Almost exactly 20 years ago, John F. Kennedy Jr.‘s plane crashed into the Atlantic Ocean just off the coast of Martha’s Vineyard in Massachusetts — killing him, wife Carolyn Bessette Kennedy and her sister Lauren Bessette.
An unbearable loss of three lives.
Two decades later, a new, in-depth biography, America’s Reluctant Prince, by historian Steven M. Gillon, excerpted in this week’s PEOPLE, examines 38-year-old John’s life and the events surrounding the fatal plane crash amid impenetrable weather conditions.
Gillon met John at Brown University in 1981 when he was a teaching assistant in a history class John attended. The two became friends, based on their mutual love of history and racquetball, which they often played together.
As he pieces together John’s final hours, Gillon describes in his book how on the afternoon of July 16, 1999, John checked the weather before he left the office for the airport in Essex, New Jersey, where he kept his plane.
• For more on John F. Kennedy’s privilege and pain and for never-before-seen photos from friends, subscribe now to PEOPLE or pick up this week’s issue, on newsstands Friday.
The forecast indicated clear skies, which “was crucial since he was flying under visual flight rules rather than relying on instruments,” Gillon writes. (John had only completed half of the lessons in his instrument training course at that time.)
But the weather deteriorated between when John left the office and when he arrived at the airport. After his plane took off at 8:38 p.m., he was heading into a thick fog.
Shortly after 9:40 p.m., John became disoriented and his plane entered a downward spiral.
“He should not have gone up that night,” Gillon tells PEOPLE. “At the first sign of danger, he should have done what a lot of pilots did that night and flew inland, away from the ocean, spend the night somewhere and then pick up the next morning.”
Such a realization, Gillon says, “was difficult to write.”
“It was [John’s] poor judgment that led to his death and the death of his wife and his sister-in-law, and there’s no way around that. John bears the responsibility of his recklessness that night and John alone,” Gillon says. “That is not easy for me to say, but when I wrote this book I decided my responsibilities as a historian superseded my responsibilities as a friend. The historical truth is what it is.”
As part of his research, Gillon explored the multiple traumas that John survived in his young life and interviewed a psychologist at Columbia University who specialized in trauma.
“John experienced more death in his brief life than most people do,” Gilllon notes: his father’s assassination as the nation’s 35th president but also the killing of his uncle Robert Kennedy, among others.
“When you think about the trauma that John had, it’s not just his father’s assassination, it’s his uncle [RFK] who became like a father figure, and then Aristotle Onassis, who was his stepfather,” Gillon says. “The trauma is compounded by the fact that John leaves the only house he ever knew, the White House; they moved to four different homes in the year after the assassination. And then there’s the Secret Service, a constant reminder of what happened to his father and that his own life might also be in danger.”
In speaking to the psychologist, Gillon wanted to understand how it may have affected John.
“What I learned was that one of the ways people respond to that type of trauma is to seek out danger,” he says. “Because they realize life can be snuffed out at any minute, they want to live life to the fullest. At the same time, they’re drawn to danger and the possibility of further trauma.”
RELATED VIDEO: JFK Jr. & Carolyn Bessette’s Marriage ‘Struggles Were Much More Real Than People Realize,’ Book Says
• For more on JFK Jr.’s world and sudden death, pick up PEOPLE’s 96-page special edition John F. Kennedy: An American Life, available now on Amazon and wherever magazines are sold.
John, according to GIllon, “had escaped death and danger so many times. … I think John just always believed something was going to save him, but it just didn’t that night.”
Gillon stresses the purpose was not to psychoanalyze John but to better understand him.
“It’s just one possibility among many,” he says.
Now that so much time has passed, Gillons hopes his book will bring new understanding to John’s complex life.
“He will always be remembered for the promise that went unfulfilled,” says Gillon.
John, he says, should “be remembered for who he was: a complicated and an extraordinarily decent human being.”