During a 14 CFR Part 135 scheduled commuter flight, the airplane received substantial damage when it landed with its landing gear retracted on a gravel runway. The pilot reported that during the landing sequence he was distracted, and inadvertently forgot to lower the landing gear. He did not confirm that all of the prelanding checklist items were completed. He said he did not hear the landing gear warning horn until the airplane was on the ground.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The pilot's inadvertent wheels-up landing. Factors contributing to the accident were the pilot's failure to complete the prelanding checklist, his diverted attention, and a delayed gear warning horn alarm.