What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
At FL274 loud whoosh noise. Balloon ascended to FL330. More noise and jolts. Dumped helium. Descended. Bailed out (.4) the global hilton roziere gas balloon experienced a rupture of its main gas cell's bottom 10 to 12 minutes after it reached its ceiling. The pilots continued to hear pops, rips, and tearing as the balloon descended to approximately 9,000 feet MSL. Eighteen propane bottles and three oxygen bottles surrounded the gondola. The ground crew reported surface winds of 30 to 35 knots, and the surface terrain was rugged with canyons and rock formations. The crew decided that a safe heavy weight standup landing would not be possible, and they parachuted to the ground. The unmanned balloon continued flight for 7 hours and 375 NM until it impacted wires and was consumed by postimpact fire. The manufacturer stated that the main gas cell had 13.273 square feet of opening for the two appendixes to release surplus gas at ceiling altitude. Postaccident examination revealed that the balloon appendixes had only 8.96 square feet of opening. The manufacturer modified appendixes were buckled to the balloon's side, which further restricted the openings by 56%. The base circle in the bottom of the main gas cell 41 inches in diameter, 21.75% smaller than design specifications. (-23) see narrative #FTW98FA089
As the FAA filed it
AT FL274 LOUD WHOOSH NOISE. BALLOON ASCENDED TO FL330. MORE NOISE AND JOLTS. DUMPED HELIUM. DESCENDED. BAILED OUT (.4) THE GLOBAL HILTON ROZIERE GAS BALLOON EXPERIENCED A RUPTURE OF ITS MAIN GAS CELL'S BOTTOM 10 TO 12 MINUTES AFTER IT REACHED ITS CEILING. THE PILOTS CONTINUED TO HEAR POPS, RIPS, AND TEARING AS THE BALLOON DESCENDED TO APPROXIMATELY 9,000 FEET MSL. EIGHTEEN PROPANE BOTTLES AND THREE OXYGEN BOTTLES SURROUNDED THE GONDOLA. THE GROUND CREW REPORTED SURFACE WINDS OF 30 TO 35 KNOTS, AND THE SURFACE TERRAIN WAS RUGGED WITH CANYONS AND ROCK FORMATIONS. THE CREW DECIDED THAT A SAFE HEAVY WEIGHT STANDUP LANDING WOULD NOT BE POSSIBLE, AND THEY PARACHUTED TO THE GROUND. THE UNMANNED BALLOON CONTINUED FLIGHT FOR 7 HOURS AND 375 NM UNTIL IT IMPACTED WIRES AND WAS CONSUMED BY POSTIMPACT FIRE. THE MANUFACTURER STATED THAT THE MAIN GAS CELL HAD 13.273 SQUARE FEET OF OPENING FOR THE TWO APPENDIXES TO RELEASE SURPLUS GAS AT CEILING ALTITUDE. POSTACCIDENT EXAMINATION REVEALED THAT THE BALLOON APPENDIXES HAD ONLY 8.96 SQUARE FEET OF OPENING. THE MANUFACTURER MODIFIED APPENDIXES WERE BUCKLED TO THE BALLOON'S SIDE, WHICH FURTHER RESTRICTED THE OPENINGS BY 56%. THE BASE CIRCLE IN THE BOTTOM OF THE MAIN GAS CELL 41 INCHES IN DIAMETER, 21.75% SMALLER THAN DESIGN SPECIFICATIONS. (-23) SEE NARRATIVE #FTW98FA089
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.