A police helicopter that crashed at a South Carolina airport was missing a bolt that should have Grant Prestonbeen removed and reinstalled during maintenance about six weeks earlier, federal officials said in a report.

A second bolt on the Charleston County Sheriff’s Office helicopter also was loose and the pilot, who survived, told investigators he felt like his foot controls to move the aircraft’s tail rotors weren’t working, according to the preliminary report from the National Transportation Safety Board.

“It felt as if the pedals were not attached,” the pilot said.

The tail rotor is key to keeping the helicopter stable and steering it. About 35 minutes into the Aug. 1 flight from Sumter to Charleston, the pilot reported the helicopter wanted to keep pulling to the right, according to the report.

The pilot declared an emergency and tried to land at the Charleston International Airport. Surveillance video from the airport showed as the helicopter hovered about 20 feet (6 meters) from the ground, it pulled right, rose, then plunged into the ground

The helicopter had been to a shop in Sumter, which was not named in the report, twice for maintenance in the past six weeks.

On June 28, the missing bolt and the bolt that was loose because a pin was missing were both supposed to be removed and reinstalled, the report said.

The helicopter flew for about 15 hours before the pilot took it back to Sumter for more maintenance on the day of the crash.

The pilot, Charleston County sheriff’s Lt. Scott Martray, has been with the agency since 2006 and is the chief pilot for the sheriff’s office. He was released from the hospital a day after the crash.