Factual error: In circling over Washington Dulles, a plane would fly over several airports that they could land at with perfect communication, including Richmond, Baltimore, Andrews AFB, etc. Also, there is no communication from the airport to the plane but the plane would be in range of no fewer than 15 transmitting stations that could have relayed messages.
Factual error: When McClane is trapped in the cockpit of Esperanza's plane, and the terrorists throw grenades in, it sure takes them a long time to explode. At least a good 20 seconds passes before he ejects from the plane and the grenades go off. Normal grenades would have gone off long before 20 seconds.poehitman
Factual error: Firing a full magazine of blank cartridges from an automatic weapon in the police station office as McClane does would be painfully loud. Nobody shows the slightest effect - nobody even winces. Obviously the gunfire flash was a CGI effect and the sound was looped in later. (01:37:40)
Factual error: When McClane (Bruce Willis) is brought into Capt. Lorenzo's (Dennis Franz) office at Dulles Airport for the first time, Lorenzo mentions that McClane was in violation of several District of Columbia laws. Dulles Airport is in Virginia, not DC, therefore any DC laws would not apply to Dulles. (Although VA may very well have similar laws about airport misconduct.) (00:19:55)
Factual error: Near the beginning of the film when John McClane goes to the pay phone and calls his wife Holly on the airplane, that was impossible at the time. Those phones you see on the seats on the plane can only be used from the air to the ground not the other way around. Holly does answer on the plane phone and not on any cell phone she had in her purse. (00:04:20)
Factual error: At the end when John lights the fuel with a lighter, this isn't possible with Jet A-1 which is what the Boeing 747 is fuelled with. This type of fuel is extremely hard to light. Even if you drop a match into a bowl of jet A-1, it will not ignite. Jet A-1 has to be compressed or have its temperature raised to a minimum of 38c/100f in order to ignite (which the compressing also does) so fuel in snow would never ignite in the way shown.
Factual error: The plane from which Bruce Willis escapes by using an ejector seat is a non-existing plane. The fuselage is from an old transport plane from the US Air Force made by Chase. But there has never been a Chase with 4 engines buried in the wing. America uses underslung engines. In this case, it is the wing of an Arado Blitz prototype from the second world war and the fuselage of a Chase cargo plane. (01:15:10)
Factual error: Shortly after the terrorists first start taking over the airport, the airport's chief engineer is shown scurrying about with an E6B flight computer in his hands. The E6B is a mechanical device, usually made out of aluminium, that is similar to a old-style slide rule. But it is used only by pilots to calculate things like course corrections due to winds - there is absolutely no reason that an airport chief engineer would carry one on the ground, especially in a time of crisis. Plus the mechanical E6B, even by 1990, had largely been replaced by electronic calculator type E6Bs by the airlines and even many private pilots.
Factual error: When the terrorist clears the nearly fuel-exhausted plane to land on the lowered ILS, the terrorist says, "Windsor 114, you are cleared to land on Dulles Runway 29, ILS." Problem is: There is no Runway 29 at Dulles. The closest runway alignment for a 290 degree heading is Runway 30. (00:53:35)
Factual error: Several runway numbers are mentioned in the movie: runway 10, 15, 25 right and 25 left. Runway 25 means course 250. The opposite end would then be Runway 7 (course 70). It would be unusual for an airport to have runways running course 70, 100 and 150, as that is way too close. And Dulles certainly does not. In the church occupied by the terrorists, the radar display (the upright one with the circular LED pattern, not a scope) shows the runway configuration of Las Vegas McCarran airport, not that of Washington Dulles airport. McCarran does have runways 25R and 25L, which are mentioned in the film.Jacob La Cour
Factual error: When the bad guys 747 is blown up it is about 40 or 50 metres off the ground and travelling at take-off velocity, yet when Holly's plane is landing you can see that the debris field is perfectly circular. Surely the 747s speed and angle of descent would mean the debris field would be elongated? (01:50:30)barryween23