This article originally published at Helicopter crashes into kilometer-long slackline in Arizona, killing four.

Federal investigators are examining if a slackline was properly authorized following the deadly helicopter crash near Superior that claimed the lives of four people on Friday, ...

The people who strung the line - which is used in a sport akin to tightrope walking - had filed an aviation safety notice, raising questions about the air alert system.

A helicopter collided with a 2,800-foot-long slackline across Telegraph Canyon in Arizona, killing all four passengers.

Investigators say a helicopter hit a highline stretched across Telegraph Canyon near Superior, killing four. Here’s what to know.

A helicopter crash on Jan. 2 claimed the lives of four family members from Oregon in a remote area of Pinal County, Arizona. Officials said the aircraft struck a slackline stretched across a canyon ...