Visible crew/equipment: On site at the construction accident with the back injury victim, when Roy climbs over the tower's railing we can see the yellow canvas strap attached through the leather loop of his lifebelt, but when he descends to the injured victim, the yellow canvas strap is now also attached to a carabiner protruding from under his turnout coat, by his pants, which presumably is attached to additional hidden support.
Camera Bug - S4-E10
Visible crew/equipment: After Johnny snaps the picture of Marco on the engine, when he prods Chet to go stand by the map, as the camera moves to the left we can see the reflection of production equipment/crew on the back of the squad, and we can even make out the shape of someone seated on a director's chair.
Camera Bug - S4-E10
Visible crew/equipment: When the stretcher with the unconscious teenager from the school fire is wheeled into the ER, while Roy is using the Ambu bag, just before they reach treatment 3 we can see the top of the set down the hall, near the nurses' station.
The Lighter-Than-Air Man - S5-E8
Visible crew/equipment: When Johnny brings in the box and Chet removes the wrapping for the baby layette, note the unfinished set wall past Engine 51 in the apparatus bay, which we can see since the front bay door is open, but when Captain Stanley walks in telling John about the phone call, the front bay door is now closed, then when the tones drop that set wall can be seen once again.
Daisy's Pick Blind Date - S4-E7
Visible crew/equipment: After Brackett's examination of Jerry, the unconscious 3 year old, when he goes to the waiting room and introduces himself to Jerry's parents, the top of set can be seen over treatment 1.
Visible crew/equipment: When the boy who ingested ant poison is being wheeled into treatment 3, in the shot from the hallway we can see the electrical cord and plug lying across the floor, but in the next shot from inside treatment 3, that cord has vanished.
Visible crew/equipment: At the horse ranch, after Bill falls off the horse again while the squad is chasing after him, when Roy kneels beside Bill we can see the shadow being cast by production equipment, presumably the reflector screen, on the ground behind Roy. Then after John checks Bill's ears and pulse, just as he contacts Rampart for the second time, we see movement which looks like a sleeve on the right side of the screen, beside John.
Visible crew/equipment: After Roy tells Jason that he has time to pop up to the orthopedic ward because it's Johnny's turn to cook, when Roy heads out receiving we can see the top of the set over treatment 1, right behind Johnny.
Paper Work - S6-E11
Visible crew/equipment: At the warehouse, when the foreman yells at Ed for stacking the flammable nitromethane steel drums unsafely, the outline of the mic transmitter is visible on the front left side of Ed's T-shirt.
Visible crew/equipment: When Station 51 is being dispatched to 'man down' at the hotel, in the overhead shot of the apparatus bay as the guys are getting into the rigs, the reflection of moving production equipment can be seen on Engine 51's windshield.
Visible crew/equipment: After rescuing the injured worker from the top of the sky-tower at Oceanland Park, when Mike has a problem starting 51's engine, we see reflections of array lighting on the squad's surface. And when Captain Stanley moans that he'll have to call Charlie, he stands in front of the engine and calls out, "Why me?" and one of the location's array lighting units is visible at the left side.
Visible crew/equipment: When Station 51 is on scene at the freeway accident, after the two girls are rescued from the wreck, when the explosion occurs Roy and John dive to the ground, and as the camera zooms out we can see the top of the location's array lighting unit, just past the engine's hose bed at the bottom left corner.
Visible crew/equipment: During the rescue at the jail, while Roy is hanging on the line, the outline of the mic transmitter is visible on his shirt at his left side.
Fair Fight - S6-E5
Visible crew/equipment: When Johnny and Roy get back to the station and walk into the day room, right after Marco says, "Well, either he's sick, or he's the laziest dog ever lived," we can see the shadow of the boom mic moving back and forth across the top of the wall, on the right.
Visible crew/equipment: After Station 51 is dispatched to the fire at a singles club, when Engine 51 pulls into the parking lot it and then turns around, the reflections of multiple array lighting can be seen on the engine's surface and Mike's window when he opens the door.
Pressure 165 - S5-E7
Visible crew/equipment: When Roy and Johnny are with Chef Michel, the outline of the mic transmitter can be seen on the front of Johnny's shirt.
It's How You Play the Game - S4-E19
Visible crew/equipment: When Johnny walks into the kitchen and gets the cold shoulder from Marco and Mike, and then when Chet walks in, the reflection of production equipment is visible on the oven's glass.
It's How You Play the Game - S4-E19
Visible crew/equipment: After Mike and Marco ignore Johnny as he walks into the kitchen, when Roy holds the chrome coffee pot and pours Johnny a cup of coffee, the reflections of the camera/lights are visible on the coffee pot's chrome surface.
Visible crew/equipment: When Roy tells Karen that she'll know when she can do it on her own when she'll have to, the reflection of set lighting is visible on the squad's chrome spotlight. Additionally, when Station 51 is dispatched to the structure fire the rear bay door closed, but when the rigs roll out the rear bay door is open.
Visible crew/equipment: After Roy and Johnny speak to Chet's friend the realtor, when Station 51 is being dispatched to the accident on Harbor Freeway, in the overhead shot of the apparatus bay, we can see the shadow/reflection of production equipment moving on the engine's windshield.
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.