If they are there, what you're looking at is an automatic fire suppression system. These systems are made up of canisters full of a chemical agent that deploys when thermal detectors sense a fire.

The system's warning consists of a loud beeping and a flashing red light that both audibly and visually signals that the automatic extinguisher has gone off. When a STOP-FYRE® automatic fire ...

FedEx Express announced on 6 October plans to install a new automatic fire suppression system on all 59 McDonnell Douglas MD-11 freighters and new Boeing 777Fs. A FedEx special projects group ...