Aircraft launch under their own power using a ski-jump to assist take-off (rather than using a catapult like most carriers). However, these are conventional, rather than STOVL aircraft, and thus require arrestor wires to land on the ship. The STOBAR system is simpler to build than CATOBAR — but it works only with light, and lightly armed, fighter aircraft that have a high thrust to weight ratio. As of 2013, it has only been used regularly on Russian and Chinese carriers. Electromagnetic Aircraft Launch Systems have been proposed for STOBAR operations.