Jessica Kaplan, screenwriter who made her first script sale when she was 16, died in a plane crash Friday June 6 in Los Angeles. She was 24.Kaplan was a passenger on the airplane that crashed into an apartment building in the Fairfax area not far from CBS Television City, killing four other people, including her uncle, Jeffrey Siegel, the pilot. Cause of the crash is still under investigation. The young writer first made news in 1995 when her spec script “The Powers That Be” was bought by New Line for $150,000. She was entering her senior year at Santa Monica’s Crossroads School at the time. Script — based on her own observations of affluent white classmates in West L.A. who mimicked gangster culture — earned her representation at Endeavor, where she had since remained a client. “The Powers That Be” has gained significant traction recently. Project was rewritten by Stephen Gaghan and is skedded to begin shooting in the fall with the new title “Havoc.” Barbara Kopple is directing. After graduating high school, Kaplan stayed in L.A. to continue her writing career rather than attend college. Over the next five years she worked doing rewrites for a number of different studios and also on an adaptation of the novel “The Basic Eight” by “Lemony Snicket” author Daniel Handler. “Despite her young age, Jessica was incredibly poised,” said Bridget Johnson, who was producing that project. “She was extraordinarily mature, but there was still a lovely, trusting, young quality around her.” After a year spent traveling in South America, Kaplan returned last year and wrote a pilot with new partner Jamie Hawkins entitled “Telegraph Hill.” Based partially on Kaplan’s own experiences being thrust into the spotlight at a young age, the pilot was bought by CBS. She and Hawkins were planning to continue to develop projects with producer Pariah Television. During her time abroad, Kaplan also worked on a collection of short stories and poetry, a representation of what her writing partner said was Kaplan’s diverse interests in writing. “She just wanted to tackle everything,” Hawkins said. “And I’m sure she would have. She was a visionary herself and was always able to inspire her friends.” Kaplan is survived by her parents, Josh and Renee Kaplan. A memorial service will be held 3 p.m. Fridayat Kehillat Israel, 16019 W. Sunset Blvd., Pacific Palisades.