Dale Crane's Oral and Practical Exam Guide: Airframe questions with correct answers

Why must a switch be derated if it is used in a circuit that supplies incandescent lamps? CORRECT ANSWER The high-inrush current caused by the low resistance of the cold filament requires that the switches be derated What is an SPDT switch? CORRECT ANSWER A single-pole, double-throw switch Where could you find the part number of a switch in an aircraft electrical system? CORRECT ANSWER In the equipment table or bill of materials on the electrical circuit diagram for the aircraft If no specific instructions are available, which way should the operating handle of an electrical switch move to run a component on? CORRECT ANSWER Forward or upward What is meant by a trip-free circuit breaker? CORRECT ANSWER A circuit breaker that cannot be closed while fault exists, regardless of the position of the operating handle What is meant by a slow-blow fuse? CORRECT ANSWER A fuse that will allow more current than its rating to flow for a short period of time, but will open the circuit if more tan its rate current continues to flow