When Aubrey briefs Mitchel Gant about the homing device, he mentions that it will pick up Mother-1 within 100 miles. However, on board the Firefox when Gant's homing device picks up Mother-1, he is over 140 miles out.
When Col. Kontarsky receives the sketch of Gant he recognizes "him" as the "GRU Officer" who confirmed the order to have the dogs search the tree line. GRU Officers were members of military intelligence and wore the standard uniforms of the Soviet Army, Red insignia and piping for most Army officers and light blue for Airborne. Yet Gant/Eastwood is wearing the same dark blue colors, only worn by the KGB, as Kontarsky. No KGB officer would mistake their own uniform for GRU. Additionally, GRU had no internal security function and held a deep rivalry with KGB, making it highly unlikely a GRU officer would be allowed near any KGB guarded project like the Mig-31.
After the explosion in the hangar, you can see Mr. Gant in the shower during the alarm. A few moments later he's seen in his pilot's uniform heading toward the "Firefox". It's very unlikely that Mr. Gant can go from the shower to having a pilot's uniform in the hanger area in such a short period of time.
When the submarine goes up to break through the ice, you can see an antenna or periscope sticking out above the submarine. When seconds later it's broken through the ice and at the surface no antenna or periscope is visible.
In the scene where Pytor Baranovich is in the Firefox, Colonel Kontarsky is staring at him, at a short distance away from the Firefox plane. Baranovich looks at him with his head turned to the left. But when the camera has a closer shot of Colonel Kontarsky looking at Baranovich, Baranovich is looking back at him, this time with his head turned to the right.
When Gant gives the command to fire the missiles, he uses the command "skaitie pierva rakieta" which translates roughly as "Launch First Missile." However, this is the only command that is given (i.e. he does not give a command to launch the second, third, or fourth missiles) to launch all his ordinance.
After Gant takes off from the ice after refueling, he retracts the front stabilizers of the Firefox into a "V" shape. The next shot of the plane shows them out at 90 degrees again. This is actually a shot of Col. Voskov's Firefox in pursuit of Gant. However, during the climatic dogfight, Gant does indeed extend the forward wings to their full, 90 degree extension.
Gant is shown in the cockpit of a white T-38A jet fighter trainer, and then it immediately cuts to a blue-camouflaged aggressor squadron F-5 Freedom Fighter. This happens twice in the training sequence.
When the dissidents describe the pilot to Gant, they use his correct title of "colonel". However, when Gant runs into the chief of security in the hangar (Gant's first view of the Firefox), whilst Gant is wearing his Colonel's uniform, the chief of security addresses him as "captain".
After the Firefox is stolen, General Vladimirov explains to the First Secretary that in order to maximize fuel range, Gant will have to control his speed and fly low to conserve fuel. The part about controlling his speed is true enough: speed, particularly with afterburners, is the enemy of fuel consumption, but flying low is exactly the opposite of what he should do. Airplanes - jets, in particular - burn far less fuel at higher altitudes where the air is thin than down low where it is thicker.
In the Soviet Union no foreign car were used by state owned
companies like delivery service. But despite having Soviet's offroader UAZ logo on the hood and similarity with UAZ 452 in general, they do drive a foreign delivery car from Moscow to Bilyarsk.
The Aeroflot plane that Gant buzzes shortly after stealing Firefox from the Soviet airbase is clearly a Boeing 727 as opposed to the similarly configured Tupolev Tu-154 that would've been flying in the Aeroflot fleet at the time. Also, the plane's livery features a wide red stripe down the fuselage, whereas all Aeroflot liveries throughout the Cold War have been blue.
When the US submarine, code name "Mother 1" surfaces, you see an underwater shot of the vessel pushing out air from the ballast tanks in order to surface. This is actually the exact opposite of how a submersible works. Air would not be taken from the ballast tanks but instead pumped in.
The missiles that were "borrowed" from the MIG 25 in Syria were too small. The missiles carried by the MIG 25 are roughly 15 feet long and weight close to a ton and would not be able to be carried by hand as the crew of the sub is seen doing.
When the sub crew hooks up the SPR (Single Point Refueling) connectors, they twist the handles to lock the connector and then move away. This was only half of the movements required to transfer fuel. There is an arm the must be pushed forward after the connection is made which opens a valve inside to allow fuel to flow. The crew doesn't move these arms, so no fuel would flow into the aircraft.
