In 2018, an advisory was issued by the G-Switch manufacturer of the ACR Artex C406 series ELTs. The advisory indicated that rotary aircraft using the C406 ELT must replace the non-hermetically sealed G-Switch with an updated, hermetically sealed G-Switch. ACR SB1000 reiterates the guidance issued to ACR by the G-Switch manufacturer directing the testing of original G-Switches and/or replacement at the next service event. SB1000 compliance is only required for rotary-wing aircraft with more than 5 years in service.