A lot of information at these links below.
http://www.xbow.com/Support/appnotes.aspx
http://www.xbow.com/Support/Support_...tification.pdf
http://www.xbow.com/Support/Support_...ion_Manual.pdf
3.5 CRM500GA-[] Alignment with the aircraft
The CRM500GA-[] must be level on the yaw and roll planes of rotation
when the aircraft is in straight and level flight. The pitch axis must be level
to the aircraft when aircraft is leveled for weight and balance measurements.
The CRM500GA-[] will measure gravity and the earth magnetic field
vector along the axes of its sensors. The CRM500GA-[] sensors are aligned
with the baseplate. The baseplate references are noted in the installation
drawing and are used as reference surfaces for aligning the CRM500GA-[]
sensor axes with the aircraft. The CRM500GA-[] should be aligned as
closely as possible with the axes you define in your system. Errors in
alignment will contribute directly to errors in measured earth magnetic field
vector relative to your system axes.
It is important that the CRM500GA-[] be aligned carefully with the
longitudinal axis of the aircraft and NOT with the outer skin of the fuselage.