Revealing mistake: During the rescue of the man trapped in the submerged car, when 110's Captain hands John and Roy (in the water) the special cave-in gear's air hose, then when he opens the O2 valve and also when he revs up the jaws, we see that The Boat's port side has a taught line tying it off at the stern in the closeups (seen from The Boat's deck) to prevent it moving, but in the long shots there is no line.
Revealing mistake: After Brackett has played the tape of 110's rescue for Roy and Johnny, when they get into the squad, the usually highly reflective chrome surface of the driver's side spotlight has been sprayed with a 'dulling spray', to temporarily dull the finish for this shot.
Dinner Date - S2-E10
Revealing mistake: In episode 2x5, "Peace Pipe", when Brackett gets on the line with Johnny, who's at the scene of the drunk driver's accident, Brackett presses two buttons - the third and fifth, to record the conversation on the tape machine. However, in this episode when Dixie gets on the line with Johnny, while he's with the little girl whose arm is stuck in the pool drain, Dixie presses only one button - the second, to record the conversation.
Revealing mistake: After Squad 51 is dispatched to the motorcycle accident, there are wide shots of the squad driving through the hills, then in the closeups of Roy and John, the squad shakes from side to side to mimic driving, but we can see that the surrounding rocky area behind the squad (matte painting) does not actually change at all.
Above and Beyond... Nearly - S5-E20
Revealing mistake: When Roy and Johnny are on the cliff loading the unconscious victim onto the stokes, as they try to lift each of the victim's legs, we can see the unconscious man also lifting his own leg to assist the actors.
Revealing mistake: After the snakebite, when the guys carry Johnny and place him at the back of Engine 51, the chrome spotlights are shiny and reflective, but in the closeups the spotlight near Marco has been partially sprayed with a dulling spray, to prevent the camera's reflection.
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.