37 Services of an aircraft engineer or a flight mechanic, namely, inspection prior to maintenance and repair, maintenance and repair, as well as mounting and installation works related to the conversion and modernisation of aircraft, cabin equipment and of parts thereof; installation, inspection of aircraft prior to maintenance and repair, as well as of aircraft parts and aircraft fittings, electric and electronic apparatus, data processing equipment and computers; all the aforesaid services exclusively for use in aircraft, in aircraft maintenance, in aircraft operation and in equipping the cabins of aircraft for entertainment purposes and for operating cabin equipment; inspection prior to maintenance and repair of aircraft and parts thereof; maintenance or repair of aircraft and parts thereof; mounting and installation works for equipping and fitting of factory-supplied or marketable new or used aircraft in the field of cabin equipment, the interior of aircraft, as well as parts of the cabin equipment or the interior; mounting and installation services for the conversion and modernisation of aircraft and parts thereof, as well as of aircraft cabin equipment; repair and maintenance of electronic and optical aircraft equipment, aircraft engines, aircraft motors and aircraft drive units consisting of machine parts, for third parties