WEST CHICAGO, IL, USA
N20367
Cameron CAN-56
THE COMMERCIAL FREE BALLOON PILOT AND TWO PASSENGERS WERE PARTICIPATING IN A BALLOON RACE. THE PILOT HAD SELECTED A FIELD IN WHICH TO LAND, AND HIS CHASE CREW WAS POSITIONED IN THE FIELD WATCHING HIS APPROACH. THE PILOT DID NOT ADD HEAT AS HE CROSSED THE FINAL TREELINE. AS THE BALLOON CROSSED THE TREELINE AND ROAD WHICH BORDERED THE UPWIND EDGE OF THE LANDING FIELD, THE GONDOLA, SUPPORT CABLES, AND BOTTOM OF THE ENVELOPE CONTACTED POWERLINES AND THE PROPANE TANKS IGNITED. THE THREE OCCUPANTS FELL 30 FEET TO THE GROUND, SUSTAINING IMPACT INJURIES. THE EMPTY BALLOON REASCENDED, AND FINALLY CAME TO REST 5 MILES DOWNWIND OF THE POWERLINE IMPACT.
HISTORY OF FLIGHT On June 25, 1994, at 0715 central daylight time, a Cameron Balloons CAN-56 free balloon, N20367, owned and operated by Mr. David L. James of Larwill, Indiana, contacted powerlines during approach to an open field in West Chicago, Illinois. The balloon caught fire and was destroyed. The commercial certificated free balloon pilot and two passengers sustained serious injuries. Visual meteorological conditions existed at the time of the accident. The flight was conducted under 14 CFR Part 91 as part of the Geneva, Illinois, Swedish Day Balloon Festival. The flight departed from an open field in Geneva, Illinois, at 0602 along with 20 other free balloons. The event was a "Hare and Hound" race, and the lead balloon had dropped a target at a golf course, 1/2 mile south of the Dupage Airport. The accident balloon passed north of this site, and the pilot remarked to his passengers that "we aren't in the competition." They then continued beyond the airport after crossing one of the runways south of the Air Traffic Control Tower (ATCT), and began to look for a landing site. After passing Dupage Airport, the pilot disconnected the main fuel line to one burner from the #1 tank (right front position) and reconnected it to the #3 tank (right aft position). The pilot stated he made this tank change when the tank gauge indicated 10% fuel. He stated that he left reserve fuel in the tank to ensure he would have some available if he needed it later. After this tank switch, all occupants described 1 more burn of the blast valves to initiate an ascent. No line changes were made to the left burner or #2 tank (aft left position). According to the festival coordinator, once a tank gets down to 40% fuel level, longer burns are required to produce an equivalent amount of heating compared to short burns at higher fuel levels. He stated that this is due to reduced fuel pressure within the tanks. A low pass was made in a residential area, and the pilot remarked to the passengers that he would land there if alone, but not with passengers. Another ascent was described, and then the target landing field was sighted. The balloon ground crew was in the field, and had established communications with the pilot on a handheld radio. A low pass was made over another crop field, the pilot stated he did not want to land there due to crop damage and recovery difficulty. Another burn was initiated to clear trees beyond this field, which bordered the target landing field where his ground crew was now stationed. The pilot described clearing the trees by 30 or 40 feet. None of the occupants described any further burning of the blast valve after the ascent to clear these trees. The pilot and 1 passenger stated they had seen the power poles near the landing field earlier. The pilot described the balloon beginniung to descend as they crossed the trees. As the road was crossed the balloon contacted the powerlines. All three occupants described the flight as uneventful until contact was made with the powerlines. The passengers stated that they felt electricity pass through their bodies and then jumped or fell from the gondola. One passenger stated he consciously climbed out of the gondola, and when he jumped, his watch got stuck on the basket. He hung on the outside until his watch broke, then fell to the ground. He described the fire as coming up from below the basket and burning his legs. Both passengers sustained spinal and leg injuries and the pilot-in-command sustained head and arm injuries. The balloon reascended and travelled downwind another 5 miles, coming to rest in trees alongside a highway. The basket was consumed by fire, two of the three fuel tanks exploded and detached from the balloon. The third fuel tank was recovered intact along with the balloon envelope. PERSONNEL INFORMATION The pilot was a commercially certificated free balloon pilot with no other aeronautical ratings. He had been a crewmember on balloons since the mid-1980's, and began to pilot balloons in September of 1993. He had accumulated 65 hours of flight time in free balloons, all in the accident balloon. The Balloon Festival Organization Manual, Section III, specified that: "Only crewmembers may be carried on board an aircraft operating under the Certificate of Waiver. All crewmembers must be designated by the Pilot-in-Command and have been given appropriate training in the conduct of their duties. These designated crewmembers must sign a statement that they have been trained in balloon operations, and that they understand the