Other mistake: As the woman that threw the grenade into the Medevac helicopter runs away they shoot at her from another helicopter. You can see by the puffs of smoke on the ground that the machine gun fire is not going anywhere near her, or her friend running in front of her as they fall to the ground dead. (00:44:30)
Continuity mistake: Right after the helicopter pilot says, "my tail rotors out, I've got control" they blow up the entire Vin Din Dop bridge ending with the side closest to the beach. In the next shot they blow up the same side of the bridge again closest to the beach. (00:44:45)
Continuity mistake: When Colonel Kilgore shows Lance the surf as they fly over the beach he says, "look, good six-foot swells" and his surf board is not on the side of his helicopter as it is in the next shot when they land. (00:45:10)
Continuity mistake: On the beach Colonel Kilgore says to one of his soldiers, "what do you know about surfing major, you're from New Jersey" look closely at the Vietnamese prisoners walking on the opposite side of the beach. They're always walking from left to right but several times in this scene they change their starting position from further down the beach (left of screen). (00:45:50)
Continuity mistake: There have been many shots of the surfboards as they flew to Vin Din Dop and they were all on the skids of the helicopters, now when Colonel Kilgore says, "do you wanna surf, soldier" we see the surfboards placed next to each lengthwise through the helicopter with their fins sticking out the side doors. (00:46:05)
Continuity mistake: After the helicopter attack when the chopper drops the patrol boat into the water, you can see the canopy and the radar type antenna break and collapse. When you see it again it's in perfect condition. (00:46:55)
Continuity mistake: As Colonel Kilgore calls out to the soldiers surfing in the water Captain Willard's band-aid on his right cheek appears out of nowhere for the first time in the movie. He had no band-aid on his face before this and we don't see him put one on, and there's no indication from the last time we saw his face that his scar started to bleed. (00:47:00)
Visible crew/equipment: As they sit in the foxhole watching the surfers, Lance's helmet gets wet and you can see the reflection of two studio lights, and the crew standing between them, in it. (00:47:10)
Audio problem: On the beach Colonel Kilgore takes the radio phone from one of his soldiers and calls in the napalm attack on Vin Din Dop. If you look closely at his lips they do not go along with what he's saying. This happens again two shots later when he sends the Vietnamese woman and her baby to the hospital by helicopter. (00:47:25)
Continuity mistake: Before the napalm attack we see a shot of the spotter plane flying over Vin Drin Dop and the place hasn't been attacked yet even though the battle has been going on for a while. There's no smoke and the bridge is still intact. (00:47:25)
Continuity mistake: The attack on Vin Din Dop starts out as a bright sunshiny morning and stays that way until Clean and Chief Phillips watch their boat drop into the river. There's no cut in the action but after this shot the cloud cover turns darker and it's late afternoon. (00:47:35)
Factual error: When LtC. Kilgore requests the air strike, you can see that the F-5s are not carrying any ordnance under their wings, except for a centerline fuel tank. Also, their color scheme varies from a white to a greyish one. (00:47:48)
Continuity mistake: There are four shots of the fighters that drop the napalm. The first time we see the jets there's only three of them and the part of the nose in front of the cockpit is painted black. The second time we see them there are five planes, the third time we see them there are four without black paint and the last time we see them there are three. (00:47:55 - 00:48:45)
Continuity mistake: Before the napalm attack as Colonel Kilgore gives Lance a pair of shorts to wear while he's surfing, there is yellow smoke visible on the beach between them and the other side of the bay. As the jets fly by and this spot is again visible the yellow smoke canister is not there. (00:48:35)
Visible crew/equipment: After a soldier hands Colonel Kilgore the Air-Cav shorts that he gives to Lance, the reflection of several crew members can be seen moving in the middle of the megaphone to the right of the screen. (00:48:40)
Other mistake: Kilgore watches from the beach after he calls in the napalm attack on Vin Din Dop. We see a large explosion but the three fighters never actually drop any napalm, they just fly over. (00:48:50)
Visible crew/equipment: Kilgore points at the jets as they approach the tree line just before the napalm explosion. Look closely above Lance's head as some stage equipment makes a very quick appearance. (00:48:50)
Continuity mistake: During the napalm attack there's one group of men marching on the other side of the bay. The next time we look over there right after the explosions there are two groups of men marching. (00:48:55)
Continuity mistake: Right after the napalm explosion there's a wide shot of the beach as Colonel Kilgore and the two soldiers with him look across at the destruction. We also see Lance sitting alone in the crater and Captain Willard is nowhere near them. They cut away to the PBR for three seconds then back to the crater and the Captain is sitting next to Lance again. (00:48:55)
Continuity mistake: The actual napalm attack burns quite a large area of the tree line and just two shots later Colonel Kilgore speaks the famous lines, "I love the smell of napalm in the morning!" At this time, when we see this area is still smoking, quite heavily, however, the amount of destruction is much less and there is very little fire visible. (00:48:55)
Answer: It should be noted that "transmutation" is a word Coppola has used to describe the film making process. Https://m.youtube.com/watch?v=LFTQcwgq4CY.
Bishop73