Chief Engineer Logan.
Lieutenant Logan was one of the Chief Engineers aboard the USS Enterprise-D in 2364. He came at odds with Geordi La Forge when the latter was placed in charge of the Enterprise. (TNG: "The Arsenal of Freedom")
Background
Logan was played by Vyto Ruginis. He appeared to have replaced Lieutenant Commander Argyle as Chief Engineer. However, Commander William T. Riker's line in TNG: "Where No One Has Gone Before" that engineering matters were overseen by "one of our chief engineers, in this case, [Mr.] Argyle" seems to imply that the ship had more than one chief engineering officer at the time. Therefore, it is possible that Sarah MacDougal, Argyle, and Logan all served as chief engineer simultaneously. This practice of having more than one chief engineer seems to have come to an end by 2365, when Geordi La Forge became the sole chief engineer of the Enterprise.