Aviation Accident Summaries

Aviation Accident Summary CEN15FA310

Auburn, WY, USA

Aircraft #1

N8362H

AERONCA 7BCM (L-16A)

Analysis

Witnesses reported seeing the airplane flying at a low altitude and the rear occupant dropping candy to people on the ground. The airplane then proceeded east and crossed a highway before beginning a turn to return for another pass. One witness reported that the airplane then made a sudden turn and the nose of the airplane dropped; another witness reported that the airplane suddenly dipped. The airplane impacted the front yard of a private residence. A postcrash examination of the airplane showed flight control continuity. No anomalies were found with the airplane's engine or other systems. It is likely the pilot exceeded the airplane's critical angle-of-attack following the turn, which resulted in an aerodynamic stall at low of an altitude to recover.

Factual Information

HISTORY OF FLIGHT On July 21, 2015, about 1845 mountain daylight time, an Aeronca 7BCM (L-16A), N8362H, impacted terrain in front of a residence in Auburn, Wyoming. The pilot and passenger were fatally injured. The airplane was destroyed. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan had been filed. The local flight originated from Afton (KAFO), Wyoming, about 1830. Eight witnesses observed the airplane, but only three submitted statements. They reported seeing the airplane fly over the Auburn LDS (Church of Christ of Latter Day Saints) Shelter and the rear occupant dropped candy out the window to those below. The airplane banked steeply to the west, then south, and then east and crossed Highway 238. before starting a turn. Witnesses said it appeared the pilot was going to come back and make another pass. According to one witness, the airplane pulled up steeply, stalled, and did a tail slide. The nose dropped and the airplane impacted the front yard next to a driveway in front of 4390 State Highway 238. There was no fire. PERSONNEL (CREW) INFORMATION The pilot, age 64, was identified by the sheriff's office as being in the front seat. He held a private pilot certificate with an airplane single-engine land rating. He also held a third class airman medical certificate, dated July 15, 2015, with the restriction, "Must wear corrective lenses." According to a flight instructor at KAFO, he gave the pilot a biennial flight review on March 3, 2015. He stated that at that time, the pilot had logged in excess of 1,800 flight hours. He further stated that the pilot flew his airplane at least three times a week and he considered him to be an excellent pilot. According to the airplane's co-owner, as of November 1, 2014, the pilot had logged 1,799.44 total flight hours, of which 456.5 hours were in N8362H. Flight time logged thereafter was kept in a logbook in the airplane. The logbook was recovered from the wreckage and contained entries from March 30, 2009, to July 13, 2015. Beginning after November 1, the pilot flew the airplane 25 times between November 6, 2014, and July13, 2015, for a total of 14.6 hours. The student pilot-passenger, age 22, was seated in the rear seat. He was scheduled to take his airman medical examination the following day and solo four days later. According to the same flight instructor at KAFO, he had logged 11 hours total time, all of which were in a Mooney M20C. AIRCRAFT INFORMATION N8362H (serial number 7BCM-126), a model 7BCM, was manufactured by the Aeronca Aircraft Corporation in September 1947. It was formerly a U.S. Army L-16A (serial number 47-912). It was powered by a Continental C-85-8FJ (serial number 29895-7-8), driving a McCauley 2-blade, all-metal, fixed pitch propeller (model number CM7043/1B90, serial number55796)). N8362H was a single-engine, 2-place tandem seating airplane with a fixed conventional landing gear and a steerable tail wheel. The wings-level power-off stall speed was 38 mph. According to the maintenance records, the airplane received an annual inspection on January 14, 2015, at a total time of 2,096.04 hours. The tachometer read 727.12 hours. At the same time, the engine received a 100 hour inspection. Engine total time was 1610.13 hours, and 755.67 hours had accrued since major overhaul. METEOROLOGICAL INFORMATION The following pertinent weather observation was recorded at the Afton Municipal Airport (KAFO) at 1835: Wind, 300 degrees at 3 knots; visibility, 10 miles; sky condition, 7,500 feet, scattered, 12,000 feet scattered; temperature, 21 degrees Celsius (C.); dew point, 11 degrees C.; altimeter, 30.04 inches of mercury; remarks, lightning distant south. WRECKAGE AND IMPACT INFORMATION The on-scene investigation commenced and terminated on July 22, 2015. The wreckage was located in a driveway in front of a residence at 4393 Wyoming Highway 238 in Auburn. This was the address of one of the airplane owners. Evidence collected at the accident site was consistent with the airplane striking the ground in a nose low-right wing low attitude. The airplane then slid across a gravel driveway for 57 feet on a magnetic heading of 137 degrees before coming to a stop. The fuselage, from the empennage to the cabin area, was aligned on a magnetic heading of 190 degrees and the nose section was aligned on a magnetic heading of 200 degrees, or canted 10 degrees to the right. The relatively straight left wing bore no leading edge damage. The right wing had advanced forward and the outer portion of the leading edge was crushed aft. The elevator trim tab, located on the left elevator, was deflected full up. The elevator trim tab control was in the full nose down position. All major components were accounted for and remained attached. Control continuity was established from the flight control surfaces to the cabin area. The elevator trim tab was jammed in the full up position, and the overhead control was jammed in the full nose down position. The propeller remained attached to the flange but the flange had separated from the crankshaft. A small portion of the crankshaft was inside the hub and bore evidence consistent with torsional overload. Blade A (descending) was bent aft. There were longitudinal scratch marks on the cambered surface and 90 degree scratch marks on the flat surface. Blade B (ascending) was bent in an "S" fashion and the tip was curled aft. There were longitudinal scratch marks on the cambered surface near the hub. Both blades bore leading edge gouges. . Examination of the cockpit revealed the mixture control was in the full rich position, the throttle was full forward, the primer was in and locked, and the cabin heat was off. The airspeed indicator registered 80 mph, the altimeter registered 0 feet (no Kollsman window), and the tachometer registered 0 rpm and indicated 0739.75 hours. The needle of the turn and slip indicator was straight up, and the ball was displaced one ball width to the left. The cylinder head temperature read 225 degrees F., the magnetic compass read 330 degrees, and the outside air temperature gauge read 24 degrees C. (75 degrees F.). MEDICAL AND PATHOLOGICAL INFORMATION According to the autopsy reports, both occupants died as a result of "multiple blunt traumatic injuries." According to the pilot's toxicology report, no carbon monoxide was detected in blood and no ethanol was detected in vitreous. However, chlorthalidone was detected in liver and blood. According to FAA's Forensic Toxicology, chlorthalidone is a diuretic drug used to treat hypertension. It is described as a thiazide diuretic, because it acts similarly to the thiazides. According to the pilot-rated passenger's toxicology report, no carbon monoxide was detected in blood, and no ethanol was detected in the vitreous. A cyanide test was not performed. No drugs were detected in the urine. ADDITIONAL INFORMATION The wreckage was released to the regional claims manager for Aviation LS, Prescott, Arizona, on July 29, 2015. The Federal Aviation Administration was a party to the investigation.

Probable Cause and Findings

The pilot's failure to maintain airspeed while turning at low altitude, which resulted in the airplane exceeding its critical angle-of-attack and entering an aerodynamic stall.

 

Source: NTSB Aviation Accident Database

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