What could cause radiation hazards on an aircraft?

Antennas and RADARS can pose radiation hazards on an aircraft due to their function in transmitting and receiving electromagnetic signals. These systems operate at various frequencies and power levels, which can emit radiation in the surrounding area. For instance, RADAR systems used for navigation and weather detection may produce radiofrequency emissions, and exposure to these levels of radiation can be harmful to both crew and passengers if proper safety protocols are not observed.

In contrast, while propellers and landing gear are crucial components of an aircraft, they do not emit radiation and therefore do not create radiation hazards. Aircraft windows are primarily designed to provide visibility and structural integrity without significant risks of radiation exposure. Thus, the option highlighting antennas and RADARS accurately identifies a source of potential radiation hazards on an aircraft.