When Gant sets the co-ordinates for home, the display shows C - 70' 42 2, B - 80' 18 0. Firstly it should show 70° 42' 2" and 80° 18' 8" - the first figure in a co-ordinate is degrees, not minutes. A co-ordinate in minutes only makes no sense.
We can assume that the C and B refer to North and East (Severo and Vostok in Russian, but Russian S looks like C, and Russian V looks like B). The co-ordinates 70° 42' 2" N and 80° 18' 8" E are in the permafrost forest about 80 miles from the Kara Sea, which about where Gant may well have been when he downed the enemy Firefox, in which case the error is that he claimed to have set the co-ordinates, whereas the display still shows where he is now.
His nearest US destination would be Clear AFB in Alaska, at 64° 17' 27" N, 149° 10' 48" W, a distance of 2,817 miles, a tight but not impossible run skirting the geographic North Pole, given that it was stated in the film that the Firefox has a 3,000 mile range. A slightly shorter run would be to the NATO base at Thule, Greenland operated by the US 821st Air Base Group. At 76° 31' 52" N, 68° 42' 11" W, the distance is only 2,182 miles, although he remains in Russian airspace longer on this flightpath, and despite his speed, may be vulnerable to Russian ground-to-air defenses.
All of the air control/defense technicians manning the various consoles at Bilyarsk wear the proper shoulder badges, but they all wear the distinctive dark blue collar flashes and shoulder boards with the Cyrillic characters "GB" for KGB. KGB troops would never be trained or assigned to such purely technical air force duties. These personnel should be wearing the same light blue piping and flashes as the air force generals commanding the center.
"Speed is in excess of Mach 5, even Mach 6 and able to maintain it. Our best body design begins to melt at Mach 3." The SR-71 Blackbird had a cruising speed of Mach 3.2 and could achieve even faster speeds without "melting".
The Firefox is described as being able to reach "Mach 5, even Mach 6, and maintain it." However, the overall design of the aircraft is not nearly aerodynamic enough for such speeds. Experimental Mach 6 aircraft flown by NASA resemble surfboards with fins, not the design sported by the Firefox. Also, the aircraft is powered by turbine engines, which are unable to operate above speeds much higher than Mach 3 (the real life SR-71 Blackbird, the fastest plane in the world, used turbojet/ramjet engines and was able to reach speeds of only Mach 3.35, about half the Firefox's top speed).
Whenever the Firefox launches a missile, it shows a single launch from the Firefox's weapon's display, yet from the target view, two balls of light representing the missiles are showing - no air-to-air missile, known or unknown, can split mid-flight, let alone track the same target twice.
The entire performance of the "thought guided" missile system that was highly touted was never realized as the breakthrough it was, albeit it totally unrealistic. His contact inside the U.S.S.R. even said, "now, you don't even have to push a button...", yet in the first battle scene inside the Firefox, Gant is manually arming the weapons systems, with the gun firing (red) button, no less. Additionally, we are told at the beginning that the "sensors inside the helmet" automatically seek out and detect threats according to the pilot's thoughts, yet in the final scenes, it is a long, drawn-out dogfight. If what was true about the thought-guided threat attack system, the second prototype that was attacking Gant would have never survived after the first missile attack. Instead, Gant is taking evasive action for minute after minute, needlessly flying through mountains, doing barrel rolls and all kinds of acrobatic maneuvers. Yet, he did not think to launch the "rearward" missile until after he recovered from his flat spin by lowering the landing gear?
After the Firefox has landed on the ice floe, he asks the sub commander to steam off a 3,000 foot runway in the three minutes he has until the Soviet investigative forces arrive. There is no way that the sub crew could steam a section of ice that long in three minutes, let alone go back to the sub, find the hoses, hook them up, let alone have 3,000 feet of steaming hose, let alone having enough pressure to do the job.
After one of the metro trains pulls out of the station in 'Moscow', the German word 'KURZZUG' (=short train) is clearly visible on the wall behind it - indicating that a German-speaking country (in fact Austria) was used to double for the USSR.
When Gant is walking towards his hotel (Moscow) we can see Red Square with St. Basil's cathedral at the background which is obviously a picture, not a real thing, and of poor quality besides. Moreover, there's no hotel by Red Square in the direction he was walking. Hotel Moscow is situated at the opposite side, about 2km distance from the point of "shooting".