Three U.S. Marines died over the weekend when an Osprey aircraft crashed off the east coast of Australia in an incident the Marines are calling a “mishap.”

The exact cause of the crash is still under investigation, but the accident has brought the Osprey aircraft that they were flying back into sharp focus again.

Since it first took to the air in the late 1980s, the Osprey has garnered a reputation of being dangerous and unreliable. Even Navy Pilot Jack McCain, Sen. McCain’s son, said in 2014 that the aircraft was a “piece of junk.”

It looks like a combination of an airplane and a helicopter with propellers that can change position. Set in a vertical setting, the Osprey can land and take off like a helicopter, and the propellers can be rotated forward which allow the aircraft to fly like a plane.

To better understand the Osprey’s capabilities — and limitations — I spoke with Professor Jerry Kidrick at Embry-Riddle Aeronautical University in Prescott.

I started by asking him if the Osprey’s design makes it harder to operate.