[gvb]

It is interesting and informative to compare SN9 to SN8.

SN8: https://youtu.be/ap-BkkrRg-o?t=6884

SN9: https://youtu.be/_zZ7fIkpBgs?t=704

With SN8, you can clearly see two engines lighting and burning properly until just before it (crash) lands.

With SN9, you can clearly see one engine lighting and burning properly, but the second engine did not light cleanly and did not stay lit.

[zaroth]

I don’t think that’s quite right. With SN8 they ended up with low pressure in the header tank and not enough fuel for the turbo pumps.

A so called “engine-rich” burn resulted, which is why there’s a flash of green flame.

Total thrust was much lower than spec, hence the hard landing even though both engines ignited.