FAA AMT Airframe Practice Exam 2026 – All-in-One Study Guide to Master Aviation Maintenance Technician Certification!

Photoelectrical devices are sometimes called optical or photoelectric smoke detectors. They detect smoke by using a light source and a sensor. When smoke particles obstruct the light beam, the sensor registers a change and signals an alarm. Ionization detectors, on the other hand, use a small amount of radioactive material to ionize the air inside the detector chamber. When smoke enters the chamber, it disrupts the ionization process and triggers the alarm. Aspirating detectors are similar to photoelectrical devices, but they use a fan to draw in air for sampling. Finally, thermal alarms use a heat-sensitive element to detect an increase in temperature, which can be caused by smoke or fire. While all of the options listed are types of smoke detectors, only photoelectrical devices use light transmissibility as a means of detection. Therefore, option C is the correct answer.