What is the primary function of optical smoke detectors on the flight engineer panel?

The primary function of optical smoke detectors on the flight engineer panel involves their ability to respond to airborne particles or smoke in the cabin or cargo hold. These detectors utilize a light beam that is disrupted or scattered when smoke enters the sensing area, triggering an alert.

This functionality is critical for safety in flight operations, as it allows for early detection of fire or smoke, greatly enhancing the crew's ability to respond appropriately. The detectors analyze air samples and detect variations caused by smoke, which can indicate a fire hazard. By specifically monitoring the air for smoke particles, these detectors play a vital role in maintaining safety within the aircraft, particularly in areas such as the cargo hold where visibility is often limited and the presence of smoke could indicate a serious problem.

Other options do not align with the primary function of the smoke detectors, as they address different safety and monitoring concerns within the aircraft.