What are two types of smoke detection systems used in aircraft?

Photoelectric and ionization smoke detection systems are commonly utilized in aircraft due to their effectiveness in detecting different types of smoke particles.

Photoelectric smoke detectors operate by using a light source and a sensor. When smoke enters the sensing chamber, it scatters the light beam, causing a change in the amount of light that reaches the sensor. This allows the system to detect smoldering fires effectively, which produce larger smoke particles.

Ionization smoke detectors work by utilizing a small amount of radioactive material to ionize air within a sensing chamber, creating an electrical current. When smoke enters this chamber, it disrupts the ionization process, leading to a drop in current that triggers the alarm. Ionization systems are particularly sensitive to fast-flaming fires, which usually produce smaller particles.

Both types of systems are essential for ensuring safety in aircraft, as they can detect various types of fires and smoke conditions. The other choices listed do not correctly represent the primary smoke detection technologies used in aviation today.