Electrostatic charging of the NH90 helicopter

This article discusses electrostatic charging of the NH90 medium transport/utility helicopter and assesses the safety of transported products against electrostatic discharges originated from the helicopter. Key questions were to determine charging characteristics of the composite material body NH90 compared to metal body helicopters as well as the charging levels in typical operating situations and climate conditions in Northern Europe. Most attention was paid to a situation where a load was winched to ground from a levitating helicopter at 40–80 feet altitudes. The measurements were supported with a simplified numeric simulation model and calculations of the charging of the helicopter. According to the study, there is no significant difference in electrostatic charging characteristics between composite body NH90 helicopter and metal body helicopters. The tight grounding net of the NH90 helicopter enables the charge currents to discharge in the same manner as in metal body helicopters. In all measured situations, the electrostatic charging of the NH90 or a person moving inside the helicopter is under the transport requirements depicted in the standard STANAG 4235.