Similarities and differences of operations and maintenance of three versions of the Bell 206B JetRanger III helicopter

U Hrvatskom ratnom zrakoplovstvu koristi se helikopter Bell 206B u provedbi praktične obuke studenata–vojnih pilota, za zadaće izviđanja, prijevoza ili zadaćama traganja i spašavanja. Postoje 3 inačice helikoptera: VFR (engl. Visual Flight Rules), IFR (engl Instrument Flight Rules) te NVG (engl. Night-Vision Goggles). Sve tri inačice se koriste za različite zadaće, pa su, prema tome, neke inačice opremljene uređajima i sustavima koje ostale dvije inačice nemaju. Helikopteri koji su opremljeni različitim sustavima, odnosno, opremom koja je prilagođena trenutnim uvjetima u kojima se djeluje, isto tako, imaju i određene različitosti kada se govori o održavanju istih. Svaki od pojedinih dijelova opreme u svakom trenutku leta mora biti ispravan i siguran za provedbu zadaće, tj. kako bi helikopter bio plovidben, što se postiže redovnim i kontinuiranim održavanjem i provjerama helikoptera dok je zemlji. Cilj rada je usporediti sve tri inačice helikoptera koje se koriste u Hrvatskom ratnom zrakoplovstvu na temelju njihove primjene, odnosno, na vrstu operacija koje obavljaju, vrste i načina održavanja istih. Također, analizirat će se program održavanja te zapisi i podatci o naletu i održavanju za duži vremenski period te na kraju utvrditi pojedine sličnosti i razlike između održavanja različitih inačica.The Croatian Air Force uses the Bell 206B helicopter in the implementation of practical training of students-military pilots, for reconnaissance, transport or search and rescue tasks. There are 3 versions of the helicopter: VFR (Visual Flight Rules), IFR (Instrument Flight Rules) and NVG (Night-Vision Goggles). All three versions are used for different tasks, so some versions are equipped with devices and systems that the other two versions do not have. Helicopters that are equipped with different systems or equipment that is adapted to the current conditions in which they operate, also have certain differences when it comes to maintaining them. Each of the individual pieces of equipment, at all times during the flight, must be correct and safe to perform the task, i.e., to keep the helicopter navigable, which is achieved by regular and continuous maintenance and inspections of the helicopter while on the ground. The aim of this thesis is to compare all three versions of helicopters used in the Croatian Air Force based on their application, i.e., the type of operations they perform, the types and methods of their maintenance. Also, the maintenance program, records and operation and maintenance data for a longer period of time will be analyzed, and finally some similarities and differences between maintenance of different versions will be determined