S3I requires at least four subject matter expert installers who have received formal (preferably military AND general aviation) avionics training and experience, or have received equivalent training and experience with an Original Equipment Manufacturer, Modifications will be accomplished under the provisions of CFR14 FAA Part 145. S 3 , Inc. is a rapidly growing Technical Services Company founded in 1991 and headquartered in Huntsville, AL, that provides technical, programmatic, and logistic services to U.S. Department of Defense, other U.S. Government agencies, and Partner Nation militaries, co-located with Government requirements.