Other mistake: Many times during the series, soldiers are around the OR carrying a loaded weapon (magazine attached for example), when there is a sign outside the entrance that says "all weapons must be cleared before entering the building" or similar.
Suggested correction: With the rampant rule breaking seen in the show, why would this be a mistake?
Other mistake: In all the opening sequence of each episode, a group of people are waiting on the pad to get the wounded off the choppers. If you look closely as the group goes to move, the character Mulcahy is there, but it's George Morgan, who played the role in the pilot episode. From the third episode on, it was played by William Christopher, so it's the wrong actor for all the other episodes.
Continuity mistake: After Frank picks up the still, his hands alternate from left hand above right to right hand above left between angles.
Audio problem: The original "gin machine" is entirely metal, but when Frank throws it on the floor, you hear porcelain breaking.
Continuity mistake: This episode has the heater in Henry's office in front of the window, and the wall by the window blank. Later the stove is by the window, with the diploma by the stovepipe.
Factual error: In the Swamp, Frank is complaining about everything, and goes to grab the still. The stove it's sitting on is a Coleman model 413E camping stove, a unit not seen until 1954, and the series takes place in 1950.
Continuity mistake: When Radar walks into Henry's office to tell him that there's a general there to see him, we get a good view of Henry's new desk and its beautiful ornate design, but later when Hawkeye and Trapper are carrying the desk and then it's lifted out by chopper it's a completely different desk - also note that this desk has casters.
Factual error: Hawkeye and Trapper are concerned about the theft of a stock of hydrocortisone, but that drug wasn't introduced by the FDA until 1952.
Character mistake: In the opening scene, Hawkeye and Trapper are operating on a two-star general. But neither one of them or the nurse is wearing their masks. They are under their chins.
Requiem for a Lightweight - S1-E3
Continuity mistake: In the first shot of Trapper running behind the jeep, he has a large patch of sweat on his chest. For the rest of the scene it is dry. (00:13:00)
Requiem for a Lightweight - S1-E3
Continuity mistake: The bag used by Trapper for training is marked "Property of MAJ. Frank W. Burns". However, later in the series Frank's middle name is revealed to be Marion.
Requiem for a Lightweight - S1-E3
Other mistake: At the end of the show Trapper has a steak over his eye covering the black eye he received. Throughout the series the characters constantly complained about the food yet they have the audacity to waste a perfectly good steak.
Requiem for a Lightweight - S1-E3
Audio problem: When Margie is saying she is impressed, Trapper replies "I should hope so", but his mouth doesn't move.
Visible crew/equipment: When General Barker opens the doors to Henry's office and finds Radar sitting behind the desk, we can see Barker's curved chalk foot marks on the floor beside the desk, where the actor will stand in a moment.
Other mistake: At the end, after General Barker tells Henry that he should give Frank a high colonic and send him on a 10 mile hike, Klinger shows up in front of them supposedly naked, but we can see the top of whatever the actor's really wearing.
Character mistake: As Hawkeye goes to help Maj. Burns right at the end of the episode, he touches the patient with his bloody, contaminated gloves he used to work on the last patient. Such a blatant error would be anathema to any surgeon from the civilized world of the 20th century, let alone one of Hawkeye's caliber.
Other mistake: When they're playing poker, Hawkeye is sitting at an angle so that Sgt. Baker cannot see the earpiece that Hawkeye is wearing. However, Hawkeye sometimes turns his head enough for us to see his ear and, since the camera angle is over Baker's shoulder, Baker must have been able to see the earpiece too and realise he was being cheated. (00:13:20)
