WHEN a parachute fails to open or a bungy jump fails to bunge, someone usually gets hurt. Terry Pearce, manager of Phuket's Jungle Bungy, still has sleepless nights over that jump in July that went awry.

A dramatic official dive video shows British tourist Rishi Bajeva smiling broadly, then taking the plunge from the 50 metre tower. He heads down, down . . . but only the cord bounces back up.

Mr Bajeva keeps going. He hits the water of the lagoon at high speed and survives, although suffering severe internal injuries in the process.

One of the jumpmasters is heard to exclaim: ''Oh.''

While the adventurous engineering graduate is recovering at home and contemplating sky diving as his next slice of fun, the video of his mishap has become a must-see item online.

After Britain's Daily Mail published an article and the video on the bungy jump that did not bunge, the mishap attracted an online audience around the world.

For Terry Pearce, it's a reminder of one of the worst days of his life, certainly the worst of his five years on Phuket as manager of the Jungle Bungy.

''We've had 140,000 jumps here over 17-and-a-half years,'' he said. ''And this is the only one that went wrong.''

He has watched the video more than once, and in agonising slow-motion.

''The guy didn't listen to the jumpmasters,'' Mr Pearce said.. ''He went feet-first and his knees go up. He was young enough and strong enough to kick his way free.

''We've changed a couple of things since. The leg-wrapping we now use grips like hell. I've tried it myself.''

The day of the mishap, Mr Pearce was not working but he hurried to the bungy centre in Kathu on hearing of the plunge that went wrong.

''It shook us all,'' he said. ''The two jumpmasters were widely experienced.

''Everyone found it difficult to believe. We were pretty upset.''

Mr Bajeva returned to Britain after treatment at Phuket International Hospital and in Bangkok, with the bugy jump's insurance meeting costs.

Mr Pearce even gave Mr Bajeva's parents a copy of the official video. ''It cannot happen again,'' he said. ''We are committed to safety.''

Jumpers were rare in wet weather yesterday but Mr Pearce expects visits will pick up, although numbers are never likely to return to 1992 figures, when bungy was the big new Phuket thrill.

So the Phuket jump's ''100 percent safety record'' has to be modified to ''99.9999 percent.'' Mr Pearce insists that a bungy jump is still far safer than riding a jet-ski, a go-kart, or a rented island motorcycle.

The US Navy apparently agrees. While American sailors visiting Phuket are told not to ride jet-skis, motorcycles, or even hire a car, bungy jumping is apparently regarded as 99.9999 percent safe.