limitations of the waiver under which they are operating, and that they are designated crewmembers for the purpose of the specific flights." The 2 non-pilot occupants were on board in a crew capacity. They both signed a required "Crewmember Statement" which designated them with specific functions. Neither non-pilot occupant had previous balloon experience. According to the pilot, the duties assigned to qualify them as crewmembers were for one to be the lookout for power lines, and the other to be the lookout for towers. The pilot stated that he gave the other occupants a brief on duties prior to departure. One of the other occupants stated he had received a safety/duty brief, but it was treated as a formality, not taken seriously, and "made light of." Both passengers wore prescription glasses, and had them on during the flight. The pilot did not wear glasses. The pilot did not have, nor was he required to have, a current FAA medical exam. AIRCRAFT INFORMATION The balloon was Cameron CAN-56, special shape balloon (Coffee Can). The pilot described a total volume of 90,000 cubic feet, and a heated volume of 70,000 cubic feet. The Pilot Operating Handbook described a heated volume of 77,000 cubic feet. CAN-56 blueprints specify an effective volume of 77,000 cubic feet. Cameron marketing technical data specifications described the CAN-56 as a 12 gore, 56,000 cubic foot envelope. The balloon was configured with 2 rotation vents, in addition to a control and "rip" vent. The envelope had 12 primary vertical support cables, which attached in clusters of 3 at each corner of the basket/burner frame. The balloon was equipped with a MK-IV Double Burner, and 3 ten gallon Worthington aluminum propane fuel tanks (1 master and 2 standard). The liquid fuel fittings were threaded fittings, and the vapor lines had quick disconnect fittings at the tanks. Each tank was provided with an overpressure relief valve. Each burner was equipped with a vapor pilot light and a main liquid fuel line, separated by a crossfeed valve. The burners could be operated individually or in tandem. The gondola was a Cameron 42" x 58" "Aristocrat" semi-rigid basket. The gondola was supported by 4 primary support cables, 2 per side, which attached to the envelope support cables via carabiners at the burner corner plate. The basket support cables each had a slip prevention fitting swaged to it in the gondola floor. The gondola itself was a wicker weave vegetable material. The burner support frame rested on 4 semirigid support tubes which mounted to the gondola corners. These provided rigidity, but were not weight bearing structure. All structural support from the envelope was borne by the cables. All support cables (envelope and gondola) were steel. COMMUNICATIONS The pilot maintained radio contact with his ground crew on a handheld radio. The passengers remarked that there were discussions between the pilot and his crew concerning landing sites. WRECKAGE AND IMPACT INFORMATION The double burners were recovered with the envelope. Both fuel valves were open (valves in the in-line position) and the crossfeed valve was closed. Both blast valve handles were in the closed position. The Double Burner assembly was recovered, and both pilot light valves were in the ON position. The #1 position fuel tank (forward right) was recovered approximately 1/4 mile downwind from the original impact site. The fuel valve was in the closed position. This tank was ruptured outward at a point just above the equator of the cylinder. The #2 position fuel tank (aft left) was located with the main and vapor fuel valves on. This tank had a 1/4 inch hole in the bottom, with metal loss similar to an electrical arc welding burn through. The #3 position fuel tank (aft right) was not recovered. Review of a video taken by a witness showed 2 distinct explosions each followed by what appeared to be a cylinder falling from the balloon. Neither of the pressure relief valves on the recovered tanks were open. The balloon envelope was recovered from a tree approximately 5 miles downwind from the original impact site. The envelope received substantial tear damage during recovery. Post crash inspection of the envelope revealed large areas of burned and melted nylon, concentrated on the lower horizontal (bottom of the can) panels, and on the vertical panels extending as high as panel "I" along cables 11, 12, and 1. "A" is the bottom panel and "M" is the uppermost. The distance between the lowest 3 power lines which carried 12 Kilovolts (KV) and were phased (A, B, C), and the ground was 30 feet. The next 2 higher lines carried 34 KV and were 36 feet high. The next highest line also carried 34 KV and was located 42 feet 10 inches above the ground. This wire displayed visible burn marks. Beginning at the lower 3 wires, the vertical distances between wires is 6 feet, then 6 feet 10 inches. The distance from the bottom of the gondola to the carabiner cable attachment at the burner plate was approximately 6 feet 11 inches. Envelope support cable #6 was melted at the carabiner. The distance from the burner plate to the location of melted envelope support cable #7 and #8 was 7 feet. One basket support cable on each side was severed by melting. The location