The Hawker Siddeley HS 121 Trident (originally the de Havilland D.H.121 and the Airco DH 121) was a British short- (and later medium-) range airliner. It was the first T-tail rear-engined three-engined jet airliner to be designed. It was also the first airliner to make a blind landing in revenue service in 1965. Many countries use it and Trident services ended in China in the early 1990s.
Photos here are company public domain release.