叛逃飞行员说的

https://content.time.com/time/subscriber/article/0,33009,946651,00.html

Belenko told his American interrogators that at 80,000 ft. his jet could fly safely at only Mach 2.8 (1,850 m.p.h.), rather than the Mach 3.2 of prototype MIG-25s. Even at Mach 2.8, he complained, his engines overheated and the four air-to-air missiles slung under the wings vibrated dangerously.