Llano, TX, USA
N5796L
AMERICAN AA-1
The flight instructor and student pilot departed for an instructional flight to perform traffic pattern work. A witness saw the airplane on the downwind leg of the traffic pattern and thought the airplane was operating at a very high angle-of-attack. He observed the airplane again a few minutes later, in the same location and operating in the same manner. A helicopter pilot reported that he saw a “flash” of an airplane wing, and then the accident airplane quickly departed controlled flight and descended to the ground. The airplane wreckage was located about 1 mile southeast of the airport. The examination of the engine and airframe did not reveal any additional abnormalities that would have precluded normal operation. A review of the student pilot’s logbook revealed that he had a total of 14.7 flight hours, including 12.5 hours in the accident airplane. His logbook’s last five entries were annotated as patterns and touch-and-go takeoffs; there was no record of any stall or spin avoidance training noted in his logbook. The airplane’s stall warning switch, located in the wing, did not indicate any electrical continuity when activated; a small amount of corrosion was observed under the terminal ends of the wires and the wire contact area. The wiring and screws were reassembled and the test was repeated; when activated, electrical continuity was noticed on the meter. The student pilot (who was the airplane owner) had told family members that the stall warning switch was not working properly, so the flight instructor would disable it for each flight. However, even with the stall switch disabled, the instructor should have noticed that the airplane was operating at low speed and high angle of attack yet he did not take corrective action. Based on the circumstances surrounding the accident, it is likely that the student pilot stalled the airplane while performing a high angle-of-attack turn to the downwind leg in the traffic pattern. The airplane’s low altitude would not have provided the pilots with sufficient time or altitude to recover. Additionally, toxicological testing on the flight instructor detected an antihistamine that is commonly used as a sleep aid in the liver and blood at a potentially impairing level; the antihistamine has potential side effects including cognitive and psychomotor impairment. It is likely that the flight instructor’s use of the sedating medication contributed to his failure to take remedial action when the student flew the airplane at such a high angle of attack at a low altitude.
HISTORY OF FLIGHT On August 25, 2012, about 1045 central daylight time, an American AA-1 airplane, N5796L, impacted terrain near Llano, Texas. The flight instructor and student pilot were fatally injured. The airplane was substantially damaged during the accident. The aircraft was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight originated from the Llano Municipal Airport, (KAQO). The airport manager reported that he saw the student, who owned the airplane, pull the airplane from the hangar and add fuel. The manager also saw the student and instructor depart the runway, but stay in traffic pattern practicing takeoff and landings. The manager also reported that he told the instructor, via the radio, that a jet was scheduled around 1100 inbound to the airport. The instructor acknowledged the transmission. There was no additional communication with the accident airplane. The manager added that he thought the student and instructor had departed the traffic pattern and was not concerned until about 1400, when the instructor’s next student showed up. After the airport manager contacted several nearby airports and could not locate the airplane, a local pilot departed the airport to search for the airplane. Within a few minutes the pilot reported that he had spotted the missing airplane’s wreckage, southeast of the runway. The wreckage was located in a lightly wooded area with cactus plants, approximately one mile southeast of the airport. A witness, reported he was flying a helicopter on the day of the accident and approached the Llano airport about 1045. He noted that there were several airplanes in the traffic pattern and he saw a flash of a wing and an airplane quickly departed controlled flight towards the ground. He added that he flew near the area and since he didn’t see any wreckage, dismissed the sighting as someone flying a radio controlled ( RC) airplane. An additional witness reported that he and several other people were working near the airfield between 1000 and 1200. He stated that he saw an airplane on the downwind leg of the traffic pattern, but what was unusual, was that the airplane was operating at a very high angle-of-attack. He added, that a few minutes later he observed the