I've known my big brother for 27 years and I like him quite a lot. Which is why, as I watch him almost stop being my brother by flying into a rock, I'm a little worried.
Patrick has pulled too hard on the lines controlling the fluorescent canopy above his head. Already skimming the frozen slope at brain-shaking speed, he takes off, lurching like a wounded Messerschmitt towards a herdsman's hut. Gravity intervenes just in time and he slams into the ground, a blur of skis and snow. Seconds later, a thumb rises from the heap. He's OK, which means it's my turn.
I've joined Patrick in Val d'Isère in the French Alps to try one of the newest sports in the thrill-seeker's repertoire. The crazed bastard child of paragliding and big-mountain skiing, speed-riding, which is also known as speed-flying, took off six years ago. French paragliders looking for a bigger buzz developed half-size wings that allowed them to ski faster and harder, simply soaring over anything in their way. For skiers who gawped at their aerial exploits on YouTube, the sport seemed about as achievable as, well, flying.
But in a remarkably swift leap towards the mainstream, speed-riding is being offered as a course in a handful of resorts. UCPA, the French non-profit hostelling organisation that champions the outdoors, offers a week's instruction at its Val d'Isère centre. We're here with Action Outdoors, UCPA's British partner. This is adrenalin on a shoestring. When you consider a lift pass alone in Val d'Isère costs £230 for a week, it seems almost indecent to throw in the pass and everything else (except travel and alcohol) for as little as £500. Riding out the recession shouldn't be this much fun.
Day one starts inside as the group gets to grips with new kit – harness, sail, helmet, back protector, radio – under the guidance of Jean-Pierre and Maxence. Jean-Pi is a veteran paraglider. Maxence, a young hot-shot telemarker and all-round action man, is a YouTube daredevil in his own right. Both are also qualified ski instructors. But first we must learn the ropes – it takes all morning to negotiate the often tangled web of lines that link harness to sail.
Suited up after lunch, with wings packed into giant sacks that dangle suggestively from our harnesses (the big-balls symbolism isn't lost on the all-male group – we decide we'll need them), we make our first trip up the mountain for a short practice run. Once the chute is laid out above me I grip the loops that lead via pulleys to the rear of the sail and push off. "More speed more speed," Jean-Pi barks into my radio earpiece. Immediately, the sail inflates and rises above my head as I accelerate. There is a sense of weightlessness as I ski on, rather than through, the snow at a speed that would be impossible without assistance.
By the middle of the week we've mastered straight-lining and begin to use our arms to initiate long, fast turns. A pull on the right line curls down that side of the wing, creating drag that results in a turn in that direction. Strong legs are required to follow through and, since speed-riding can be done only off piste away from other people, beginners must already be comfortable skiing aggressively and fast on wind slab, powder and everything in between.
Soon I'm storming down long runs, linking turns at hair-raising speed. But we're itching for air – to get a few feet closer to emulating the pros. Glancing left as I traverse, I spot a lip that should provide the lift I'm looking for. Pulling left as I turn towards it, I'm travelling too fast to notice in time that I'm heading for a near-vertical kicker. I slam into the wall of snow, leaving my skis behind as I head-butt the snow and slide to a stop like a rag doll. "One of the ideas of speed-riding is that we don't ski into the wall," Jean-Pi says over the radio.
The colour drains from our instructors' faces a few times during the week, but, despite appearances, speed-riding has a good safety record. If that changes, the relatively relaxed regulations governing the sport may not last – it's already banned in several resorts. "We should enjoy it now," Maxence tells me on the chairlift.
As Patrick gathers his chute after his crash-landing, I want a last shot at flying. We've moved to a longer line that ends in a steep slope. It cranks up speeds to a new level and as I approach a snow-covered rock I pull gently on both lines. And it happens – my skis slip into flight. The wing accepts my weight and I glide for what feels like several metres before reconnecting with snow. It's an astonishing feeling – a real-world answer to those staircase-vaulting dreams I had as a kid. The sense of breathless elation that follows a thigh-burning, rib-rocking ski run just got a bit higher.
How to get there
Simon Usborne was the guest of Action Outdoors (0845 890 0362; action-outdoors.co.uk), which offers speed-riding weeks with UCPA at Val d'Isère on 2 January, 9 January, 17 April and 24 April from £560 per person, including seven nights' shared accommodation, all meals, equipment hire, full-time instruction and lift pass. Flights and transfers cost extra.