Factual error: As the 1st Battalion, 7th Cavalry lifts off from LZ X-Ray at the end of the battle, it can be seen that there are no more American troops left at the battlefield. However, by the time 1/7 CAV left LZ X-Ray, it had been relieved by two full battalions (2/7 CAV and 1/5 CAV). There were around 700 American soldiers occupying LZ X-Ray by the time 1/7 CAV lifted off.
Factual error: Throughout the battle, the artillery rounds impact far too soon after they have been called in. While the artillery supporting 1/7 CAV at Ia Drang did have some pre-planned targets, it is impossible for any gun crew to receive a fire mission, adjust the gun, and fire the round as quickly as depicted (i.e., in a matter of seconds).
Factual error: At the end of the movie, Maj. Crandall is depicted as flying a UH-1 gunship, and attacking the NVA positions. Maj. Bruce Crandall was the Company Commander of A Co., 229th Assault Helicopter Battalion, 1st Cavalry Division at the time of the Ia Drang battle. A/229th was a "lift" company, flying UH-1D "slicks" (troop carriers). There were no gunships assigned to that company. The gunships (UH-1Bs) supporting the battle were from D Co., 229th AHB. It's highly unlikely that Maj. Crandall would have commandeered an aircraft from the gunship company to attack the NVA.
Factual error: Just after Lyndon Johnson announces that the air mobile units will be sent to Vietnam (1965), a dance/party scene has everybody dancing and singing 'Hold On I'm Comin' by Sam and Dave. It was a hit, but not in 1965. It was a mid/late 1966 hit, almost a year after that party. The Ia Drang Valley battle took place in November, 1965, before that song was recorded.
Factual error: Towards the end of the movie, at the last fight scene, you see the 1st air cav charging the NVA. As they go over a hill, you see the NVA waiting for them and then a helicopter gunship hovers down and kills all of the enemy. The gunship was using mini-guns which fires 6,000 rounds a minute. These were not used in Vietnam until late 1967. and were not in-country in 1965. In 1965, the gunships had two Flex M-60 machineguns on each side.
Factual error: The helicopter pilots wear two-tone Nomex fireproof gloves - these were not in use yet in 1965. Black leather flying gloves were issued back then.
Continuity mistake: During the transportation of the first wave of Air Cav soldiers (the one led by Lt. Col. Moore), the number of helicopters changes from around six, to around sixteen, then back to six.
Deliberate mistake: During the last assault against the hill, a duo of helicopters is mowing down the Vietnamese soldiers with miniguns. In one shot, you can see one chopper coming up behind a tree, all guns blazing. However, the tree, which is in the way of the helicopters right side minigun, remains totally untouched, although, looking at the carnage the guns do to the Vietnamese soldiers, it should have been reduced to toothpicks. (01:51:00)
Revealing mistake: The scene right after Mrs. Moore delivers the first batch of telegrams shows Lt. Col. Moore kneeling beside several "dead" soldiers. I could see at least the first four breathing.
Factual error: In the scene where the Chinook brings the reporters to the field at the end they use a CH-47D model. The 228th A.S.H.B, the Cav's Chinook unit, used CH-47A models with a tapered tail and no conical shrouding around the engine air intakes. Also the last round window in front of the engines in the A model was removed and not the bubble type on the D models. The D model was not used in the Vietnam war.
Continuity mistake: In the beginning where the soldiers are ambushed. One person goes to blow the trumpet (puts it in his mouth) and then the next frame has an up close shot bringing it up to his mouth again. (00:01:47)
Continuity mistake: During the scene where the cameraman is helping carry the badly burned US soldier he grabs the wounded man's legs. The leg skin & muscle slides down to his ankles exposing bone due to the severity of the burned flesh. A short while later the camera man is carrying the wounded man and his legs are blackened but no bone is showing.
Audio problem: When Hal Moore is looking at the strong guy through the binoculars during training, the guy's mouth doesn't match what he is saying.
Factual error: When Mel Gibson is ordering the soldiers at the dried river shore to expect an all out attack, text on screen tells us we are at dawn. Sunlight and shadow positioning reveals that it is actually 12 PM. Why didn't they film this at dusk? At least the light would have been more believable.
Continuity mistake: The blood on the face of the second-in-command of the French forces in the beginning constantly changes. First he got sprayed by blood from his commander, but even as he runs his fingers over the right side of the face its perfectly clean, the blood only covers front right side of his kepi, then as he covers from the jeep explosion its further back on the kepi. As he then gives orders to the trumpeter, the right side of the face is covered in blood, the trumpeter stands on the commanders left and sprays blood everywhere when he gets shot, but the commanders left side stays completely clean. Moments before and as he is stabbed, both his face and kepi is clean of any blood.
Factual error: When "Broken Arrow" is given over the air, there are shots of Navy A-6's being launched from carriers. The paint scheme on the aircraft is a modern blue-grey camouflage, not the white pattern used during Vietnam. More than the paint scheme, the Intruders depicted are the A-6E tram version which did not make their operational debut until 1979.
Other mistake: In the scene where Mel Gibson fires off a few rounds into the nearby woods and bushes to see if there are any NVAs, there is a M60 crew, the weird thing about them is that you can only see the muzzle flame from the M60 the first couple of rounds - after that there is no muzzle flame, but the M60 continues to fire at the same rate.
Factual error: Some scenes in the movie pertaining to activities at Fort Benning, Georgia are incorrect for the time period (1964-65, I believe). Scenes around the parachute training area (jump school) show a static display of a C-47 transport aircraft. I went through jump school in 1967 and the aircraft was not on display then. It is there today and was obviously there when the movie was being filmed.