The Girl on the Balance Beam - S5-E18
Visible crew/equipment: When Brackett and Morton go to the outdoor eating area to speak with Nancy's father, just as Brackett sits down and crosses his legs, the actor's T-mark is visible on the floor in front of his chair.
The Girl on the Balance Beam - S5-E18
Other mistake: The dispatcher gives the address of "woman trapped on a wire" as "Commercial Studios,1122 Dellini Plaza", and as Engine 51 drives past the front gates, the large sign reads "World Pictures Corp." Additionally, the address of World Pictures Corp is 1731 Carlson, when we see the same footage of Engine 51 driving past the sign in episode "The Exam" in season 6.
The Girl on the Balance Beam - S5-E18
Other mistake: Twice during this episode, when they're dispatched to a "woman trapped on a wire" and also to the "train fire", we see Engine 51 heading out with two firemen standing at the back of the engine, and they are Johnny and Roy. This footage is actually from the episode "The Old Engine" in season 3, when they got the new Ward La France engine for Station 51, and since Roy and Johnny were waiting for the previous shift to return with the squad, Captain Stanley told them to jump on the back and go with them on their first run with the new engine.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: When Johnny talks to Morton about the young gymnast and the responsibility of coaches and parents, the outline of the mic transmitter is visible on the left side of Johnny's shirt.
The Girl on the Balance Beam - S5-E18
Continuity mistake: When Roy and Johnny arrive on scene with the injured gymnast, as they enter the building in the exterior shot it's the last door that's open, but in the next interior shot that last door is shut, and it's the second to last door that's open.
The Girl on the Balance Beam - S5-E18
Continuity mistake: When Johnny and Roy are at the movie studio, while they're dangling from their lifelines they're trying to help the actress dangling from her own lines, but when she freaks out she drops her wand (yes, a wand) in the wide shot, but next closeup she's still holding it.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: While en route to the woman trapped on a wire, the reflection of the cameraman is visible on the windshield after Mike drives past the entrance to Commercial Studios. We see it's not Captain Stanley, but instead it's someone wearing a white shirt, holding up something (presumably the camera) with both hands.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: At the gym, when Nancy wants to prove that she's feeling fine, she tries to do a cartwheel, and the outlines of the mic transmitter and wire are visible on the back of her leotard.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: When the ambulance arrives at the scene of the drunk driver's car accident, and then when the drunk man is loaded into the ambulance, the reflection of the location set lighting is visible on the window, at the side of the ambulance.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: When Roy and Johnny are with the young gymnast, the outlines of the mic transmitter and wire are visible on the left side of Roy's shirt, as he takes her vitals and places the oxygen mask on her face.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.