"Parts of the aircraft were found as far as six-tenths (estimated) of a mile from central wreckage. The parts were scattered north to south. The aircraft came straight down in a horizontal position and landed on the left side. The left wing came off while in the air and landed 100 feet from the central wreckage. The aircraft did not slide forward after contact with the ground."
It was noted in the record that Mantell had "Violated AAF [Army Air Forces] Reg. 60–16 Par. 43. However Capt. Mantell was requested by Godman Field Control Tower to investigate objects in the sky, causing this Officer to go above limits of AAF Reg. 60–16."
They recommended, quite naturally, that all pilots again be briefed on the use of oxygen equipment and the effects of the lack of oxygen on the human body and mind.
It's clear from the reports and documentation available that the cause of the accident was Mantell's violation of the regulations and his climb above 25,000 feet. Contrary to what some writers have suggested, there were no mystery wounds on Mantell's body, the aircraft was not riddled with nearly microscopic holes, or that outside forces knocked the plane from the sky. Mantell had made a tragic mistake by climbing too high. The lack of oxygen and oxygen equipment is what killed him.
But even with a mundane explanation for the crash and Mantell's death, there was no explanation for what Mantell had chased. That was the second prong of the investigation.
Air Force investigators, or in this case, Air National Guard investigators, explained the UFO as Venus. According to the astronomical charts available, at the time of the initial UFO sighting, Venus could be seen in the daylight sky in the approximate location of the UFO. Satisfied that they had found an answer, they completed their work.
Astronomers consulted acknowledged that Venus would have been visible, but doubted that a random search of the sky would have found it. Although bright enough to be seen in the daylight, it would have blended easily into the surrounding sky. If there was even the lightest of haze, Venus probably wouldn't have been visible to those on the ground. Or, in other words, Venus was not an acceptable explanation, and the cause of the sighting would have to be found elsewhere.
Later, official investigations suggested a huge balloon, or two balloons, and finally two balloons and Venus had caused the sighting. The investigating officers believed that someone in the tower sighted Venus, lost sight of it, but then as they searched the sky for the unknown object, spotted one of the two balloons. They suggested that Mantell had chased a weather balloon.
There were those inside the military who weren't happy with that answer. They spent a great deal of time on the Mantell case probably because of the sensational aspects of it. Here was a World War II ace killed while chasing a flying saucer. There was a closed casket funeral and a secret investigation. It certainly had all the elements of a great mystery, a great story and a grand conspiracy.
At one point Air Force investigators settled on Venus as the final answer. In the official files, one of the reports goes into depth about Venus. "However, under exceptionally good atmospheric conditions and the eye shielded from the direct rays of the sun, Venus might be seen as an exceeding tiny bright point of light. It can be shown that it was definitely brighter than the surrounding sky, for on the date in question, Venus has a semi-diameter of six seconds of arc… While it is thus physically possible to see Venus at such times, usually its pinpoint character and large expanse of sky makes its casual detection very unlikely." They were, in effect, saying that Venus was visible but they didn't think it was the answer.
The Air Force investigator was not finished with the Venus double-talk, however. He wrote, "The chances, of course, of looking at just the right spot are very few. Once done, however, it is usually fairly easy to relocate the object and call the attention of others to it. However, atmospheric conditions must be exceptionally good."
What all this does, is suggest that after saying the object might have been Venus was that it couldn't have been Venus. Although Venus was in the right spot at the right time, it probably does not account for the object seen by those in the tower.
Venus was no longer the preferred answer. The official report said, "It had been unofficially reported that the object was a Navy cosmic ray balloon. If this can be established, it is to be the preferred an explanation."
But this report was anything but consistent. Having said that it was Venus, that it wasn't Venus, and that it was a balloon, the investigator now explained why it wasn't a balloon. "If one accepts the assumption that reports from various locations in the state refer to the same object, any such device must have been a good many miles up… 25 to 50… in order to have been seen clearly, almost simultaneously, from places 175 miles apart."
Now, having run through all sorts of explanations, the investigator wrote, "It is entirely possible, of course, that the first sightings were of some sort of balloon or aircraft and that when the reports came to Godman Field, a careful scrutiny of the sky revealed Venus, and it could be that Lieutenant [sic] Mantell did actually give chase to Venus."
Having gone through all that, the investigator now explained why he believed that Mantell had chased Venus. It did not appear to move away from him. Of course, if the object was, in fact, an extraterrestrial spacecraft, it might be that it was maneuvering to avoid the close approach of Mantell's fighter. That idea didn't seem to cross the mind of the Air Force investigator, and that says something about the mindset of the military as they were writing their reports.
The final conclusions of the report are a masterpiece of double-talk. Now the investigator wrote, again, that it was Venus, but for that explanation to work properly, he needed a balloon and one other object as well. Given these three items, though there is no evidence that all three existed, he believed he could explain the case. He wrote, "Such a hypothesis [that is, Mantell chasing Venus] does still necessitate the inclusion of at least two other objects."
All of this suggests something about the investigations as they were being carried out in that era. It was a search for labels, but not necessarily a search for solutions. They were willing to accept nearly anything as an answer as long as they could remove a mysterious case from the files. And Mantell's case, because of the sensational aspects, as well as the public interest, was certainly one of those to be solved at all costs.
By late 1948, the Air Force became disgusted with the idea of UFOs. In the reports Air Force officers created, they explained as many of the cases as they could and suggested the remainder could be explained if there was sufficient information. They found nothing to suggest that UFOs were real. The problem, if ignored, would go away.
In 1952, a major magazine wanted to print an article about how spectacular UFO sightings had been explained through proper research and investigation. Because the spin of the article was that flying saucers did not exist, the Pentagon cooperated with the writer and the magazine. High-ranking Air Force officers assured the magazine editors that Mantell had chased Venus. In a move that was sure to anger the reporter and the magazine editor; a week after the magazine was published, the Air Force released a new answer. Mantell had chased a balloon.
In the early 1950s, the UFO project was reorganized, and cases that had been "solved" were again examined. Ed Ruppelt, seeing that the Mantell case was one of the thickest, asked for a microfilm copy of it. Unfortunately, something had been spilled on part of it, so that it was difficult, if not impossible, to read.