Fluid level sensing arrays for aircraft

An aircraft comprising:

• a fuselage;
• a fluid container having one or more side walls, the fluid container configured to hold a fluid;
• a fluid level sensing array comprising:
• a mounting strip coupled to an inner surface of the one or more side walls of the fluid container, the mounting strip defining an internal cavity and an outer surface;
• and
• a plurality of fluid sensing nodes coupled to the mounting strip in a collinear arrangement, each fluid sensing node switchable between a plurality of fluid detection states including a fluid present state and a fluid absent state, each fluid sensing node comprising:
• a prism;
• a photoemitter coupled to the outer surface of the mounting strip such that the photoemitter is interposed between the prism and the mounting strip, the photoemitter configured to emit light into the prism;
• and
• a photoreceptor coupled to the outer surface of the mounting strip such that the photoreceptor is interposed between the prism and the mounting strip, the photoreceptor receiving greater than a threshold amount of light from the photoemitter internally reflected by the prism in the absence of fluid around the prism to switch the fluid sensing node to the fluid absent state, the photoreceptor receiving less than the threshold amount of light from the photoemitter when the prism is covered in fluid to switch the fluid sensing node to the fluid present state;
• and
• a processor to determine a fluid level of the fluid container based on the fluid detection states of the fluid sensing nodes;
• wherein, the photoemitter and the photoreceptor are located outside the internal cavity of the mounting strip;
• and
• wherein, the prism is coupled to the outer surface of the mounting strip via the photoemitter and the photoreceptor.