airplane, in the same location, operating in the same manner. PERSONNEL INFORMATION The flight instructor held commercial pilot certificates for airplane, single and multi-engine land, and instrument airplane. He also held flight instructor ratings for single, multi-engine and instrument airplane. A second-class Federal Aviation Administration (FAA) medical was issued on August 31, 2011 with the restriction that he must wear corrective lenses. The instructor’s logbook was not provided; however, the instructor reported on his last medical certificate he had accumulated 8,577 total flight hours with 783 hours in the last six months. The student pilot did not hold a student pilot or medical certificate. A review of FAA records revealed that the student applied for a medical certificate on August 17, 2012; however, the certificate was not issued pending additional information. At the time of the application, the student pilot reported a total of 15 flight hours with 15 hours in the last six months. A review of the student pilot’s logbook revealed that he had a total of 14.7 flight hours, with 12.5 hours in the accident airplane; the last recorded entry was on August 24, 2012. A detailed review of the student’s logbook revealed that he had two flights in February and one in March with a different instructor, as well as a different make/model of airplane then the accident airplane. Starting on June 29, 2012, the student pilot and accident flight instructor flew the accident airplane on a weekly basis. The June 29th flight was recorded as a 1.0 hour flight with the annotation of: “orientation flight Grumman”. The student pilot logbook’s last five entries were annotated as; patterns, touch-and-goes and there were no records of any stall or spin avoidance training noted in his logbook. AIRCRAFT INFORMATION The accident airplane was an American AA-1 airplane, which is an all-metal, side-by-side, two-seat low-wing airplane with fixed landing gear. The accident airplane was a 1969 model; according to FAA records, the student pilot purchased the airplane in April, 2012. The airplane was powered by a 108hp Lycoming O-235-C2C engine, that drove a fixed-pitch, two-bladed, metal propeller. According to maintenance records, the airplane's most recent annual inspection was completed June 26, 2012, with an airframe total time of 1,683.01 hours and tachometer time of 873.01 hours. The review of the maintenance records also revealed that a note annotated in the logs read; “Removed, inspected, and tested ELT, IAW FAR 91.207(d) no defects noted, new ELT battery due date is 5-14”. METEOROLOGICAL INFORMATION At 1055, the automated weather observation facility located at KAQO, recorded wind from 190 degrees at 13 knots, gusting to 16 knots, visibility 10 miles, clear of clouds, temperature 86 degrees Fahrenheit (F), dew point 44 F, and a barometric pressure of 29.95 inches of mercury. A review of the carburetor icing probability chart, located in the FAA's Special Airworthiness Information Bulletin CE-09-35, dated June 30, 2009, and relevant meteorological data, revealed that the weather conditions for carburetor icing were favorable for serious icing at glide power. AIRPORT INFORMATION Llano Municipal Airport (KAQO), is a public use airport, located about 2 miles northeast of Llano, Texas. The airport is non-towered and pilots are to use the Common Traffic Advisory Frequency (CTAF). The airport features an asphalt runway, 17-35 which is 4,202-foot long and 75-foot wide and a turf runway, 13-31 which is 3,209-foot long and 150-foot wide. COMMUNICATIONS The pilot was not in contact with air traffic control and there were no reported distress calls from the pilot. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board, inspectors from the Federal Aviation Administration (FAA), and a technical representative from the engine manufacturer examined the airplane wreckage on site. The impact area was between trees and covered with small bushes and cacti. Two ground impact scars were located just in front of the wreckage. The engine and front fuselage sections displayed extensive crushing. Both wings remained with the wreckage, but the wing spar was broken at the wing root on the left and right side of the fuselage. Both wings had extensive buckling and dents over their entire area. Just a short distance from the wreckage, on the other side of a wire fence, was an open, grass field. The airplane wreckage and ground scars were consistent with a steep nose down collision with terrain. The airplane’s left and right wing fuel tanks, which was also the main wing spar, had been breached and absent of fuel; vegetation blight and fuel odor was not detected on-site. The propeller remained bolted to the engine crankshaft; one blade had only a slight bend. The blade’s black and white