Video: 'American Experience The Kennedys 1' (Kennedy's death at 53:57)

(Thursday, May 13, 1948, 6:30 p.m. local time) — Kathleen Cavendish, Marchioness of Hartington, the 28-year-old daughter of Joseph P. Kennedy, Sr. and Rose Kennedy, sister of future U.S. President John F. Kennedy and widow of the heir to the Devonshire dukedom, died today in a plane crash in the French Alps at Saint-Bauzile, Ardèche, France.

Lady Hartington, also known as “Kick” Kennedy, and her married partner, Peter Wentworth-Fitzwilliam, a wealthy 37-year-old British Lord, were flying from Paris to the French Riviera for a vacation when their de Havilland DH.104 Dove was battered by raging thunderstorms.

Kathleen was instantly killed, along with Fitzwilliam, pilot Peter Townshend, and navigator Arthur Freeman.

Video: 'The Mystery Why Kathleen 'Kick' Kennedy Was Disowned By Her Family Is Now Reveal'