Undetected cracks led to aircraft landing gear collapse in Fort Simpson, NWT

Today, the Transportation Safety Board of Canada (TSB) released its investigation report (A23W0039) into a 2023 landing gear collapse that occurred in Fort Simpson, Northwest Territories.

On April 14, 2023, a British Aerospace Jetstream Model 3112, operated by Northwestern Air Lease Ltd., was conducting a training flight with two pilots on board. Shortly after landing, the left main landing gear unit collapsed, causing the aircraft to veer off the runway. There were no injuries. The aircraft sustained significant damage to its left main landing gear, engine, propeller, wing tip, and belly cargo pod.

The investigation determined that several cracks on the upper portion of the left-hand main landing gear grew until the structure eventually failed during landing. The material used was susceptible to stress corrosion cracking and had been exposed to both tensile stress and a corrosive environment. This was a known issue and there were several periodic inspections required of the main landing gear. However, the inspections were unable to detect the defects on the occurrence aircraft. The defects remained undetected during service and contributed to the failure.

Following the occurrence, a service information letter and several service bulletins were revised highlighting the requirement for corrosion protection and surface finish for main landing gear components.

See the investigation page for more information.