Spuds Help Improve Boeing's In-Flight Wi-Fi

Boeing engineers have been using an unusual mix of high-tech and low-tech to improve the wireless internet connection on flights.

Sacks of the humble potato were used as stand-ins for passengers while the aircraft maker's experts worked to eliminate weak spots in in-flight wireless signals.

The Chicago-based engineers needed full planes to get accurate results during signal testing, but they could not ask people to sit motionless for days while data was gathered.

"That's where potatoes come into the picture," says Boeing's Adam Tischler.

Researchers dubbed the project Synthetic Personnel Using Dialectic Substitution, or SPUDS.

But there was a serious purpose to their work as in-flight Wi-Fi on many flights can have patchy signal strength.

Airlines and aircraft makers have been striving to improve this with the growing use of wireless devices 35,000 feet (10,700m) up.

It turns out that potatoes - because of their water content and chemistry - absorb and reflect radio wave signals much the same way as the human body does, making them suitable substitutes for airline passengers.

"It's a testament to the ingenuity of these engineers. They didn't go in with potatoes as the plan," Mr Tischler said.

A member of the research team stumbled across an article in the Journal of Food Science describing research in which 15 vegetables and fruits were evaluated for their dielectric properties, or the way they transmit electric force without conduction.

Its conclusions led the Boeing researchers to wonder if potatoes might serve just as well as humans during their own signal testing, said Mr Tischler.

Despite some doubts, they ended up buying 20,000lbs (9,000kg) of them.

Video and photos of the work, which started in 2006, show a decommissioned plane loaded with row upon row of potato sacks that look like large, lumpy passengers.

The sacks sit eerily still in the seats as the engineers collect data on the strength of wireless signals in various spots.

The Boeing engineers added some complicated statistical analysis and the result was a proprietary system for fine tuning Internet signals so they would be strong and reliable wherever a laptop was used on a plane.

Boeing says the system also ensures Wi-Fi signals won't interfere with the plane's sensitive navigation and communications equipment.