I am studying propulsion and thinking to change my specialty to aircraft maintenance , is it good option for long term .
I think these are two very different areas and it really depends on what your goal is for the future (and what you like to do). My Air Force experience is quite diverse and I have worked in both areas. I have been an aircraft maintenance manager and I have worked on jet propulsion projects. There is huge job scope in both areas, although aircraft maintenance is much more specific to that area.
From a propulsion perspective, the study could lead to roles in new technology, research and design or in a more managerial role for engine development and capability.
From an aircraft maintenance perspective, you're managing maintenance resource and procedure. Understanding implications of maintenance on aircraft, identifying risks, improving procedures, looking at alternative ways to achieve a task. There is a lot of problem solving required and working with / bringing together your team to achieve this.
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