General Aviation news has reported that recently, a Mitsubishi MU-2B was forced to make an emergency landing when thick black smoke filled the cockpit. It was later discovered that a hand-held GPS receiver and antenna had been set on the glare shield and a metallic portion of the antenna had inadvertently made contact across the windshield heater terminal strips. This resulted in an electrical short circuit causing the loose equipment to burn which filled the cockpit with smoke.
The incident has since led the USA’s FAA to issue a Special Airworthiness Information Bulletin to remind mind owners, operators and installers of the potential hazards related to having loose equipment in the cockpit – especially items placed on the glare shield of an aircraft with a windshield heater system. The FAA Bulletin noted that aircraft owners should have any exposed terminal strips insulated or covered to lessen the risk of an occurrence.
In addition to the risk of a short, the FAA Bulletin noted that loose equipment can also obscure the pilot’s field of view, impact the accuracy of the plane’s magnetic compass and become a hazard during turbulence. Hence, pilots also need to secure any loose items prior to and during a flight as well as isolate such items from other equipment in the cockpit.