Can the owner of a light-sport airplane add new equipment such as avionics, instruments or additional lighting?
New equipment and accessories can be installed in normal-category airplanes through the FAA’s STC process or by FAA field approval. The FAA issues an STC (supplemental type certificate) to describe exactly how new equipment, avionics for example, can be installed and in which models of airplanes. Licensed mechanics make the installation and record in the logs that the work was performed in accordance with the STC specifications. Another method is the field approval, which can be difficult to obtain, in which an FAA inspector examines the modification and approves it just for that individual airplane. In an LSA it is the original manufacturer that affirms that the airplane meets the ASTM standards that define the category. Because an LSA design is not specifically certified by the FAA as a normal-category airplane is, the FAA cannot issue an STC for the airplane. That means only the original LSA manufacturer can approve adding new equipment or making other changes in the airplane. If so
