Our target zone was 200 meters (656 feet) in diameter, which I could usually strike. Once in about ten times I could hit within 50 meters (164 feet) of the center. We had practice bombs that replicated the size and weight of the actual H-bomb, but made of steel and cement. I dropped practice bombs 200 times.
Then, in late 1970, we had a problem with the H-bomb itself. During a test at the Lop Nor test site, the bomb exploded, but the expected atomic reaction did not occur. The H-bomb had failed; the cause would have to be investigated. My work preparing for the Q-5A for the mission came to a halt. I returned to my unit in Shandong.
The next year, in September 1971, a political event occurred that eventually determined the timing of the H-bomb project. Vice Premier Lin Biao was killed in an airplane crash while trying to flee to the Soviet Union after a failed coup attempt. There had been an upheaval in the PLA, and to raise morale, Chairman Mao Zedong decided that we would drop the H-bomb that year.
The date of the mission was kept secret. Once the date was chosen, and Chairman Mao concurred, all of the personnel at the nuclear site were restricted to base.
The director of the nuclear weapons institute took me aside and privately briefed me on what I could expect when the bomb exploded. He assured me that I would not be in any danger. Because of that and the many practice missions I had flown, I did not feel any differently when I carried the live bomb.
A & S: And on the day of the actual flight?
Yang: On December 30, 1971, weather conditions were good. I took off from the airbase in the late morning and headed toward the target, ground zero at Lop Nor, three hundred kilometers (186 miles) away. I flew at 900 kilometers an hour (559 mph) and an altitude of 300 meters (984 feet), following the procedures we had established. Twelve kilometers (7.5 miles) from the target, I started my 45-degree-angle climb, and exactly at 1,200 meters (3,936 feet) released the bomb.
Nothing happened! The bomb did not separate from the aircraft. The indicators on the panel showed that it was still attached. I turned back toward the target and prepared to do everything again a second time.
We had planned for emergencies. There were three separate release mechanisms, mechanical links to the bomb shackle, of which two were backups in case the first one failed. I tried all three; none worked.
On my second approach I followed the same procedures, and again the bomb failed to release. I turned to try again. I made a third approach, and for the third time the bomb would not release. The situation was now critical. I was running short of fuel.