Leaders need to be either the expert or able to speak knowledgeably with whomever the experts are under their direction. Many times someone is placed in a leadership position of something he/she is not an authority. It would best to become the subject specialist as quickly as possible, to ensure your appreciation for what others do and are expected to know. 

Personally, in my Marine Corps career, I was at times placed in a leadership position in charge of a skill group of which I was the least knowledgeable. I made a decided effort to become as competent as possible as fast as I could.  Examples would be, as a ballistic meteorologist, I became a noncommissioned officer in charge of a position survey squad. I had to learn how to determine True North using theodolites and the star Polaris. I needed to run traverse and triangulation surveys to within .001 mils of accuracy. This was a decade before GPS made this all unnecessary. 

Later, as a staff sergeant assigned to a howitzer battery, I became the operations chief in charge of fire direction control.  This would include organizing target data, forward observer information, position survey, meteorological reports, ammunition capabilities, and muzzle velocity variances for eight 155 mm howitzers. This, three months before being deployed to Southwest Asia to join the Desert Storm assault of Iraqi Forces occupying Kuwait. 

Most people know that there is seldom any time to casually learn a new job, let alone be the head of the operation. Knowledge, in extreme cases, saves lives. In normal situations, speeds the success of projects and earns the confidence and cooperation of all those you lead.