Aviation Accident Summaries

Aviation Accident Summary DFW07FA149

Groesbeck, TX, USA

Aircraft #1

N2801W

SOCATA TB-20

Analysis

The instrument-rated commercial pilot departed on a cross-country flight through instrument meteorological conditions (IMC). The pilot made radio transmissions to ground control, tower, low radar approach control, and high radar approach control that he was "new at instruments" and that he had not flow in IMC "in a long time." While maneuvering back to get back on the centerline of the airway, while operating in an area of heavy precipitation, the pilot lost control of the airplane after he became spatially disoriented. Recorded radar data revealed flight with stable parameters until approximately 1140:49 when the airplane is recorded making an unexpected right turn at a rate of 2-degrees per second. A turn at this rate may not have been noticed by the pilot since there were no radar calls to departure control. The right turn continues until radar contact is lost at 1141:58 at which point that airplane is turning at a rate of approximately 5-degrees per second and descending at over 3,600 feet per minute. Wreckage and impact information was consistent with a right bank, low-angle, high-speed descent. Instrument meteorological conditions prevailed in the area at the time of the accident. The descent profile was found to be consistent with the "graveyard spiral." Prior to flight, for unknown reasons, the telephone conversations with the Flight Service Station progressed from being conservative to a strong desire to fly home, consistent with the pilot phenomena "get-home-itis." The 26-year old pilot, was reported to have accumulated a total of 456.7 hours, of which 35.8 hours were in the same make and model. Prior to the accident flight, the pilot had accumulated a total of 2.5 hours of actual instrument time, with 105.7 hours of simulated instrument time.

