Major Alteration:

An alteration not listed in the aircraft, aircraft engine, or propeller specifications,    that:

(1) Might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) Is not done according to accepted practices or cannot be done by elementary operations.

Major Repair:

A repair that fits one or more of the following:

(1) Might appreciably affect airworthiness by changing weight, balance, structural strength, performance, powerplant operation, or flight characteristics if improperly done; or

(2) Is not done according to accepted practices or cannot be done by elementary operations.