NEW HAVEN, MI, USA
N72145
C.B. WITHUN T-BIRD II
The pilot of the homebuilt experimental airplane advised air traffic that he was doing high speed taxi testing on runway 18. Shortly after making this announcement, a witness said he saw the airplane takeoff downwind on runway 36. Witnesses near the airport said they saw the airplane at a low altitude as it was climbing onto a downwind leg. One witness said the airplane was about 100 to 200-feet above the trees when it suddenly '...dropped nose down into the trees.' The on-scene investigation revealed the pusher propeller had a blade root angle set to 43-degrees at the hub. The propeller manufacturer said the blade angle for the propeller should normally be between seven and 14-degrees at its tip. With a 43-degree angle at the blade's root, the blade's tip angle would be about 20.5-degrees, according to the manufacturer's representative. No anomalies with the engine, airframe or flight control system were observed that would prevent flight.
On October 29, 1998, at 1400 eastern standard time (est), a C.B. Withun T-Bird II, N72145, piloted by a private pilot, was destroyed during a collision with trees and the ground following an uncontrolled descent while flying a downwind leg for runway 36 at the Macomb Airport, New Haven, Michigan. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The pilot was fatally injured. The flight departed New Haven, Michigan, about 1355 est. A pilot flying in the pattern at the airport said he saw a red ultralight airplane taxiing on runway 18-36. The pilot said he heard the pilot of the red ultralight announce on the radio he was doing high speed taxi tests on the runway. The pilot said, "A few minutes later we heard the subject in the ultralight indicate he was departing runway 18." A witness said the airplane took off on runway 36 and made a low altitude left turn to what looked like a left downwind leg for that runway. He said the engine was still running when the turn was completed. He said the airplane "...started sinking going south over the trees and suddenly stalled and crashed into the trees." A third witness said "The ultralight climbed out slowly without gaining much altitude- he could have made a landing on [the] south runway... but went south... and dropped nose down into the tress." This witness said the engine was "screaming." Another witness said he "...saw the ultralight... [it] appeared to be very low but flying southbound... west of runway 18-36." The on-scene examination revealed N72145's 2-blade pusher propeller had blade pitch angles that were 43-degrees. This angle was observed at each blade's root area. According to the propeller's manufacturer, the normal pitch range used with this propeller would be 7 through 14-degrees measured at the tip. According to the manufacturer, the propeller's blades can only be manually adjusted while on the ground and the engine is not running. The manufacturer's representative said that a 43-degree propeller blade root angle is equal to about 20.5-degrees at the propeller blade tip. Runway 36/18 is a sod and asphalt runway. It intersects runway 09/27. The overall length of runway 36/18 is 2,200 feet. Its width is 130 feet. The north end of runway 36 has an asphalt center that is 900 feet long and 30 feet wide. The asphalt extends from the approach end of runway 18 to about 100 feet south of the runway 09/27 intersection. The autopsy on the pilot was conducted on October 31, 1998, by Dr. Werner U. Spitz at the Martha T. Berry Hospital in Mount Clemens, Michigan. The examination revealed "Advanced coronary artery sclerosis with reduction of the right coronary artery lumen to 20-percent. [The] LAD to 10 to 12-percent." The toxicological examination was conducted by the Federal Aviation Administration's Civil Aeromedical Institute. The toxicological report showed 0.114 (ug/ml. ug/g) of Chlorpheniramine was detected in the liver fluid and 0.048 (ug/ml, ug/g) of Chlorpheniramine was detected in the kidney fluid. Pseudoephedrine was detected in the kidney and liver fluids and Ephedrine was detected in the liver fluid. Phenylpropanolamine was also detected in the liver and kidney fluids. Atenolol was detected in the liver and kidney fluids.
the improper installation of the propeller by the owner/pilot- mechanic and the pilot not maintaining the airplane's airspeed while approaching the trees along the airplane's flight path. A factor in this accident was the stall encountered by the pilot.
Source: NTSB Aviation Accident Database
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