Aviation Accident Summaries

Aviation Accident Summary DFW07LA124

Boerne, TX, USA

Aircraft #1

N39AJ

Adams RV-6A

Analysis

The commercial pilot lost control of the single-engine homebuilt airplane during takeoff from a private 2,300-foot long turf runway. An FAA safety inspector, who traveled to the accident site, performed an on-scene examination and documentation of the wreckage. Family members and neighbors witnessed the accident sequence. Some witnesses reported that the airplane appeared to have made a normal takeoff. At about 100 to 150 feet above the ground the airplane was observed to have attained a pronounced nose-high attitude, and subsequently rolled abruptly to the left as the airplane assumed a nose-low attitude. The airplane impacted the ground in the inverted position. A post-impact fire consumed most of the airplane. The wreckage of the airplane was recovered to a secured location for further evaluation. Flight control continuity was established to all flight controls. A detailed engine examination of the airframe and the engine failed to reveal any anomalies that could have prevented normal flight operation. The nearest weather recording station was the San Antonio International Airport (KSAT). At 1053 local, KSAT was reporting wind from 180 degrees at 10 knots, visibility 10 statute-mile, a broken layer at 2,400 feet, temperature 27 degrees Celsius, dew point 21 degrees Celsius, with an altimeter setting of 29.95 inches of Mercury. The density altitude was calculated at 3,126 feet msl. .

Factual Information

On May 30, 2007, approximately 1035 central daylight time, a single-engine Adams RV-6A homebuilt airplane, N39AJ, was destroyed following a loss of control during initial takeoff climb from runway 22 at the John Henry Key airport (7TA8) near Boerne, Texas. The commercial pilot, sole occupant of the airplane, was fatally injured. The airplane was registered to, and operated by the pilot. Visual meteorological conditions prevailed throughout the area, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The 178-nautical mile cross-country flight to the David Wayne Hooks Airport (DWH) was originating at the time of the accident. Local authorities were notified of the mishap via a 911-phone call. The remains of the airplane came to rest along a fence in a ravine in a rugged area about a quarter-mile from the departure end of Runway 22. There were no reported injuries to anyone on the ground. A post-impact fire consumed most of the airframe. The 1990 model RV-6A homebuilt airplane, serial number 20065, was completed by John E. Adams, of Portland, Oregon, on June 1990. The airplane was reported to have been purchased by the pilot on August 21, 2004. The tricycle gear airplane was configured for two occupants seated side-by-side. Both seats were equipped with seat belts and shoulder harnesses. The airplane was powered by a 180-horsepower Lycoming O-360-A1A engine, serial number L-13884-36A, which was reported to have been installed on the airplane on January 20, 2004. The engine was driving a two-bladed Hartzell constant speed propeller model HC-C2YK-1B, serial number CH-7717. According to the maintenance records provided, the last condition inspection was completed on April 14, 2006, at 1,222-airframe hours. The pilot was reported to use the airplane on a daily basis to commute to and from the Houston area, where he was employed. He had been a Naval aviator and was reported to be an active member of the Armed Forces Reserves where he served as a UH-60 helicopter pilot. He was reported to have accumulated 1,798 flight hours in military helicopters. The pilot's logbooks were not available during the course of the investigation. The pilot was reported to be very familiar with the airplane and the airport. Family members and neighbors witnessed the accident sequence. Some witnesses reported that the airplane appeared to have made a normal takeoff from the upslope 2,300-foot long runway. One of the witnesses added that after the airplane became airborne, it stayed close to the runway and gained speed. At about 100 to 150 feet above the ground the airplane was observed to have attained a pronounced nose-high attitude, and subsequently rolled abruptly to the left as the airplane assumed a nose-low attitude. One of the family was reported to make a statement to the effect that the engine "went quiet" during the initial takeoff-climb phase of the flight. An Federal Aviation Administration (FAA) safety inspector, who traveled to the accident site, performed an on-scene examination and documentation of the wreckage. The inspector reported that the airplane came to rest in a heavily wooded ravine, in the inverted position on a measured heading of 030-degrees. A handheld GPS carried by one of the first responder established the field elevation of the accident site at 1,522-feet. Damage sustained by the cedar/mesquite trees and impact signatures at the accident site were consistent with the airplane impacting the top of the trees and terrain in a left turn while in a nose-low attitude. All of the components of the airplane and wreckage were found within a 50-foot radius of the main wreckage. All aircraft components were accounted for at the accident site. Flight control continuity could not be established at the accident site due to impact and fire damage. The cabin area and the left wing were consumed by the post-impact fire. The engine sustained extensive thermal damage. All engine components and lines were heavily damage. The engine remained attached to the engine mounts and the engine firewall. The propeller spinner was consumed by fire and the propeller remained attached to the propeller flange on the engine crankshaft. The wreckage of the airplane was recovered to a secured location near Lancaster, Texas, for further examination and testing. The John Henry Key Airport (7TA8) is an unlit private airstrip featuring a single 2,300-feet long, by 100-feet wide turf runway oriented on 040/220 degrees heading. The elevation at the approach end of runway 22 was 1,416-feet, while the elevation at the departure end of the runway was 1,448-feet, which confirmed that Runway 22 had a slight upslope gradient. A detailed engine examination/teardown and a wreckage layout was conducted on June 20, 2007, under the supervision of the NTSB investigator-in-charge. The wreckage lay-out revealed that the tail section and the right wing of the airplane were not burned and remained undisturbed. The right fuel cell was also undamaged. The full-swivel nose landing gear strut was found undamaged and remained attached to the engine mounts. The flaps were found in the fully retracted position. The airplane was equipped with an electric elevator trim tab; however, the position of the elevator trim tab could not be determined. The carburetor (bottom of the engine) was also undamaged and remained attached to the engine. The throttle lever at the carburetor was found in the full-power position. The propeller remained attached to the engine and sustained minimal damage. The badly burned fuel selector was found in the left tank position. Barbed wire was found tightly wrapped around the propeller shaft. The damage found at the wreckage examination was consistent with the reported ground impact in the invested position. Engine valve train continuity was established. Both magnetos and their respective wiring harnesses were destroyed by fire. The left magneto was a conventional Bendix magneto, while the right magneto featured a "Light Speed" electronic ignition system. No mechanical defects were found that could have prevented normal engine operation. The nearest weather recording station was the San Antonio International Airport (KSAT). At 1053 local, KSAT was reporting wind from 180 degrees at 10 knots, visibility 10 statute-mile, A broken layer at 2,400 feet, temperature 27 degrees Celsius, dew point 21 degrees Celsius, with an altimeter setting of 29.95 inches of Mercury. The density altitude was calculated at 3,126 feet msl. .

Probable Cause and Findings

The pilot's failure to maintain the best angle of climb speed resulting in an inadvertent stall. A contributing factor was the high density altitude.

 

Source: NTSB Aviation Accident Database

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