主题：波兰空难：失事飞机实际飞行了五千小时、一千八百次起降 -- leqian

While it's true that the aircraft that crashed was some 20 years old, it had also undergone a complete retrofit in December. According to Aviakor, the Russian company that did the Tu-154 retrofit for the Polish plane, the process involves replacing all 3 engines with updated versions as well as completely gutting and replacing all critical aircraft systems (electrical, mechanical, hydraulic and avionic systems).