NTSB Identification: FTW99FA016.
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Accident occurred Friday, October 23, 1998 in BRYAN, TX
Probable Cause Approval Date: 08/03/1999
Aircraft: Kolb Company TWINSTAR TA-2, registration: N4281Z
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
A witness observed a shinny piece of metal trailing behind the ultralight. The witness stated that 'the nose of the ultralight bobbed up and down a couple of times' followed by the 'airplane nosing over to the near vertical position.' According to the manufacturer, the ultralight is not equipped with an elevator trim tab. Trim in the standard ultralight is accomplished by adjusting the spring tension on the elevator control cable from inside the fuselage cage near the control stick. The accident ultralight had been modified by the addition of a fabric covered trim tab surface on the trailing edge of the left elevator. The silver painted trim tab measured approximately 5 by 20 inches. Paint transfers, chaffing and rubbing found on the rudder and right elevator indicated that the elevator trim tab had separated from the trailing edge of the left elevator prior to ground impact. The mounting for the outboard bracket, supporting one side of the trim tab, was found loose. Paint transfer and chaffing on the trailing edge of the elevator indicated that the bracket had been loose prior to the accident.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's loss of control as result of the partial separation of the elevator trim tab resulting in the inability to maintain aircraft control. A factor was the improper design and installation of the elevator trim tab. Full narrative available
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