CEN17FA364

The pilot's improper decision to return to the runway instead of landing straight ahead when the engine lost power and his failure to maintain adequate airspeed while maneuvering for an emergency landing, which resulted in an exceedance of the airplane's critical angle of attack and an aerodynamic stall. Contributing to the accident was the pilot's failure to properly secure the left main fuel tank cap after refueling, which resulted in a loss of engine power due to fuel starvation during the takeoff climb.

After refueling the airplane, the pilot and the pilot-rated passenger took off in the airplane to return to the pilot's home airport. During the initial climb, the airplane accelerated to about 67 knots and reached an altitude of about 170 ft above ground level before it began to slow and lose altitude, consistent with a loss of engine power. Although more than 2,300 ft of relatively level grassy terrain suitable for an emergency landing remained ahead of the airplane, the pilot made a left turn back toward the departure end of the runway. During the turn, the airplane entered a steep left spiral, impacted the ground, and caught fire. The airplane's left main fuel tank cap was found on the left side of the runway about 1,000 ft from the threshold and 4,500 ft from the main wreckage. The cap's locking lever was engaged, and it showed no fire or impact damage. The fuel selector valve was found positioned to the right main fuel tank feed position. Flight control continuity was confirmed, and no other preimpact anomalies were found. According to the pilot operating handbook for the airplane, the fuel selector should be on the left main fuel tank for takeoff. It is likely that the left main fuel tank cap was not secured after the airplane was refueled and fell off the airplane's left wing onto the runway during the takeoff. Without the cap in place, fuel escaped from the left main fuel tank and subsequently starved the engine of fuel during the climb, resulting in the power loss. The pilot likely switched the fuel selector to the right main fuel tank in an attempt to restart the engine. When the pilot tried to turn back to the airport, he failed to maintain a safe airspeed, and the airplane exceeded its critical angle of attack and entered an aerodynamic stall.

