[Takahashi, Sato, Horiuchi]

1. Inspected inside the cup of BF wiith a fiber scope. The FR was around center height. The yaw picomotor is in the CCW side.
2. Lifted up the F0 keystone. The BF was released from the bottom stopper of 75mm by 1mm at the F0 height of -13mm. The keystones of F1, F3 and BF went to free, but the keystone of F2 was in upper limit (the same status in O3).
3. Exchanged the stoppers (short/long M8 screws) for F0 keystone. Put the top plate with the yaw FR on the F0 keystone.
4. Replaced the side stoppers for BF from the old type to the IX/IY type.
5. The F0 was overloaded. The compression for all GAS blades was decreased to 13mm, but the F0 did not go to free.