NTSB Factual Report

On February 28, 1999, approximately 1015 central standard time, a Keil Jaeger D-IX amateur-built experimental airplane, N257JK, was destroyed when it impacted the ground in an uncontrolled descent near Santa Fe, Texas. The private pilot, who was the owner and builder of the single seat biplane, received fatal injuries. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight that originated from the Johnnie Volk Field Airport in Hitchcock, Texas, about 1000.

One witness reported that he "heard a weird sound, turned around and noticed the left wing break off and plane flying like a rock." Another witness stated that she "heard the sounds of engine trouble, looked up, [and] heard a pop." She further reported that "the wing was off and the plane was going straight down."

According to the FAA inspector, who responded to the scene of the accident, the right upper and lower wings of the biplane were found approximately 250 to 300 yards from the main wreckage. The front and rear spars of both wings had broken at or near the attachment brackets to the fuselage. The inspector stated that all the breaks "appeared fresh with no previous cracks or deterioration of the wood noted." The upper right aileron was found an additional 60 to 70 feet from the right wings. The lower right aileron remained attached to the lower right wing. The fuselage, with both left wings and the empennage attached, came to rest in a nose down attitude with the engine buried approximately 5 feet into the ground.

The pilot held a private pilot certificate with a single engine land airplane rating issued on June 28, 1984. He held a third class medical certificate dated June 24, 1998, with the limitation: must wear corrective lenses. Additionally, he held a repairman certificate for the accident airplane issued on June 23, 1993. The pilot's logbook indicated that he had accumulated 867 hours of flight time.

An autopsy of the pilot was performed at the Galveston County Medical Examiner's Office in Texas City, Texas. Toxicological tests performed by the FAA's Toxicology and Accident Research Laboratory were negative for carbon monoxide, cyanide, ethanol, and drugs.

The airplane was issued an airworthiness certificate on June 23, 1993. Examination of the airplane's maintenance logbook revealed that the pilot completed the most recent condition inspection on March 1, 1998, at a recording tachometer time of 633.41 hours. The logbook entry for the inspection stated, in part, "check aileron cable tension 30#" and "increase aileron down spring tension slightly." The last entry in the logbook, dated February 24, 1999, at a recording tachometer time of 664.12 hours, stated "check new tail wheel spring. OK."

The airplane wreckage was examined on July 21, 1999, by an NTSB investigator. No evidence of contact was noted between the leading edges of the ailerons and the trailing edges of the wings. The aileron travel stop bolts, which were located near the bottom of the pilot's control stick, displayed no impact marks on the heads, and the shanks of the bolts did not appear to be bent.

The top and bottom aileron cables for the right upper aileron were separated, and the separated ends displayed a "horsetail" appearance. Approximately 1 foot of cable remained bolted to the aileron's upper cable attachment horn, and approximately 6 feet of cable remained bolted to the aileron's lower cable attachment horn. The lower horn was bent inboard about 90 degrees.

The rod that connected the right upper and lower ailerons was missing. However, pieces of the rod remained bolted to each aileron. Visual examination of the fracture surfaces on the rod pieces revealed no evidence of fatigue cracking. There was a linear tear in the aluminum and fabric leading edge skin of the lower aileron extending aft from the connecting rod attach point to the aileron spar.

The three rod ends used to attach the right upper aileron to the upper wing were all fractured. The ball sockets of the rod ends remained bolted to the aileron, and the threaded portions of the rod ends remained attached to the rear wing spar. The ball sockets were removed and taken to the NTSB Materials Laboratory for examination. The examination indicated that the fractures resulted from overload.

The airplane was released to a representative of the owner on September 27, 1999.

NTSB Probable Cause

The separation of the right upper aileron for an undetermined reason.