The Arkansas State Crime Laboratory, Medical Examiner Division, Little Rock, Arkansas, performed autopsies on the pilot and the pilot-rated passenger. For both pilots, the cause of death was blunt force injuries. The Federal Aviation Administration's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed forensic toxicology testing on specimens from the pilot and the pilot-rated passenger. The pilot's test results showed 26 (mg/dl, mg/hg) ethanol detected in urine with no ethanol detected in blood. These results are consistent with postmortem ethanol production. The pilot-rated passenger's test results were negative for drugs and alcohol. A review of recorded data from the CDH automated weather observation station revealed that, at 1815, conditions were calm wind, visibility 10 miles, clear skies, temperature 28°C, dew point 23°C, and altimeter setting 29.89 inches of mercury. The pilot, age 42, held a commercial pilot certificate with ratings for airplane single-engine land, rotorcraft-helicopter, instrument airplane, and instrument helicopter. The pilot also held a flight instructor certificate. The pilot's most recent Federal Aviation Administration (FAA) second-class airman medical certificate was issued on August 19, 2009, with no limitations. The medical certificate expired for all classes on August 31, 2014. The pilot was actively serving as a UH-60 helicopter pilot for the Arkansas Air National Guard at the time of the accident. According to his Army Individual Flight Record and Flight Certificate, the pilot completed a military flight physical examination on October 22, 2016. Title 14 Code of Federal Regulations 61.23(b)(9) states that when a military pilot of the U.S. Armed Forces can show evidence of an up-to-date medical examination authorizing pilot flight status issued by the U.S. Armed Forces and (i) the flight does not require higher than a third-class medical certificate; and (ii) the flight conducted is a domestic flight operation within U.S. airspace, that person is not required to hold a medical certificate. Army flight records indicated that the pilot had 2,175.7 total hours of flight experience of which 1,844.3 hours were in military helicopters and 331.4 hours were in civilian airplanes. The pilot completed a military standardization evaluation check flight on October 27, 2016, in a UH-60L helicopter. Title 14 Code of Federal Regulations 61.56(d)(1) states that a person who has passed a U.S. Armed Forces proficiency check within a 24-month period need not accomplish a flight review. Insurance records indicated the pilot had 440 hours of flight experience in the accident airplane make and model as of January 27, 2017. The pilot-rated passenger, age 31, held a commercial pilot certificate with ratings for airplane single-engine land, rotorcraft-helicopter, instrument airplane, and instrument helicopter, and an FAA first-class airman medical certificate issued July 27, 2017, with no restrictions. The pilot-rated passenger reported no flight hours on the application for this medical certificate; however, during his prior medical exam on October 28, 2010, he reported 20 total hours of civilian flight experience. The accident site was in a field on airport property about 172 ft east and 1,000 ft south of the departure end of runway 01. The airplane was upright and oriented on a 200° heading. With the exception of the left wing fuel tank cap, all the wreckage was contained in an area that was 33-ft long, extending from the initial impact point to the empennage, and 35-ft wide, encompassing the right wing and left outboard wing sections. Grass and bushes immediately surrounding the wreckage were burned. The left wing fuel tank cap was located about 4,500 ft south of the main wreckage on the left side of the runway at the 1,000-ft marker. The locking lever was engaged, and the cap showed no fire or impact damage. A 10-ft-long, 4-ft-wide, and 1-ft-deep ground scar preceded the main wreckage, which was located 2 ft farther to the northeast. Pieces of broken clear plastic, the main cabin door and part of the door post, and one propeller blade were in the ground scar. The main cabin door was broken out at the door hinges, intact, and charred by fire. Fire consumed the forward fuselage aft of the engine, most of the cabin section, the inboard portions of the left and right wings, the landing gear, the baggage compartment, and the fuselage immediately aft of the baggage compartment. The forward windscreen was broken out and fragmented. The instrument panel, glare shield, and control yokes were broken aft, melted, and consumed by fire. The cabin floor, seats, cabin interior, and baggage compartment were charred, melted, and consumed by fire. A 10-ft-long outboard section of the right wing, two 4- to 5-ft-long sections of the outboard left wing, an 8-ft-long section of the aft fuselage, and the V-tail empennage survived the fire. The right outboard wing was broken upward along the leading edge at the root. The lower wing skin was charred by fire, and the upper skin was bent aft and buckled. The right main bladder fuel tank was consumed and melted. The right main fuel tank cap was located 10 ft south of the main wreckage. The right main landing gear door and strut were charred and melted. The right main tire was charred and consumed by fire. The forward portion of the right tip fuel tank was consumed by fire. The right flap was charred, melted, and consumed, and the right aileron was bent downward 14 inches inboard of the outboard end. The left wing was broken upward and aft at the wing root and fractured into two pieces at midspan. The inboard section of the left wing was crushed aft, charred, and melted. The left flap was broken out, bent aft, and melted. The left main landing gear and door were charred and melted, and the left main tire was charred and consumed by fire. The left main bladder fuel tank was charred and consumed by fire. The outboard section of the left wing was twisted upward and broken aft. The left aileron was bent upward at the inboard edge and buckled downward about 10° at midspan. The end of the wing where the left tip fuel tank was located was charred and melted. The left tip fuel tank was broken aft and separated from the wing. It was located on the ground immediately aft of the wreckage and was charred and consumed by fire. The airplane's engine, engine cowling, and the propeller hub with one blade attached were located at the front of the wreckage. The cowling was broken open. The nose landing gear and doors were charred by fire. The nose wheel tire was consumed by fire. The engine was intact and broken downward at the mounts. Several of the engine accessories sustained fire damage. The propeller spinner was crushed over the front of the hub aft to the counterweights. One blade remained with the hub and was bent aft about 60° about 8 inches outboard of the hub. The blade showed no signs of S-bending or chordwise scratches. The other propeller blade was broken out at the hub mounting clamps and was bent aft about 10° about 12 inches outboard of the hub. The blade showed chordwise scratches and leading edge rubbing from midspan to the blade tip. The aft fuselage section was upright on the ground and rested on its left side supported by the airplane's left stabilator. It was fractured circumferentially aft of the baggage compartment. There was charring from fire at and aft of the fracture. The empennage was relatively undamaged. Flight control continuity was confirmed from the forward cabin area to all the control surfaces. On November 20, 2017, an examination of the airplane was conducted at Clinton, Arkansas. The examination showed that the landing gear was down and the flaps were up at ground impact The propeller and accessories were removed from the engine. The left and right magnetos, starter, alternator, and the electric propeller contro