NTSB Factual Report

HISTORY OF FLIGHT

On August 15, 2015, at 1002 eastern daylight time, a Cessna T206H, N63TV, impacted trees and terrain after a loss of engine power during initial climb at Essex County Airport (CDW), Caldwell, New Jersey. The commercial pilot was fatally injured, and the airplane was destroyed. The airplane was registered to Stalactite, LLC, and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the positioning flight, destined for Teterboro Airport (TEB), Teterboro, New Jersey.

According to a friend of the pilot, the pilot planned to fly to TEB, pick up the owner of the airplane and fly with him to South Hampton, where the owner had a residence. The friend owned a Cessna 182 and was interested in purchasing a Cessna 206 like the one the pilot was flying, so the pilot invited him to come to CDW before the flight and see the airplane.

The friend arrived at the airport about 0930 and noticed that the pilot had already completed the preflight inspection of the airplane. The pilot appeared to be "fine, his usual self, and doing good that morning," The pilot's friend was in the fixed base operator's (FBO) lobby when he heard the airplane's engine start. The airplane stayed on the ramp for a few minutes and then taxied out. About 10 minutes later, the pilot's friend saw the airplane as it passed by a window in the FBO. The airplane seemed quieter than it should have to him, and he thought that it did not seem to be moving very fast. About 10 minutes later, a line service agent entered the FBO and said that there had been an airplane accident.

According to information provided by the Federal Aviation Administration (FAA), the pilot contacted the CDW air traffic control tower, requested to taxi, and advised the controller that he had the current weather that was being transmitted by CDW's automatic terminal information service. The controller subsequently instructed the pilot to taxi to runway 22 and to hold short of the runway at intersection "November," which was normally used for airplanes departing on runway 22. The airplane taxied to the designated location and remained there for about 5 minutes. According to FAA inspectors, during the time that the airplane remained stationary, a student pilot heard the airplane's engine go from near idle to full power about five times and reported that the engine did not "sound right."

The air traffic controller cleared the pilot for takeoff with a left turnout. Shortly after becoming airborne, the pilot advised that he had a "problem," declared an emergency, and requested to "return to the field immediately." The controller cleared the pilot to land on any runway, and the pilot reported that he was unable to maintain engine power. There were no other communications from the pilot.

Review of security camera video revealed that, during the takeoff, the airplane appeared to accelerate slowly and rotated about 1,800 ft. after the pilot initiated the takeoff roll." Once airborne, the airplane began to pitch slightly up and down while remaining in ground effect and then slowly climbed. The airplane momentarily reached an altitude that was just above the trees that surrounded the airport, then began to lose altitude, and turned left about 90°. The airplane disappeared from view of the camera, and a smoke cloud then rose from behind a tree line.

According to witnesses who saw the airplane just before impact, the airplane was at the same height as the trees and appeared to be gliding toward the ground. One witness stated that the airplane appeared to be "in slow motion;" it then banked sharply to the left and pitched steeply down. Another witness reported that the airplane made "a hard-left turn, went into a nose dive, and exploded when it hit the ground." Three additional witnesses reported similar observations. The witnesses heard no noise coming from the airplane before the impact.

PERSONNEL INFORMATION

According to FAA and pilot records, the pilot held a commercial pilot certificate with ratings for airplane single-engine land and instrument airplane, a flight instructor certificate with a rating for airplane single-engine, and a ground instructor certificate with an advanced ground instructor rating. His most recent FAA third-class medical certificate was issued on March 30, 2015. He had accrued about 1,941 total hours of flight experience, 16 hours of which were in the accident airplane make and model.

AIRCRAFT INFORMATION

The airplane was a 6-place, single-engine, high-wing monoplane of conventional metal construction. It was equipped with fixed-tricycle-type landing gear and was powered by a turbocharged, 310-horsepower, Lycoming TIO-540-AJ1A engine, driving a three-blade, McCauley, controllable pitch propeller.

According to FAA and maintenance records, the airplane was manufactured in 2009. Its most recent annual inspection was completed on April 17, 2015. At the time of the inspection, the airplane and engine had accrued 1,155.4 total hours of operation.

According to the maintenance provider who had maintained the airplane since December 2011, anything that bothered the owner about the airplane would get fixed. Most of the items that were addressed by the maintenance provider were cosmetic or routine maintenance, such as oil and filter changes, gauges, starter replacement, lights, accessories, battery replacement, and compliance with airworthiness directives and service bulletins. The maintenance provider reported that the owner's landings could be a little rough, so they had also replaced some tires as he had experienced a few flat tires, and, as a result, the owner would keep a spare set in the airplane in case he blew a tire on landing.

