Mid-Continent Instruments has received an approved model list (AML) supplemental type certificate (STC) from the FAA for its MD835 lithium emergency power supply. The award is the first FAA Part 23 approval for a lithium nanophosphate battery through the AML STC process. Thirty aircraft are included in the STC, including the King Air 90, 200 and 300 series, Beech 1900, Beech Premier and Cessna Citation 501, 525A/B. The new battery offers operators of these aircraft an easily installable option for the standby battery requirement. Mid-Continent’s TSO C179-certified MD835 is a direct replacement for older lead-acid L-3 PS-835 batteries and incorporates the same mounting rack, power harness and cockpit arm/off/test switch. The new battery weighs less than five pounds, a saving of more than eight pounds compared with the lead-acid design. Operators will see a reduced maintenance schedule as well, since the MD835’s bi-annual check is half as frequent as the yearly legacy battery’s required service, and its life expectancy of 10 years is more than three times longer.