Koepcke was a German Peruvian high school senior student studying in Lima, intending to become a zoologist, like her parents. She and her mother, ornithologist Maria Koepcke, were traveling to meet with her father, biologist Hans-Wilhelm Koepcke, who was working in the city of Pucallpa.
The LANSA Lockheed Electra OB-R-941 commercial airliner was struck by lightning during a severe thunderstorm and broke up in mid-air, disintegrating at 3.2 km (10,000 ft). Koepcke, who was seventeen years old, fell to earth still strapped into her seat. She survived the fall with only a broken collarbone, a gash to her right arm, and her right eye swollen shut. "I was definitely strapped in [the airplane seat] when I fell," she said later. "It must have turned and buffered the crash, otherwise I wouldn't have survived."
Her first priority was to find her mother, who had been seated next to her, but her search was unsuccessful. She later found out her mother had initially survived the crash, but died from her injuries several days later.
Koepcke found some sweets which were to become her only food. After looking for her mother and other passengers, she was able to locate a small stream. She waded through knee-high water downstream from her landing site, relying on the survival principle her father had taught her, that tracking downstream should eventually lead to civilization. The stream provided clean water and a natural path through the dense rainforest vegetation.
During the trip, Koepcke could not sleep at night because of insect bites, which became infected. After nine days, several spent floating downstream, she found a boat moored near a shelter, where she found the boat's motor and fuel tank. Relying again on her father's advice, Koepcke poured gasoline on her wounds, which succeeded in removing thirty-five maggots from one arm, then waited until rescuers arrived. She later recounted her necessary efforts that day: "I remember having seen my father when he cured a dog of worms in the jungle with gasoline. I got some gasoline and poured it on myself. I counted the worms when they started to slip out. There were 35 on my arm. I remained there but I wanted to leave. I didn't want to take the boat because I didn't want to steal it."
Hours later, the lumbermen who used the shelter arrived and tended to her injuries and bug infestations. The next morning they took her via a seven-hour canoe ride down river to a lumber station in the Tournavista District. With the help of a local pilot, she was airlifted to a hospital – and her waiting father – in Pucallpa.
Koepcke's unlikely survival has been the subject of much speculation. It is known that she was seatbelted into her seat and thus somewhat shielded and cushioned, but it has also been theorized that the outer pair of seats – those on each side of Koepcke, which came attached to hers as part of a row of three – functioned like a parachute and slowed her fall. The impact may also have been lessened by thunderstorm updraft and the landing site's thick foliage.
Her experience was widely reported and is the subject of one feature length fictional film and one documentary. The first was the low-budget, heavily fictionalized I miracoli accadono ancora (1974) by Italian filmmaker Giuseppe Maria Scotese; it was released in English as Miracles Still Happen (1975) and is sometimes called The Story of Juliane Koepcke. Twenty-five years later, director Werner Herzog revisited the story in his film Wings of Hope (1998). Herzog was inspired to make the film as he narrowly avoided taking the same flight while he was location scouting for Aguirre, Wrath of God. His reservation was canceled for a last minute change in itinerary.
Koepcke moved to Germany, where she fully recovered from her injuries. Like her parents, she studied biology at the University of Kiel, graduating in 1980. She received a doctorate from Ludwig-Maximilian University and returned to Peru to conduct research in mammalogy, specializing in bats. Koepcke published her thesis, Ecological study of a bat colony in the tropical rain forest of Peru, in 1987. Now known as Juliane Diller, she serves as librarian at the Bavarian State Zoological Collection in Munich. Her autobiography, Als ich vom Himmel fiel (When I Fell From the Sky), was released on 10 March 2011 by Piper Verlag, for which she received the Corine Literature Prize in 2011.Koepcke, Juliane (2011). Als ich vom Himmel fiel (in German). Munich: Piper Malik. ISBN 978-3-89029-389-9.
When I Fell From the Sky, Titletown Publishing, 2011, ISBN 978-0-9837547-0-1