The People’s Liberation Army announced last week that their J-20 fighter aircraft has begun operational service. This is significant as apparently it is their first fifth-generation fighter. While the aircraft’s performance looks spectacular in airshow demonstrations it is unclear how ‘stealthy’ it really is.

Watch a pair of Chinese J-20’s in Action

The forward-mounted canards, poorly shielded engines and underside vertical stabilizers all limit the amount that its radar cross section — which determines how visible the aircraft is to a radar — can be reduced,” Justin Bronk, a research fellow at the Royal United Services Institute in London, has written.