Precision Compass Compensator

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Part# 10-07900
MFR Model# PBB-475


The vertical card compass is very sensitive to stray magnetic fields within the aircraft. If the compensators of the compass will not bring the compass within tolerances, it will be necessary to install the PBB475 compensator ("balanced balls"). These balls contain magnets which permit the compass to be properly compensated.
Instructions furnished.

Note: These compass compensators are made specifically for the Precision aviation compasses. The mounting holes may not match other compasses.



They work very well help to avoid the deviation of the vertical commas affected for the AC fan motor

Sergio G Verified Purchase


July 22, 2021

good quality did not fix the problem

Richard L
March 18, 2021


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: I have been unable to install a magnetic compass in my tube aircraft due to magnetism. I would like to buy a vertical compass. Will this Compass Compensator negate those magnetic errors?

Per the manufacturer, this should work as long as the magnetic variation is not greater than 20 degrees. It is also recommended to use magnetic shielding with the compass compensator.

Q: How can you use the magnetic shield material on a Vert. Card compass located on top of the dash?

The compass compensator comes with directions for mounting this behind the compass.

Q: Will this work with the Airpath Compass?

This will not connect to the Airpath Compass as the Airpath compass is a different design.

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