CEN18FA053

A total loss of engine power due to the failure of the No. 4 piston, which resulted in an attempted forced landing in dark night conditions and a subsequent in-flight collision with trees and terrain. Contributing to the accident were the pilot's situational stress and fatigue, both of which degraded his performance.

The airline transport pilot and two passengers, one of whom was pilot-rated, were conducting a cross-country flight in dark, night visual conditions. During an en route climb to the assigned cruise altitude, the airplane experienced a loss of engine power about 6,600 ft above ground level (agl). The pilot identified a diversionary airport located about 4 miles northeast of the airplane's position and subsequently established a course toward that airport. The air traffic controller immediately informed the pilot that the airport was closed. However, based on the pilot's stated intention to divert to the airport, the controller provided radar vectors to assist the pilot. The airplane subsequently overflew the airport about 3,000 ft agl. However, instead of circling the airport, the pilot continued about 1 1/2 miles north and entered a right gliding turn until the airplane impacted trees and terrain about 2 miles north of the airport. A postaccident airframe examination did not reveal any anomalies consistent with an airframe structural failure or a malfunction of the flight control system. An engine examination revealed that the No. 4 piston had failed. Specifically, the perimeter of the No. 4 piston crown had separated, resulting in the separation of the upper compression ring and compression ring insert. Metallurgical examination determined that the piston failure was caused by the disbonding of the upper piston ring insert from the piston body. Lead deposits were present on parts of the piston body that formed an interface with the insert. The deposits were abraded in areas exposing the underlying piston material. The abraded areas where the deposits had been worn away could only have occurred if the upper piston ring insert had disbonded from the piston body before the piston failed. The disbonding of the insert was likely caused by a manufacturing anomaly; however, due to the extensive damage to the piston and the insert, it was not possible to determine with any more precision where the failure started or the nature of the defect that might have caused it. An airplane performance study revealed that no airports other than the diversionary airport were within the power-off glide range of the airplane at the time of the loss of engine power. Thus, the location of the airplane at the time of the loss of engine power presented the pilot with limited options for a forced landing. Furthermore, the pilot's ability to discern a suitable off-airport landing area was hindered by the dark night lighting conditions. Although, an interstate highway was below the airplane, attempting to execute a forced landing on an unlighted roadway at night presented significant hazards. In contrast, approach paths to an airport are generally free of obstructions. Therefore, the pilot's decision to alter course toward the diversionary airport, even though it was closed and unlighted, was understandable. However, once the airplane was positioned over the airport, the pilot did not circle but continued to fly north into an area with more limited opportunities for a successful forced landing. A review of the available medical information did not reveal the presence of any condition or medication that would have led to an incapacitation or impairment of the pilot. However, the pilot was likely fatigued at the time of the accident due to the length of time he had been awake, and the significant amount of flight time completed on the day of the accident. This may have narrowed the pilot's attention during the emergency. Additionally, situational stress imposed by the engine failure and the necessity to find a forced landing site in dark night conditions further reduced the pilot's ability to maintain situational awareness. The pilot-rated passenger's medical history included conditions and medications that, while unlikely to cause any sudden incapacitation, could potentially be impairing. However, the investigation was unable to determine the extent of impairment, if any, that might have been present at the time of the accident.

