LAS VEGAS (AP) — A new federal report says parts of the right wing on a medical transport plane that crashed last month in rural Nevada, killing all five people aboard, fell far from the main wreckage site.

The National Transportation Safety Board’s findings released Wednesday could support the agency’s initial theory that the aircraft had broken apart before hitting the ground. But NTSB did not release a probable cause in its three-page preliminary report.

The agency says parts of the plane’s right wing were located as far as three-quarters of a mile (1.1 kilometers) from where the single-engine Pilatus PC12 crashed in Stagecoach, Nevada, a rural community of about 2,500 residents outside of Reno.

Authorities have said the Care Flight piloted by Scott Walton, 46, was headed from Reno to Salt Lake City, Utah, when it crashed around 9:15 p.m. on Feb. 24 amid a winter storm. Care Flight is a service of REMSA Health, and its aviation vendor is Guardian Flight.

In a statement Wednesday, Guardian Flight said it was reviewing the preliminary report and assessing any “additional steps” to strengthen its safety protocols: “The safety and well-being of our patients and crew is our utmost priority and we will continue to make significant investments to bolster our commitment.”

The other victims also included 69-year-old patient Mark Rand and his 66-year-old spouse Terri Rand, as well as two medical crew members, Edward Pricola, 32, and Ryan Watson, 27.

Walton contacted air traffic control minutes before the crash to report that the plane was climbing past 15,400 feet (4,694 meters), according to the report. But “no further radio transmissions were received” from the pilot, the report states.

Just minutes later, the plane began to fall — dropping about 8,000 feet (2,440 meters) in 30 seconds — before the aircraft’s navigation tracking system went dark, according to the report.

Dan Rose, an aviation attorney representing relatives of the Rands, told The Associated Press he was disappointed by the lack of attention given in the report to weather conditions at the time.

The National Weather Service said it was snowing steadily when the flight left Reno, with winds around 20 mph (30 kph) and gusts up to 30 mph (50 kph). Visibility was under 2 miles (3.2 kilometers) with a cloud ceiling about 2,000 feet (600 meters).

Rose said he thought the crash was “absolutely preventable,” noting that “the family would want the NTSB to look carefully” at the initial decision to fly at all during a storm.

According to Rose, Mark Rand’s condition wasn’t “life critical” when the decision was made to transfer him to another facility.

“It really starts with the decision to go in the first place, which never should have been made,” Rose previously told AP, shortly after he was retained by the Rand family. Rose is a former Navy pilot who has been litigating aviation cases for 25 years.

NTSB is expected to release its final report with a probable cause within two years.