Visible crew/equipment: When Station 51 is dispatched to the injured sky diver, we can see the area around the electrical tower when they arrive, particularly where Roy and Johnny start climbing up. When Johnny rappels down with Lucky, in the wide shot, just as they reach the ground the crew's ladder can be seen at the right side of the screen, in the same area where Johnny and Roy started their climb.
Visible crew/equipment: When the dispatcher drops tones for the trapped victim of a traffic accident, just after we hear Captain Stanley say, "KMG365," we can see movement between the front passenger and driver seats of Engine 51, precisely where the camera is. Captain Stanley is still at the radio base station and Mike hasn't opened the door yet.
Continuity mistake: When Johnny and Roy are with the heart transplant patient who is having chest pains, after they contact Rampart, in the wide shots Johnny has the stethoscope around his neck, but in his closeups the stethoscope is gone.
Visible crew/equipment: When Gage and DeSoto are stuck cleaning the squad again before The Inspection, Captain Stanley walks in and the actor's T-mark is visible on the floor just before he steps on it. Additionally, when Stanley walks away, and Chet catches up to him, another T-mark is visible on the floor near the doorway.
Continuity mistake: Just before the opening credits both Engine 51 and Squad 51 are inside the station. The alarm goes off and when Squad 51 leaves the station Engine 51 has vanished.
Continuity mistake: During the actual rescue of the boy from the overturned car in the water, Roy's, Johnny's, and Chet's shoes are water-type shoes, which then change back to their uniform shoes.
Other mistake: When Squad 51 is dispatched to an 'unknown type rescue', as the squad rolls out we can see the Crown engine from the show's first two seasons parked in the apparatus bay, instead of 51's current Ward LaFrance.
Revealing mistake: When Station 51 responds to the traffic accident, after Captain Stanley hands Johnny the Ajax tool, in the closeup it's obvious that the hands are not really Johnny's. Then there's another shot of the real Johnny, but once he removes his goggles, interestingly it's the stunt double who's in the following shots by the car, even when Johnny cuts himself, it's the stunt double.
Continuity mistake: After Station 51 is dispatched to 'traffic accident, victim trapped', when they get the anti-shock suit on the boy Roy's watch reads 5:25. Then at the hospital, when Johnny asks Roy about the time, Roy looks at his watch and says "About 5:00."
Continuity mistake: During Roy and Johnny's rescue of the sky diver, the stuntmen are not wearing the fire department uniform shoes, they are wearing different shoes, and Roy's watch differs as well.
Continuity mistake: When Johnny walks into the office to drop off the trash bin, he sees the Chief's clock on the wall and it reads 2:09, but when Johnny brings the clock to Captain Stanley and he gives it to Chet to hide, the clock's hands read 6:44. And when they're all dispatched, the timeout is 14:15.
Continuity mistake: At the scene of the vehicle accident, when the boy is removed from the overturned car, he has a bruise near his chin that reaches below his mouth area. When he's in the ER, that bruise is now twice the size and reaches his cheek area.
Continuity mistake: When Roy and Johnny climb the electrical tower to rescue the sky diver, in the closeups Johnny hangs onto the diagonal cross beam when he reaches out to Lucky, but in the wide shot the stunt double hangs onto the tower's main vertical frame when he reaches out to Lucky.
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.