Smyrna Air Center has authorized Stevens Aviation to participate in the Power 90 upgrade program. Under the terms of the agreement Stevens Aviation is authorized to install the GE M601 engine on 90-series King Airs. Smyrna Air Center holds the rights to the Power 90 conversion STC. According to a spokesman for Smyrna Air Center, the Power 90 upgrade is a conversion program for owners of the King Air 90, A90, B90, C90 and E90 in which the original PT6s are replaced with 705-shp GE M601E-11As. According to a July 2010 Conklin & de Decker analysis performed for GE Aviation on the King Air C90 Power 90 upgrade, it provides “significantly increased operating efficiency, reduced variable costs and net savings.” The comparative analysis of the GE engine against its competition was acknowledged by Vref, which recently recognized 100-percent of the conversion cost in the value added to a C90 after installation of the GE engine upgrade.