Arizona [USA], January 4 (ANI): A private helicopter crashed in a rugged, mountainous region of central Arizona on Friday, killing all four people on board, local authorities confirmed.

According to the Pinal County Sheriff's Office, the victims included the 59-year-old pilot, two women aged 21, and another woman aged 22. The identities of those killed have not yet been made public, pending notification of their families, reported Kens5.

The crash occurred at approximately 11 a.m. near Telegraph Canyon, a remote area located about 64 miles east of Phoenix. Preliminary information indicates the helicopter may have struck a recreational slackline stretched across the canyon. Authorities said the line extended more than half a mile across the mountainous terrain.

The sheriff's office said an eyewitness contacted emergency services after observing the helicopter collide with part of the slackline before plunging into the canyon below. The impact caused the aircraft to fall into a difficult-to-access area, complicating rescue and recovery efforts.

The helicopter had reportedly departed earlier in the day from an airport in Queen Creek, a town located around 29 miles west of the crash site. Due to the isolated location and rough terrain, emergency crews had to walk for several hours to reach the wreckage.

As a precautionary measure, temporary flight restrictions were imposed over the area to ensure the safety of response teams and to prevent further incidents, the sheriff's office said.

Federal authorities have launched a formal investigation into the crash. The Federal Aviation Administration (FAA) and the National Transportation Safety Board (NTSB) will jointly examine the circumstances leading up to the incident, including the aircraft's flight path, mechanical condition, and the placement of the slackline, reported Kens5.

Officials have not yet determined whether the slackline was properly marked or visible from the air. Investigators are expected to assess whether safety regulations were followed and if additional measures are needed to prevent similar accidents in the future.

'Our prayers are with the victims and their families during this difficult time,' the Pinal County Sheriff's Office said in a statement, adding that more details would be shared as the investigation progresses.

The incident has raised renewed concerns about aviation safety in recreational areas where aircraft and outdoor activities intersect. (ANI)