of these severed cables was under the floor of the gondola, 8" and 11" inboard from the aft edge respectively. The severed cable were immediately adjacent to the location of the #2 and #3 fuel tanks, and adjacent to melt through holes in the metal support tubes. The burn through on the cable and support tube under the #2 (master) tank was also adjacent to the hole in the bottom of the tank. MEDICAL AND PATHOLOGICAL All three occupants sustained second degree burns on their heads and arms. The passenger who hung on the outside of the gondola sustained second and third degree burns to his lower legs. The passengers sustained multiple fractures of their hips, legs, feet, and hands. Both passengers sustained spinal fractures. The pilot sustained multiple fractures of his elbow and skull, resulting in loss of sight in one eye. All three occupants underwent stabilizing surgery later on the day of the accident at the Central DuPage Hospital, Winfield, Illinois. FIRE Occupant statements indicate that no fire existed prior to the impact with the wires. The 2 passengers describe "glowing wires" and "the feeling of electricity" through their bodies. All occupants described sparks from over their heads, and the initial fire from underneath the gondola. One of the passengers remarked to his wife and son, while hospitalized, that there was no problem or fire until contact with the wires. This was confirmed during interviews with both passengers and the pilot. A video tape taken by a bystander showed the gondola and lower areas of the balloon enveloped in flames after the impact with the wires. The balloon continued to ascend during the video, deforming and partially deflating. During the film, 2 distinct explosions take place, each followed by the visible separation of a cylindrical object. After the second explosion, flame is no longer visible and the smoke changes from black to white. The available fuel sources were the propane fuel, the wicker basket, and the ripstop nylon in the envelope. The frontal air scoop was a nomex, fire resistant material. The basket was completely consumed by fire, and only leather edge and wooden skid remnants were recovered. The 2 fuel tanks which were recovered were open to the atmosphere. Tank #1 (forward right - standard configuration) had ruptured outward and displayed a 12 inch bulge adjacent to the torn metal. This tank was recovered from the ground, approximately 1/4 mile downwind of the initial impact. Tank #2 (aft left - master configuration) was recovered with the balloon, and although not distorted, displayed a 1/4 inch hole in the bottom. This hole was surrounding by a uniform reduction of metal thickness, and corresponded to the location where the support cable and basket frame tube displayed melting holes. All holes were similar in appearance to arc welding metal burn through holes. SURVIVAL ASPECTS Accident response by local authorities took 4 minutes. The accident was observed by the balloon ground crew. The burning balloon was observed by personnel on duty at a local fire station, who notified their dispatcher as they responded. The Central DuPage Emergency Medical Services patient care record show: 0711 Call Received 0711 Dispatched 0715 Arr Scene 0737 Depart Scene 0743 Arr Hospital The fire station was located approximately 1 mile from the crash site. The hospital was located approximately 2 miles from the site. ADDITIONAL INFORMATION The Pilot Operating Handbook provided by Cameron Balloons US lists as the first item in the APPROACH TO LAND checklist: Powerlines - Special check of powerline network. The same section states "The most important aspect of the landing is to AVOID POWERLINES!" A further section on POWERLINE CONTACT is written in Section 4; Normal Procedures (attached). Section 3 - EMERGENCY PROCEDURES devotes section 3.1 and 3.2 to avoiding and reacting to contact with powerlines. Both stress that if powerline contact is inevitable, "Pull the parachute or rip line to terminate the flight." Section 4 describes under 4.2.10 PASSENGER BRIEFING, that "Passengers should be briefed that, during all landings, it is imperative that the pilot concentrate on checking for obstacles, checking for powerlines...the passengers should not talk or otherwise distract the pilot." The FAA stresses in FAA-P-8740-34, "Powerlines and Thunderstorms - Balloon Safety Tips," that "fuel tanks can be burned through by arcing power lines. It is unlikely that a pilot can do much to protect tanks from this exposure except by avoiding power lines." The same document states that "the hazard of power lines is generally accepted as ballooning's greatest danger. Contacting power lines at or below the equator of the envelope will generally result in burning through the flying wires as the envelope drags the gondola over the wires. If contact is made at or below the superstructure (of the gondola) a good chance of a fuel tank or fuel line rupture exists from power line arcing."
the pilots failure to maintain vertical clearance above powerlines which bordered the field in which he intended to land. A factor associated with the accident were the powerlines.
Source: NTSB Aviation Accident Database
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