Aviation Accident Summaries

Aviation Accident Summary DFW07LA090

Sinton, TX, USA

Aircraft #1

N606S

Schilleci RV-6

Analysis

The 18,730-hour airline transport rated pilot lost control of the homebuilt airplane while executing a GPS instrument approach to Runway 14 at a non-towered airport. The airport has two instrument approaches to Runway 14; a VOR/DME and a GPS. The published weather minimums for the GPS approach to Runway 14 was 500-foot ceiling and one mile visibility. One witness stated that the pilot made "two passes" before crashing at the runway's east end, and also stated that heavy fog prevailed at the time of the accident. Another witness said that they heard two "loud pops," came outside and saw smoke and a small fire, but no airplane. This witness also confirmed that it was foggy at the time. A post-impact fire consumed most of the airframe. A detailed examination of the airplane failed to reveal any anomalies with the airframe, structure, or systems. The engine was examined, and no mechanical anomalies were found. The examination of the propeller revealed one blade was slightly bent "forward"; the other blade did not have the appearance of being bent. Both blades had leading edge polishing. The propeller signatures are consistent with a propeller absorbing rotational energy with power into soft soil or sand. The flap actuator was found in the extended position, corresponding to a flaps "up" position. The automated weather station, located approximately 17-miles south of the accident site, reported at 0851; a 5-mile visibility in mist, a scattered sky at 10,000 feet and winds from 140 degrees at 6 knots.

Factual Information

HISTORY OF FLIGHT On April 2, 2007, about 0830 central daylight time, a single-engine Schilleci RV-6 airplane, N606S, was destroyed upon impact with terrain following a loss of control while executing an instrument approach to the Alfred C "Bubba" Thomas Airport (T69), near Sinton, Texas. The airline transport pilot, sole occupant of the airplane, was fatally injured. The homebuilt airplane was registered to and operated by a private individual. An instrument flight rules (IFR) flight plan was filed for the 116-nautical mile cross-country flight that originated from the Kestrel Airpark (1T7), at 0753. Instrument meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations Part 91. A Texas Department of Public Safety (DPS) officer, who was in the area approximately 20 minutes prior to the crash, reported that heavy fog prevailed in the area at the time of the accident. Another witness, whose residence is near the airport, reported that she heard two "loud pops" and came outside; and saw smoke and a small fire, but did not see the airplane. Additionally, she reported that the weather was foggy. According to an Federal Aviation Administration (FAA) Inspector, who responded to the scene, witnesses reported that the airplane circled [the airport] a couple of times; and was in-and-out of the clouds. PERSONNEL INFORMATION The pilot held an airline transport pilot certificate for airplane multi-engine land, and a commercial certificate for single and multi-engine land and sea. His last first class Federal Aviation Administration (FAA) medical certificate was issued on March 24, 2007. At the time of his last medical examination, the pilot reported a total of 18,730 flight hours. AIRCRAFT INFORMATION The Vans RV-6 airplane is an all-metal, single-engine, low-wing airplane, which the builder assembles from a kit. The tailwheel-equipped airplane was configured with 2 side-by-side seats. The airplane was powered by a single Lycoming O-360-A1A reciprocating engine, rated at 180-horsepower. The engine was equipped with a Sensenich 2-blade fixed pitch propeller. The airplane was equipped for instrument flight, including a two axis auto-pilot system. The maintenance records for the airplane were not located during the course of the investigation. METEOROLOGICAL INFORMATION At 0851, the automated weather station at KCRP, located approximately 17 nautical miles south of the accident site, reported winds from 140 degrees at 6 knots, an altimeter setting of 29.99 inches of Mercury, temperature 73 degrees Fahrenheit, dew point 71 degrees Fahrenheit, 5 miles visibility in mist and a scattered sky at 10,000 feet. COMMUNICATIONS A review of the voice transcript, between N606S and Corpus Christi Airport Traffic Control Tower (ATCT) had N606S cleared for the GPS Runway 14 approach. No problems were reported to the controllers and no emergency or distressed calls were received from the pilot prior to the accident. AERODROME INFORMATION The Alfred C "Bubba" Thomas Airport (T69) is a public use airport, located near Sinton, Texas. The airport does not have a control tower, but has a local area common traffic advisory frequency (CTAF). T69 features two runways. Runway 14-32 is a 4,050-foot long and 50-foot wide asphalt runway. Runway 03-21 is a 2,800-foot long and 50-foot wide grass runway. The field elevation is 48 feet mean sea level (msl). The airport has four instrument approaches, a VOR/DME and a GPS to Runway 14; and a VOR/DME and a GPS to Runway 32. The published weather minimums for the GPS Runway 14 are a 500-foot ceiling and one-mile visibility. WRECKAGE AND IMPACT INFORMATION The FAA Inspector examined the wreckage at the accident site. The inspector reported that all major components of the airplane were accounted for at the scene of the accident. A post-impact fire consumed much of the cabin area and the remaining wreckage consisted mainly of the empennage and wings. The initial impact point was a ground scar that exhibited red paint transfer on the taxiway consistent with the paint scheme of the airplane. The ground scar started on the parallel taxiway at approximately a 45-degree angle between the runway heading and path to the main wreckage. Pieces of the red, left-wing navigation light, lens was found in the ground scar near the initial impact point. Further along the ground scar were the spinner and propeller; the canopy laid just to the left of the ground scar and prior to the main wreckage. The wreckage path continued for a short distance to the main wreckage, which came to rest facing about 90-degrees from the initial impact point. The wreckage and impact marks were consistent with the airplane being in a steep, left bank or turn upon contact with the terrain. The wreckage of the airplane was recovered to Air Salvage of Dallas (ASOD) for further examination. On June 27, 2007, at ASOD, engine serial number L-36193-36A was examined under the supervision of the NTSB investigator-in-charge (IIC), along with a technical representative from the engine manufacturer. The propeller remained bolted to the propeller hub, but had separated from the engine near the crankshaft flange, with a 45-degree shear lip fracture. An adapter was connected to the vacuum pump accessory drive pad and the engine was rotated. Thumb compression and suction were obtained. Valve train continuity was observed through the accessory gears. The oil suction screen was removed and was observed free of any contaminants. All of the engine accessories were fire destroyed beyond the ability of to test. The carburetor was badly deformed and burned. The fuel inlet screen was destroyed by fire. The engine was inverted and the bottom sparkplugs were removed. The bottom sparkplugs were consistent with normal operation and in good condition when compared with the Champion Sparkplug Wear Guide. The examination of the engine did not reveal any pre-impact mechanical anomalies that would have prevented normal engine operation. The examination of the propeller revealed one blade was slightly bent "forward"; the other blade did not have the appearance of being bent. Both blades had leading edge polishing. Flight control continuity was established, and the flap actuator was found in the extended position, corresponding to a flaps "up" position. MEDICAL AND PATHOLOGICAL INFORMATION Autopsies were performed by the Nueces County Medical Examiner, Corpus Christi, Texas. Toxicological Testing was conducted by, the FAA Toxicology Accident Research Laboratory. Oklahoma City, Oklahoma.

Probable Cause and Findings

The pilot's loss of control while performing an instrument approach. A contributing factor was the prevailing fog.

 

Source: NTSB Aviation Accident Database

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