Corrected entry: 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 Plus the mechanical E6B, even by 1990, had largely been replaced by electronic calculator type E6Bs by the airlines and even many private pilots.
Corrected entry: Just before McClane drops down from the vent to rescue the guy that's about to be killed from be the terrorist dressed as a painter, he fires 9 shots, and then he drops down and proceeds to shoot 14 more shots in the process of killing other terrorists, without reloading. His gun could not have held that many rounds. (00:45:45)
Corrected entry: When the aircraft start landing at the end, they all come in one after another, and we see them all parked at the end of the runway, (we don't see any of them turn off the runway onto the taxiways). That would never happen with commercial passenger aircraft. What if one of them had skidded on the ice and slammed into the rest? One would not land until the runway ahead was clear.
Corrected entry: Right before The Windsor flight crashes, the stewardess tells two passengers that they've made arrangements so they would make their next flight. Obviously this could only be done with communication with the ground. If they had sky phones the tower would have called them to warn what was happening.
Corrected entry: The terrorists some how raise the elevation of the airport in relation to the ILS (instrument landing system). This causes one of the jets to crash. The ILS glide slope is broadcast from a fixed antenna beside the runway, 1000 feet from the approach end. The glide slope is fixed at (usually) 3 degrees. Even if someone changed the slope (ie, degrees of slant), it would still terminate on the runway at the touchdown zone. Besides, the pilots have charts that give all pertinent information about the ILS and also have altimeters, radar altimeters, ground proximity warning systems (GPWS), and brains (duh). All of those systems listed are on board the aircraft, independent of the ground based systems. They would not have descended into the ground even if the terrorists had tampered with the ILS. (00:52:40)
Corrected entry: When John McClain sends Officer Powell the fax of the fingerprints, notice the direction he feeds the page into the fax. The middle two fingers' prints are the first two prints to go across the scanner, followed by the outer two fingers' prints. With a fax, the first thing scanned is the first thing printed. Therefore, when Powell received the fax, the middle two prints should be at the bottom of the page with the outer two prints higher up on the page. You can see when Powell removes the page out of the machine that this is not the case. (00:24:20)
Corrected entry: When McClain is arguing with Lorenzo in the police station, McClain shoots the gun at him with the blanks in it to make his point. Lorenzo walks over to the phone, picks it up, and says, "This is Chief Lorenzo." It has been established throughout the movie that Lorenzo holds the rank of Captain. (01:38:00)
Corrected entry: In the scene where McClain lights the trail of jet fuel, and the fire catches up with the wing of the airplane, for 11 seconds there are several shots of the wing explosion showing fire moving from the rear to the front, engulfing the bad guys. In the very next shot, there is a side view of an airplane exploding from the front to the rear. (01:50:25)
Corrected entry: At the start of the film when Bruce Willis is getting his car towed, he says says to the police officer 'Come on, cut me some slack, will you. Look, I used to be a cop in New York city. I only moved to LA because my wife took a job there. Come on, what do you say. Here we are, in Washington DC. The heart of democracy' it was meant to be Dallas International Airport in Texas?
Corrected entry: Look at the people carefully when they run out of the airport. They don't seem to have any hurry or rush. You have to watch single people to see it. (01:38:20)
Corrected entry: In the beginning when the terrorists enter the baggage area they go in, in civilian attire with nary a blink from anyone. 1st off, I don't care how lax security is, someone would have noticed. In fact, when McClane approaches the door, a ramp worker is right beside it. Was he asleep a minute ago? 2nd, they seemed to open the door with no problem but when Bruce Willis tries, the door is locked. 3rd, why is there not a soul in the baggage area beside 3 men shooting guns?
Corrected entry: Bruce Willis takes two torches out on the runway to try and save the plane that the terrorists are crashing on purpose. He is waving his arms back and forth in a fanning motion. When Dennis Franz and Fred Thompson see him from the tower, the orange lights that are supposed to be Willis are simply flashing on and off.
Corrected entry: A major plot element is that the terrorists have taken over the airport's radio system and that the hero's can't communicate with the planes overhead. The characters go to extraordinary (fatal) lengths to attempt to gain access to a radio that they can use to talk to the airplanes. The problem with this is that there are airplanes at airports. Every airplane has multiple radios that could communicate with other airplanes. All the vehicles that drive around the airport have radios. People carry handhelds. There are desktop units all over an airport.
Corrected entry: The error most fatal to this silly plot is the notion that shutting down the airport's communications will mean that no one can contact inbound aircraft. All one would have to do is go to any plane on the ground or use a handheld radio set to the tower frequency to advise inbound traffic of the problem. During the infamous blackout of 1965 that affected the entire northeastern U.S. for several hours, over 200 commercial aircraft landed safely at JFK airport in New York, in the dark, with no ILS, no runway lights, and no radio communication except radios working on aircraft sitting on the ground.