For WiFi to become a reality on commercial flights today, companies had to run all kinds of tests to certify the technology miles above the ground. In 2012, Boeing engineers found a solution that was as absurd in appearance as it was brilliant in practice to improve the connectivity of its aircraft. They had to reproduce the conditions of a cabin full of passengers and discovered that they could replace them with something much cheaper, quieter and easier to handle: tons of potatoes.
The problem was with the passengers. Most people don’t know this, but the Wi-Fi connection on an airplane can vary significantly depending on the seats, the number of passengers and their movement within the cabin. The reason? The human body absorbs and reflects electromagnetic waves, resulting in areas with strong signals and others where coverage is weak.
As engineer Dennis Lewis explained to WIRED a few years ago, even the movement of service carts changes the distribution of signals, making the interior of an airplane a particularly complex electromagnetic environment.
An unexpected solution. To study the problem, Boeing had to fill a plane with people and have them sit there for long days while their engineers took measurements. That means recruiting dozens of volunteers, landing an airplane, and repeating countless tests to identify the areas with the worst coverage.
Researchers began looking for materials capable of reproducing the human body’s interaction with wireless signals and found a surprising candidate: potatoes. Its high water content, close to 80%, and its dielectric properties allow it to absorb and reflect waves substantially like passengers.
Nine tons of potatoes on board. Thus began an experiment for the history books, with Boeing practicing the exercise using a decommissioned plane and filling its seats with sacks containing 20,000 pounds of potatoes, about 9,072 kilos. In this way, engineers could work for hours without worrying about fatigue, movement or the need for volunteers, while recording how the signal was distributed throughout the cabin.
The project was named SPUDS, an acronym for Synthetic Personnel Using Dielectric Substitution, a play on the English word for potato. The results obtained with these improvised passengers were later contrasted with real people to check their reliability.
Two weeks to ten hours. Plus: The experiment was part of a method developed by Boeing Laboratories to measure the strength and propagation of wireless signals using special equipment and statistical analysis. In fact, thanks to the measurements, engineers can identify points of weak coverage and adjust the connection system to achieve a more uniform distribution while respecting the safety requirements aimed at avoiding interference with the necessary electronic equipment of the aircraft.
As Boeing itself confirmed in December 2012, the new method made it possible to reduce tests that previously took more than two weeks to just ten hours.
The genius behind potatoes. This food choice makes it possible to reproduce a busy cabin without relying on dozens of people during measurements, facilitating a much faster and repeatable testing process along the way. The experiment also showed how a simple solution combined with advanced instrumentation and scientific knowledge can help solve complex technical problems.
In short, this is how Boeing was able to improve its approach to studying wireless connectivity and left behind one of the most amazing anecdotes in aeronautical engineering: where, to perfect Wi-Fi on its planes, it had to fill one with nine tons of potatoes.
Picture | Boeing
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