Plot hole: Commodore Decker takes over command of the enterprise but Spock says if McCoy can certify him incompetent (which he obviously is) he can be relieved of command. McCoy says he will certify him now, so why doesn't he? In other episodes it has been stated that McCoy can order anybody regardless of rank to an examination to see if they are physically or mentally fit.
Star Trek (1966)
1 plot hole in The Doomsday Machine - chronological order
Visible crew/equipment: After McCoy examines Charlie and they talk about how Charlie learned to talk by just listening to the ship's tapes, when Charlie stands up the two actors' marks can be seen on the floor - the short one for Charlie and the longer one for McCoy, where they both will stand momentarily. (00:04:56)
Trivia: Gene Roddenberry created the transporter as an easier (and cheaper) way of getting Enterprise crew members onto a planet's surface, rather than landing the ship on the planet.
What Are Little Girls Made Of? - S1-E8
Question: When the Enterprise is in orbit, it uses the Impulse engines to maintain orbit. The Impulse engines are located on the back (aft) of the primary saucer. Why were these not on or lit up? Unless they're using gravity, but there are the familiar engine sounds.
Chosen answer: If they're in orbit, they're being pulled along by the planet's gravity well, therefore, impulse engines would only be used for minor corrections and would be "on standby" while in orbit, but not active. (Like keeping your car idling without revving the engine and creating plumes of exhaust).
Thank you for the info.
Answer: Happy to help.