Sandy Dahl, the widow of the pilot of the flight that crashed into a Pennsylvania field on September 11, 2001, has died.

The body of 52-year-old Dahl was found Friday, and her charity says she died of natural causes.

A family friend tells the Denver Post she died in her sleep.

Dahl's husband Jason was captain of United Airlines Flight 93, which was heading from Newark to San Francisco when it was hijacked.

Passengers fought back and the plane went down in a field near Shanksville, Pa.

Dahl later founded a scholarship fund in honor of her husband, and spoke publicly to ensure those on board were not forgotten.