Swinging the Compass for the SA Air Force

When flying an aircraft it is mandatory to have a functioning magnetic compass on-board in order to navigate effectively in the event of electronic navigation device failure.  Electrical systems occasionally do fail, while the Earth’s magnetic field never does. Not only that, but your compass must be accurate enough that it won’t lead you astray because of misleading or excessive deviation errors.

To obtain the greatest accuracy from a compass it is important to determine the extent of its deviation errors and eliminate, or at least minimise, them by a process referred to as “swinging the compass”.

The compass swing procedure is necessary to determine how to measure and compensate for the magnetic field of an aircraft, which will cause a deviation to the compass reading once located in the cockpit, due to the proximity of steel or iron components and  by the effects of current flowing in nearby electrical circuits.

The compass swing procedure is executed at predetermined intervals (between 3 months and 3 years, depending on the type of aircraft), or at any time when the magnetic properties of an aircraft have changed.

South African Air Force Avionics staff member conducting a compass swing procedure

The procedure requires an external magnetic reference like a calibrated landing compass, a “magnetically clean environment”; free of steel structures, underground cables, or equipment that produces magnetic fields, to assure it is free of interference, and most importantly you require qualified personnel. SANSA Space Science is one of the only South African organisations that can offer this type of training with the necessary expertise and facilities to perform training in the compass swing procedure on-site.

SANSA Space Science has been presenting training courses on the execution of compass swings to the South African Air Force for more than 15 years and recently hosted a five day Compass Swing Training Course and a three day Compass Swing Refresher Course.  The course is presented by SANSA engineers and physicists who have many years of relevant magnetic navigation ground support experience.

South African Air Force personal during the SANSA Space Science Compass Swing Training Course

Commercial and private users in the aviation industry are required by the South African Civil Aviation Authority (SACAA) to receive training of this nature, meeting certain requirements. As a result the Compass Swing Training Course presented by SANSA was adapted to comply with these requirements and has been approved by the SACAA.

SANSA Space Science has a dedicated compass swing area set up to simulate the procedure  ground support staff would have to perform at the Air Force base before an aircraft is flown.  These courses are well attended and have dramatically increased the technical knowledge of Air Force Ground Support staff members and reduced the maintenance cost of support equipment.

Vaneshree Maharaj