Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications -
(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or
(2) That is not done according to accepted practices or cannot be done by elementary operations.
14 CFR § 1.1
As used in Subchapters A through K of this chapter, unless the context requires otherwise: