37 Construction of aircrafts, aeroplanes, helicopters and structural parts, fittings and components therefor, including rudders, fuselage panels, empennages, leading edges of wings, tailplanes and fins, landing gears, arresting hooks, gearboxes, skin panels, tails of aeroplanes and helicopters, elevators, wing flaps, ailerons, flaperons, doors, wing tips, stabilizers, horizontal tail planes, vertical tail planes and fins, winglets, sponsons, avionic bays, electric wiring harnesses, switchboxes and switchboards; installation services for electrical systems, computer systems; maintenance, modification and repair of electric and electronic devices and instruments for use in air vehicles and of electric and electronic apparatus for defense purposes; maintenance, repair, rebuilding, overhaul and modification of aircrafts, air vehicles, land vehicles and rockets and structural parts, fittings and components therefor including rudders, fuselage panels, empennages, leading edges of wings, tailplanes and fins, landing gears, arresting hooks, gearboxes, skin panels, tails of aeroplanes and helicopters, elevators, wing flaps, ailerons, flaperons, doors, wing tips, stabilizers, horizontal tail planes, vertical tail planes and fins, winglets, sponsons, avionic bays, electric wiring harnesses, switchboxes and switchboards; repair of aircraft parts; modification of land vehicles, air vehicles and rockets, as well as their structural components, parts and accessories