Butler National Corporation Announces FAA-Approved STC for CHRONOS Digital Clock with USB Chargers on Learjets

Mid-Continent Instruments and Avionics announced Butler National has received FAA Supplemental Type Certificate (STC) approval of the CHRONOS digital clock, that includes USB-A and USB-C chargers, on Learjet Model 24, 24B/D/E/F, 25, 25B/C/D/F, 28, 29, 31, 31A, 35, 35A, C21A, 36, 36A, 55, 55B, 55C, 60 and 60XR airplanes.

The FAA STC approval, STC No. ST00235MC authorizes the replacement of the existing OEM-installed clocks with the Avcon Industries/Butler Avionics designed installation of the Mid-Continent Instruments and Avionics CH93 Series CHRONOS Digital Clocks with USB Chargers. The installation fits within the same panel location and requires only circuit breaker and wiring changes. 

“Butler is pleased to have worked with Mid-Continent Instruments and Avionics to offer this very desired USB charging capability in the cockpit. Butler/Avcon has designed this retrofit installation to minimize customer impact and down time. Mr. Reedy added, “We received interests and requests to provide the new USB charging capabilities for the flight crew. CHRONOS mechanically installs the same as the existing clock.  Butler Avionics will make STC kits available for field installation of the clock with USB chargers. The STC is presently applicable to legacy Learjets and the extension of the applicability to other models will be gauged upon customer interest,” said Christopher Reedy, president and CEO of Butler National.

“CHRONOS is a simple, drop-in replacement for most existing clocks,” said Van Winter, director of aftermarket sales and support for Mid-Continent Instruments and Avionics.  “This cost-effective upgrade adds superior, FAA-approved functionality to the flight deck with minimal impact to the instrument panel.”