MIA95LA013

The private pilot experienced a failure of the basket suspension cables while tethering at about a 75 feet in an open field. Review of the balloon logbooks revealed the last annual inspection was recorded as logged 48 days before the accident. The repairman who performed the annual inspection stated he visually inspected the suspension cables. Examination of the suspension cables by the NTSB Materials Laboratory revealed the cables failed due to corrosion and overstress separations.

On October 29, 1994, about 0800 eastern daylight time, a Semco, Challenger, hot air balloon, N2048J, registered to Michael G. Evain, operating as a 14 CFR Part 91 personal flight, experienced a failure of the basket suspension cables while tethering at about 75 feet in an open field in the vicinity of Miami, Florida. The balloon sustained substantial damage, and the private pilot reported minor injuries. Visual meteorological conditions prevailed and no flight plan was filed. The flight originated about 1 minute before the accident.

The pilot stated this was his first flight in the balloon since it came out of annual inspection. He was at about 75 feet agl with the tethering line attached when the wind blew the envelope towards the north-northwest, and the basket suspension cables failed. He initiated an emergency deflation of the envelope. The basket fell beneath the envelope towards its side, and the propane tank melted the envelope. The pilot exited the basket without further incident.

Review of the aircraft logbook revealed the last annual inspection was recorded as completed on September 12, 1994, by Stephen A. Hoffman, Ashland, Virginia. Mr. Hoffman stated the registered owner brought the balloon to his facility in May 1992, for an annual inspection. The annual inspection was not completed and the balloon remained at his facility. A work order was initiated on March 25, 1993, and the annual inspection was completed on September 12, 1994. Mr. Hoffman stated a visual inspection of the suspension cables was performed without removing the cables from the basket, and recorded on the inspection checklist.

The basket suspension cables were forwarded to the NTSB Materials Laboratory labeled cables "1" and "3" and "2" and "4" for analysis.

Cables "1" and "3" were approximately 8 feet long and contained an end terminal at one end and a break at the other end. The fracture faces on the individual wires from each strand were examined with a binocular microscope, and revealed that all wires were necked down or had a slant profile, consistent with overstress separations, and were almost completely unraveled. Visual examination of the cables revealed heavy deposits of iron oxide (rust) between strands and between the wires in the strands in an area located between 3 feet 6 inches and 3 feet 8 inches from the terminal ends.

Cables "2" and "4" separated about 3 feet 7 inches from the terminal ends, which corresponds to the location where cables "1" and "3" were heavily corroded. The broken ends of cables "2" and "4" exhibited very little unravelling. Visual examination revealed the wires and strands in the areas adjacent to the fractures were covered with heavy accumulation of corrosion deposits.

The terminal ends of cables "1" and "3" and "2 " and "4" was equipped with a fitting and a washer approximately 7 inches away from the end terminals. All four cables were subject to corrosion in the vicinity of the fittings. The cables were kinked and individual wires and strands were broken corresponding to the position of the washers. (For additional information see NTSB Metallurgist's Factual Report No. 95-52).

The basket suspension cables were released to Michael G. Evain, on February 4, 1995.