or informally referred to as "skipper." Commanding officers of aviation squadrons and smaller shore activities may also be informally referred to as "skipper" but never as "captain" unless they actually hold the rank of captain, e.g., military pay grade O-6, as would be the case for certain Fleet Replacement Squadron commanding officers and a wide range of both small and large shore activities. A commander in the Coast Guard may typically command a medium endurance cutter or a small air station. Like their Navy counterparts, a Coast Guard officer in the rank of commander who commands a cutter may also be referred to as "captain" as a courtesy title, or informally referred to as "skipper." Commanding officers of joint USN/USMC/USCG aviation training squadrons and small Coast Guard air stations and shore activities may also be informally referred to as "skipper" but never as "captain" unless they are commanding a large air station or shore activity and actually hold the rank of captain, e.g., military pay grade O-6. Although it exists largely as a maritime training organization, the Maritime Service also has the grade of commander. The commission is appointed by the president via the Secretary of Transportation, making it a federally recognized rank with a corresponding paygrade. In addition to its use as a rank title, the Navy also uses commander as a "position title" for senior captains or flag officers in command of multiple independent units, each with their own "commanding officer". For example, the senior officer in a Navy aviation squadron is the "commanding officer" (CO) because he or she is in command of that singular unit. That officer's immediate superior in command will likely be an air group or air wing "commander", with the latter being responsible for multiple squadrons. This is in keeping with the naval tradition of "commanding officers" commanding single units, but "commanders" commanding multiple units. Police ranks The Los Angeles Police Department was one of the first American police departments to use this rank. A commander in the LAPD is equivalent to an inspector in other police departments, such as the New York City Police Department. The LAPD rank was originally called inspector as well, but was changed in 1974 to commander after senior officers voiced a preference for the more military-sounding rank. A commander is the third-highest rank in the force, above the rank of captain and below deputy chief. Duties are