Magnets and airplanes do not mix easily — a stray magnetic field can disturb a plane's navigation. So air-freight treats magnetic materials as restricted cargo: under IATA rules, magnetized parts are Class 9 dangerous goods, measured before they are accepted.
Two measurements decide everything
Whether your package flies depends on the field it produces at two distances. Three outcomes are possible:
- Below the limit at 2.1 m — ordinary cargo, no restrictions.
- Above the 2.1 m limit but below at 4.6 m — accepted as restricted Class 9 dangerous goods.
- Still too strong at 4.6 m — refused by air; use sea or ground freight.
The limits are tiny because a magnet's field fades quickly with distance. A strong NdFeB block easily trips the limit on its own, yet the same block inside good shielding passes — packaging is what makes the difference.
Shielding, not demagnetizing
Freight people sometimes call it "degaussing", but no magnetization is removed. The fix is a steel shielding box that channels the field to circulate inside, so little leaks out. Large consignments need several layers.
If your product must arrive magnetized — a rotor, a sensor ring — reject any "solution" that demagnetizes it. Shielding meets the limit without touching the magnetization.
The magnetic inspection report
Airlines require a magnetic inspection report before accepting magnetic cargo, issued by a civil-aviation-accredited agency. The inspector measures all six faces of each package without opening it — packaging must be final before testing. Reports are valid for the calendar year.
Practical notes
- Domestic express carriers usually route magnetic packages by ground; international couriers require the inspection report.
- Sea and ground freight have no field limits — the simplest route for large consignments.
- Measure the shielded package before booking and label the carton as magnetic material.
Read on: shipping magnets: packaging and logistics → · magnet safety basics →