Accident Summary
On July 15, 2008, at 1008 eastern daylight time, an amateur-built, experimental Drochak Aventura II amphibian aircraft, registered N621CD, was destroyed when it impacted trees and terrain after a loss of engine power during takeoff climb from Dalton Airport (3DA) in Flushing, Michigan. The pilot, the sole occupant, received fatal injuries. The flight was conducted under 14 Code of Federal Regulations Part 91 as a personal flight departing from runway 27 for a local flight. Visual meteorological conditions prevailed, and no flight plan was filed.
Witness Observations
A witness reported seeing the airplane heading westbound from the airport at about 100 feet above ground level (agl). The airplane then entered a left turn to the south, made another left bank, and suddenly nosedived into the ground. Other witnesses provided similar statements.
Security Camera Footage
A hangar at 3DA was equipped with a security system comprising four video cameras and an area microphone. The cameras captured the following events:
- At 10:07:46, takeoff power was applied; the airplane was not in sight.
- From 10:08:00 to 10:08:07, camera 4 showed the airplane after liftoff flying over the runway before moving out of view. Engine noise was audible.
- At 10:08:06, cameras 1 and 3 showed the airplane's shadow over the runway; engine noise was heard.
- From 10:08:08 to 10:08:18, camera 2 showed the airplane's shadow over the runway, then departing the runway end and turning left over trees; engine noise continued.
- At 10:08:19, the engine sound ceased.
- At 10:08:23, the airplane was heard crashing into trees.
Aircraft and Pilot Information
The 60-year-old pilot held a private pilot certificate and was operating as a sport pilot. He was not required to possess a current FAA medical certificate. He had accumulated about 209 total flight hours, with approximately 41 hours in the accident airplane make and model.
The two-seat, amateur-built, experimental Drochak Aventura II amphibian was powered by a 100-horsepower Rotax 912 ULS engine. The last conditional maintenance inspection occurred in July 2007, and the aircraft had flown 47 hours since that inspection. The stall speed was about 42 mph in clean configuration and about 30 mph in landing configuration. The airplane had two throttle control handles: one for the left seat on the left side, and one for the right seat on the right side, located about 20.5 inches from the cockpit center. The carburetor throttles were spring-loaded to the full open position if the throttle linkage was disconnected.
Wreckage Examination
The airplane collided with a tree and impacted the front lawn of a house west of the road bordering the west side of the airport. The wreckage was confined to the initial impact site. The nose of the fuselage was crushed aft and broken at the cockpit instrument panel. The engine, mounted aft of the high wing, exhibited forward buckling of the engine mounts, wing spars, and struts, compromising the cockpit space. The left wing's leading edge was crushed aft, and its spar was broken. The right wing remained intact with no leading edge damage. The empennage showed no impact damage. Flight control cables exhibited continuity from controls to surfaces.
The three-bladed composite propeller remained attached to the engine: one blade was straight and undamaged; the second was straight but had impact damage at mid-span; the third was broken 12-15 inches from the hub. No propeller blades exhibited leading edge gouges or chordwise scratching.
The engine was separated from the fuselage during recovery. It was rotated by hand with no internal damage noted, and an engine run test showed it operated.
An 18-gallon fuel tank behind the pilots' seats remained unruptured, with about 8 gallons of fuel remaining. Both switches for the dual electronic ignition were found in the OFF position; it was not determined if a first responder had turned them off.
Engine and Throttle Examination
The pilot's throttle handle, handle strap, throttle control tube, and a portion of the left wing spar were examined at the NTSB Materials Laboratory. The wing spar fracture occurred near a hole with a smooth bore; the fracture surfaces exhibited plastic deformation and a 45-degree shear lip consistent with ductile fracture due to tension and bending overstress. No preexisting damage was found.
The throttle control assembly consisted of steel inserts pressed into each end of an aluminum tube. The insert connected to the throttle hand strap was found separated from the tube. Both inserts had the same diameter, but the intact one was slightly shorter. The separated insert had a chamfer around the crosswise hole, while the tested one had a square shoulder; the hole location differed by 0.02 inch. A tension test on the intact end recorded a maximum force of 1,191 pounds before gradual extraction.
The throttle hand strap showed plastic deformation consistent with multiple applied forces from various directions.
Medical and Toxicology
First responders reported the pilot initially survived but was unresponsive. Time of death was 1118. An autopsy on July 16, 2008, by the Genesee County Medical Examiner stated the cause of death as "Blunt Force Injuries Due to an Airplane Crash." Toxicology tests were negative for all substances tested.