Because the weak stray magnetic field interferes with the aircraft's navigation system and control signal, the International Air Transport Association (IATA) lists magnetic goods as class 9 dangerous goods, which must be limited during collection and transportation. Therefore, now some air cargo with magnetic materials need magnetic testing in order to ensure the normal flight of the aircraft. Magnetic materials, audio materials and other instruments containing such magnetic accessories shall be subject to magnetic testing.

Magnet air transport standard

According to the relevant provisions of iata902: if the maximum magnetic field intensity measured 2.1m away from the measured object does not exceed 0.159a/m (20nt, i.e. equal to 2mgs = 0.002gs), the article is not limited as a magnetic material and can be treated as a common goods.

If the maximum magnetic field intensity measured 2.1m away from the tested object exceeds 0.159a/m, but any magnetic field intensity 4.6m away from the surface of the tested object is less than 0.418a/m, the goods can be collected and transported as dangerous goods.

If any magnetic field intensity 4.6m away from the surface of the tested object is greater than 0.418a/m, the object is strictly prohibited from air transportation.

How to meet air transportation standards:

In order to meet the above air transportation requirements, it is necessary to demagnetize the magnets transported by air. Although it is called demagnetization, it is not demagnetizing the magnets, but through special shielding packaging to make the magnetism displayed on the package meet the specified requirements for safe air transportation. Shielding packaging generally uses high magnetic conductivity materials, such as cold rolled sheet, galvanized sheet, etc. if the amount of magnetic materials is large, it should be packaged in several layers. The permeability of high magnetic conductivity materials is very high. According to the Faraday cage principle, the magnetic field mainly circulates in the box after packaging, and there is little leakage. The shielded outer packaging is packaged in cartons or wooden boxes.

Packing matters needing attention during air transportation:

1. For instruments such as magnetron and illuminance meter, the opposite magnetic poles of the device must be placed relative to each other.

2. Permanent magnet materials must be equipped with magnetic armature or shielded to prevent compass instrument deviation

3. Each package of magnetic materials must be correctly marked and labeled in accordance with Chapter VII of the IATA Dangerous Goods rules

4. Ensure that the magnetic field strength measured 4.6m (15 feet) from the surface of the package does not exceed 0.418a/m (0.00525 Gauss) before shipment

5. It is recommended to pack large pieces in wooden cases