A private helicopter crashed in a remote mountainous area of central Arizona on Friday, killing all four people on board, including a 59-year-old pilot and three younger women. The crash occurred near Telegraph Canyon, approximately 64 miles east of Phoenix. Preliminary information suggests the helicopter may have struck a long recreational slackline stretched across the canyon. An eyewitness reported seeing the helicopter hit the line before falling. The Federal Aviation Administration and National Transportation Safety Board are investigating the incident.