What happened
Prior to landing, the pilot performed a pre-landing checklist and deployed the landing gear. Upon deployment, the pilot noted that a green light was not observed. The pilot attempted to recycle the landing gear, but the issue persisted.
After contacting the control tower, the pilot was informed that a medical evacuation aircraft was in close proximity. Both the control tower and the pilot of the medical evacuation aircraft subsequently advised the pilot that the landing gear appeared to be in the down position. Despite this external confirmation, the pilot did not perform the manual gear extension procedures specified in the aircraft checklist and proceeded with the landing.
During the landing rollout, the landing gear collapsed. There were no fatalities or injuries reported.
The investigation
An examination of the aircraft revealed that the navigation lights were active at the time of the incident. Investigators found that when the navigation lights were turned off, the landing gear indicator light transitioned to a full bright position. Conversely, when the navigation lights were turned on, the landing gear light would dim for night operation.
The aircraft was placed on jacks, and the landing gear was successfully extended using the manual gear extension method. A functional check of the landing gear warning horn and the light system was performed, which yielded negative results.