Leader understands that he/she doesn't have to know everything in order to lead. But he/she know that they need to have a skill to search for resources within his/her own circle: the people he/she is leading. Here is one great example,
Henry Ford took a journalist to court for libel as the journalist had claimed in the article that Henry Ford was not only a bit dull but really rather stupid.
The defending barrister at the libel action put Henry Ford into the witness box and bombarded him with questions on general knowledge and history, asking such diverse questions as: 'Will you explain Einstein's theory of relativity?' etc.
To the majority of the questions Henry Ford replied with: 'I am sorry, I don't know the answer to that.'
The lawyer turned to the jury after this lengthy questioning and said: 'I think I've proved my point.'
To which Henry Ford the replied: 'Hang on a minute. You have been asking me all these questions for the past two hours, none of which, if I knew the answers, could help me to run my business or help me to build more effective motor cars. On my desk I have a console of buttons and if I needed to get the answer to one of those questions while in my office I know exactly which button to press and could provide you with the answer within seconds."
He went on to win his case. You don't need to know everything, people around you may have the answers, and that is what team for.
Do you have your 'buttons' to push when you need answer?