The Galactic Empire: An Empire Reborn
Imperial Officers' Manual
Major Revision: 2.0 – 2008.10.31
An adaptation of the pre–Endor document and policies.
RIP  cylinders
... A Lieutenant's Rank Insignia ...

Within the standard Imperial Navy, the rank of Lieutenant (LT) is afforded to squadron leaders of starfighter squadrons and bridge crew team leaders.

A Lieutenant leads and manages the day to day operations of a Starfighter Squadron, consisting of twelve starfighters and up to eleven other pilots, and are to see to the efficient operation of their squadron. Alternatively, a Lieutenant may lead an Bridge Crew, consisting of up to seven other junior officers.