TAHLEQUAH — The National Transportation Safety Board on Thursday released its probable causes report on a helicopter crash that killed two people in October 2009.

NTSB officials determined the pilot, 26-year-old Mark James Mahaney, was impaired “due to recent heavy use of methamphetamine, recent use of a narcotic pain reliever, and fatigue.”

Records indicated Mahaney had been prescribed a combination of propoxyphene and acetaminophen for pain following a tooth extraction and repair performed a day before the crash.

Darci Lynn Scraper, 20, was also killed in the crash, which occurred shortly after the 2007 Robinson R22 left Mahaney’s home en route to the Tahlequah airport, according to a factual report issued by the NTSB last April.

The NTSB also said Mahaney’s lack of instrument experience and training contributed to the crash. An exam of the aircraft and its systems revealed no anomalies, and Mahaney was not certified for instrument flight. There was also no evidence he had received any instrument training, or that he was certified for night flight.

Friends and family members of Mahaney said he’d been up all night watching movies, and intended to fly to Tahlequah Municipal Airport to meet a friend, hanger his helicopter, and go hunting. The helicopter never arrived, and the friend left the airport without reporting the overdue aircraft.

Scraper’s family filed a missing persons report Oct. 15, 2009, and the wreckage was located near Mud Valley Road after being spotted from the air by a pilot with the Oklahoma Highway Patrol.

Mahaney held a private pilot certificate with a rotorcraft helicopter rating that was issued July 31, 2009. He’d reported a total flight time of 85 hours when he applied for that certificate.

NTSB investigators said a review of Federal Aviation Administration records revealed Mahaney was sent a letter of investigation Sept. 2, 2009, which alleged he provided “false or fraudulent information” on his medical certificate application dated April 28, 2008, and had failed to report a motor vehicle action within 60 days, as required by FAA regulations.

The FAA said Mahaney didn’t respond to the letter or provide any evidence or a statement regarding its receipt. The FAA was initiating enforcement action against Mahaney when the crash occurred.

The NTSB says the crash occurred at approximately 4:50 a.m. Oct. 14, 2009. The Robinson R22 was destroyed on impact, and a fire erupted. The personal flight was not being conducted under the provisions of federal regulations, NTSB said.

According to the NTSB, several witnesses in the immediate vicinity of the departure point of the helicopter said the weather was cold with low, overcast skies and limited visibility due to light rain and mist.

A weather observation station at Tahlequah’s airport reported that, at 4:32 a.m. the morning of the crash, there were calm winds, a visibility of 5 miles, and overcast skies at 400 feet.

The NTSB said there is no record Mahaney obtained an approved weather briefing from the FAA Flight Service Station or Direct User Access Terminal System.

The helicopter was registered to Trevor Noble, Terry Noble and Robert Koudelka. Trevor Noble and Koudelka both died in a separate aviation accidents on Nov. 5, 2007, and Nov. 2, 2008, respectively.

A mechanic came forward and provided copies of the maintenance entries performed on the aircraft. The most recent maintenance conducted on the chopper was a 100-hour inspection in accordance with the R22 manual, which was done July 27, 2009.

The helicopter was not certified for instrument flight, according to the NTSB.

On Oct. 30, 2009, Scraper’s mother, Juanita Kristine Scraper, filed a wrongful death suit against Mahaney’s estate; his father, James Mahaney; his mother, René Rozell; Robinson Helicopter Co. Inc.; the estate of Trevor B. Noble; and five John Does. In April, James Mahaney was dismissed without prejudice from the suit, court documents show.

The matter is set for a Nov. 1 civil jury sounding docket.