Peace on Us - S7-E2
Revealing mistake: Klinger says "The sun is going to ruin my comb-out", fingering his hair net. He has curlers under his hair net, but his hair is not around the curlers, they're just stuffed into his hair net. (00:01:10)
Peace on Us - S7-E2
Visible crew/equipment: When Radar gets off the phone with the guard at Panmunjom and tells Colonel Potter and BJ that Hawkeye's gone on ahead, at the start of the next shot we can see the back of the soundstage set at the top, right side of the screen. And notice that Hawkeye's and the guards' voices are echoey on the soundstage in this shot.
Peace on Us - S7-E2
Revealing mistake: When Colonel Potter's in the Swamp telling Hawkeye, BJ, and Charles that surgeons' rotation points have increased from 36 to 45 Hawkeye becomes incensed, and in these two shots from this angle we can see the edge of the Swamp set at the top, left corner of the screen.
Peace on Us - S7-E2
Continuity mistake: When Hawkeye, Charles, and BJ are in the Swamp, Hawkeye starts his roll about being sick of green, and by the time he heads outside and talks to Margaret the blood splatter on his surgical gown changes.
Peace on Us - S7-E2
Continuity mistake: As Hawkeye storms out of the Swamp, he leaves Charles, Potter, and BJ behind. After the angle changes, you can see there is nobody in the tent, and the still is missing.
Answer: The C-42 was a military variant of the Douglas DC-2. Very few C-42's were built, so it's questionable that Potter would specifically have seen that particular model, but, given his military background, it's not entirely unreasonable that he might use the military designation even when the aircraft in question is actually a civilian DC-2.
Tailkinker ★