Q&A: Needle in a Haystack
Aug 01, 2020 | by Julie Bonette | Dartmouth Engineer
On September 30, 2017, an Airbus A380 took off from Paris headed for Los Angeles. It never arrived. While flying over the Greenland ice sheet, one of its engines failed and a fan hub split, with one part falling from the plane. The crew landed in Canada without further incident, but the part remained on the ice sheet.
The Geological Survey of Denmark and Greenland (GEUS) assembled a search team to locate the missing part to help determine what went wrong. But finding the piece on the ice sheet was like trying to find a needle in a hazardous haystack. Enter Thayer PhD students Joshua Elliott and Austin Lines. They joined the GEUS team with FrostyBoy, an autonomous, electric-powered vehicle capable of towing ground-penetrating radar across unstable crevasses.
Tell us about FrostyBoy.
Austin Lines: We found that the robots previously designed by Dartmouth students were not adequate for the low-cohesion terrain of Greenland. So we decided to rebuild a robot with larger wheels that could handle the loose terrain and had lower surface pressure to navigate the fluffy snow of Greenland. FrostyBoy is a one of a kind.
How did you come up with the name?
Lines: FrostyBoy is actually the name of a soft-serve ice cream machine in McMurdo Station, a U.S. Antarctic research station on the south tip of Ross Island. We like machines named after machines, so we decided to name the robot FrostyBoy.
How did you begin the search?
Joshua Elliot: We wanted to survey three likely spots, but two of them were in crevasse zones. There had been some overflights with a special radar-equipped airplane, which gave us a general sense of where the crevasses were. The idea was to create a path from safe areas out to the crevasse field. We selected the area and the route and then sent out the robot. Once the robot did the survey, then came the task of looking through all of the data, which is really labor-intensive. Then we handed that off to the mountaineer, who made the call whether to drive over it with a snow machine or go in with rope teams and walk on the ground.
Lines: In the search for crevasses, we detected an anomaly in the ground-penetrating radar data. After multiple surveys, it kept showing up. When we actually found the signal using the metal detector, we were very excited—but we were also in the middle of a crevasse zone. We smiled, snapped a picture, got on the helicopter, and left.
What’s the big picture?
Lines: Once they inspected the part, they found there was a crack that had formed due to the metallurgical process of making the fan hub. Now they’re requiring all A380s to go through rigorous testing for the flaw. If the same problem is found with the metallurgy, they have to rebuild the whole engine. It costs $750,000 per engine and there are four engines per plane—so it really adds up.
Editor’s Note: Lines and Elliott have been contacted by a team looking for lost WW II planes in Greenland and are eager to start their next expedition.