Concorde

Temperature sensors are required on type certified aircraft that employ nickel cadmium aircraft batteries for starting engines or auxiliary power units to comply with the requirements stated in FAR 23.1353, 25.1353, 27.1353, and 29.1353. Although there is no similar requirement for lead acid aircraft batteries, functioning temperature sensors are provided allowing aircraft to be converted to Concorde lead acid batteries without modifications as true drop in replacements.