Review of maintenance records revealed that the airplane's engine had been receiving regular oil changes since new as well as spectrometric oil analysis. Review of oil analysis reports provided by the maintenance repair organization indicated that a sample of the engine's oil that was taken on March 5, 2012, contained elevated levels of iron, nickel and chromium. Another sample taken on December 19, 2013, contained elevated levels of aluminum, chromium, iron, and nickel. In a report dated March 9, 2015, the laboratory commented about an oil sample that had been taken on March 4, 2015, stating that:

"These numbers are a lot easier to take than the high aluminum, chrome, iron, and nickel we saw last time. The shorter oil run obviously helped, but most of the metals are lower on a ppm/hour basis too, meaning that the engine really did wear better. If anything, nickel could still stand to be lower. 13 ppm is almost high enough to get a mark, so that's one we'll be monitoring next time. There's a trace of fuel to report this time, but that's not anything to worry about. It's likely just from normal use. Much better at 1,151.6 hours S[ince ]New."

In a report dated August 12, 2015, for an oil sample that was taken on August 4, 2015 (11 days before the accident), the laboratory commented that:

"Steady as she goes for this sample out of N63TV. If we're being picky you could say that iron should have come down as a result of the shorter oil run, but 39 ppm isn't bad at all for one of these engines after 20 hours on the oil. Everything else is in good shape, so we'd be surprised if the extra iron on a per-hour basis turned out to be an issue. No problems with the oil itself were found, making for a very nice report overall."

Maintenance records indicated that two repairs requiring replacement of major components of the engine had been accomplished. The first repair followed a report from the owner that the engine was experiencing high oil consumption. According to a maintenance entry dated January 21, 2013, and the associated work order, this resulted in the maintenance provider inspecting for the cause of the oil leaks by first washing down the engine, and then after a test flight, tightening loose rocker box return line coupling clamps, replacing a cracked air/oil separator, replacing leaking oil dipstick gaskets, and replacing a leaking fitting on the turbocharger wastegate actuator. During this inspection and maintenance action, maintenance personnel noticed oil on the inlet scroll of the turbocharger and oil on the belly of the airplane, so they replaced the turbocharger "due to oil leaking past shaft seal intake system."

The second repair occurred about 4 months later, when the owner again reported high oil consumption. According to a maintenance entry dated May 22, 2013, and the associated work order, this resulted in the maintenance provider checking the compressions and borescoping the cylinders.

During this inspection and maintenance action, maintenance personnel found pooled oil in the Nos.3, 5, and 6 cylinders. Per guidance from a Lycoming representative, they attached an airspeed indicator to a modified oil dipstick cap and then ran the engine. No excessive crankcase pressure was found. Next, they ran the engine to get the temperature up and shut down the engine at 1,300 rpm. Then they borescoped the cylinders again and found that all of the pistons were damp, all of the spark plugs were dry, and there was pooled oil in the Nos. 3, 5, and 6 cylinders. After these tests, maintenance personnel removed the Nos. 3, 5, and 6 cylinders and found the oil control rings stuck in the pistons. They installed new Nos. 3, 5, and 6, cylinder assemblies.

The maintenance records did not indicate that the check valve on the turbocharger oil supply line was cleaned or replaced following either of these engine repairs.

Turbocharger System Information

The airplane was equipped with a turbocharging system manufactured by Hartzell Engine Technologies (HET) that forced air into the engine's combustion chamber, allowing the engine to maintain sea-level manifold pressure as altitude increased. The turbocharging system consisted of a turbocharger, controller, wastegate, and pressure relief valve.

The turbocharger converted wasted energy, in the form of hot exhaust gases from the engine exhaust, into increased manifold pressure to increase power available from the engine. After air and fuel were burned in the cylinders, the exhaust gases from combustion were used to spin a turbine wheel at high speeds. The turbine wheel was connected to a compressor wheel that compressed induction air supplied through an opening in the lower cowl, that was ducted through a filter and into the compressor, increasing its density. The pressurized induction air would then pass through the throttle body and induction manifold into the engine cylinders, completing the cycle.

The controller sensed manifold pressure to maintain sea level horsepower at altitude, without over-speeding the turbocharger or over-boosting the aircraft's engine. It did this by controlling pressurized engine oil to hydraulically actuate the wastegate. The wastegate (exhaust bypass valve), used speed or compressor discharge pressure (boost) during certain conditions of a flight. Managed through the controller, the wastegate opened to allow exhaust gas to bypass the turbocharger, limiting speed and boost.