Factual Information

HISTORY OF FLIGHT On July 6, 2007, at approximately 1143 central daylight time, a single-engine Socata TB-20 airplane, N2801W, was destroyed upon impact with terrain following a loss of control near Groesbeck, Texas. The instrument rated commercial pilot, sole occupant of the airplane, was fatally injured. The aircraft was registered to a partnership and was being operated by Maximum Aviation of Diboll, Texas. Instrument meteorological conditions (IMC) prevailed and an instrument flight rules (IFR) flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The 130-nautical mile cross-country flight departed from the Waco Regional Airport (ACT), near Waco, Texas, approximately 1130 and was destined for the Angelina Country Airport (LFK), near Lufkin, Texas. All times in this report will be based on central daylight time using a 24-hour clock. The pilot telephoned Flight Service Station (FSS) six times with the first phone call about 2232 on July 5 and 1050 on July 6 to request weather reports and forecasts. The first phone call at 2232 lasts approximately 18 minutes during which the FSS briefer forecasts IMC conditions for the route of flight and briefs an Airman's Meteorological Information (AIRMET) for IFR conditions. The pilot stated that he did not try to take off on July 5 with weather at Lufkin because he recalled that his certified flight instructor who gave him his instrument rating and a retired pilot told him not to take off if he didn't feel comfortable. The second phone call at 0552 lasts approximately 2 minutes. The pilot stated that he was instrument rated but did not want to take any chances. The FSS briefer forecasts light rain and marginal conditions for visual flight rules (VFR). The third phone call at 0825 lasts approximately five minutes during which the FSS briefer gives weather, the AIRMET, and forecasts a cycle of storms for the day of flight. The pilot responds that it sounds like a pretty bad day to fly. At 0845, the pilot talks to FSS for 13 minutes. The pilot states that an old flight instructor at Waco said that he should try to wait it out because the weather is "pretty bad right now." The FSS briefer agrees and briefs light to moderate rain shows in the area between Waco and Lufkin, and the AIRMET for IFR conditions. The FSS briefer states that after 1100 the weather should improve. At 1032 the pilot calls FSS again and sounds distressed. The pilot states that he wants to get home, hasn't showered in a day and a half, is getting tired, and want to depart as soon as possible. The FSS briefer briefs the AIRMET for IFR conditions and forecasts IFR enroute. At 1055 the pilot phones FSS for the final time and talks for approximately seven minutes. The pilot files an IFR flight plan. The FSS briefer states improving conditions and recommends delaying the pilot's departure to allow conditions to improve. Radar data from Waco Tower captured the flight as it transitioned from Low Radar to Approach Control High Radar. The flight path appeared to be a normal cruise at an assigned altitude of 5,000 feet, with a groundspeed between 140 and 150 knots with a general heading of 098 degrees. The pilot discussed changing his IFR clearance to a visual flight rules (VFR) on top clearance. After a discussion with the approach controller, the pilot reported that he is "back in the clouds now" and that he will maintain IFR "unless something happens." Initially the airplane followed a direct course but drifted about 2 NM left of course. At 1136:35, the pilot questioned High Radar if he "is on the correct course" and that he did not know what was wrong with his Global Positioning System (GPS). The airplane is turned right approximately 30 degrees towards the plotted centerline of direct Lufkin. The pilot then reports that everything is stable. The airplane slightly overshoots the centerline and made a correcting left turn. Before establishing on course centerline, the airplane turns right at approximately 2 degrees per second. At 1141:03, High Radar gives a hand-off frequency to the pilot. The airplane has turned to a heading of 118 degrees and descends at approximately 1,000 feet per minute. At 1141:20, the High Radar approach controller queries the pilot about his right turn and descent and instructs the pilot to turn to 090 degrees and climb to 5,000 feet. At 1141:29 the pilot made a radio call stating he was lost and going to descend. The airplane is now heading 244 degrees and descending through 4,400 feet MSL. Radar tracked the airplane's descent for the next 29 seconds where the airplane continued the right turn and descends at a rate of approximately 3,600 feet per minute. The last radar hit at 1141:58 shows the airplane heading 037 degrees and descending through 2,900 feet MSL. Approach control and two pilots attempted to assist the pilot during his descent. The last transmission from the pilot was made at 1142:13, the pilot made no radio call explaining his right turn. The wreckage of the airplane was located by a helicopter search party with assistance of the emergency locator transmitter. There were no reported eyewitnesses to the accident. PERSONNEL INFORMATION The pilot, age 26, held a commercial pilot certificate for airplane single-engine land and airplane instrument ratings issued June 10, 2006. A current second-class airman medical certificate was issued on November 22, 2006. The pilot's logbook was recovered for examination. The logbook revealed that the pilot had logged a total of 456.7 hours, with 35.8 hours in the same make and model aircraft, 2.5 hours of actual instrument time, and 105.7 hours of simulated instrument time. The pilot's logbook revealed that in the year prior to the accident, the pilot logged two flights with instrument time, both in a Piper PA-24: 1.7 hours on August 16, 2006, and 0.2 hours logged on January 5, 2007. AIRCRAFT INFORMATION The four seat, low-wing, retractable gear airplane, serial number 1158, was manufactured in 1990. The airplane was powered by a single 250-horsepower Lycoming IO-540-C4D5D engine and equipped with a three-bladed steel Hartzell constant speed propeller. Review of the maintenance records revealed that an annual inspection was completed