Depends in which sector you work; Line Maintenance engineers interact with several parts of an operator's set-up every day. Keeping a cool head in an AOG situation is vital; communicate regularly with your Maintenance control department and let them deal with all the other people. Stand your ground if you know you are right but do not be afraid to ask if you are not sure of anything. It is a great job (most of the time!).
In short, you do need some "people skills" but common sense and common courtesy will get you a long way.