What happened
During the approach phase of the flight, the captain acted as the pilot monitoring while the co-pilot performed the flying duties. The captain reported extending the flaps and the landing gear; however, upon touchdown, the landing gear remained retracted. While the co-pilot noted observing the gear lever and the three green lights during the approach, cockpit voice recordings showed the crew focused on various checklists, including flap settings and engine ignitions. As the aircraft descended to approximately 300 feet, the captain noted the status of the yaw damper and air valves before landing.
Following the landing, the captain reported that the aircraft made contact on the flaps and the keel. After the engines were shut down, the crew performed a gear swing test, which confirmed the gear could cycle properly and that all indicator lights functioned correctly. An inspection of the aircraft revealed scrape marks on the outer rims of both outer tires, as well as damage to the gear door fairings and the flap hinge fairings.
Findings
Post-incident inspections identified that the gear not extended horn failed to activate when the gear was retracted with the flaps fully extended and power levers at idle. The investigation determined that a faulty set of contacts in the relay prevented the warning horn from sounding. When the relay was bypassed, the horn functioned as intended.