Aviation Accident Summaries

Aviation Accident Summary MIA97LA251

TROY, NC, USA

Aircraft #1

N2554V

Cessna 170

Analysis

The pilot stated that he performed an engine run-up before starting a takeoff with no discrepancies noted. He positioned the airplane on the 2,300 foot grass airstrip (runway 17), and began taking off with a right quartering tailwind from 310 degrees at 8 knots. He applied full throttle, and noted that during the early portion of the takeoff roll, the engine rpm was at the red line. At about midfield, he noted that the acceleration seemed sluggish. He continued the takeoff roll, and about 2/3 down the runway with the tailwheel still on the runway surface, he aborted the takeoff. However, he was unable to stop the airplane before colliding with a tree beyond the end of the airstrip. Investigation revealed the magnetos were not properly timed. Also, there were indications that the carburetor and accelerator pump were not functioning properly.

Factual Information

On September 29, 1997, about 1125 eastern daylight time, a Cessna 170, N2554V, registered to a private individual, collided with trees during an aborted takeoff from a private airstrip near Troy, North Carolina. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 personal flight. The commercial-rated pilot and one passenger were not injured. The flight was originating at the time of the accident. The pilot stated that 2 days before the accident, he mowed the runway grass to a height of about 6 inches. Before departure he performed a preflight to the airplane and drained about 4 ounces and 1.5 ounces of water from the right and left fuel tanks respectively. He also performed an engine run-up with no discrepancies noted then taxied onto the 2,300-foot runway with a tailwind of about 10-12 knots from 10 degrees behind the right wing. He applied full power and during the early portion of the takeoff roll, he noted that the engine rpm was indicating near the red line. About midfield he noted that the acceleration was sluggish but continued the takeoff roll. About 2/3 down the runway with the tailwheel still on the runway surface, he aborted the takeoff by reducing the throttle to idle, applied the brakes and full aft elevator control, and maneuvered the airplane toward a path in trees that were ahead. The right wing collided with trees which caused the airplane to yaw to the right. The airplane came to rest upright on a westerly heading. Postaccident inspection of the airplane by an insurance adjuster revealed no contaminants in the fuel tanks or gascolator. The engine was removed and sent to the manufacturer's facility for an engine run. According to the engine manufacturer's report, the magnetos were not properly timed to the engine which was started and operated to full rated rpm. It was noted that the acceleration check was poor; and that gradual throttle advancement would allow the engine rpm to increase, but the engine would hesitate to respond to rapid throttle advancement. The report which is an attachment to this report also indicates that the poor acceleration "...would indicate that the accelerator pump and the carburetor was not pumping fuel properly." Review of the maintenance records revealed that the engine had been remanufactured and overhauled on September 1, 1969, and June 1, 1980, respectively. The entry in 1969 indicated that the remanufactured engine was shipped with in part a remanufactured carburetor. The entry in 1980 does not indicate that the carburetor was overhauled. An entry dated May 26, 1996, indicates that a one-piece venturi and nozzle kit was installed in the carburetor. There was no record of the carburetor being overhauled after the entry in 1969. The airplane minus the retained engine was released to Mr. James T. Brewer, on December 5, 1997. The retained engine was also released to Mr. Brewer on February 6, 1998.

Probable Cause and Findings

delay of the pilot to abort the takeoff after noting sluggish acceleration during the takeoff roll. Factors relating to the accident were: improper timing of the magneto(s), and a malfunction of the carburetor.

 

Source: NTSB Aviation Accident Database

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