The helicopter had just picked up a load of water to dump on Utah’s raging Widemouth 2 Fire and was preparing to release it when the aircraft disappeared.

Moments before, its two pilots were communicating with crews on the ground. They’d verified their target and planned to do a second pass before making the 2,650-gallon drop.

The helicopter veered to the right, over a knoll and out of sight. Then, a ground supervisor heard one of the pilots over the radio: “Oh (expletive), we have a problem.”

Another second later, a second transmission: “Mayday, mayday, mayday.”

Then silence.

Those last communications are detailed in a preliminary report released Tuesday from the National Transportation Safety Board, the independent federal agency charged with investigating aviation crashes.

The four-page report is the first document to offer insight into the deadly Aug. 7 crash that killed both pilots. They have since been identified as Chris Andersen, 64, of Stateline, Nevada, and Miles Elliott, 50, of Porterville, California.

A cause has not yet been determined, and the crash remains under investigation.

The report says the helicopter — identified as a Sikorsky brand CH-54A Skycrane — had departed Richfield’s municipal airport in Sevier County at about 10:21 a.m. to join firefighting efforts on Widemouth 2, the biggest in Utah this season.

The two pilots established radio communication with the fire’s aerial supervisor and had received authorization to enter the restricted air space near the blaze, the report states. They were directed to fill up at a set water source, then continue to a designated drop area.

All of that, according to the report, went as planned.

As the helicopter got closer to the drop site, the aerial supervisor transferred communications to the ground supervisor to better direct the pilots on their specific target area for the drop.

On their second pass, though, about 23 minutes after taking off, the helicopter crashed, according to the report.

The report says it hit into a hillside. A fire after the crash “consumed much of the airframe.”

The investigator in charge visited the crash site two days later with an aerospace engineer and helicopter specialist to examine the wreckage.

“During the on-scene investigation, components were retained for further examination and testing,” the report states.

The results of those are pending. Additional recovery of the wreckage will take place “when fire conditions and logistical considerations allow,” the report adds.

Sevier County Sheriff Nathan Curtis previously said that it took more than a full day for first responders to safely reach the site, which became overwhelmed by flames.

“It was not an easy choice,” he said.

The helicopter that Andersen and Elliott were flying was under contract with the U.S. Forest Service; the pilots worked for Helicopter Transport Services.

The Widemouth 2 Fire has expanded to 129,741 acres as of Tuesday. It is considered 93% contained, marking the perimeter of the blaze that crews feel confident it will not breach.

The fire was discovered on July 27. It was initially sparked by lightning and remained relatively small. But roughly a week later, it ballooned in size and threatened the perimeters of three towns.