You can say goodbye to the quadcopter. That much is obvious. But what about aeroplanes? Passengers on commercial airlines actually have little to worry about, as IEEE Spectrum explains today.
IEEE Spectrum put the drone-airliner crash question to George Morse, founder of Failure Analysis Service Technology, a company that specialises in analysing foreign-object damage to aeroplanes. Morse hasn’t dealt with any drone collisions, but he has investigated a lot of birdstrikes — a lot because it’s an incredibly common problem.
The biggest hazard is when birds, or in this case drones, are sucked whole into an engine. Here’s what Morse has to say to IEEE Spectrum:
The drone will hit the leading edge of the fan blades and would probably break up into small pieces. The fan blade itself is not likely to break, in Morse’s view. “There’s a good chance it will take the engine out at high power,” says Morse, but not necessarily. “It’s absolutely amazing how they will still run.”…But what about the lithium-ion batteries that these little drones carry? Aren’t they hard enough to create real problems for a turbofan engine? “Ice can be hard, too,” says Morse. And as for the worry about the volatile material from a battery ending up in the combustion chamber: “The engine will probably burn it up.”
Even if the drone does take out an engine, the plane is not going to fall out of the sky. Modern airliners are designed to fly even with one engine down. (They usually have two or four.) In cases where birds have taken down planes, such as the US Airways flight that emergency landed on the Hudson in 2009, a whole flock of birds took out all the engines. Quadcopters at least don’t fly around in huge swarms — well, as least not yet.
But today’s drone collision question is a fascinating window into the world of hardcore engine testing. Birdstrikes are a serious enough problem that chickens are sacrificed to the cause. A chicken gun shoots real or simulated birds made of gelatin into engines — often the last step in extensive engine testing process. Here’s Mythbusters shooting some frozen and thawed chickens out of a gun:
But even if drones are unlikely to take down an aeroplane engine, they can still cause expensive damage and delayed flights. And they pose a bigger hazard to smaller planes with smaller engines that may not be able to handle several pounds of plastic or metal. This isn’t an idle problem either. The number of drone sightings by pilots has been creeping up, with 193 sightings in a period of less than a year. Buckle up, guys. [IEEE Spectrum]