"Fourth failure, serial 7L
November 23, 1972: serial number 7L – regular
Soyuz 7K-LOK (Soyuz 7K-LOK No.1) and dummy
LK module-spacecraft for Moon flyby
The start and lift-off went well. At T+90 seconds, a programmed shutdown of the core propulsion system (the six center engines) was performed to
reduce structural stress on the booster. Because of excessive dynamic loads caused by a
hydraulic shock wave when the six engines were shut down abruptly, lines for feeding fuel and oxidizer to the core propulsion system burst and a fire started in the boattail of the booster; in addition, the #4 engine exploded. The first stage broke up starting at T+107 seconds and all telemetry data ceased at T+110 seconds. The launch escape system activated and pulled the Soyuz 7K-LOK to safety. The upper stages were ejected from the stack and crashed into the steppe. An investigation revealed that the abrupt shutdown of the engines led to fluctuations in the fluid columns of the feeder pipes, which ruptured and spilled fuel and oxidizer onto the shut down, but still hot, engines. A failure of the #4 engine turbopump was also suspected. It was believed that the launch could have been salvaged had ground controllers sent a manual command to jettison the first stage and begin second stage burn early as the stage failed only 15 seconds before it was due to separate at T+125 seconds and it had reached the nominal burn time of 110 seconds according to the cyclogram.
[58][59][60]"
When I read that, it screams to me, "worked pretty well"