would lead to a catastrophic event. On the other hand, the airframe of the SKY-Jet was proved efficient for a belly landing with minor damages to the passengers and heavier damages for the aircraft.

On-line vibration monitoring sensors hooked up to the landing gear strut and Pintle House would greatly enhance safety, without relying in optical surveys in hard to access and inspect areas of the landing gears mechanisms housings.

Analytic methods were adopted and spreadsheet solutions were developed for the MLG main loading situations, along with design issues concerning mechanism kinematics and dynamics, stress analysis and sizing of the MLG structural members, as well as fatigue issues related with the mechanism operation. Spreadsheet solutions were incorporated to this survey to analyze the most conceivable loading situations, and important factors of the mechanism design for an initial evaluation of safety implications.