Factual error: At the end we see a soldier replacing the canister that the Zyklon B is kept in. However, he is not wearing an SS badge as all SS soldiers did. Zyklon B was only handled by members of the SS, as no other unit had authorisation to carry the sensitive stuff. (01:28:00)
Factual error: When Goodspeed crashes the Ferrari, his airbag deploys and he must shoot it to get out of the car. In reality, airbags inflate and deflate again in less than a second - the gas escapes through vents or the material itself, so there's no way for one to stay inflated.
Factual error: The actual Tsavo lions responsible for the killings had no manes - see for yourself; they are on display at the Field Museum in Chicago. [The filmmakers employed artistic license in using maned lions. They were also certain to include - at the very end of the movie - footage of the real Tsavo man eaters, as they appear in the Field Museum.]
Factual error: After the first victim they claim to have found a shell with 'Megan Turner' on it. That's not possible as we see Ron Silver fire at the victim and immediatley run away. If it had been an automatic then the gun would eject the shell, but it's a revolver, which doesn't eject shells.
Factual error: During the custody hearing, the Maryland flag in the courtroom is upside down. The rule for a Maryland flag is "black and gold, top of the pole," this flag has the red symbol at the top.
Factual error: When Jean-Claude is chased by the helicopter in the woods alongside the river, the man in the helicopter fires a MP5 machinegun, but it causes huge explosions, this is impossible, it's not a grenade launcher!
Factual error: We see Jason Statham walking into a shop in 1971 which has a Visa/Barclaycard logo on the door. Only problem with that is that the name Visa wasn't brought in until 1977.
Factual error: When Oddjob has the Lincoln crushed at the junkyard, it is smashed into a small rectangle, and dropped into the little falcon pickup. Even though the crushed car fits into the bed of the Falcon, it still weighs at least 2 tons. That weight would have dropped the back of the truck to the ground, but the truck doesn't even squat a few inches, let alone being able to handle that load with the tyres it has. (01:16:55)
Factual error: There is no possible way to cause a power line to drop from its support pylons and hit a person on target. These wires are fastened extremely securely, designed to withstand extremely high tension through all kinds of weather, and they are not equipped with some sort of explosive charges to release them.
Factual error: When Joe Patroni is attempting to move the stuck 707, Bakersfeld is standing beside his car watching, very close to the plane. Without some form of hearing protection, he would have been very quickly deafened by the noise - a 707 at takeoff thrust is incredibly loud. I once watched a 707 take off from about a half mile away and forgot to cover my ears - it was so loud it actually hurt.
Factual error: The scene where Nightfox steals the Faberge Egg is all wrong. A laser security system must have a photoelectric receptor at the other side to detect if somebody pass between the two devices. As shown in the film, the laser beams points everywhere, so the system can't work and somebody could cross a beam without starting the alarm. Even if it was some weird system based on measuring distance it wouldn't work - if the laser hits the floor at an angle it won't bounce back to the source, it will reflect towards the ceiling.
Factual error: The Apaches in the film are depicted with dual machine guns on each side of the cockpit, mounted directly on the windows. In real life, Apaches cannot mount such cannons, and instead use an M230 Chaingun in a turret underneath the helicopter, which the film Apaches have, but for some reason do not use. (00:49:25)
Suggested correction: Yes, we can all see they are supposed to be Apaches but not once are they mentioned by name. The US Army obviously didn't allow for real Apaches to be used. This isn't a mistake as there would have been no official licence to use the real deal.
Factual error: The cops try to get in the building by cutting some metal part of the door, it might be the lock. All they have to do is break the glass. SWAT teams aren't going to worry about a bit of property damage with hostages' lives on the line.
Factual error: In one scene they attempt to divert the ship by manually activating the ship's bowthruster. A thruster is a propeller in a transverse direction. This allows the ship to turn more efficiently when docking. However the thruster loses any efficiency above approximately 5 knots. In the film they use it at 17 knots. Secondly, a thruster is powered by an electric motor of at least 500 kW, yet they manage to turn it by hand. That handle does not exist in real life, and no one would be able to turn it anyway.
Factual error: When the air hose on the truck is severed, the brakes release. In reality, on an air-braking system, if the air hose is severed, the brakes lock on as a safety measure.
Factual error: The grenade Robert Neville uses at the end of the movie has a blue and brown colored lever. This feature is only used on the M69 practice grenade and not the real M67. The lethal grenade lever is completely green.
Factual error: During the chase with the semi, McClane is shown struggling to keep the truck under control with the freeway collapsing/blowing up all around him. He is shown making a left turn on a ramp, and the truck going up on 9 wheels, almost rolling. The shot cuts back to McClane steering left to to try to control the truck. If he were to steer left, as depicted, he would be guaranteed to roll the truck. If he was trying to get the wheels back down, he'd have to steer into the roll, or right, to bring it back on the wheels. At the end of the shot, you can actually see the stuntman brings the wheels down with a short right turn of the steering wheel. The similar entry in corrections is right, the person making the correction is wrong. During 15 years of driving a semi, I had a very similar situation with the truck almost rolling. I had to steer into the roll to bring the truck back on the wheels, not away from it, as the film showed McClane doing.
Factual error: When the action moves to England after the failed award ceremony, the British Union Flag hanging from the wall is upside down. The broad white band should be at the top left (nearest the top of the flag pole).
Factual error: As the two fast boats start heading up river towards the finale shootout, one boat has its navigation lights reversed. It has a red light on the starboard/right side, and a green light on the port/left side. It should be the other way around. (The lights on the other boat are correct.)
Factual error: The movie is supposed to take place over the course of a single summer. In one section of the film, Bobby is reading a story about VP Nixon's recent Presidential nomination, which took place in 1960. Later, he is reading a story of Maury Wills base stealing record, which occurred in 1962. (00:25:00)