The pressure relief valve acted as a supplementary safety device in the airplane turbocharger system. The valve was set to open at a pressure slightly above the maximum turbocharger discharge pressure, should the controller or wastegate not adequately limit the boost pressure.

According to HET, the turbocharger operates at speeds over 100,000 rpm and at temperatures exceeding 1,650ºF, and oil is required at the correct flow rate and pressure to lubricate the bearings, stabilize the rotating shaft and bearings, and act as a coolant. The system's lubricating oil comes directly from the engine's oil system, so shutting down the engine immediately stops

the flow of oil to the turbocharger. If the turbocharger is still turning at a high rate of speed when oil flow is cut off, the turbocharger bearings can be damaged. In addition, any stagnant oil remaining around the extremely hot turbine shaft will overheat and "coke" or burn.

The controller and the wastegate also use engine oil and pressure for operation and control of the turbocharger. If either one is contaminated by oil, does not receive the correct oil flow rate, or lacks sufficient oil pressure to function, system performance is compromised. In the event of malfunction of a turbocharged engine, HETs experience is that maintenance personnel assume that the turbocharger is at fault and replace it. Frequently the replacement unit fails, which prompts an investigation into the real cause of the initial failure. According to HET, the major cause of turbocharger failures is faulty lubrication systems.

The accident airplane was equipped with a check valve on the turbocharger oil supply line, which was located upstream from the turbocharger and regulated the supply of oil that it received. HET does not require the use of check valves, and the check valve installed on the airplane was supplied by the engine manufacturer. The check valve was used to prevent oil from draining into the turbocharger after shutdown and pooling in the turbocharger body. According to HET, this pooling can result in stagnant oil remaining around the extremally hot turbine shaft and coking or burning. Along with coking, bearing damage can occur that causes the bearings to orbit instead of spin, which can lead to turbine and/or compressor rub, wear, and failure.

If a check valve sticks in an open or partially open position, this allows the turbocharger's center body to fill with oil; the oil then leaks past the seals because the oil cannot drain and is not being scavenged. The absence of turbo air pressure (both in the compressor and turbine housings) also does not assist in preventing oil leakage past the piston rings, which can result in the presence of oil in the compressor/induction system (evidence of oil in the combustion chambers) and/or the turbine/exhaust system (resulting in smoking during engine start).

METEOROLOGICAL INFORMATION

The recorded weather at CDW, at 1012, about 10 minutes after the accident, included: variable winds at 3 knots, 10 miles visibility, clear skies, temperature 28°C, dew point -17°C, and an altimeter setting of 30.13inches of mercury.

AIRPORT INFORMATION

CDW was owned by the Essex County Improvement Authority and was located 2 miles north of Caldwell, New Jersey. It was classified by the FAA as a publicly owned, tower controlled, public use airport.

The airport elevation was 172 ft above mean sea level and was oriented in a 10/28 and 4/22 runway configuration. Runway 22 was asphalt, in good condition, and measured 4,552 ft long by 80 ft wide with a 0.2% gradient. The threshold was displaced 134 ft. The runway was equipped with high intensity runway edge lights and runway end identifier lights and was marked with nonprecision markings in good condition.

WRECKAGE AND IMPACT INFORMATION

The accident site was located in a wooded area about 0.3 nautical mile from the departure end of runway 22 on a magnetic heading of 156°. Examination of the accident site revealed that the airplane impacted terrain on a 20° magnetic heading after striking several trees. Further examination revealed that the airplane impacted in a nose-down, inverted attitude. During the impact sequence, the engine separated from its mounting location. The empennage was displaced about 20° to the left of the fuselage centerline and was partially separated from the aft fuselage. The wings were separated from their mounting locations. The fuselage came to rest upright on a 100° magnetic heading against the base of a tree. The majority of the fuselage was consumed by a postimpact fire.

The wing flaps were found in the up position. The elevator trim was near neutral. The fuel selector valve was in the "BOTH" position, and there was no evidence of fuel blockage. Control continuity was established from the ailerons, elevator, and rudder to the flight controls in the cockpit. There was no evidence of any inflight structural failure.

Examination of the propeller revealed that one of the three blades separated during the impact sequen

NTSB Probable Cause

A loss of engine power due to a malfunction of the turbocharging system likely due to contaminated oil. Also causal were the pilot's decision to continue the takeoff although the airplane was not performing normally and his failure to maintain adequate airspeed following the loss of engine power, which resulted in the airplane exceeding its critical angle of attack and an aerodynamic stall. Contributing to the accident was the engine manufacturer's inadequate guidance regarding inspection and maintenance of its turbocharged engines.