NTSB Releases New Report On Owasso Plane Crash That Killed Dr. Perry Inhofe

The National Transportation Safety Board has released a new report on the plane crash that killed Dr. Perry Inhofe in Owasso last year.

Dr. Inhofe, 51, was the son of U.S. Senator Jim Inhofe. He died when his twin-engine turbo-prop Mitsubishi MU-2B-25 crashed while on approach to Tulsa International Airport on November 10, 2013. He was the only person on board. 

In an unusually detailed Factual Report, the NTSB investigator goes to great lengths to detail the difficulties involved in controlling an MU-2 at low speeds and low altitude with one engine not running.

Read the NTSB's Factual Report on the crash.

Several witnesses told the NTSB the landing gear was down and the left propeller was not turning or was turning very slowly just before the crash.

11/11/2013: Related Story: Dr. Perry Inhofe, Son Of Sen. Jim Inhofe, Killed In Owasso Plane Crash

According to this report, the airplane had taken off from Salina, Kansas at 3:03 that afternoon. The airplane had been refueled and had a total of 279 gallons of fuel when it left Salina, the NTSB says.

At 3:34, Dr. Inhofe contacted controllers in Tulsa about landing. At 3:42, a controller cleared him to land on runway 18L, asking him to reduce speed to 150 knots or less, to provide time for an airplane on the same runway to take off.

The report says that as the MU-2 neared the runway, it suddenly started turning to the left. At 3:44, the tower radioed the pilot, "Mitsubishi six Juliet tango, Tower." The pilot replied, "I've got a control problem." The controller said, "Okay, you can just maneuver there, if you can maneuver to the west and do you need assistance now?"

The pilot responded, "I've got a left engine shutdown."

The tower controller contacted another controller about the problem and warned that other airplanes might have to be cleared out of the area.

At 3:45 the controller asked Dr. Inhofe if he was declaring an emergency. The controller tried two more times to contact the pilot but didn't get a response. At 3:46, radar contact was lost, after the plane had made a 360-degree turn to the left.

The NTSB says Inhofe had 2,874 flight hours, with more than half of that in multiengine airplanes.

The investigator interviewed three pilots who'd flown with Dr. Inhofe in the months before the accident. Although interviewed separately all three pilots described him as a very good aviator who was studious and modest about his pilot skills. None of them recalled him displaying any negative or bad flying habits.

The report explains that the FAA requires pilots who fly the MU-2B get special training and have a certain level of experience. The NTSB says Dr. Inhofe had recently purchased the MU-2 and completed ground school the week before the crash at Professional Flight Training in Salina, Kansas. He also completed training flights in the accident plane that week, according to the NTSB.

Dr. Inhofe had performed a single-engine landing on the morning of the accident as part of his training, according to the NTSB. The accident flight was the first time he flew the MU-2 alone, the NTSB says.

The report says the school developed a training checklist which the FAA had not approved for the MU-2B-25. The NTSB says the checklist was not approved because it did not follow most of the guidelines set for forth in the special rules for flying the airplane which the FAA adopted in 2010.

The NTSB investigator found a copy of the unapproved checklist near the pilot's seat after the crash and another copy in the back of the airplane.

The investigator says the airplane would have been near the limit of controllability because it was so low, so slow and only the right engine was running. The pilot had three choices, according to the report, which were: increase power on the running engine, trade altitude for speed or some combination of both.

The investigator says the pilot also could have retracted the landing gear to reduce drag.

According to the report, the investigator disassembled and examined the engines and didn't find evidence of any pre-crash malfunction.  

As is standard procedure for the NTSB, the Factual Report contains no conclusions about the cause of the crash, including why the left engine wasn't running. The cause of the crash will be addressed when the NTSB releases its Probable Cause Report, probably in a few months.