Ke iho mai nei ko luna - S9-E13
Continuity mistake: McGarett is going to free dive to Neptune 1 to take some scuba tanks to the crew below. We see him get in the water, and there is one tank ready to be passed to him. In the next shot he is being given the tanks, only now there are two. (00:37:10)
Ke iho mai nei ko luna - S9-E13
Factual error: Full aluminum scuba tanks are 1.5 pounds negatively buoyant when full of breathing air. Two of them would be 3 pounds negative. Yet McGarrett is using them to propel him down to 127 meters as if they were very heavy weights. (00:37:25)
Ke iho mai nei ko luna - S9-E13
Factual error: Three divers arrive at Neptune 1 submarine station where they test the atmosphere at 3% oxygen, 80% helium, 17% nitrogen. Breathing that much helium would make their voices quite high pitched. But their speech is normal. (00:14:30)
Ke iho mai nei ko luna - S9-E13
Factual error: A Neptune 1 dweller is suffering from a panic attack. One of the Five-O members asks if they have any oxygen. Using pure oxygen at that depth could be fatal. At 14 atmospheres of pressure - the pressure of Neptune 1 - pure oxygen would definitely cause oxygen toxicity. Oxygen toxicity is a concern for scuba divers who dive beyond recreational depth limits, use gas blends such as enriched air nitrox, or use 100% oxygen as a decompression gas. Pulmonary oxygen toxicity causes a burning sensation in the trachea, coughing, shortness of breath, and eventually lung failure. (00:14:45)
Hala I Ke Ala O'i'ole Mai - S9-E11
Character mistake: Ensign Rollins is shown in her office in a flashback. Her boss comes up and addresses her as "Lieutenant Rollins". An Ensign (O-1) is not a Lieutenant (O-2 or O-3). (00:32:40)
Hala I Ke Ala O'i'ole Mai - S9-E11
Continuity mistake: The McGarrett team is seen loading a US Coast Guard C-130H. Shortly thereafter, a takeoff shot shows a C-130, but it is not a Coast Guard aircraft. (00:08:10 - 00:11:00)
Pio ke kukui, po'ele ka hale - S9-E10
Continuity mistake: Before the gunfight, Joe tells Steve not to wait too long to find someone. There's a shot of the boards over the window beside him, and they're fully intact. Seconds later, when he says "no visual", well before the gunfire actually starts, they're suddenly riddled with bullet holes.
Mimiki Ke Kai, Ahuwale Ka Papa Leho - S9-E3
Continuity mistake: At the start, Meaghan Rath winds down her window and leans out to yell at the guy behind her. Leans back in, we cut to a shot outside the car and her window is instantly up.
Pua a'e la ka uwahi o ka moe - S9-E7
Other mistake: This episode shows a newspaper article about a Rolls Royce Phantom involved in an accident/murder. The article specifies it is a black car with a red interior. When the car is dug up, it has a black interior. (00:37:45)
Pua a'e la ka uwahi o ka moe - S9-E7
Continuity mistake: McGarett starts to work on a case file on his kitchen table. It is evening. His wrist watch says 9:13. The scene dissolves several times as he yawns and finally falls asleep. The wrist watch now says 9:10. (00:09:45)
Pua a'e la ka uwahi o ka moe - S9-E7
Continuity mistake: Right at the beginning of the show McGarrett and Dano are driving. The left windshield wiper is missing, then it is there in the next shot. Then both wipers are missing missing a few seconds later. (00:00:50)
Audio problem: After Steve and Danny are seated in Jerry's car, the sliding door they just entered through is already closed while still making a closing sound.
Continuity mistake: Steve chases Jesse into a building. She opens a heavy door to the outside, slowing her down, and as she goes through he's about 10 feet behind her. We then cut to her running along a walkway and he's somehow dropped back another 20 feet.
Pa Make Loa - S2-E21
Continuity mistake: When he picks up the NCIS agents at the airfield, Danny drives his car up behind the plane and parks very close to it. As the three go back to his car however, it is parked at least fifty meters away and parallel to the plane.
Character mistake: Owing to a common misconception, several people in the episode claim that the consulate is Russian soil. Foreign diplomatic missions are awarded special privileges, but they are not considered sovereign territory of the represented state.
Factual error: Contrary to what Steve says, the U.S. do have an extradition treaty with France, which has been in effect since 2002.
Continuity mistake: During the police chase there are flashing blue lights visible on Chin and Kono's faces during the interior shots, but from the outside of the car only the flashers in the grille are working.
Character mistake: In episode 6-6 Steve explains to Danny that a 'klick' means a kilometre, 0.62 of mile, to which Danny replies: "Oh, thank you, G.I. Jerk, for the pedantic, uh I know what a klick is." In this episode, when Steve again uses the term 'klick', Danny replies: "You know, no-one can understand you when you say stupid things like klicks.", which prompts Kono and Chin to give the exact same explanation as Steve did in season 6.
Factual error: The plane taking McGarrett from Panama to Mexico purports to be owned by a Mexican fishing company. But the registration number on the plane starts with an N and has 5 numbers and a letter. First of all, a Mexican aircraft would not have a registration number starting with an N. That is reserved for aircraft of US registry. All that aside, the registration number is invalid. US aircraft have at most five characters after the N. The registration - as I suspected - was shown to be in an invalid format when queried in the Federal Aviation Administration database. (00:11:18)
Ke iho mai nei ko luna - S9-E13
Other mistake: A Five-0 member makes an atmosphere check of the Neptune 1 air. It shows 0.7% oxygen, 80% helium, and 16% nitrogen. A previous check had shown these were the only gases present. So what happened to the other 2.3% of the air? Helium and Nitrogen should have been proportionately higher so as to add up to 100%. (00:29:45)
Chosen answer: They are Junior's SEAL buddies.