The Mad Belgian

Louis-Philippe Loncke is 49, Belgian, an engineer by training, and the reason a stretch of Australians started calling foreigners "crazy" a specific way. In 2008 he became the first person to attempt, and complete, an unsupported, on-foot crossing of the Simpson Desert from north to south, through its geographic centre, hauling everything he needed on a 32.5-kilogram aluminium cart. Australians, who had spent decades treating the Simpson as a place you cross by 4WD if you cross it at all, started calling him the Crazy Belgian. Years later, after a winter crossing of Tasmania, the nickname got an upgrade: Mad.

He has now tried the Simpson three times. He succeeded once. The most recent attempt, in 2024, ended after roughly twenty days when a tendon injury he'd been managing since day two finally forced him to turn back, short of the centre, with a decision to make about how much risk was left in his knee versus how much desert was left in front of him. He now believes no one, including him, will ever finish a fourth crossing. Not because it hasn't been done. Because, in his telling, the maths no longer works.

The desert that is not a desert right now

The Simpson is, by Loncke's own definition, Australia's most arid desert (hyper-arid, in his framing, meaning under 200 millimetres of rain a year). It runs roughly six times the size of Belgium, about a third the size of France, and is shaped by 1,100 parallel sand dunes running the same direction, so that crossing it on foot means going up and down, up and down, with a new “surprise” (his word) in every valley between dunes: flat nothing, a stand of a few hundred trees, a valley solid with yellow flowers, or pink, or white, or a few camels standing in it. “It's completely new,” he says. “Suddenly it could be flat and nothing, or you could have a little forest... you never know what you're going to get.”

The shortest way across is east-west, about 400 kilometres, and almost everyone who drives it uses the French Line, a 4WD track. There has never been a marked route north-south, which runs closer to 600 kilometres through the centre. That was the version Loncke chose.

As it happens, in July 2026, at the moment of this interview, none of that matters, because nobody can cross the Simpson at all. A run of rain dumped roughly 400 millimetres in a few days, and Lake Eyre, the normally dry lakebed south of the desert that catches the runoff, is full for what Loncke says is only the second time in about seventy years. "It's completely filled up with water," he says. "The largest lake of Australia is 99.9 percent of the time completely dry, except now." One of the rivers feeding it is too high for vehicles to cross, closing the desert to 4WDs as well as walkers. It is a small, temporary irony for a man who has spent two decades trying to cross it on foot precisely because almost nobody could stop him.

Two hundred and fifteen kilograms of cart

Loncke was not the first person to attempt a Simpson crossing without a vehicle. In the 1970s, two men crossed part of it hauling a cart, resupplied once by an aircraft dropping water and food; they covered something like 450 kilometres, off-track the whole way, dropped and picked up by air only where the 4WD road stopped. Three people have completed unsupported, off-track, on-foot crossings of the Simpson: Lucas Trihey (Australia) in 2006, Michael Giacometti (Australia) over 24 days in 2008, and Loncke (Belgium) over 36 days in 2008, weeks after Giacometti. He carried no water drops, no food caches, no air support. His cart and supplies started at 215 kilograms.

The cart itself he built to survive one specific enemy: prickles, hardened seed-spikes from local plants, sharp enough to flat a car tyre, let alone a bike tyre. He spent time tracking down an English company making airless, "flat-free" tyres: solid rubber threaded with microscopic air bubbles, immune to punctures, at the cost of some weight. It meant he didn't need tyre-repair tools, a spare air chamber, or the time it takes to find a leak by dunking a wheel in water, time he didn't have to spend "laying on the ground in the heat" in a desert where the water in question was also his drinking supply. He is matter-of-fact about why this decision mattered more than almost anything else he brought: most people who have tried the Simpson since him, he says, failed because their wheels went flat, bent a spoke, and turned the cart from a tool into 150-plus kilograms of dead weight that has to be evacuated.

By day one, hauling that weight through total silence, he heard something he says he has never read about in another adventure book. "I started to hear the blood pumping in my heart because of the little veins in my ear," he says. "It was so silent, no engines, no people talking, no animals, no wind." He credits it, half-seriously, to a body working that hard in a place that quiet. It is the kind of detail that does not survive a support vehicle.

