OCTOBER 22, 2013 - UNITED STATES - Forty years ago today, a four-man crew of an Army Reserve helicopter was flying over Mansfield, Ohio, around 11:00 p.m. when they "encountered a near midair collision with an unidentified flying object," according to the official report, signed and submitted by the crew after the incident. A full explanation for this terrifying UFO close encounter has never been offered, and to this day, the helicopter-UFO incident remains one of the most credible -- and terrifying -- in the history of the subject. The commander of the helicopter, Maj. Larry Coyne, and his crew, thought at first that the light on the horizon was a radio tower beacon. "We were flying along at about 2,500 feet when the crew chief on the helicopter observed a red light on the east horizon. He then informed me that the light was closing on the helicopter -- that it was coming at us on a collision course," Coyne told this reporter in 1975. "I looked to the right and observed that the object became bigger and the light became brighter, and I began to descend the helicopter toward the ground, to get out of the collision course path. We were descending and this object was like a missile locked onto the helicopter, only it came at us on a perpendicular angle, to hit us almost broadside. "It looked like we were going to collide with it and we braced for impact, and then I heard the crewmen in the back say, 'Look up!' and I observed this craft stopped directly in front of us -- stopped -- it was hovering, right over the helicopter!" (See main story illustration above)WATCH: Watch this video excerpt of the Coyne account from a documentary report. This 1973 UFO incident, while certainly dramatic and terrifying for the helicopter crew involved, is not the only time that conventional aircraft have had encounters with unknown objects. Many crew members of major airlines have witnessed unusual objects near their aircraft but have been reluctant to tell their stories publicly. In 1999, Richard Haines, a retired senior research scientist for the NASA-Ames Research Center in California, created the National Aviation Reporting Center on Anomalous Phenomena, or NARCAP, to give pilots and air traffic controllers a confidential place to report their own unusual sightings of what Haines refers to as unidentified aerial phenomena, or UAP. "We have two objectives: To make flying safer with regard to unidentified and poorly understood phenomena in the atmosphere. And the second objective is to collect, analyze and then report high quality data from the aerospace world on the phenomena, to help us understand them better," Haines, 76, told The Huffington Post. According to Haines, on an average daily basis, since the creation of NARCAP, he's received six to 12 reports a year. He absolutely believes there are real dangerous or safety issues that come up between pilots and some UAP. "Based upon analysis of past cases, a potential for a very serious event does exist," Haines said. "We have reviewed a great many encounters in flight where several things can happen. One of them is an electromagnetic effect in close proximity to the phenomenon, where cockpit instrumentation are affected -- it might be a magnetic field, radio interference or even an inertial effect, and that's obviously unsafe. Pilots don't want to be flying airplanes where they can't trust their instruments." Another area of concern that Haines and his colleagues have found is similar to what Coyne and his helicopter crew experienced in 1973. "It's where a UAP is near the airplane, perhaps ahead of the plane, and the pilot makes a rapid emergency dive to avoid a perceived collision. That's not very common, but it would have to be reported. It has happened in the past and there are still near-misses that occur which sometimes are associated with a nearby UAP." Haines has always been impressed with the Coyne helicopter incident. "It qualifies as a genuine UAP encounter. Multiple witness cases are very important and should command the attention of aviation officials. In the Coyne case, its color, speed and apparent shape -- those are all important physical characteristics that can be related to other pilot sightings. "I think the Coyne case ranks very, very high in credibility. One reason is Coyne's reputation as a good pilot before this happened. And his courage -- the fact that he was willing to come forward with this very bizarre story and to stand by it says an awful lot. And he would give encouragement to other pilots to do the same. "If everybody remains silent, we're never going to get to the bottom of this." - HUFFINGTON POST.