On August 31, 1997, about 1930 eastern daylight time, a Thunder and Colt AX-10, a hot air balloon, N834TC, tipped over upon landing near Akron, Pennsylvania. The certificated commercial pilot and eight passengers were not injured. A ninth passenger received serious injuries. The balloon was not damaged. No flight plan had been filed for the local sight seeing flight. The flight originated from a field near Stroudsburg, Pennsylvania, about 1825, and was conducted under 14 CFR Part 91. In the NTSB Pilot/Operator Aircraft Accident Report, the pilot stated: "...I had a smooth standup inflation. I told the passengers to climb in, gave pilot briefing and started my launch. The flight was smooth, I observed a balloon making a smooth stand up landing. I was the 4th of 6 balloons that launched from the field. During the flight, I called for current surface wind, they reported less than 6 [knots] approx. 6:45 PM. After checking winds & looking for signs of slow wind I chose a landing site w/ a tree line. After clearing the trees, I told the passenger[s] to get down for hard landing. I descended into the field, we touched down & then settled in for landing. After balloon was over on side, passenger complain[ed] of pain due to broken arm...." In a follow-up telephone interview, the pilot reported he had used a PIBAL prior to departure and estimated the winds at 5 to 6 knots. He estimated the winds at 8 knots during landing. After the bounce, the basket was upright and stationary. As the envelope continued to deflate, the wind caught it and tipped the basket over on its side. The total distance of the flight from takeoff to landing was about 4 miles. The passenger briefing included hanging onto the ropes during landing, and ducking down when told. In a follow-up telephone interview, the injured passenger reported the balloon touched down hard, bounced and then stopped. She was hanging onto the rope when the basket tipped over and another passenger fell onto her. She was not able to identify the passenger who fell upon her. The investigation revealed the pilot was using a 210,000 cubic foot envelope. The basket was rectangular in shape, about 92 inches long, 61 inches wide, and 43 inches high. The pilot station was along one of the long sides, in the middle, and partitioned off from the rest of the passenger compartment. The passenger compartment was split into two sections approximately 46 inches by 61 inches by a divider running between the pilot station, and the opposite side. Ropes were available inside the passenger compartments, on the edges, for passengers to hang onto. There were no restraining devices to prevent a passenger from falling onto another passenger should the basket tip over. The winds at Lancaster airport, about 5 miles west of the accident site were recorded as from 180 degrees, at 10 knots at 1947. According to personnel familiar with the AX-10, when landing with winds between 5 and 7 knots, with the 210,000 cubic foot envelope, there was a possibility of the basket tipping over. With winds at 8 knots or greater, there was a higher probability of the basket tipping over on landing.