ACR Electronics Issued ELT System SB (Service Bulletin) SB1000, on January 14, 2019. This was followed up by an FAA SAIB (Special Airworthiness Information Bulletin) on June 18, 2019 and an EASA AD (Airworthiness Directive) on September 21, 2019. All of these Notices call for the replacement of the original non-hermetically sealed G-Switch on an ARTEX ELT with an updated hermetically sealed G-Switch.
The issue behind all these notice is an airworthiness concern about the ELT not transmitting its alert and distress location signals in the case of an accident, due to a non-functioning G-switch. ELTs located in high vibration environments, such as the tail of a helicopter, could have its acceleration sensor deteriorate after having been subjected to high levels of shock and vibration. All notices recommend replacing the ELT’s G-Swtiches or decreasing the inspection intervals. They are applicable to the following ARTX ELT models and part numbers.
| ELT Model | Part Number |
| G406-4 | 453-2012 |
| C406-1 | 453-5002 |
| C406-1HM | 453-5003 |
| C406-2 | 453-5000 |
| C406-2HM | 453-5001 |
| C406-N | 453-5060 |
| C406-NHM | 453-5061 |
If you do not elect to replace the ELT G-Switch, it is recommended to follow a revised shorter inspection interval as follows.
| ELT in service: | Inspection interval: |
| Between 5-7 years | Every 4 months |
| Between 7-9 years | Every 3 months |
| More than 10 years | Must have G-Switch replaced |
Duncan Aviation is currently the only Authorized Service Facility in the continental USA, other than the OEM, with the capability to work on ARTEX ELTs.
ACR Electronics considers this to be a Mandatory SB on all applicable units. Therefore we do as well. If you send your unit to us for reprogramming or repairs, we will comply with SB1000. A SB1000 identification label will be placed on the ELT stating the month and year in which the g-switch was replaced.
For more information, contact a Duncan Aviation Components Customer Account Rep at +1 402.475.2611