BUTLER, Mo. — A preliminary report issued by federal safety investigators did not point to any serious safety failures that could have led to the plane crash last month during a skydiving excursion in Missouri that killed all 12 people on board, including several highly experienced jumpers.

The National Transportation Safety Board issued a preliminary report Thursday based on inspections of the wreckage. The report said it found no indication of any pre-accident mechanical malfunctions or engine failures that would have prevented normal operation of the plane.

The federal agency also said a post-crash sample of the fuel truck found the fuel was free of sediment or debris, and a review of skydiving business operators’ software showed the plane had met weight and balance limitations for the flight.

The plane was not equipped with a crash-safe voice or data recorder, such as those that record flight data on commercial airliners, nor did it need to be, investigators said. However, the NTSB report noted that its investigators had recovered damaged GoPro cameras from the rubble.

The federal agency’s investigation into the crash was ongoing and a final report typically takes a year or more to complete.

The June 14 crash occurred about an hour south of Kansas City, when the plane carrying a pilot and 11 paratroopers took off from Butler Memorial Airport at 11:25 a.m. on a clear day.

During the initial climb, the plane began a gradual turn to the left, with both wings eventually becoming nearly perpendicular to the ground before crashing into a field, nose down, and bursting into flames, investigators said.

The fire caused significant damage to the plane’s major structural components, as well as the cockpit, cockpit and fuel system, investigators said.

Some relatives of the deceased were at the airport to witness the jump and witnessed the accident, authorities said. The United States Parachute Association, skydiving’s governing body, said its chief technology officer, Jen Sharp, was among the dead.

On the day of the crash, Dennis Jacobs, acting airport director and director of the Bates County Emergency Management Agency, said he thought the plane was losing power and that the pilot had been attempting to land on the nearby highway before crashing.

The plane was operated by Skydive Kansas City, which called the crash a “devastating loss.”

Poor maintenance is often a factor when skydiving planes crash, and the NTSB has previously expressed concerns about weak oversight of skydiving operators in previous accident investigations. The agency said after a 2019 crash that killed 11 people in Hawaii that the FAA’s regulatory system is not strong enough to ensure the safety of skydiving flights.

The Federal Aviation Administration has yet to adopt the NTSB’s recommendations, but said it established a committee in April that will recommend ways to increase skydiving safety and consider the safety board’s proposals.

The United States Parachute Association said Skydive Kansas City meets safety standards set by the world’s largest skydiving organization, including all FAA maintenance requirements. The skydiving industry says it has a strong safety record. The association said nearly 3.5 million jumps were completed last year and 16 civilians died, most due to human error.

The crashed Pacific Aerospace 750XL is a popular model for skydiving and has also proven useful for carrying cargo, conducting aerial reconnaissance and medical evacuation flights. The plane can carry more than 1,800 kilograms (4,000 pounds) and is capable of taking off and landing on short runways, according to the manufacturer.

The single-engine turboprop plane was built in 2010, according to FAA records. It made nine successful flights in the days before the crash, including two on Sunday morning, according to FlightAware, a digital flight tracking company.

Investigators said the pilot had a commercial pilot certificate and had accumulated more than 4,100 total flight hours. This year was the pilot’s second consecutive jump season working for Skydive Kansas City, the NTSB said.

Skydive Kansas City reported no prior concerns with the pilot, investigators said, calling him safety-oriented and conservative in his decision-making as a jump pilot.