Pilot The Hamilton County Coroner's Office conducted an autopsy on the pilot and determined that the cause of death was multiple blunt force injuries sustained in the accident. The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing on specimens of the pilot that identified atenolol, azacyclonol, and fexofenadine in blood and liver tissue samples. No ethanol was detected in vitreous fluid. The blood sample was not suitable for carbon monoxide testing. Atenolol is a beta blocker commonly used in the treatment of hypertension. Azacyclonol is the active metabolite of fexofenadine and terfenadine. Fexofenadine is an over-the-counter antihistamine commonly used to manage allergy symptoms. Pilot-rated Passenger The Hamilton County Coroner's Office conducted an autopsy on the pilot-rated passenger and determined that the cause of death was multiple blunt force injuries sustained in the accident. The autopsy also revealed that the pilot-rated passenger had significant cancer metastasis. No evidence of thrombus, metastatic brain lesions, or acute coronary or nervous system disease that would be contributory to his death were noted. The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing on specimens from the pilot-rated passenger that identified: acetaminophen in urine; 0.0024 µg/mL of 11-nor-9-carboxy-delta-9- tetrahydrocannabinol (THC, the main psychoactive component in marijuana) in blood; 0.0466 µg/mL of 11-nor-9-carboxy-delta-9- THC (an inactive metabolite of THC) in urine; 0.0142 µg/mL of 11-hydroxy-delta-9-THC (an active metabolite of THC) in urine but none in blood; atorvastatin, famotidine, and ranitidine in blood and liver tissue; and 0.099 µg/mL of diphenhydramine in blood. Acetaminophen is an over-the-counter analgesic medication commonly used for pain management. Atorvastatin is a prescription statin medication commonly used to lower cholesterol. Famotidine and ranitidine are medications commonly used to treat stomach ulcers or severe reflux. These drugs are not generally considered impairing. Diphenhydramine is an over-the-counter sedating antihistamine commonly used to manage allergy symptoms or as a sleep aid. The pilot-rated passenger's medical history included high cholesterol and known metastatic cancer for which he had had multiple treatments. He was using the prescribed medications to treat his cholesterol and his symptoms from the cancer and the effects of its treatment. The National Weather Service surface analysis chart current at the time of the accident depicted clear skies and winds from the south at 10 knots or less for the station models surrounding the accident site. The surface analysis did not depict any significant weather in the vicinity of the accident site. The regional weather radar mosaic immediately surrounding the time of the accident depicted no significant echoes over the route. No in-flight weather advisories were in effect. The current winds aloft forecast noted southwesterly winds at 36 knots or greater at 3,000 ft msl. At 2045, the BAK automated weather observing system (AWOS) recorded clear skies, a wind from 190° at 9 knots, and 10 miles visibility. The HLB automated AWOS remained operational even though the airport was closed. At 2055, the HLB AWOS recorded overcast clouds at 7,500 ft above ground level, variable wind at 5 knots, and 10 miles visibility. The AWOS was not equipped with a precipitation discriminator; as such, no precipitation data were available. Both the moon and the sun were more than 15° below the horizon and provided no illumination. Dark night conditions existed at the time of the accident. Pilot The pilot held an airline transport pilot certificate with single and multi-engine land airplane ratings. He also held a flight instructor certificate with single and multi-engine airplane, and instrument airplane ratings. He was issued a second-class airman medical certificate on August 30, 2016, with a limitation for corrective lenses. According to the pilot's logbook, his most recent flight review was completed on July 27, 2016. The pilot's final logbook entry was dated November 18, 2017. He had logged a total of 2,986.0 flight hours, with 2,902.8 hours as pilot-in-command and 1,363.9 hours as flight instructor. Of that total flight time, 2,006.4 hours were logged in single-engine airplanes, 979.6 hours in multi-engine airplanes, 291.2 hours as night flight time, 318.6 hours in actual instrument conditions, and 152.2 hours in simulated instrument conditions. During the 2-year period preceding the accident, the pilot had logged 35.8 hours in the accident airplane. He had accumulated about 10 hours additional flight time on the day of the accident; all in the accident airplane. The pilot was listed as the pilot-in-command for each flight on the day of the accident, including the accident flight. FAA regulations (14 CFR 91.3) stated that "in an in-flight emergency requiring immediate action, the pilot in command may deviate from any rule contained of this part to the extent required to meet that emergency." Pilot-rated Passenger The pilot-rated passenger held a commercial pilot certificate with single-engine land airplane and instrument airplane ratings. He held a current flight instructor certificate with single-engine airplane and instrument airplane ratings. He also held a ground instructor certificate with advanced and instrument ratings. His was issued a medical certificate on October 28, 2015, with a limitation for near vision corrective lenses. The certificate had expired on October 31, 2017. FAA records indicated that he had not applied for a subsequent medical certificate, nor had he applied for BasicMed. According to the pilot-rated passenger's logbook, his most recent flight review was completed on April 2, 2016. The pilot-rated passenger's final logbook entry was dated October 30, 2017. He had logged a total of 2,136.7 hours flight experience, with 1,998.0 hours as pilot-in-command and 782.6 hours as flight instructor. Of that total flight time, 2,085.2 hours were logged in single-engine airplanes, 265.2 hours as night flight time, 31.0 hours in actual instrument conditions, and 516.1 hours in simulated instrument conditions. The pilot-rated passenger was not a required flight crew member. As a result, there was no requirement for him to maintain medical currency as a passenger. The accident site was located in a wooded ravine about 2 miles north of HLB. The debris path was oriented on an approximate 315° magnetic course. The initial tree strike was located about 190 ft southeast of the main wreckage. The main wreckage consisted of the fuselage, right wing, and engine. The right-wing tip had separated and was located in a tree at the initial impact point. The left wing, empennage and propeller were separated and located in the debris path. The wing flaps were up and the landing gear was retracted at the time of impact. An airframe examination did not reveal evidence of any anomalies consistent with a preimpact structural failure or flight control system malfunction. A teardown examination of the 6-cylinder engine revealed that the No. 4 piston had failed. (A detailed summary of the airframe and engine examinations is included in the docket associated with the investigation.) The engine examination revealed extensive damage to the No. 4 piston. The cylinders, remaining pistons and valves exhibited mechanical damage consistent with impact (peening) from the piston and ring fragments. Examination of the induction and exhaust system revealed a significant amount of metallic debris, consistent with piston and piston ring material, in the intake balance tube and the exhaust system. No debris was observed within the oil sump. The engine pistons were fabricated from a cast aluminum a