Above and Beyond... Nearly - S5-E20
Visible crew/equipment: In the dental clinic, when the possible MI is being examined, two actors' black tape marks become visible under the patient's chair, one below the footrest and another below the headrest.
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.
Visible crew/equipment: When Squad 51 arrives at Homer's house, we can see the outlines of the mic transmitter and wire on the back of the old cowboy's shirt.
How Green Was My Thumb? - S3-E17
Visible crew/equipment: When Johnny follows the nurse as she gets off the elevator on the fourth floor, the outlines of the mic transmitter and wire are visible on the back of the nurse's white uniform.
Visible crew/equipment: While Squad 51 is parked at ER receiving, John and Roy tell Dr. Early about the squad's engine problem, and when Early fixes the engine problem, we can see the reflection of numerous set lighting on the squad's chrome spotlight.
Loose Ends - S6-E12
Visible crew/equipment: During the fire at the train yard, when they carry out the second toxic fume inhalation victim from the boxcar, just before they pass the camera, the shadow of the camera tracking backwards is visible on the boxcar, to the left.
Visible crew/equipment: When Station 51 is being dispatched to 'auto accident with injuries' there's a closeup of Sam Lanier, the dispatcher, and in the next overhead shot of the apparatus bay, we can see the reflection/shadow of equipment moving on Engine 51's windshield, at the bottom left corner.
Captain Hook - S6-E8
Visible crew/equipment: When Roy, John, and Chet are standing near the stove talking about Hookrader's party, as they walk towards the table, the shadow of the overhead boom mic is moving over the cabinets on the right.
Visible crew/equipment: After John and Roy rescue the elderly man from the burning house, while Roy gets the man's vitals in the closeups, the large 12-light par bank rig is visible behind Roy at the left of the screen.
Visible crew/equipment: When Brackett, Early, and Morton enter treatment 1 to examine the hallucinating veteran, inside there's a young doctor standing to the left of the door. After Brackett tells Morton he wants an EEG, skull x-rays, and brain scan, when Morton heads to the phone to order the neurological workup, we can see the actor's white tape mark under the gurney, where the young doctor had been standing.
Visible crew/equipment: After the ambulance arrives at the lion pit, just as the attendants reach the fence where John and Roy are standing, and the stokes is loaded onto the stretcher, we can see the two white tape marks on the ground, where the zoo employee is standing.
Visible crew/equipment: When we hear Station 51 being dispatched to the structure fire at Kiddytime Toy Factory, just as Roy rushes to the squad's door to open it, we can see the reflection of the camera dolly through the squad's windshield as it moves.
Visible crew/equipment: After Engine 51 rolls up to the scene of Paula's car accident, when Captain Hammer stands up in the engine's cab, the reflection of production equipment is visible on the engine's chrome spotlight.
Visible crew/equipment: At the start, when Squad 51 rolls up on the car accident scene, in the shot from inside the squad we can see the entire area around the wrecked car, and there's only a utility pole, short wood fencing, and trees. When Roy and John are treating Paula, and then removing her from the car, in the overhead shots as the camera faces the wrecked car and 51's rigs, there's a very large rectangular shadow being cast over the car, which is presumably from a reflector screen facing the front of the car.
Visible crew/equipment: After Squad 51 is dispatched to the cliff rescue, when Roy and Johnny board Copter 10 at Rampart, the reflection of the production vehicle/equipment is visible on the glass surface at the helicopter's nose.
Visible crew/equipment: When the police officer who was struck by lightning is wheeled into the ER, just as Dixie, Brackett, and Early walk up the hallway, the two tape marks are visible on the floor right outside the doorway of treatment 2, where Dixie is about to stand. Additionally, we can see the outline of the transmitter wire on the back of Dixie's uniform.
The Wedsworth-Townsend Act - S1-E1
Visible crew/equipment: When Station 10 arrives first on scene at the factory fire, as 10's third rig pulls up and lays the line in the wide shot, at the left of the screen in the background, we can see the hidden second cameraman who is shooting the footage from that angle, of all the rigs pulling in and turning.
Visible crew/equipment: During Johnny's surgery, the top of the set is visible over the door area when the camera angle tilts up, just before Morton comments that there's blood and wonders where it's coming from.
Visible crew/equipment: While the guys are at the table eating Marco's stew, when Johnny remembers that he spent $8.42, numerous set lights are reflected on the coffee pot's chrome surface.
Visible crew/equipment: When Station 51 is dispatched to The Boat explosion, just after Captain Stanley responds, "KMG365," as he walks past the camera to the engine, we can see the open top of the set at the rear corner of the apparatus bay.
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.