Aviation Accident Summaries

Aviation Accident Summary CEN09LA288

Katy, TX, USA

Aircraft #1

N45YV

SMYSOR KEVIN VELOCITY

Analysis

The airplane's experimental two-bladed fixed-pitch propeller had recently been replaced with an experimental three-bladed constant-speed propeller. The pilot was flight testing the new propeller at the time of the accident. During the third flight of the day, one of the propeller's blades separated from the propeller hub during flight. The pilot lost control of the airplane and entered an uncontrolled descent. The airplane impacted in a flat, lightly wooded area. Flight control continuity was confirmed and no preimpact anomalies were discovered with the airplane's engine or other airplane systems. An examination of the propeller conducted by the National Transportation Safety Board Materials Laboratory discovered several areas of disbonding with signatures of low adhesion between the propeller shank, adhesive, and propeller ferrule.

Factual Information

HISTORY OF FLIGHT On May 9, 2009, at 1317 central daylight time, a kit-built Velocity airplane, N45YV, was substantially damaged upon impact with terrain following a loss of control near Katy, Texas. The private pilot, the sole occupant of the airplane, was fatally injured. The airplane was owned and operated by a private individual. Visual meteorological conditions prevailed and the personal flight was being conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. No flight plan was filed for the local flight which departed the Houston Executive Airport (TME), Katy, Texas, at 1310. The airplane’s propeller had recently been replaced. Reportedly, the pilot/owner had been performing maintenance on the propeller and airplane prior to takeoff. The airplane was last seen in the traffic pattern around 1300 to 1315 and was later reported missing/overdue by a friend. The wreckage was located about 0200 on May 10, 2009, by an officer of the Waller County Sheriff's Department. PERSONNEL INFORMATION The pilot, age 46, held a private pilot certificate for airplane single engine land. A third class medical certificate was issued on January 7, 2008, with the restriction that the pilot must wear corrective lenses. A review of the pilot’s log book revealed he had logged over 672.6 hours of total flight time and could have over 250 flight hours in the accident airplane. The pilot’s last flight review occurred on April 21, 2009, in the accident airplane. AIRCRAFT INFORMATION The four-seat, swept-wing, canard equipped, fixed gear airplane, serial number SV4101, was manufactured in 1992, and had an Experimental-Amateur built airworthiness certificate. It was powered by a 200 horsepower Lycoming IO-360-C1E6, serial number L-9090-51A, driving an experimental three-bladed composite Vesta GP3-68 propeller. A review of the maintenance log books revealed the last conditional inspection was performed on September 1, 2008, at a Hobbs meter time of 711.3 hours. The last log book entry was dated January 15, 2009, for the maintenance work performed to the landing gear. The airplane’s propeller had been changed from a Catto propeller to a Vesta GP3-68 propeller. No log book entries were found to show the date of propeller installation. In addition, no paperwork was received by an FAA Flight District Standards Office (FSDO) concerning the change of propeller and proposed flight testing. METEOROLOGICAL INFORMATION At 1253 an automated weather reporting station located at the Sugar Land Regional Airport (SGR), located 15 nautical miles southwest of the accident site, reported winds from 160 degrees at 8 knots gusting to 16 knots, scattered clouds at 3,800 feet, temperature 31 degrees Celsius, dew point 21 degrees Celsius, and a barometric pressure of 29.95 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The airplane wreckage was located approximately two miles southeast of TME. The airplane was inverted in a flat, lightly wooded area. An on-scene examination of the wreckage discovered fuel was present in the tanks and two engine mounts were found fractured. Additionally, one blade of the three-bladed propeller separated from the propeller hub and was found approximately 200 yards west of the wreckage. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot on May 11, 2009, by the Joseph A. Jachimczyk Forensic Center, Houston, Texas, as authorized by the Justice of the Peace, Precinct 4, Waller County, Texas. The autopsy listed the cause of death as "multiple blunt force injures" and the manner of death an "accident." Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report found no carbon monoxide, cyanide, ethanol, or drugs in the specimens. TEST AND RESEARCH Garmin GPSMap 496 The global positioning system (GPS) unit was sent to the National Transportation Safety Board (Safety Board) laboratories for data download. Four track logs were recorded on the day of the accident (active log 030 through 033). Active log 030 data points were consistent with a “high speed taxi” down the runway. Active log 031 tracked the airplane as it departed from the runway, entered a left downwind pattern and landed back at the airport. Active log 032 tracked the airplane as it departed from the runway, entered a left downwind pattern, completed two orbits above the runway, and landed back at the airport. Active log 033 tracked the airplane as it departed from the runway and started a left turn, wide pattern around the airport. At 1316:58, the airplane turned left through 029 degrees traveling at 165 miles per mph (mph) in a slight descent. At 1317:01, the airplane turned left through 029 degrees and rapidly decelerated to 94 mph. Data revealed that the airplane continued to decelerate and descend until it impacted terrain. Vesta GP3-68 Propeller The installed propeller was an experimental (non-certified) model produced by Vesta Inc. According to the manufacturer’s website, “The Vesta propeller is constructed out of a combination of carbon graphite uni[directional fabric], S-glass, and E-glass cross weave, with high temperature epoxy.” The website also stated “The retention system on the blades is like no other. First, each of the 30 layers of carbon graphite are woven into aluminum rings at the base of the blade. The blade is then cast into a steel ferrule which is serrated on the inside and forms a 'baseball bat' type shape at the end of the blade. Then 8 steel pins are drilled and set through the steel ferule, the aluminum rings, and uni into the solid core. In addition there is a 3/4 [inch] grade 12.9 bolt cast into the center of the blade with a nut on the end that is threaded into the steel ferrule. The end result is that the retention system is designed to hold 100,000 lbs. and is tested to 80,000 lbs. The FAA would require Vesta to demonstrate twice the actual centrifugal force used in flight if certification was desired. The typical centrifugal load at 2,700 RPM is about 20,000 lbs.” The company states that the propeller is not deemed airworthy and that it is the pilot’s responsibility to ensure that the propeller is properly tested prior to flight. On May 17, 2010, an examination of the propeller was conducted at the NTSB laboratories. The examination of the liberated blade revealed several areas of disbonding between the blade shank and the ferrule. Along the shank’s radial surface there were signatures consistent with low adhesion between the blade radial surface and the flox (epoxy resin reinforced with flocked cotton fibers) adhesive. In addition, signatures consistent with low adhesion were discovered between the adhesive on the blade butt and the ferrule surface. A borescope inspection of the liberated blade’s bolt hole revealed numerous pores along the wall of the bolt hole suggesting that there was entrained air (air pockets) during the bonding process. An examination of the bolt threaded through the center of the blade revealed that approximately 20 percent of the adhesive had separated from the bolt, with the remaining adhesive being broken away from the blade. There was no evidence of pre-treatment of the bolt surface to promote adhesion. Flox adhesive on the ferrule’s radial surface displayed signatures of fracture and degrading consistent with mechanical battering. In addition, the eight steel set screws were found fractured.

Probable Cause and Findings

The pilot's loss of control following an in-flight failure of the propeller.

 

Source: NTSB Aviation Accident Database

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