Lieutenant Logan was one of the chief engineers aboard the USS Enterprise-D in 2364. He came at odds with Lieutenant junior grade Geordi La Forge when the latter was placed in charge of the Enterprise-D by Captain Jean-Luc Picard.
Logan came to the bridge and asked La Forge to hand his command over to him explaining that he was the Starfleet officer having more experiences in such situations. La Forge asked him several times to leave the bridge and later gave him the direct order to go back to main engineering while fighting a Minosian weapon in orbit of Minos.
When La Forge decided to do a saucer separation and battle the enemy only with the stardrive section, he placed Logan in command of the saucer section and gave him the order to approach Starbase 103. (TNG: "The Arsenal of Freedom")
|Chief engineers of the starships Enterprise|
|Enterprise NX-01:||Tucker • Kelby|
|USS Enterprise-D:||MacDougal • Argyle • Logan • Lynch • La Forge|
|USS Enterprise-E:||La Forge|
|ISS Enterprise NX-01:||Tucker|
|ISS Enterprise (NCC-1701):||Scott|
|USS Enterprise (alternate reality):||Olson • Scott • Chekov|
Logan was played by actor 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-D.