History of Flight
On June 29, 2011, at 1915 eastern daylight time, an experimental amateur-built Bosonetto Thorp T-18, registration N8AL, was substantially damaged after colliding with terrain and a house while maneuvering to land at Livingston County Airport (OZW) near Howell, Michigan. The private pilot and a flight instructor onboard were fatally injured. The flight was conducted under 14 CFR Part 91 without a flight plan, in day visual meteorological conditions. The flight originated at an unknown time from Canton-Plymouth-Mettetal Airport (1D2) near Plymouth, Michigan, and the purpose was for the pilot to obtain a flight review.
A witness in an airplane near the departure end of runway 31 observed the accident airplane in the traffic pattern for that runway. After turning onto final approach, the airplane was higher than the normal glidepath and appeared slow, executing a forward-slip maneuver. During the forward slip, it suddenly entered a spin to the right and descended out of view.
Another witness inside a residence along the final approach path reported seeing the airplane yawing side-to-side. He heard the engine increase to full power as the airplane pitched up, then it nosed over and descended into his front yard, ultimately striking the south wall of his house. The engine continued at full power until impact.
A third witness driving on M-59 saw the airplane on final approach roll left and right before descending behind a treeline.
Personnel Information
Pilot
The pilot, aged 43, held a private pilot certificate with a single-engine land airplane rating. His last aviation medical examination was on November 7, 2006, granting a third-class medical certificate with no limitations. FAA records showed no previous accidents or enforcement actions. The pilot's most recent logbook entry was dated November 13, 2010, showing 166.3 total flight hours, all in single-engine land airplanes, including 43.4 hours in the accident airplane. His first flight in that airplane was February 8, 2009. The logbook indicated 13.2 hours flown in the past year, none in the previous 6 months, though the airplane hour meter suggested up to 6.6 hours in the 6 months before the accident. The pilot's previous flight review was on April 5, 2009, in a Cessna 152. He held an endorsement for tailwheel airplanes dated February 17, 2007.
Flight Instructor
The flight instructor, aged 70, held a commercial pilot certificate with single-engine land and instrument ratings, and a flight instructor certificate for single-engine and instrument airplanes. His last medical examination on December 24, 2010, issued a third-class certificate with a limitation for corrective lenses. No previous accidents or enforcement actions were found. His most recent logbook entry was July 1, 2010, when he completed a flight review in a Piper PA-28R. An accurate flight history could not be determined as the logbook lacked forwarded times. According to FAA records, on December 13, 2006, he reported 4,750 total flight hours. The flight instructor kept a provisional log for his personally owned Piper PA-28R, showing his last flight on June 27, 2011, and 100 hours in the past year, 45 in the previous 6 months, 19 in the last 90 days, and 4 in the last 30 days. He had not flown with the pilot or in the accident airplane before.
Aircraft Information
The accident airplane was a 1982 Bosonetto Thorp T-18 amateur-built, serial number 238, powered by a 150-horsepower Lycoming O-320-A1A engine (serial L-2285-27) with a fixed-pitch, two-blade Sensenich W66LM74 wood propeller. It was tailwheel-equipped with a maximum takeoff weight of 1,600 pounds. An experimental airworthiness certificate was issued November 10, 1982, and reissued July 9, 1987, after modification. The hour meter indicated 268.7 hours at the accident site; total airframe time was 577.1 hours. The engine had 127.9 hours since a field overhaul on July 9, 1987. The last condition inspection was June 1, 2011, at 571.5 hours. No unresolved airworthiness issues were found in maintenance records.
Meteorological Information
At 1914, the automated surface observing system at OZW reported wind from 300 degrees at 7 knots, visibility 10 miles, clear sky, temperature 25°C, dew point 8°C, and altimeter setting 30.06 inches of mercury.
Aerodrome Information
Livingston County Airport (OZW) was approximately 3 miles northwest of Howell, Michigan, with a single runway 13/31 (5,002 by 100 feet, concrete). Airport elevation was 962 feet msl; runway 31 threshold elevation was 943 feet msl. A four-light precision approach path indicator was installed for runway 33.
Wreckage and Impact Information
Postaccident examination confirmed all structural and flight control components were present at the site. The main wreckage was located about 0.34 miles southeast of runway 31 threshold, oriented north-northwest. A ground depression consistent with an initial impact from the aft fuselage was found in a residential front yard, continuing on a north-northwest heading to where the airplane struck a brick wall of a residence.
The main wreckage included the entire airframe, flight controls, and engine. A fractured propeller blade was under the aft fuselage, with additional fragments along the debris path and in the backyard. All structural failures were consistent with overstress. Flight control continuity was established between surfaces and cockpit controls. The flap position could not be determined due to damage. The throttle and mixture controls were full forward; carburetor heat was partially engaged; the magneto switch was in the LEFT position. The fuel tank was breached from impact and contained residual fuel.
The engine remained attached to the firewall. Internal continuity and valve train function were confirmed when the crankshaft was rotated. Compression and suction were noted on all cylinders. Upper spark plugs showed normal operation. Both magnetos produced spark. No obstructions were found from the air filter to the carburetor inlet. The fuel supply line and carburetor bowl contained fuel; samples were free of water or particulate contamination. Mechanical continuity from engine components to cockpit controls was confirmed.
The postaccident examination revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
Medical and Pathological Information
Autopsies performed on June 30, 2011, at Sparrow Forensic Pathology Services in Lansing, Michigan, attributed the cause of death for both individuals to multiple injuries sustained in the accident.
Toxicology tests on the pilot's samples detected no carbon monoxide, cyanide, or ethanol. Amlodipine (a calcium channel blocker) was found in urine and blood.
Tests on the flight instructor's samples detected no carbon monoxide or ethanol. Blood cyanide was 0.6 ug/ml. Alfuzosin (for benign prostatic hypertrophy), Dextromethorphan and its metabolite dextrorphan (cough medication), Fexofenadine (non-sedating antihistamine, metabolized to azacyclonol), Naproxen (analgesic), and Rosuvastatin (cholesterol medication) were detected in various samples.
Survival Aspects
First responders reported that the pilot was not wearing his lap-belt or shoulder harness upon arrival. The flight instructor was wearing both.