The Flight Crew Felt A Bump/Thud In The Back Of The Airplane, Which They Thought Was Caused By Something Falling Into The Aisle Analysis: About 10,000 ft mean sea level during a repositioning flight, the flight crew felt a bump/thud in the back of the airplane, which they thought was caused by something falling into the aisle from the lavatory. The flight crew observed that the landing gear unsafe light was illuminated. The flight crew stated that they followed emergency/abnormal airplane checklist items and reset the landing circuit breaker, which did not retract the landing gear.
