N8849HNorth American NAVION · 1947

On November 10, 2016, about 0915 eastern standard time, a North American Navion, N8849H, was substantially damaged following a loss of control during engine startup at Blairstown Airport (1N7), Blairstown, New Jersey. The private pilot was fatally injured. The airplane was operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the planned personal flight to Capital City Airport (CXY), Harrisburg, Pennsylvania.

According to a mechanic who witnessed the accident, the pilot, who was the owner of the airplane, last flew the accident airplane in December 2015; it was damaged during a gear-up landing at 1N7. The airplane remained at the airport while the mechanic repaired the damage. The repairs were completed, and another pilot had planned to ferry the airplane to CXY for an annual inspection the day before the accident, but the flight was postponed due to poor weather. The other pilot was not available on the day of the accident, and the owner elected to fly the airplane to CXY himself.

On the morning of the accident, the mechanic taxied the airplane from the hangar to the fuel pump. During the taxi, he performed an engine run-up and did not notice any anomalies. The mechanic added that he had performed several run-ups while the airplane was at 1N7 and never experienced any anomalies with the throttle control or brakes. After fueling the airplane and completing a preflight inspection, the pilot started the engine and it went immediately to full power. The engine remained at full power and the airplane taxied about 1,000 ft at high speed into a tree.

The pilot, age 73, held a private pilot certificate with a rating for airplane single-engine land. His most recent Federal Aviation Administration (FAA) third-class medical certificate was issued on January 30, 2016. At that time, he reported a total flight experience of 1,445 hours. The most recent entry in the pilot's logbook was dated February 1, 2016. According to the logbook, the pilot had accrued a total flight experience of about 1,478 hours. The pilot reported 422 hours in the accident airplane make and model on his most recent insurance application.

The four-seat, low-wing, retractable tricycle-gear airplane was manufactured in 1947. It was powered by a Continental IO-520, 285-horsepower engine, equipped with a constant-speed Hartzell propeller. The pilot purchased the airplane in 2009. Its most recent annual inspection was completed on August 21, 2015. At that time, the airframe had accumulated about 2,052 total hours of operation and the engine had accumulated about 417 hours since major overhaul. The airplane had been operated for about 14 hours between the time of the last inspection and the accident.

Pocono Mountains Municipal Airport (MPO), Mount Pocono, Pennsylvania, was located about 15 miles northwest of the accident site. The 0853 recorded weather at MPO included wind from 310° at 10 knots; visibility 10 miles; few clouds at 1,200 ft; temperature 3°C; dew point -1°C; altimeter 30.02 inches Hg.

The four-seat, low-wing, retractable tricycle-gear airplane was manufactured in 1947. It was powered by a Continental IO-520, 285-horsepower engine, equipped with a constant-speed Hartzell propeller. The pilot purchased the airplane in 2009. Its most recent annual inspection was completed on August 21, 2015. At that time, the airframe had accumulated about 2,052 total hours of operation and the engine had accumulated about 417 hours since major overhaul. The airplane had been operated for about 14 hours between the time of the last inspection and the accident.

Examination of the wreckage by an FAA inspector revealed substantial damage to the wings and fuselage. The inspector noted that the throttle, propeller, and mixture controls were all in the full-forward position. Additionally, the engine had separated forward of the airframe during the collision with the tree.

The wreckage was examined again by an NTSB investigator after recovery. The propeller remained attached to the crankshaft and all three blades exhibited rotational signatures, such as torn blade tips, chordwise scrapes, and leading edge gouges. The throttle body/fuel metering unit was separated from the engine and remained attached to the induction system inlet and wye plenum, which were also separated from the airplane. The throttle and mixture control levers were fractured and their respective shafts were bent. The fractured control lever ends remained attached to the control cable rod ends. Examination of the throttle body/fuel metering unit revealed that the throttle lever was loose on the throttle control shaft; however, it was displaced and bent. No preaccident anomalies were noted with the unit.

The airplane was equipped with push-button Vernier throttle, mixture, and propeller controls. The propeller control knob was fractured and its cable was cut. Examination of the throttle control knob in the cockpit revealed that it was stuck in the full forward position and could not be pulled aft by depressing the push-button release. Examination of the mixture control revealed that it was also in the full forward position. Manual manipulation of the mixture control (both the push-button rapid adjustment mode, and the rotational fine adjustment mode) resulted in normal movement of the control knob with no anomalies noted. The throttle and mixture control knobs and cables were removed from the airplane and forwarded to the NTSB Materials Laboratory, Washington, DC.

Computed Tomography (CT) scanning of the throttle and mixture controls revealed that the outer sleeve within the throttle control did not appear to be fully seated within the knob, consistent with the throttle cable being pulled forward during engine separation in the accident sequence (for more information, see Computed Tomography Specialist's Factual Report in the public docket for this investigation).

The throttle and mixture control arms appeared to have been manufactured from bronze. According to the engine manufacturer, both lever arms should have been replaced with stainless steel arms per Continental Motors Category 2 Critical Service Bulletin (CSB) CSB08-3C, dated March 14, 2008. The CSB was issued after reports that bronze mixture and throttle control arms were inadequately torqued and became loose, which could lead to a loss of engine control or engine power.

The Teledyne Continental Motors Aircraft Products Division publication Tips on Engine Care describes engine “hot start” difficulties as, “simply heat soaking of the fuel lines inside the engine cowling or nacelle after engine shutdown in hot weather.” This condition leads to the vaporization of fuel in the lines in the cowling, and results in fuel starvation to the engine. The publication recommends running the auxiliary fuel pump for about 20 seconds just before starting the engine, with the mixture set to full lean or cut-off and the throttle set to full open, in order to purge the lines of the hot fuel and vapor.

The Morris County Medical Examiner, Morristown, New Jersey, performed an autopsy on the pilot. The autopsy report noted the cause of death as "multiple injuries."

Toxicological testing was performed on the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. Review of the toxicology report revealed:

5.172 (ug/ml, ug/g) Ketamine detected in Urine

2.634 (ug/ml, ug/g) Ketamine detected in Blood (Cavity)

1.834 (ug/mL, ug/g) Norketamine detected in Urine

0.736 (ug/mL, ug/g) Norketamine detected in Blood (Cavity)

Midazolam detected in Blood (Cavity)

Naproxen detected in Urine

Katamine, Norketamin, and Midazolam were consistent with emergency medical treatment that the pilot received after the accident. Naproxen is a non-sedating analgesic and not considered impairing. Additionally, according to an ambulance report, the pilot was awake and alert after the accident.