Questions are not problems
Questions are not problems, questions bring us one step closer to solutions. When an employee comes to you (Manager) with a question he is not bringing a problem, he is bringing you one step closer to the solution. He expects you to have better overview of the situation and hence the question to you. Don't think questions are problems and tell your staff don't bring problems, bring solutions. If he doesn't question he may spend time in trying to figure out a solution for a problem that doesn't exist. A question is a a way to know something that we don't know currently. Encourage staff to question more.