Incident Overview
On March 16, 2013, at approximately 1130 eastern daylight time, a Mooney M20F, registration N9387V, sustained substantial damage during a gear-up landing at Leesburg International Airport (LEE), Leesburg, Florida. The commercial pilot, who was the sole occupant, was not injured. The flight was conducted under 14 CFR Part 91 as a personal flight, with visual meteorological conditions prevailing. No flight plan was filed for the local flight, which had departed LEE about 1030.
Pilot Actions and Landing Gear Failure
According to the pilot, while practicing slow-flight, he attempted to extend the flaps and landing gear. The flaps extended normally, but he heard a "snap" and the landing gear did not extend. Additionally, there was no cockpit indication of the landing gear position. The pilot referenced the pilot operating handbook and cycled the landing gear without success. He then attempted the emergency manual landing gear extension procedure, which also failed. A low pass was performed, and LEE control tower personnel confirmed that the landing gear was not extended. The pilot subsequently executed a gear-up landing on a grassy area at LEE. The airplane came to rest upright, but the empennage sustained substantial damage.
Maintenance Findings
An examination by a mechanic, under the supervision of an FAA inspector, revealed that the emergency manual gear extension cable terminated with a spline drive at the landing gear actuator. The mechanic observed that the spline drive was seized, and the cable portion behind it rotated freely in its sheath. At some point in the airplane's history, the emergency gear cable had separated from its terminating spline drive. This would not normally affect the landing gear system unless the emergency landing gear extension cable was engaged from the cockpit via a knob. However, the mechanic also noted that the emergency gear extension cable was previously mis-rigged, which allowed it to contact the actuator arm and engage the cable during normal gear operations. With a seized spline engaged to the electric landing gear motor via the actuator, during normal gear operations, the electric landing gear motor could not overcome the seized spline to actuate the landing gear.
Logbook and Inspection History
Review of the airplane's most recent airframe logbook revealed entries dating back to May 2006. The landing gear actuator (part number 4196-00-1C) was removed and replaced on February 16, 2009. After replacement, maintenance personnel cycled the landing gear five times, checked the emergency manual landing gear disengage system, and manually extended the landing gear. No other entries pertained to the emergency gear extension system, though the logbook entry for the most recent 100-hour inspection noted "performed three landing gear retraction cycles."
The most recent 100-hour inspection was completed on May 24, 2012. A Mooney Maintenance Manual, 100 Hour-Annual Inspection Guide, specified "8. Check emergency landing gear extension system; extend gear using emergency gear extension system." The mechanic who performed that inspection reported that he typically does more than the standard logbook entry of three retraction cycles, with the first one done manually (emergency), which he performed on the accident airplane. He added that the standard logbook entry does not differentiate between normal or emergency retraction cycles. The mechanic was very familiar with the airplane, having owned it for 14 years prior to the current owner, and did not experience any landing gear system problems during the most recent inspection or prior. At the time of the inspection, the airplane had accumulated 3,497.9 total flight hours. An additional 59 hours of operation occurred between the last annual inspection and the accident.