Chief engineer

Definition from the Star Trek Encyclopedia: A Reference Guide to the Future 2nd Edition...

Chief Engineer. Aboard a Federation Starship, the officer charged with responsibility for the operation and maintenance of the ship's power, environmental, and other key systems.

Lieutenant Craig Mitchell, USS Excalibur
 * Chief Engineers
 * Commander Charles Tucker III, Enterprise NX-01
 * Commander Caitlin Berry, USS Enterprise (NCC-1701)
 * Commander (1701)/Captain (1701-A)Montgomery Scott, USS Enterprise (NCC-1701), USS Enterprise (NCC-1701-A)
 * Commander Geordi LaForge, USS Enterprise (NCC-1701-D), USS Enterprise (NCC-1701-E)
 * Chief of Operations Miles O'Brien, Starbase Deep Space 9/ Starship USS Defiant
 * Lieutenant Nog, Starbase Deep Space Nine/USS Defiant
 * Lieutenant Commander Be'lanna Torres, USS Voyager
 * Lieutenant Commander Vorik, USS Voyager
 * Lieutenant Commander Burgoyne 172, USS Excalibur
 * Lieutenant Jil Barnak, USS DaVinci
 * Lieutenant (j.g.) Nancy Conlon, USS DaVinci