30.310Level 530.31Manufacture of civilian air and spacecraft and related machinery30.31001Building of helicopters30.31002Manufacture of ultralight power-driven aircraft30.31003Manufacture and assembly of parts and accessories of aircrafts: fuselages, wings, doors, empennages, control surfaces, landing gear, fuel tanks, nacelles, etc.30.31004Manufacture and assembly of parts and accessories of aircrafts: engines of a kind commonly used for the propulsion of aircrafts and parts of turbojet and -turboprop engines