In all of 2014, the Federal Aviation Administration recorded 238 possible drone sightings and near-misses by aircraft. Between Jan. 1 and Aug. 20 of 2015, the agency reported 678.
Many in the aviation industry have expressed concern about unmanned aerial vehicles — including drones — impacting aircraft. New research from members of Virginia Tech's Department of Mechanical Engineering shows how a drone getting sucked into a turbofan jet engine can lead to catastrophic engine damage. Now, Tech researchers are looking into how to lessen the danger to aircraft.
The research began with Javid Bayandor, associate professor of mechanical engineering and director of VT's Crashworthiness for Aerospace Structures and Hybrids Laboratory. He had previously led research into modeling the ingestion of birds into jet engines, a scenario the FAA already requires engine manufacturers to prepare for. As part of this research, his team developed a complex computer model of an advanced turbofan jet engine that could simulate damage caused by foreign objects entering the engine.
But in the last few years, numerous news reports have surfaced of pilots spotting drones flying dangerously close to airports. These reports inspired Bayandor and his team to change the direction of their research.
"We've done all of this work and we're comfortable with calculating the progressive failure effects of any other type of foreign object," Bayandor said. "We said, why don't we just try to model a drone?"
Bayandor is working with Walter O'Brien, the J. Bernard Jones professor of mechanical engineering. The research team also includes mechanical engineering doctoral students and CRASH Lab members Kevin Schroeder and Yangkun Song.
The results of their research were striking.
In one simulation, researchers modeled an eight-pound quadcopter impacting a turbofan engine. The drone breaks one blade of the turbofan at the intake of the engine immediately on impact. The resulting debris and vibrations destroy many of the fan blades in the rapidly spinning engine in milliseconds. Debris from the drone and fan blades, traveling as fast as 715 miles per hour, wreaks havoc on the rest of the engine.
The resulting damage could lead to catastrophic engine failure or, in extreme circumstances, jeopardize the structural integrity of the engine.
"Because (I’ve) only invested … $200 in a drone, I might not really care what's happening. But the implications are absolutely drastic," Bayandor said. "The drone will be sucked in if it's anywhere near the effective intake area of the engine."
Now, Bayandor and his team are turning their attention to how to lessen the danger posed by drones.
"The research question is, can we do research that will reduce the possibility of this happening?" O'Brien said. "Can we categorize the kind of damage that small and large drones would produce? And I suppose ultimately, can we define how engines could be resistant to this sort of thing?"
VT researchers are not alone in looking at this problem. The FAA is working on new comprehensive regulations to govern the use of UAVs. In October, the FAA announced that it will require all UAV owners to register their devices.
"I think the most important step was what the FAA has taken," Bayandor said. "This was something that we had suggested, that the anonymity of drone users can cause a lot of problems because they can do anything without any responsibility."
Engine manufacturers are trying to develop solutions as well. According to a statement provided to the Collegiate Times by GE Aviation, a manufacturer of jet engines, the company has started several initiatives to work on this problem. It has launched an internal program to categorize UAVs and their components to help identify specific threats to engines. The company has also partnered with the FAA and several universities to establish a process for evaluating the threats that different UAVs pose.
However, it appears likely that some of the responsibility will fall on drone operators.
"The burden is going to be on the unmanned aircraft to see and avoid the other airplanes because the pilot is not going to see the drone until it's too late," said Craig Woolsey, professor of aerospace and ocean engineering. "Even if he or she did, they may not be able to maneuver quickly enough to avoid it."
Bayandor hopes that the results of this research and the attention it has received from media outlets such as WSLS and Aerospace America will help. According to him, more awareness of the rules and dangers will keep well-intentioned drone operators from causing problems.
"We try to, by studies like this, bring a little bit of public awareness. (Operators) know that, in their right conscience, they shouldn't do this," Bayandor said. "Hopefully, with public awareness, (impacts) become less and less likely."