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On June 7, 2009, about 1745 central daylight time, a Gulfstream American Corporation model AA-5B (Tiger), N448DM, owned and operated by a non-instrument rated private pilot, was destroyed during impact with terrain near Humbird, Wisconsin. Instrument meteorological conditions prevailed at the time of the accident. The personal flight was being operated under the provisions of 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The pilot and his passenger were fatally injured. The flight departed at 1643 from Lake Elmo Airport (21D), St. Paul, Minnesota, and was destined for Sheboygan County Memorial Airport (KSBM), Sheboygan, Wisconsin.
At 1043, about six hours before departure, the pilot contacted the Lansing Automated Flight Service Station (AFSS) to obtain a weather briefing for a visual flight rules (VFR) flight from 21D to KSBM. The briefer noted that VFR flight was not recommended because of an active weather advisory for widespread instrument meteorological conditions (IMC) that encompassed the planned route of flight. The briefer noted that there were low overcast ceilings ranging 400 to 1,200 feet above ground level (agl) along the planned route of flight. Additionally, there were areas of rain showers and isolated thunderstorms with cloud tops reaching 34,000 feet. The pilot stated that he would call back in a couple of hours to check if the weather conditions had improved.
At 1558, about 45 minutes before departure, the pilot contacted the Washington AFSS to obtain an updated weather briefing. The briefer noted that VFR flight was not recommended because of an active weather advisory for widespread IMC that still encompassed the planned route of flight. The departure airport had an overcast ceiling of 1,300 feet agl and a surface visibility of 10 miles. The briefer noted that there were low overcast ceilings ranging 900 to 1,500 feet agl along the planned route of flight. The forecast was for ceilings 1,500 to 2,500 feet agl, with layered clouds up to 20,000 feet (FL200). The forecast also called for widely scattered embedded light rain showers and isolated thunderstorms. The briefer specifically advised that VFR flight was not recommended on four separate occasions during the 17 minute weather briefing. The pilot did not file a flight plan during the weather briefing.
According to aircraft radar track data, there was only one visual flight rule (VFR) beacon track that originated from 21D within the 1-hour period before the accident. This radar track began at 1643:31 and continued to the south-southeast between 1,900 and 2,000 feet mean sea level (msl). The last radar return was recorded at 1708:18 over Durand, Wisconsin, at an altitude of 1,900 feet msl. The last radar return was 42.6 nautical miles (nm) west of the accident site. The last recorded position was at the lower altitude limit for radar coverage in that area and radar contact was not reestablished with the flight.
Several witnesses located near the accident site reported hearing an airplane overfly their position. These witnesses noted that because of a low cloud ceiling, fog, and light precipitation they could not see the airplane. All of the witnesses reported hearing the sound of an airplane engine operating at a high speed. Several witnesses noted that the loudness of the airplane's engine increased and decreased several times as if the airplane was turning in flight, before they heard a ground impact. Local law enforcement and property owners immediately commenced a search for the accident site, which was subsequently located about 2045.
According to Federal Aviation Administration (FAA) records, the pilot of N448DM, age 45, held a private pilot certificate with an airplane single-engine land rating. The pilot certificate was issued on February 17, 2005. He was not instrument rated. His last aviation medical examination was completed on February 5, 2009, when he was issued a third-class medical certificate with no limitations. A search of FAA records showed no accident, incident, enforcement, or disciplinary actions.
The pilot's most recent logbook entry was dated June 4, 2009. He had accumulated 271.6 hours total flight time, of which 189.6 hours were as pilot-in-command. He had accumulated 271.6 hours in single-engine airplanes, 36.6 hours at night, 4.2 hours in simulated instrument conditions, and no time in actual instrument conditions. The most recent logbook entry that included instrument time was dated February 10, 2005, while the pilot was receiving his primary flight instruction. He had accumulated 171.5 hours in a Gulfstream American Corporation model AA-5B (Tiger) airplane.
The pilot had flown 54.2 hours during the past year, 20.5 hours during the prior 6 months, 18.6 hours during previous 90 days, and 8.4 hours during the prior 30 days. All of the flight time accumulated during those periods was completed in the accident airplane. The pilot had not flown during the 24 hour period before the accident flight.
The pilot's last flight review was completed on February 15, 2009, in a Gulfstream American Corporation model AA-5B (Tiger) airplane.
The accident airplane was a 1978 Gulfstream American Corporation model AA-5B (Tiger) airplane, serial number (s/n) AA5B0976. The model AA-5B was a low wing, all-metal, single-engine, four-place monoplane. The airplane had a certified maximum takeoff weight of 2,400 lbs. The airplane was equipped for operation under instrument flight rules. A Lycoming model O-360-A4K reciprocating engine, s/n L-25566-36A, powered the airplane. The 180-horsepower engine provided thrust through a Sensenich model 76EM8S10-0-63, s/n 23979K, fixed-pitch, two-blade, metal propeller.
