Navigation is key in aviation. Pilots must have confidence that their aircraft compass is working accurately. Aviation maintenance technicians often use the Barfield 101-01200 Sight Compass to verify aircraft compass readings. The Barfield 101-01200 Sight Compass, sometimes referred to as the Barfield SC063 Sight Compass, may show errors from time to time. To identify errors, and take steps to prevent them, aviation maintenance professionals be aware of possible causes. Keep reading to learn about Barfield 101-01200 Sight Compass calibration and troubleshooting.
Sight compass errors cause a disparity between Sight Compass North and True North. This can occur from compass deviation and/or variation. The difference between the true direction (in relation to the geographical North Pole) and the direction shown on an undisturbed compass is referred to as the variance. The difference between the actual magnetic heading of an aircraft and the compass reading for the aircraft heading is referred to as the deviation.
Hard Magnetic Parts
Magnetism from unexpected sources can create errors in compass readings. Hard magnetic parts, or hard iron, refers to aircraft parts that have permanent, constant magnetism. This error can be remedied during the compass swing procedure. In this instance, the aviation professional may use a compensating magnet. This method will work as long as magnetism does not change.
Soft Magnetic Parts
Soft magnetic parts, or soft iron parts, have variable magnetism. The effect of the magnets will change the magnetism of soft magnetic parts. This type of magnetism will cause sight compass deviation. In this scenario, it is not possible to use a compensating magnet. The sight compass should not be used in a location that is near soft magnetic parts.
When the time comes for annual Barfield 101-01200 Sight Compass calibration, let your ISO/IEC 17025 accredited calibration laboratory know if you are using compensating weights or are experiencing unexplained sight compass deviation or variation.