The man killed in a plane crash on the west side of Cook Inlet last week had spoken with his wife by phone shortly before the late-night wreck, according to federal investigators.

A preliminary report on the Aug. 23 crash that killed Jason Walkush was released Thursday by the National Transportation Safety Board. Walkush, 35, was the pilot and sole occupant of a Piper PA-18 Super Cub, which the report said went down roughly 31 miles northwest of Tyonek at about 10:45 p.m.

A report from the Kenai Municipal Airport, nearly 45 miles southeast of the crash site, said “dark night” visual meteorological conditions prevailed minutes after the crash.

Clint Johnson, the NTSB’s Alaska chief, emphasized that no conclusions had yet been reached in the investigation. He asked that anyone who may have been airborne in the area at the time call the NTSB at 907-782-4848 to describe conditions in the vicinity.

“We don’t know what the weather was at that time,” Johnson said. “We don’t believe anyone else was flying at that time.”

According to the report, Walkush was on a solo sheep-hunting trip this month. He had left Merrill Field in Anchorage on Aug. 19 for a remote airstrip near Telaquana Lake, from which he took off on the fatal flight back to Merrill Field. His wife told the NTSB that his trip was open-ended with “no set return date,” but Walkush called her at about 9 p.m. on the date of the crash to ask about weather information for the area.

“The wife instructed the pilot to call her back in about 5 minutes and she would provide him the requested weather information. The pilot never called the wife back,” investigators wrote. “About [10:20 p.m.], the wife reported that she received a text message from the pilot stating he was flying over Kenibuna Lake and he should be home around [11 p.m.].”

A satellite signal from the Super Cub’s emergency locator transmitter was received just before 11 p.m. by the 11th Air Force’s Rescue Coordination Center in Anchorage. Rescuers launched at first light the next day, but found Walkush dead at the scene.

The plane had crashed in “heavily treed terrain,” Johnson said, but there was no post-crash fire. The Piper’s wreckage will be recovered for examination by NTSB investigators, as well as representatives from Piper and engine manufacturer Lycoming.