The accident airplane was issued a standard airworthiness certificate on October 26, 1978. The pilot purchased the airplane on April 30, 2005. The airframe and engine had a total service time of 1,110 hours. The last annual inspection was completed on July 3, 2008, at 1,057 hours total service time. On September 25, 2007, tests on the static system, altimeter system, automatic pressure altitude reporting system, and transponder were completed.
A review of the maintenance records found no history of unresolved airworthiness issues.
The closest weather reporting facility was at Chippewa Valley Regional Airport (KEAU), Eau Claire, Wisconsin, located about 30 nm northwest of the accident site. The airport was equipped with an automated surface observing system (ASOS).
At 1756, the KEAU ASOS reported the following weather conditions: Wind 090 degrees true at 9 knots; visibility 10 miles; overcast ceiling at 1,700 feet agl; temperature 12 degrees Celsius; dew point 8 degrees Celsius; altimeter setting 29.96 inches of mercury.
The accident location was within the boundaries of an active instrument flight rules (IFR) weather advisory. The weather advisory was for cloud ceilings below 1,000 feet agl and surface visibilities less than 3 miles with light precipitation/mist. The forecast weather was for ceilings 1,500 to 2,500 feet agl, with additional layered clouds up to 20,000 feet (FL200). The forecast also called for widely scattered embedded light rain showers and isolated thunderstorms.
Several witnesses and local law enforcement personnel reported that there was a low cloud ceiling with light rain and fog preceding the accident and during the subsequent ground search for the accident site.
WRECKAGE AND IMPACT INFORMATION
The wreckage was located in hilly and heavily-wooded terrain. The wreckage debris path was orientated on an easterly heading and was approximately 461 feet in length. The outboard half of the right wing was found at the beginning of the debris path. The vertical stabilizer was found 423 feet west of the main wreckage. The right aileron and right flap were located about 400 feet from the main wreckage. The cockpit canopy was found 357 feet from the main wreckage. The inboard half of the right wing was located 141 feet from the main wreckage. Both elevators and their respective stabilizers were found 89 feet west of the main wreckage. The main wreckage was located in an impact crater that measured about 3 feet deep and 10 feet wide. Damage to the dense overhead foliage was limited, consistent with a near vertical descent path. The overall wreckage distribution was consistent with an in-flight breakup at a low altitude. The main wreckage consisted of the fuselage, cockpit, left wing, engine, and propeller.
All airframe structural components and flight control surfaces were located along the wreckage debris path or amongst the main wreckage. A majority of the airframe's primary structure exhibited severe impact damage and fragmentation. The lower firewall, cabin floor, and instrument panel were crushed upward and aft. Both wings were found in several sections. The observed damage to the wing and empennage load bearing components was consistent with a positive-g flight maneuver. All structural component failures were consistent with overload separations. Flight control cable continuity could not be established due to multiple cable separations. All observed flight control cable separations were consistent with overload failures.
The engine was found partially attached the fuselage firewall. The propeller remained attached to the crankshaft propeller flange. The carburetor and its induction box were separated from the engine and found amongst the cabin wreckage. The carburetor fuel inlet screen was removed and was clear of contaminants. Internal engine and valve train continuity was confirmed as the engine crankshaft was rotated. Compression and suction were noted on all cylinders in conjunction with crankshaft rotation except for the number one cylinder. The exhaust pushrod for the number one cylinder was separated due to impact damage. All cylinders were inspected with a lighted boroscope, and no discrepancies were noted. The engine-driven fuel pump had significant impact damage that precluded an operational test. Both magnetos remained attached to the engine. The left magneto exhibited extensive impact damage that prevented an operational test of its impulse coupling. The right magneto appeared undamaged, but did not produce a spark when rotated by hand. The ignition harness exhibited multiple-point fraying throughout its length. The upper spark plugs were removed, and their electrodes exhibited normal wear when compared to a manufacturer's service chart. Both propeller blades exhibited blade twisting, lengthwise bending, and leading-edge rotational scoring/burnishing.
Functional testing and subsequent disassembly of the vacuum pump showed no evidence of preimpact failure. The directional gyro and attitude indicator were dissembled and rotational scoring was noted on their gyros.
The on-scene investigation revealed no preimpact mechanical malfunctions or anomalies that would have prevented the normal operation of the airplane or its associated systems.
MEDICAL AND PATHOLOGICAL INFORMATION
On June 8, 2009, an autopsy was performed on the pilot at the University of Wisconsin School of Medicine and Public Health in Madison, Wisconsin. The pilot's cause of death was attributed to multiple blunt force injuries sustained during the accident.
The FAA's Civil Aeromedical Institute in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. No ethanol was detected in liver and muscle tissues. No drugs were detected in liver tissue.
Toxicology tests were also performed on the passenger. No carbon monoxide, cyanide, or drugs were detected in the passenger's blood samples. No ethanol was detected in urine samples.