painted tip remained and the blade was absent any leading edge gouges or polishing. The remaining blade was bent back, towards the cambered side, about mid-span, at an estimated 45-degree angle, the blade’s paint had widespread scratches and was polished off near the bend. The engine starter, located behind the propeller and crankshaft ring gear, had an impact mark, but was absent rotational scoring. The empennage exhibited only minor damage to the horizontal, vertical stabilizers, and their respective control surfaces. The rudder, elevator and trim tab, remained attached via their respective hinges. The airplane’s emergency locator transmitter (ELT) was located in the empennage section; the unit’s activation switch was found in the “off” position. MEDICAL AND PATHOLOGICAL INFORMATION The Travis County Medical Examiner’s Office, Austin, Texas, Office of the Medical Examiner, conducted autopsies on the flight instructor and student pilot. The causes of death, in both cases, were determined to be, “blunt force injuries”. The FAA Toxicology Accident Research Library, Oklahoma City, Oklahoma, conducted toxicological testing on the flight instructor. The results were negative for carbon monoxide, cyanide, and ethanol. Diphenhydramine was detected in the liver and in cavity blood at 0.051ug/ml. Diphenhydramine is a sedating antihistamine and sleep aid available over the counter in drugs marketed under the trade names Benadryl, Unisom, and Sominex. The FAA Toxicology Accident Research Library, Oklahoma City, Oklahoma, conducted toxicological testing on the student pilot. The results were negative for carbon monoxide, cyanide, and ethanol. Alpha-hydroxyalprazolam was detected in urine, but not in the blood and its parent molecule alprazolam was not identified in either. Alprazolam is a benzodiazepine anxiolytic prescribed as a Schedule IV controlled substance and marketed under the trade name Xanax. Alpha-hydroxyalprazolam is a biologically active primary metabolite of alprazolam. TEST AND RESEARCH Control continuity was established from each of the respective control surfaces to the cabin section of the fuselage. The airplane’s stall warning switch, located in the leading edge of the wing was removed. A multimeter was used to check electrical continuity. When the switch was activated, no continuity was observed. The electrical screws used to connect the wiring to the switch were removed. A small amount of corrosion was observed under the terminal ends of the wires and switch contact points. The wiring and screws were reassembled and the test was repeated; when activated, electrical continuity was noticed on the meter. A mechanic’s work order dated, August 3, 2013, contained the annotation: adjusted stall warning. A family member reported that the student pilot (and airplane owner) stated to family members a couple days before the accident that “the stall warning still was not working right” and that the flight instructor would disable it for each flight. The aircraft engine sustained heavy impact damage. Continuity from the propeller through the crankshaft and pistons, camshaft, and valve train was established. A thumb compression test was performed on each cylinder. The two magnetos had separated from the engine; damage to the magnetos prevented testing of the magnetos. The engine drive fuel pump was broken, but appeared free to move. The rocker covers were removed and the valves were able to move, when the engine was rotated. The carburetor received impact damage and had broken at the throttle plate. The carburetor’s fuel inlet screen was absent any debris or contaminates. The float bowel was opened and only residual fuel remained in the bowl, the floats were free to move, unmarked and were not damaged. A water detecting paste was used on the fuel in the carburetor bowl; the test was negative for water. The sparkplugs were removed; generally displayed light, grey deposits and were consistent with normal combustion and operation. ADDITIONAL INFORMATION FAA-H-8083-3A, Airplane Flying Handbook In the absence of the manufacturer’s recommended spin recovery procedures and techniques, the following spin recovery procedures are recommended. Step 1—REDUCE THE POWER (THROTTLE) TO IDLE. Power aggravates the spin characteristics. It usually results in a flatter spin attitude and increased rotation rates.
The flight instructor’s delayed remedial action and inadequate supervision during practice traffic pattern work. Contributing to the accident was the flight instructor’s use of sedating medication on the day of the accident and airplane’s high angle of attack at a low altitude during the traffic pattern turn, which prevented recovery during an aerodynamic stall.
Source: NTSB Aviation Accident Database
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