on April 22, 2007. At the time of the accident the airplane had a recorded tachometer reading of 1,110.9 hours, airframe total time was 2,485.5 hours and engine time since the last major overhaul was 876 hours. METEROLOGICAL INFORMATION The nearest National Weather Service automated weather-reporting stations were KACT, 31 NM northwest of the accident scene, and the Corsicana Municipal Airport (KCRS), 38 NM north-east of the accident site. At 1151, KACT reported winds 010 degrees at 9 knots, 10 statue miles visibility, ceiling overcast at 3,000 feet, temperature 78 degrees Fahrenheit, dew point 71 degrees Fahrenheit, and barometric pressure 30.03 inches of Mercury. At 1153, KCRS reported winds 020 degrees and 7 knots, 9 statute miles visibility, light rain, ceiling overcast at 1,900 feet, temperature 75 degrees Fahrenheit, dew point 72 degrees Fahrenheit, and barometric pressure 30.02 inches of Mercury. A National Oceanic and Atmospheric Administration (NOAA) Next-Generation Radar (NEXRAD), located 85 miles to the northeast of the accident site, used the clear air mode to record an area of light precipitation corresponding to a reflectivity value between +20 and -28 dBZ in close vicinity of the accident site along the intended route of flight. A Limestone County trooper on patrol near the accident site reported heavy rain limiting visibility around the time of the accident. WRECKAGE AND IMPACT INFORMATION All major components of the airplane were accounted for at the accident site. The main wreckage consisted of the inverted fuselage. There was no evidence of an in-flight or post-impact fire. The wreckage distribution, from tree tops to engine, was approximately 380-feet long and 50-feet wide that followed a general heading of 290-degrees. Trees damaged approximately 15-feet high displayed the first signs of the accident path. Right wing components were scattered starting at the damaged trees to about 100-feet which led to two ground impact scars. Following the ground path an additional 75-feet, left wing components were discovered to the right side of the path. Upper fuselage components as well as the horizontal stabilizer were found leading to the inverted portion of the fuselage over 110-feet away. The engine separated from the airframe during the impact sequence and continued approximately 105-feet past the fuselage before coming to rest in a pond. The propeller remained attached to the engine. Examination of the recovered airframe and flight controls system components revealed no evidence of pre-impact mechanical malfunction. The engine was examined by a representative from Lycoming Engines. All three propeller blades were fully intact, bent rearward, had leading edge polishing, and chord-wise scratches. The fuel inlet screen was found to be free of contaminates. The fuel flow divider was not damaged and contained fuel. Using a hand crank in the vacuum pump drive gear, rotation and valve train continuity was established. In addition, one of the vertical gyros was dismantled and had metal scoring on the inner chamber. MEDICAL AND PATHOLOGICAL INFORMATION On July 7, 2007, an autopsy was performed on the pilot by Southwestern Institute of Forensic Sciences, Dallas, Texas, as authorized by the Limestone County Justice of the Peace. The autopsy concluded multiple blunt force trauma injuries as the manner of death. Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, near Oklahoma City, Oklahoma. The toxicology report stated no ethanol was detected in the urine sample. No carbon monoxide or cyanide was detected in the blood sample. ADDITIONAL INFORMATION The Federal Aviation Administration publication AM-400-03/1 "Spatial Disorientation: Why You Shouldn't Fly By the Seat of Your Pants" states: "The reason a pilot can be unaware of such a gradual turn is that human exposure to a rotational acceleration of 2-degrees per second or lower is below the detection threshold of the semicircular canals." "The Graveyard Spiral is more common than the Graveyard Spin, and it is associated with a return to level flight following an intentional or unintentional prolonged bank turn. For example, a pilot who enters a banking turn to the left will initially have a sensation of a turn in the same direction. If the left turn continues (about 20 seconds or more), the pilot will experience the sensation that the airplane is no longer turning to the left. At this point, if the pilot attempts to level the wings this action will produce a sensation that the airplane is turning and banking in the opposite direction (to the right). If the pilot believes the illusion of a right turn (which can be very compelling), he/she will reenter the original left turn in an attempt to counteract the sensation of a right turn. Unfortunately, while this is happening, the airplane is still turning to the left and losing altitude. Pulling the control yoke/stick and applying power while turning would not be a good idea-because it would only make the left turn tighter. If the pilot fails to recognize the illusion and does not level the wings, the airplane will continue turning left and losing altitude until it impacts the ground." According to FAA advisory circular (AC) 60-4A "Pilot's Spatial Disorientation," "Surface references and the natural horizon may at times become obscured, although visibility may be above visual flight rule minimums. Lack of natural horizon or surface reference is common on over-water flights, at night, and especially at night in extremely sparsely populated areas or in low visibility conditions. A sloping cloud formation, an obscured horizon, a dark scene spread with ground lights and stars, and certain geometric patterns of ground lights can provide inaccurate visual information for aligning the airplane correctly with the actual horizon. The disoriented pilot may place the airplane in a dangerous attitude."

Probable Cause and Findings

The pilot's loss of control due to spatial disorientation. Contributing factors were the pilot's perceived need to fly to home station and his lack of flight experience in actual instrument meteorological conditions.

 

Source: NTSB Aviation Accident Database

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