Incident Overview
During the approach phase, the co-pilot was the flying pilot while the captain provided directions. The captain reported that he extended the flaps and the landing gear. However, when the aircraft touched down, the landing gear was not extended. The co-pilot stated that she had looked down at the landing gear lever and observed "three green lights" during the approach.
Analysis of the cockpit voice recorder (CVR) revealed that the co-pilot directed the captain to call inbound. The captain acknowledged and said "fifteen flaps." The co-pilot then responded, "fifteen flaps, before landing." The captain did not reply but instead made a radio transmission. Shortly after, the captain stated he was extending the flaps to 25 degrees and made another radio transmission to the tower. The co-pilot then said "final, sync, ignitions," to which the captain replied "ignitions on." Full flaps were subsequently extended.
The captain continued to give the co-pilot directions for heading, speed, and altitude during the approach. At approximately 300 feet, the captain stated, "yaw damper's off, air valves are off, ready to land." The captain reported that it became obvious that touchdown occurred on the flaps and keel. After landing, the captain raised the flaps, shut down the engines, and confirmed that the landing gear handle was in the down position.
Investigation Findings
A gear swing test was conducted, during which the landing gear cycled several times without difficulty. All red and green lights illuminated at the proper positions. However, during the test, the landing gear not extended warning horn did not function when the gear was retracted, the flaps were fully extended, and the power levers were at idle. Further inspection revealed a bad set of contacts to the relay; when the relay was bypassed, the horn sounded.
Damage to the aircraft included scrape marks around the circumference of the outer rims of both outer tires. The outer surfaces of the gear door fairings were scraped, and the flap hinge fairings were ground down.
Probable Cause
The landing gear down and locked was not verified prior to landing. The checklist was not followed, and an inoperative landing gear warning horn were factors.