“Source code” for the operation or maintenance of any inertial navigation equipment, including inertial equipment not specified in 7A003 or 7A004, or Attitude and Heading Reference Systems (‘AHRS’). Note: 7D002 does not control “source code” for the “use” of gimballed ‘AHRS’. Technical Note: ‘AHRS’ generally differ from Inertial Navigation Systems (INS) in that an ‘AHRS’ provides attitude and heading information and normally does not provide the acceleration, velocity and position information associated with an INS.