Aviation Accident Summaries

Aviation Accident Summary ERA17FA153

Monongahela, PA, USA

Aircraft #1

N4476N

HOWARD AIRCRAFT DGA 15P

Analysis

Witnesses observed the airplane touch down left of the runway centerline in gusting crosswind conditions and then attempt to go-around. As the engine noise increased, the airplane yawed 90° left and banked left, perpendicular to the runway. The airplane's nose pitched up, and the airplane subsequently entered an aerodynamic stall and rolled inverted before impacting a ravine about 400 ft left of the runway. Examination of the wreckage did not reveal any preimpact mechanical malfunctions that would have precluded normal operation. The airplane was equipped with a 450-hp radial engine. It is likely that, upon application of engine power to initiate the go-around, the pilot failed to adequately compensate for the extreme left-turning tendencies of the high-powered engine, which resulted in a subsequent loss of control and aerodynamic stall.

Factual Information

HISTORY OF FLIGHTOn April 12, 2017, about 1430 eastern daylight time, a Howard Aircraft DGA-15P, N4476N, was destroyed when it impacted terrain during a go-around at Rostraver Airport (FWQ), Monongahela, Pennsylvania. The commercial pilot was fatally injured. The airplane was registered to Pittsburgh Institute of Aeronautics and was operated by the commercial pilot as personal flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed in the area, and no flight plan was filed for the flight, which originated from Allegheny County Airport (AGC), Pittsburgh, Pennsylvania, about 1305. According to information from the Federal Aviation Administration (FAA), no air traffic control services were requested or provided after the flight departed from AGC. Review of radar data revealed that, before proceeding to FWQ, the airplane's radar track was consistent with airwork in the local area, as the track sometimes disappeared in areas that were below radar coverage. According to witnesses at FWQ, the airplane was attempting to land on runway 26, a 4,002-ft-long, 75-ft-wide asphalt runway. The airplane initially touched down left of the runway centerline then became airborne, and the engine noise increased. The airplane subsequently yawed and banked left, perpendicular to the runway, and the nose pitched up. At that point, the airplane appeared to stall and roll inverted before impacting a ravine about 400 ft left of the runway. A postcrash fire ensued. One of the witnesses had just completed several landings in a Cessna 172. He stated that, although the automated weather observation system was indicating wind from 290° at 5 knots, he encountered a wind gust during his last landing, which lifted his airplane's right wing and caused it to drift left. PERSONNEL INFORMATIONThe pilot held a commercial pilot certificate with ratings for airplane single-engine land, airplane multiengine land, and instrument airplane. His most recent FAA second-class medical certificate was issued on May 9, 2016. At that time, the pilot reported a total flight experience of 1,091 hours. The pilot's logbook was not recovered and was presumed destroyed in the postcrash fire. According to an insurance application dated October 21, 2016, the pilot reported a total flight experience of 1,109 hours, of which 30 hours were in the accident airplane make and model. AIRCRAFT INFORMATIONThe five-seat, high-wing, fixed-tailwheel airplane was powered by a Pratt and Whitney R-985, 450-horsepower radial reciprocating engine, equipped with a two-blade Hamilton Standard propeller. Review of the airplane's logbooks revealed that the most recent annual inspection was completed on March 23, 2017. At that time, the airframe had accumulated 2,184.2 total hours, and the engine had accumulated 109.2 hours since major overhaul. METEOROLOGICAL INFORMATIONThe 1425 recorded weather at FWQ included wind from 280° at 6 knots variable between 240° to 320°; visibility 10 statute miles; clear sky; temperature 16°C; dew point 1°C; altimeter 30.31 inches of mercury. AIRPORT INFORMATIONThe five-seat, high-wing, fixed-tailwheel airplane was powered by a Pratt and Whitney R-985, 450-horsepower radial reciprocating engine, equipped with a two-blade Hamilton Standard propeller. Review of the airplane's logbooks revealed that the most recent annual inspection was completed on March 23, 2017. At that time, the airframe had accumulated 2,184.2 total hours, and the engine had accumulated 109.2 hours since major overhaul. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed ground scars in the grass about 200 ft left of the runway and about halfway down the runway. Red paint chips consistent with the color of the wingtips, were observed in the ground scars. An impact crater was noted about 350 ft left of the runway, which contained a separated 8-inch section of propeller blade. The main wreckage came to rest upright, oriented on a heading about 320° magnetic and was consumed by postcrash fire. Control cable continuity was confirmed from the left and right aileron bellcranks to the mid-cabin area. Continuity was also confirmed from the stabilator and rudder to the mid-cabin area. No readable instruments were recovered from the cockpit. The engine had separated from the airframe and was resting to the left of it. Both propeller blades remained attached to the propeller hub and exhibited leading edge gouging and chordwise scratching. Additionally, both propeller blade tips had fractured and were located near the impact crater. Due to impact damage, the crankshaft could not be rotated by hand; however, cursory examination of the engine revealed no evidence of any preimpact mechanical malfunctions or anomalies . ADDITIONAL INFORMATIONThe Pilots Handbook of Aeronautical Knowledge (FAA-H-8083-25B), Chapter 5, "Aerodynamics of Flight," identifies four elements that produce a left turning tendency in aircraft equipped with clockwise-rotating propellers. These elements are torque reaction from engine and propeller, corkscrewing effect of the propeller slipstream, gyroscopic action of the propeller, and asymmetric loading of the propeller (P-factor). MEDICAL AND PATHOLOGICAL INFORMATIONThe Westmorland County Office of the Coroner, Greensburg, Pennsylvania, performed an autopsy on the pilot . The autopsy report noted the cause of death as "multiple blunt force injuries." The FAA Bioaeronautical Science Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing on the pilot. The results were negative for alcohol and drugs.

Probable Cause and Findings

The pilot's failure to maintain airplane control during an attempted go-around in gusting crosswind conditions, which resulted in an exceedance of the airplane's critical angle of attack and a subsequent aerodynamic stall.

 

Source: NTSB Aviation Accident Database

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