TB 9-5210-213-40
observed on the TI vial with the surface plate leveling screws. Rotate the TI 180 and again
remove one half the error with the surface plate leveling screws. Repeat this technique till
no further improvement can be seen.
(5) When the TI can be rotated 180 and there is no apparent change in the position
of the bubble and it is in the center area of the vial, the TI is correctly adjusted.
b. Adjustments
(1) Rotate the TI so that it indicates the greatest error in magnitude and remove the
screw dust cover from over the main vial adjustment screw.
(2) Adjust the vial with this screw to remove one half the difference between the two
readings. Again rotate the TI 180 and note the reading; then, rotate TI again and remove
one half the difference with the vial adjustment screw. Repeat this technique until no
further improvement can be seen then proceed to 8 a (4) above.
9. Final Procedure
a. Replace dust cap over vial adjustment screw.
b. Annotate and affix DA label/form in accordance with TB 750-25.