WINDSOR LOCKS, CT, USA
N9044V
Beech BE-58
The pilot smelled smoke after takeoff. He returned to the airport, landed, and taxied to the ramp. During the postflight inspection, the rotating beacon power wire was found to be burnt, the entire length of the airplane. The initiating event was suspected to be a failed beacon motor, which then initiated a short circuit; however, it was not positively confirmed. Further inspection revealed that a holding screw for the electroluminescent panel had contacted the rotating beacon switch/circuit breaker, and fractured the switch. The switch/breaker was attached to a solid buss bar behind the panel, and the screw position was directly below the toggle portion of the switch. The manufacturer's parts catalog called for the use of a specific screw, but did not give a dash number for the screw's length.
On May 8, 2000, at 2137 Eastern Daylight Time, a Beech BE-58, N9044V, operated by U.S. Check, suffered minor damage from an electrical fire, shortly after departing Bradley International Airport (BDL), Windsor Locks, Connecticut. The certificated commercial pilot was not injured, and visual meteorological conditions prevailed at the time of the incident. An instrument flight rules flight plan was filed for the flight, between Bradley and Stewart International Airport (SWF), Newburgh, New York. The cargo flight was conducted under 14 CFR Part 135. According to a Federal Aviation Administration (FAA) inspector, the pilot smelled smoke after takeoff. The airplane returned to Bradley, landed, and taxied to the ramp. During the postflight inspection, the rotating beacon power wire was found to be burnt, the entire length of the airplane. Further inspection revealed that a holding screw for the electroluminescent panel had contacted the rotating beacon switch/circuit breaker, and fractured part of the unit. The switch function was determined to still operate properly, but the circuit breaker had failed. The initiating event was suspected to be a failed beacon motor, which then initiated a short circuit; however, it was not positively confirmed. The switch/breaker was attached to a solid buss bar behind the panel, and the screw in question was one of five used to hold the panel in place. Each of the four other screws was located at a corner of the panel, while the fifth screw was located directly below the toggle portion of the switch. The Beechcraft Illustrated Parts Catalog called for the use of an AN5158632R screw, but did not give a dash number for the screw's length. The FAA inspector submitted safety recommendations to the FAA Recommendation and Quality Assurance Division, AAI-200, for a fleetwide inspection of existing switches, for the manufacturer to revise the parts catalogue to reflect screw length, and for the manufacturer to move the screw position on future airplanes.
Inadequate screw length information provided by the manufacturer, which allowed an inadvertent installation of a holding screw that was too long, and the subsequent fracture of the switch/circuit breaker. Factors included a short circuit of the beacon motor, and the location of the holding screw position within the electroluminescent panel.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
