MONROE, GA, USA
N101ET
Beech F90
The pilot stated that while taxiing for takeoff he selected max ground heat, and immediately experienced main gear retraction. The tail dropped suddenly, impacting the ramp, and the airplane slid about 30 feet before coming to rest. An FAA inspector and a manufacturer's representative examined the airplane, and found that a partially spiral wrapped wiring bundle, tied in the vicinity of the aileron control cables and turnbuckle, had some wires which had chafed. The wiring insulation had been removed due to friction exerted against either the turnbuckle, or the cable. The manufacturer's representative stated that two of the wires which had chafed through electrically shorted together when the pilot selected max ground heat, activating the landing gear's relay, and initiating the landing gear retraction cycle while the aircraft was on the ground.
On February 9, 2000, about 0905 eastern standard time, a Beech F-90, N101ET, registered to and operated by Avondale Mills Inc., as a Title 14 CFR Part 91 business flight, main landing gear retracted while taxiing for takeoff from Monroe County Airport, Monroe, Georgia. Visual meteorological conditions prevailed at the time, and an instrument flight rules flight plan was filed. The aircraft was substantially damaged, and the private-rated pilot was not injured. The flight was originating at the time of the accident. The pilot stated that while taxiing for takeoff the cabin was cold so he selected max ground heat and immediately experienced main landing gear retraction. He said that the moment he activated the max ground heat switch, the tail dropped suddenly, impacting the ramp, and the airplane slid forward for about 30 feet before coming to rest. An FAA inspector, along with a Raytheon representative examined the accident airplane and removed the splash curtain, inspecting the wiring to the J107 connector, located in the right main landing gear wheel well. They noted that several wires had chafed through the insulation. The chafing was in the area where the wires were tied to the aft wheel well compartment wire bundle, where the bundle made a 180-degree bend. At the end of the bend, four wires had chafed through the insulation, along with other wires which had partially chafed through. According to the Raytheon representative, the wires had chafed on the side, against the plastic spiral wrap, placed to protect the wire bundle connected to the J107 connector. The chafed side of the wires appeared to have rubbed against the right aileron control cable turnbuckles, which ran through the back of the compartment. The wires in the bundle which were affected are as follows: Wire # G8A22 Pin M - main landing gear motor (arcing) Wire # H39A22 Pin U - heat switch (arcing) Wire # H76A22 Pin V - heat switch Wire # D10A22 Pin F - landing gear position (arcing) Wire # G21A22 Pin H - not associated The Raytheon representative stated that wires G8A22 and H39A22 electrically shorted together when the pilot selected max ground heat to warm the cabin, and voltage from wire # H39A22 (heat switch), activated the landing gear's up relay, in landing control box K100, initiating the landing gear retraction cycle, while the aircraft was on the ground. Due to the weight of the airplane and the direction of nose gear movement during retraction, the nose gear remained down and locked.
chafed wiring that resulted in an electrical short which initiated the landing gear retraction cycle when cabin heat was activated, resulting in the main landing gear retracting during taxi.
Source: NTSB Aviation Accident Database
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