At the End of my Tether

by Richard Lofland

It was September in Stockwell, Indiana. A local high school teacher had invited me to tether fly my Cameron Concept 100 for their transportation class in the practice football field. That morning the weather was sunny, winds were 1-2 knots, forecast at less than 6 knots. It was my first commercial tether.

I showed up at 7:30 a.m., laid out and attached two nylon tether lines to the crown ring. Each of them was 300 feet long. They were in turn attached to a goal post and my truck upwind, which were stationed about 100 feet apart. With the students looking on, we inflated, and I took three or four students up at a time for a look around their school, their town, and their world. The earth is flat here as far as the eye can see. Mostly, it is covered with farms and trees.

Several groups of students enjoyed the experience. We never exceeded 180 feet. On the last tether for the day, I was flying two teachers and two students, my heaviest and also hottest load (213F) of the morning. At approximately 9 a.m., the winds aloft at 150 feet had picked up to 7 knots.

We landed gently, and after venting a bit, and waiting 25 seconds before letting anyone out, and venting again after the first passenger got out, then the other three passengers got out, but still held on to the sides, along with my crew of three. Then, with seven people weighing on, we started to move the basket back towards my truck. When the basket came off the ground, I thought it was because the crew were lifting it. The next thing I knew, my crew was yelling to "LET GO." I could see the shadow of one person three to four feet off the ground.

Balloon at the end of its tether. Note line leading away and down from top of envelope. Photo taken from TV screen.

Too much weight had left the basket too fast. So long as the passengers were leaning on the basket rim, all was well. But as soon as we tried to move the basket, much of that weight was suddenly gone. Everyone was still holding on, but their weight was now less effective. Several grabbed the handles at the basket base, but quickly let go as the basket continued skyward. One teacher held on to the handle until he was four feet off the ground, then finally released as a crew member shouted, "Let go!" A videotape taken at the time shows only the basket and not the envelope. The envelope was not full for I could see the up wind side being concaved.

Alone in the basket, I now accelerated upward. My thought as I was ascending was that the wind had concaved the envelope enough that it was lifting it like it would a kite. I burned once or twice in hopes to help fill the envelope for I feared that I would come crashing down. In about 30 seconds, I was literally at the end of my tether, and about 212 feet in altitude (by the time I looked). The tether line held the crown ring steady, while the balloon continued on up, until it had turned on its side. At this point, it was moderately pancaked, and the basket was not thrown outward and upward, but collapsed limply into the lower folds of the envelope. [We did find a 2" burn hole in the envelope about 15 feet from the mouth.] In the video, the balloon can be seen on its side, but most of the basket cannot be seen. A series of ripples passes down (or now across) the envelope from the crown to the mouth while it is on its side, probably as a result of being taken up suddenly on the tether line. The pancaking and the ripples squeeze lots of air out of the envelope. The remaining hot air has now done all the lifting it can. The basket quickly drops below the envelope, and the descent begins.

As the pancaking and the ripples squeeze more of the hot air out of the envelope, I thought: "what's keeping the parachute in place?" For the crown ring was lower than I was and what little heat there is in the envelope is now lifting the side of the envelope (now the top side). It seemed to me like I was flying for 15 minutes or more, but only a few minutes had actually passed. At one point, I did think that someone should call "911" to get help started on its way, for I did not foresee a good outcome.

Meanwhile, my crew is thinking fast. They clear the area because they don't want anyone to get hit by falling debris (like me!). They consider cutting the tether lines, but decide not to. I'm glad they didn't, because I would have dropped quickly and had no way to burn sideways as I went downwind. They also thought about pulling me down with the tether lines. If they had, I think that all of the hot air left in the envelope would have come out through the mouth, and I would have come down sideways and fast, like a kite doing a nose-dive as the wind pushes down on the top side. The envelope might have reached the ground before the basket. I'm glad they didn't do these things. They did know when to yell to "LET GO." If they had not, there may have been one less teacher.

As the descent began, I dropped fairly fast, burning as I descended. I landed with a jolt, but was not injured. There was no bounce, because several people and crew members (except one teacher) weighed on immediately. I was happy to be back on the ground.

Problems and Solutions: First: if I had a third tether line on the crown ring going downwind, the envelope would not have been able to turn on its side. It would also have stopped me from going so high. Second: there should have been tether lines on the burner frame. This would keep the envelope, burner and basket in line with each other. Third: I should have kept one or two passengers in the basket as we moved to the truck. I had plenty of help to move so I could have kept the extra weight in the basket. Fourth: with extra weight in the basket, it would have taken more heat to move the basket so the envelope would have been more full and less chance to concave.

I know that other pilots tether in different ways. I like the crown ring tethers (and now with burner frame tethers too) for they will keep control of the envelope. For where the envelope goes the basket will surely follow.

The manufacturer of this system recommends that the tether lines be attached at the burner frame. Without these lines it would be difficult in this situation to prevent the balloon from inverting, even with a third tether line attached to the crown. Whether tethering or ending a flight be careful how quickly weight is discharged from the basket. An envelope still warm enough to fly will if given a chance. Editor.