A small plane which crashed last week near Eureka, killing the former Alaska State Trooper at the controls, was flying slower than its rated stall speed before it nosed over into the ground, according to a witness.

A National Transportation Safety Board preliminary report says the Cessna 170B was being flown about 74 miles northwest of Glennallen when it crashed just before 7:55 p.m. Sept. 5. Troopers say the pilot and sole occupant, 41-year-old Anchorage man Michael S. Zobel, served as a trooper from 2002 through 2006.

In the report, investigators say Zobel had taken off from “a remote mountain ridge near the accident site” during a moose hunt in the area.

“According to a member of the pilot’s hunting party, the pilot had shot and killed a moose earlier in the day in an area of tall brush and tundra-covered terrain, but he failed to mark its location before hiking away from the site,” investigators wrote. “Unable to locate the dead moose amongst the tall brush, he hiked back to the airplane that was parked atop a mountain ridgeline, and then he departed to do an aerial search for the moose kill site.”

After taking off to find the moose, observers on the ground saw Zobel maneuvering in the Cessna 170 -- with a stall speed of 49 mph -- shortly before he crashed.

“The witness said that he observed the airplane fly by his location at approximately 80 to 100 feet above the ground, traveling at an estimated 45 mph,” investigators wrote. “He said that after it passed by it then began a left turn, and then the nose of the airplane pitched down abruptly and it began to spin. The airplane subsequently descended vertically, nose first, and it collided with the tundra and brush-covered terrain.”

According to AST, responders tried to reach the crash site but were slowed by poor weather conditions, with a LifeMed air ambulance finding Zobel already dead when the helicopter arrived. A hunting party subsequently removed his body from the plane, transferring it to the state medical examiner’s office for an autopsy.

Investigators with the NTSB, as well as a Cessna Aircraft Company representative, reached the crash site Sunday to inspect the aircraft, which still had all of its controls operable.

“The airplane impacted in a near vertical attitude in an area of brush and tundra covered terrain, at an elevation of approximately 3,750 feet mean sea level,” investigators wrote. “All the primary flight control surfaces were identified at the accident site, and flight control continuity was verified from all of the primary flight control surfaces to the cockpit.”

The wreckage of the Cessna will undergo a more extensive examination by the NTSB after it’s recovered from the crash site.

An aviation weather report from the Eureka Lodge, 38 miles southeast of the crash site, listed winds from the southwest at 8 knots. Visibility was listed at 10 statute miles, with clear skies and a temperature of 46 degrees.

Contact Chris Klint