Aviation Accident Summaries

Aviation Accident Summary CEN11LA671

Lake Jackson, TX, USA

Aircraft #1

N7167S

FISHER MICHAEL E Hyster

Analysis

The experimental airplane recently had a new engine and propeller installed, and an associate of the owner was going to test fly the airplane after the installation. Shortly after takeoff, the engine went to idle and the pilot was forced to land. While maneuvering toward an open field, the airplane collided with a power line, bounced hard on the ground, and flipped inverted. Postaccident examination of the engine and carburetor revealed that the set screw that held the throttle cable to the carburetor was loose. The cable could be moved freely by hand through the carburetor arm with no restriction. The cable showed no evidence that it had been scored or pulled when the engine separated during the accident. No marks were found where the set screw should have been tightened in place on the cable. In addition, when the cable was inserted back into the carburetor arm, it took one full turn of the set screw to make contact and secure the cable in place. The condition and lack of security of the throttle cable most likely resulted in a reduced fuel flow to the carburetor and the subsequent partial loss of engine power. Usable fuel was present in the airplane and no other malfunctions or failures with the airframe or engine were found that would have precluded normal operation.

Factual Information

On August 13, 2011, approximately 1145 central daylight time, a Fisher Hyster experimental airplane, N7167S, registered to a private individual, was substantially damaged when it collided with power lines and the ground during a forced landing while maneuvering after takeoff from Bailes Airport (7R9), Angelton, Texas. The non-certificated pilot, who was the sole occupant, received serious injuries. Visual meteorological conditions prevailed and a flight plan was not filed for the personal flight operated under the provisions of 14 Code of Federal regulations Part 91. According to the registered owner, the airplane recently had a new engine and propeller installed. An associate of the owner intended to test fly the airplane. Shortly after takeoff while maneuvering, the engine went to idle and the pilot was forced to land. While maneuvering toward an open field to land, the airplane collided with a power line, bounced hard on the ground and flipped inverted. The fuselage and wings were buckled and the engine was found separated from its mounts. An FAA inspector examined the airplane at the accident site. He reported that the fixed landing gear of the airplane had apparently contacted the power lines while the pilot was maneuvering for the forced landing. Further inspection of the engine and carburetor revealed that the set screw that held the throttle cable to the carburetor was loose. The cable could be moved freely by hand through the carburetor arm with no restriction. The cable showed no evidence that it had been scored or pulled when the engine had separated during the accident. No marks were found where the set screw would have been tightened in place on the cable. In addition, when the cable was inserted back into the carburetor arm, it took one full turn of the set screw to make contact and secure the cable in place. Usable fuel was present in the airplane, and no other anomalies were found with the engine or airframe. The NTSB IIC contacted the owner of the airplane by telephone shortly after the accident. During that conversation, the owner acknowledged that he would complete NTSB Form 6120 and return the form. During a subsequent conversation, the owner acknowledged receipt and completion of Form 6120 and stated that he would return the form. Repeated attempts to obtain the form were not successful. To this date, the Form 6120 has not been returned to the NTSB. The pilot of the airplane could not be located by either the FAA or the NTSB to provide additional information on the event. The FAA could not confirm whether or not the pilot held a vaild pilot certificate.

Probable Cause and Findings

The improper maintenance of the throttle control cable, which resulted in the engine going to idle power after takeoff.

 

Source: NTSB Aviation Accident Database

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