DEN93FA100

While on a local passenger sight seeing flight, the balloon encountered a wind shift and high winds. While drifting at high speed and low altitude, the balloon struck the static line of a power transmission span. The basket was severed from the balloon and fell approximately 108 feet.

History of flight

On August 8, 1993, at 0800 mountain daylight time, a Cameron Balloons US N-145, N4141D, collided with the static line on a power transmission span near Woody Creek, Colorado. The pilot and the five passengers on board received fatal injuries and the balloon was destroyed. The flight was a commercial operation conducting a sight seeing tour. Visual meteorological conditions prevailed and no flight plan was filed. The flight departed Snowmass Village, Colorado, at approximately 0645.

According to witnesses, the balloon drifted west down the Aspen valley, to a point approximately 5 miles from the Aspen airport, where it encountered a rapid change in wind direction and velocity. The balloon then drifted east at low level and struck the static line.

A video tape of the accident sequence was taken from another balloon at a distance of approximately one half mile. The tape does not show the basket, but does show a flash at the impact site, and shows the balloon drifting and climbing with the basket missing.

Another witness said she saw the balloon drifting east just above the trees and saw the burner emitting periodic short bursts as the balloon proceeded laterally at high speed. The witness statement is attached.

Personnel information

According to available information, the pilot had flown balloons in the local area for at least two years and had flown numerous flights in the Aspen valley.

Meteorological information

Recorded weather at the Aspen airport at 0745 local time was 6,000 feet scattered clouds, 7,000 feet broken clouds, 20 miles visibility, temperature 50 degrees Fahrenheit, dew point 44 degrees Fahrenheit, wind calm, and an altimeter setting of 30.00 Hg. Witnesses at the airport provided information that the wind at the airport often does not accurately reflect the winds in the center of the valley due to the airport being shielded by a hill from the wind which was reported by witnesses in the center of the valley where the balloon was operating.

Other weather given to the pilot, during the weather brief by Grand Junction Flight Service, is depicted in this document under METEOROLOGICAL INFORMATION.

In addition to the above discussed video tape, another tape was taken from the ground. These tapes provide a depiction of the wind in the area at the time of the accident. They show the wind to be from the west with an increasing cloud cover. Witnesses estimated the wind to be approximately 30 miles per hour.

Wreckage and impact information

According to physical evidence observed, and metallurgical examination of components on the balloon cables and static line, impact with the static line separated the balloon from the basket and the basket fell to the ground. The balloon drifted further to the east and was recovered approximately 5 miles from the accident site.

The power line complex, which the balloon collided with, spans a gully approximately 240 feet wide and 70 feet deep. From a horizontal view, only the top transmission line and static line are visible due to trees. By measurement, the static line is 108 feet above the gully floor at the point of impact and the static line is 16 feet above the top transmission line.

An abrasion mark on the static line was found directly above where the basket impacted the gully floor. The attached metallurgical report examination of the 16 sheared cables, which attached the basket to the envelope, revealed fracture features typical of tensile overstress breaks with no indications of significant preexisting wear or corrosion. The metallurgist stated that "two of the cables displayed metal transfer and analysis of the deposited material provided information that the material was primarily zinc which is used as a galvanization coating on the static line."

Examination of the basket revealed a crushed fuel tank cap, buckling and fractures of the frame, and deformation of the basket. There was no evidence of electrical arcing, and the power company automatic monitoring equipment did not record any shorts in the line.

Additional information

The wreckage was released to the owner on 08/09/93. Retained parts are listed on the Release of Aircraft Wreckage form and are being returned to the owner's representative.