HB 6129 is the Chinese aviation industry standard that specifies the lightning protection requirements for aircraft and the test methods by which compliance is demonstrated. It belongs to the same family of documents as the international guidance developed for certification of transport aircraft, but it is written for the Chinese aviation industry and is applied in the qualification of domestic aircraft and of equipment supplied to them. The standard separates the direct effects of a lightning attachment, in which the discharge current enters and leaves the airframe and must be conducted through the structure without igniting fuel vapour, damaging the composite material of the skin or disabling a critical system, from the indirect effects, in which the electromagnetic field of the stroke induces transients in the aircraft wiring that reach the equipment connected to it. For each it defines the threat levels, the test waveforms and the test configurations, and it states the criteria by which the protection is judged adequate.