Factual error: Near the end of the episode, Jackie Cooper fires a bullet into his hotel room from the balcony using a revolver fitted with a silencer. Hayward also uses a revolver with a silencer to kill Stone. This is a classic Hollywood error, as silencers do not work on revolvers (unless noticeably modified), due to the gap between the barrel and the cylinder. They also don't make gunshots nearly as quiet as shown.
Factual error: When Mrs. Williams takes Columbo flying, she does some aerobatics. Neither of them is wearing a seatbelt. No pilot would do that.
The Bye-Bye Sky High I.Q. Murder Case - S6-E3
Factual error: A "silencer" (properly called a "suppressor") does not muffle a gunshot to a whisper. An unsuppressed gunshot is about 160 dB, equivalent to a jet airliner taking off, but a suppressed gunshot still registers about 100 dB, equivalent to a power lawn mower. Also, a suppressor on a revolver is totally useless, because most of the noise comes from the gap between the front of the cylinder and the rear of the barrel.
The Most Dangerous Match - S2-E7
Factual error: Clayton tells Columbo that he had purchased a new transistor for his hearing aid. Hearing aids - even the old types in use in the 1970's - do not have any user-replaceable parts. The only thing that can be replaced is the battery.
Factual error: All LAPD officers must re-qualify with their weapons multiple times a year. If indeed Columbo could not "hit the target," as he says to another detective, he would never have made it through the police academy, much less have become a detective and have been promoted to sergeant and eventually to lieutenant.
Factual error: Columbo asks for a red wine. His host orders a Beaujolais but the butler brings a Bordeaux. Beaujolais is from Burgundy, not Bordeaux. (01:18:40)
A Bird in the Hand... - S11-E3
Factual error: The license plate on the automobile of Stallions football team owner Fred McBain reads STALLION1, but personalized California license plates can not have more than seven characters ( http://www.vanityplatebystate.com/alphabetical-listing-of-states/california/).
Factual error: Columbo solves the case based on fingerprints on the shell casings in the gun. No gun, even a prop gun that never fires live rounds, would be put away loaded.
Factual error: Columbo is sent to investigate the murder of a man near the Santa Monica Pier. Santa Monica has its own police department. The LAPD has no jurisdiction there.
Factual error: The nurse is smoking a cigarette in the sick bay. By 1975, when the show was recorded, that would not happen.
Factual error: The nurse brings Danziger a sedative and takes his blood pressure. She has her stethoscope in her ears backwards. A qualified nurse would not make that mistake. When she comes in after the murder to do it again, she has the stethoscope in correctly.
Factual error: Several times, the revolver used to murder the singer is referred to as a "Weatherby" or "British Weatherby." Weatherby is an American manufacturer of rifles and shotguns; they do not make handguns. The revolver used is a Webley, which is of British manufacture.
Factual error: Santini murders Jerome using a revolver with a silencer. Although this is one of the oldest Hollywood tropes, a silencer (properly called a suppressor) does not reduce a gunshot to a whisper; it only cuts the noise to about 110 dB, which is still very loud. In addition, suppressors do not work at all on revolvers, because most of the noise is generated in the gap between the cylinder and the barrel.
A Bird in the Hand... - S11-E3
Factual error: They are watching a football game on TV with The Stallions playing some other team. The game they are watching is actually a Canadian Football League game between the Edmonton Eskimos and the Saskatchewan Roughriders.
Answer: In the show, he was already a Lieutenant. A promotion would put him in the next rank up, which for the L.A.P.D. would be Captain. However, some of a Captain's duties would be overseeing other officers and ensuring they're compliant with policies, regulations, and standards. It would also most likely take him out of the field. This is something Columbo has no desire for as he rarely goes to police HQ's. Nor does he show interest in compliance and standards (for example, not going to his semi-annual evaluation at the firing range). However, he could still be assigned to a higher pay grade based on expertise, which is a form of promotion that does not include rank advancement. This would be going from Lieutenant I to Lieutenant II. I don't believe in the show it's ever started what his pay grade is. Although, in s02e01 (I believe) he mentions making $11K a year. Whether or not this was a true statement on his part, if you could find pay scale information for an LAPD Lieutenant in the 70's, it could give you an idea of his pay grade.
Bishop73