The centre, the dunes, and thirty-six days

The crossing took 36 days. He passed through the desert's geographic centre (marked, incongruously, by a seven-metre pole and a logbook that most visitors reach by 4WD, treating it, in Loncke's comparison, the way Australians treat climbing Mont Blanc: hard-won, remote, worth writing your name down for). He was navigating a landscape with no fixed reference points (dune 821 looks like dune 825 looks like dune 830) with GPS, map and compass, and no way to have scouted the route beforehand. "I never been to the Simpson Desert before going there," he says. "That's not the advantage I have, the others, they usually can test them... I had no way to test it."

Not every surprise between the dunes was scenery. He was chased by camels, twice, by his own account of the trip broadly, and separately, in an earlier interview, he described being chased by fourteen dromedaries as the worst thing that had happened to him in the desert, with no physical contact but real fear, because a camel, he says, can kill a person easily and "it's them who decide." He also encountered the Min Min Lights, an unexplained light phenomenon reported across the Australian outback for well over a century, and found it, in his own word, "very scary," precisely because he had no idea what he was looking at.

In 2016, Loncke returned and completed a second, partial crossing, west-east, the one crossing attempt he counts as a failure before 2024. The Simpson became something he kept coming back to, not a box he'd already ticked.

The knee, the maths, and the decision to stop

The third expedition, in 2024 (what he calls Simpson Desert Trek III), is the one that ended his run. He developed tendonitis in his knee on day two. He kept going anyway, for roughly twenty days, hauling a cart that started around 150 kilograms that year, hoping the injury would resolve. It didn't. “If I tell to a doctor on day two I have a tendonitis, and then 14 hours per day I'm doing sport holding a cart... he said I'm completely stupid, I should stop and rest,” he says. “But I did that for 20 days with the pain every single day.”

What forced the turn-back wasn't the pain alone. It was arithmetic about rescue. Push too far toward the centre with a worsening injury, and a helicopter out of Alice Springs doesn't have the fuel range to fly in and fly back out. It can only bring supplies and then wait, stranded, for a vehicle rescue that could take up to a week and would likely require three or four support vehicles, any of which could itself be stopped by a puncture or, in a wet year, bogged sand. "You need to find people who would risk their lives," he says. He turned back before that calculation became necessary, short of his goal, with the tendon still not healed.

It has left him with a conclusion he states plainly, and which functions as the actual thesis of his relationship with this desert: "I now believe no one in history will ever cross the Simpson again," he says, "because it's too warm... you need to carry more water, which means more weight, which means it's a problem on your joints and your muscles, which means you'd have an injury." Heat forces water. Water forces weight. Weight forces injury. Injury, in a place this remote, forces a decision, the same one he made in 2024, to stop before the desert makes it for you.

What "adventure" means to a man who does this for a living

Loncke resists the word "adventurer" being applied loosely, and has spent years (he is still working on a formal classification system) trying to separate what he does from travel. A supported bike ride from Paris to Madrid, he says, is a trip, not an adventure, however far it goes: "How long do I need to prepare that? Half an hour." An unsupported, off-track crossing of a named desert, where a fall or a flat tyre could mean death rather than inconvenience, sits at what he calls the top of his own scale, a scale built, he says, around risk, not distance or difficulty for its own sake.

He is unsentimental about the trade-offs of the life. He has run an online expedition database and a travel-network startup for years without either turning a profit; a job he depends on has, at points, gone unpaid for months. “I'm not lucky with women... I'm not lucky with money,” he says, mostly as a joke, though not entirely. What he says he does have is a plainly stated obsession: he wants to plant, or fund the planting of, a billion trees over the next twenty years, one per user, if his travel-network project ever reaches a billion users, which by his own admission is already five years behind schedule. He calls the ambition, half self-mockingly, becoming “the first treellionaire,” spelled with two E's.

Still watching the water

For now, the Simpson itself has the upper hand. It is flooded, closed, and, by Loncke's account, greener and louder with birdlife than it has been in decades, the "dead centre" temporarily reversed. He is not currently planning a fourth attempt. Whether that is a permanent retirement from this particular desert, or simply this particular desert waiting him out, is the one question even he does not answer.