AVIONICS EQUIPMENT, NAMELY, STALL WARNING UNITS, GROUND PROXIMITY WARNING UNITS, HEAD-UP DISPLAY UNITS, VOICE AND DATA RECORDERS, TAPE TRANSPORT UNITS AND [ INERTIAL REFERENCE UNITS, ] BORE HOLE SURVEY APPARATUS AND WELL PRODUCTION SURVEILLANCE MONITORS, INCLINOMETERS, ACCELEROMETERS, THERMAL SWITCHES, DRILL POSITION MONITORS, [ WEIGHT AND BALANCE DETERMINING UNITS; AUDIO, FILM AND VIDEO ENTERTAINMENT SYSTEMS FOR AIRCRAFT, NAMELY, VIDEO CASSETTE PLAYERS, FILM PROJECTORS, VIDEO CASSETTES, FILM CARTRIDGES, PROJECTION SCREENS, AND AUDIO TAPE PLAYER UNITS; RING LASER GYROS, ] ELECTRONIC AIRBORNE NAVIGATION SYSTEMS COMPRISING RADIO RECEIVERS, ANTENNAS, NAVIGATIONAL COMPUTERS, DATA BANKS, INDICATORS, DISPLAYS AND CONTROLLERS AND PARTS THEREFOR; COMPUTER SYSTEMS, NAMELY, COMPUTERS, DISC STORAGE UNITS WITH DISC DRIVES, VIDEO DISPLAY UNITS AND KEYBOARDS, TAPE DRIVE UNITS, INTERFACE UNITS AND COMPUTER STORAGE CABINETS SOLD AS A UNIT WITH THE FOREGOING EQUIPMENT, AND COMPUTER PROGRAMS RECORDED ON DISCS AND DISKETTES FOR RECOVERY AND ANALYSIS OF FLIGHT PARAMETER DATA FROM AIRCRAFT DATA RECORDERS, [ DATA PROCESSORS AND COMPUTER PROGRAMS ENABLING PERFORMANCE OF ACCOUNTING AND MANAGEMENT FUNCTIONS FOR USE ON BOARD AIRCRAFT, SHIPS AND TRAINS, ] AIRBORNE RADIO TELEPHONES, AND PARTS THEREFOR, TEST STANDS, FLIGHT CONTROLS COMPRISING ACTUATORS FOR PRIMARY AND SECONDARY FLIGHT CONTROL SURFACES