Clogged air filter detection for galley inserts

An air filter health monitoring system comprising:

• a filter, located on an interior side of an air inlet, spanning an air passage for filtering solids and/or liquids out of an air flow passing through the air passage, wherein air from an exterior ambient space enters the air inlet and is filtered through the filter before passing into an auxiliary cavity;
• an illuminator positioned on a first side of the filter, directed to illuminate the filter;
• an illumination sensor positioned on a second side of the filter, wherein the illuminator and the illumination sensor are a first sensing pair of a plurality of sensing pairs, each including a respective illuminator on the first side of the filter optically coupled with a respective illumination sensor on the second side of the filter, and the sensing pairs are arrayed in a pattern configured to detect area effects in the filter;
• and
• a controller operatively connected to the illuminator and to the illumination sensor, wherein the controller includes machine readable instructions configured to cause the controller to:
• illuminate the first side of the filter with the illuminators;
• detect an illumination from the respective illuminator passing through the filter with each respective illumination sensor;
• determine health status of the filter as an area phenomenon based on the illumination, wherein the area phenomenon includes a percentage of area of the filter that still has useful life;
• and
• output health information to a display, the health information comprising the percentage of area.