Visible crew/equipment: At the scene of the plane that hit the building, after the explosion, when Foam 10 arrives there's a closeup of the firemen using the foam tubing, and behind the doorway one of the 'firemen' kicks the foam tubing, but notice that he's not really a fireman, he's actually a crew member who's wearing a turnout coat, though he's also wearing jeans and work boots.
Visible crew/equipment: When Mr. Laurents visits Station 51, as the guys stand up the actor's T-mark is visible on the floor, between DeSoto and Chet, just before Chet promptly stands at his mark.
Visible crew/equipment: After Johnny and Chet begin their arm wrestling, when dispatch drops the tones, there's movement at the front seats of Engine 51 where the camera is located, while Captain Stanley is at the radio base station and Mike is putting on his turnout.
Revealing mistake: At the structure fire at an abandoned building, when Engine 164 arrives we see that it has distinctive markings beside the driver's side door and tire rim. When Engine 72 arrives the same markings are in the same place, revealing that it's the same engine and they used different magnetic number decals for the engine.
Revealing mistake: When Station 51 is dispatched to "plane that hit building," after they rescue the two aboard the plane, just before the explosion when the orange combustible drum is propelled into the air, we can see the stunt's projectile to get the drum airborne.
Continuity mistake: After Roy explains to Mrs. Evans that she shouldn't call them every time Simba runs off, when Chet finds Simba, Johnny holds him with his right hand behind the front legs and left hand under the tail, but closeup Johnny's hands are in the opposite positions.
Visible crew/equipment: At the structure fire at an abandoned building, when Engine 164 arrives, we can see the reflection of the location's array lighting in the driver's side window.
Visible crew/equipment: After Johnny reads the note from Mr. Laurents, which he left with the package of money in the fridge, Captain Stanley walks over to the counter, where the actor's T-mark is visible on the floor.
Continuity mistake: Before Mr. Laurents walks into the station with the bag of money, Roy's holding the coffee pot with his right hand, then it's in his left hand, between shots.
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.