A total of 108 Grimes lights (48 exterior, 6 interior and 54 instrument post lights) are installed on the airplane. Multiple exterior lighting systems can be selectively energized in flight to provide immediate comparison under prevailing weather conditions. Used extensively through the 1970s and early 1980s, N8640E also made numerous public demonstrations, including spectacular night flights during Urbana's Fourth of July celebrations, and several air shows, including the Paris Air Show in 1975.