Which two types of continuous loop sensing elements are used in modern aircraft?

The correct choice identifies the two primary types of continuous loop sensing elements used in modern aircraft fire detection systems: the Kidde sensing element and the Fenwal sensing element.

The Kidde sensing element operates on the principle of sensing variations in temperature through a pair of wires encased in a thin metal tube. When a fire occurs, the temperature in the environment increases, causing the sensing element to produce a continuous electrical signal that indicates the presence of heat. This type of sensor is known for its reliability and is commonly used in a variety of applications, particularly in confined spaces.

The Fenwal sensing element, on the other hand, employs a different mechanism. It utilizes a dual-wire, continuous-loop system that relies on the thermal expansion of a material to act as a thermal fuse when a specified temperature threshold is exceeded. When the cable experiences a heat increase beyond a set point, it triggers the fire detection system to alert the crew about a potential fire.

Both types are favored in the aviation industry for their continuous monitoring capabilities, allowing for immediate detection of rising temperatures that might indicate an onboard fire. This early detection is crucial for aircraft safety, enabling quicker response and potentially saving lives and property.

Understanding the function and integration of these sensing elements within various aircraft systems highlights their