Visible crew/equipment: When Evelyn and her husband pull up in front of Graymar Plaza, while they're talking in the car, in the shots facing Evelyn the reflection of crew members standing beside the car, on the driver's side, is visible on the building's glass doors.
Visible crew/equipment: When Engine 51 gets dispatched to their first run on the new Ward LaFrance engine, Captain Stanley tells Johnny and Roy to get their gear to go with them. When the paramedics go to the closet to get the turnout coats, the bulging outlines of the mic transmitters and wires are visible on the sides of their shirts before putting on the turnouts. The outline of Johnny's mic transmitter is also visible when he first walks over to the new engine.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: When the ambulance arrives at the scene of the drunk driver's car accident, and then when the drunk man is loaded into the ambulance, the reflection of the location set lighting is visible on the window, at the side of the ambulance.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: When Roy and Johnny are with the young gymnast, the outlines of the mic transmitter and wire are visible on the left side of Roy's shirt, as he takes her vitals and places the oxygen mask on her face.
Visible crew/equipment: When Johnny removes David's red helmet after his motorcycle accident, the reflection of array set lights are visible on the red surface.
Visible crew/equipment: After Roy climbs down the manhole, he leans to the right (the second time), and when he points the flashlight down the tunnel on the right, the moving shadow of camera equipment is visible on the wall. We know it's not Roy's shadow because when he leans back to the left, that shadow is still moving on the tunnel wall.
Visible crew/equipment: When Roy and Johnny are dispatched to the plant with an 18 yr old whose arm is caught in a machine, the outlines of the mic transmitters are visible on the left side of Johnny's shirt, when he's on the Biophone, and on the left side of Roy's shirt, when he's putting the tourniquet on the 18 yr old.
Visible crew/equipment: After Dianne's OD, once she passes out and Johnny begins to work on her and inserts the esophageal airway, the bulging outlines of the mic transmitter and wire are visible on the back of Johnny's shirt.
Captain Hook - S6-E8
Visible crew/equipment: When Marco is speaking with the deputy at the site of the wrecked chopper, the bulging outline of the mic transmitter is visible on the left side of his shirt, above the belt.
Continuity mistake: When Johnny and Roy are in the staff lounge waiting for Dr. Morton, Johnny's holding the newspaper's sports page, and in the page's close-up, there is a large picture of Brice centered between two columns of articles. However, when Johnny's talking to Roy and Dr. Morton, that page is entirely different even though he hasn't turned the page.
Continuity mistake: The day after the awful fish dinner, when the Merkles visit the station again, Roy is holding a can of whipped cream in his right hand in the side shots, but in the shot facing him he's holding a carton of milk.
Visible crew/equipment: When Roy and Brice are taking vitals of the possible heart attack, depending on the angle of the shot, the outlines of the mic transmitters can be seen on the backs of Roy's and Brice's shirts.
Continuity mistake: When Johnny is hit by the car, the open drug box is lying on the ground right-side up in the first shot, then upside down in the second shot.
Deliberate mistake: When Roy and Johnny are on Copter 10, just after dispatch tells them that the run is cancelled, there is a shot of Copter 10 turning around which is a flipped shot - note the backwards 10 on the tail.
Loose Ends - S6-E12
Continuity mistake: When Roy and Johnny are driving to the hamburger stand and stop to have a look at the squad's fanbelt, in the interior shots Roy is wearing his watch while driving, but when he exits the squad the watch has vanished.
Other mistake: Stoker prematurely plots 617 Kimble Road on the map as the dispatcher is barely starting to say the address. Then the squad leads in the departure from the station, but when the squad arrives to the above dispatched location the engine is already finished with the dumpster fire.
Suggested correction: 1st part of the mistake is already noted and 2nd part is incorrect. The Engine and Squad are dispatched to 617-1/2 Kimball for unknown type rescue and Squad leads. At the destination, Captain Stanley walks to the front door and rings the bell, while off camera Roy and Johnny get rescue gear and join Stanley at front door. Dispatch then sends the Engine to a trash container fire at Farber/Wilmington, while Roy and Johnny's Squad stays with the current rescue involving dieffenbachia. After this, the Squad joins the Engine.
Inventions - S3-E22
Character mistake: Dr. Brackett calls Dr. Early "Jim." In the show, Dr. Early's first name is "Joe."
Other mistake: When the plane crashes into the neighborhood and traps Gage and DeSoto in the house, you see outside shots of the squad when the other two paramedics arrive. You can see a large piece of smoking engine/plane laying on the back end of the squad, right over the spare air tanks. They would have exploded when something that heavy and hot landed on them, since they are filled with oxygen. The tanks would be full or they would not be on the back of the squad.
Suggested correction: Probably air tanks, because oxygen tanks are always painted green. Both kinds of tank are very tough. Hard to tell with how much force the plane debris might have landed except that the truck still looks pretty much intact. However, if the plot required it, I would find it completely believable that the crash could have exploded the tanks, but also don't find it strange that they didn't explode.
Smoke Eater - S4-E16
Continuity mistake: After Dr. Early is called a miracle worker and then again tries unsuccessfully to get the apple from the machine, it cuts to Squad 51 pulling backwards into the apparatus bay, and the engine we see parked in the bay is the Crown from the first two seasons, not their current Ward LaFrance.
Smoke Eater - S4-E16
Audio problem: While Roy and John are with the asthmatic boy, Roy's on the Biophone with Rampart, and we hear Early say, "Administer 0.3 milligrams epinephrin IM," but his mouth is not in sync with the last part, and it looks like he actually said, "Epinephrin IV."