I am installing a new ACK 406 ELT and was concerned about where to connect the wiring to ships power - the main bus, e-bus or the battery bus. So I contacted ACK as to what the purpose of this connection is anyway. Turns out that the ELT requires ships power to keep the circuits alive that process the GPS data. If the ELT loses ships power, then it will no longer process the GPS data even though the GPS is actively sending the signal.
This is a bit of a conundrum, as it is easy to envision an emergency situation where the master gets shut off well before the crash (think electrical fire). If I connect the ELT power to the main bus, then the GPS advantage is potentially lost as the ELT will not send GPS position if the master was shut off more than a minute before the crash. (edited)
I could connect the ELT to the battery bus, however this connection pulls 40 mA, and to my simple electrical mind this will kill my little 17 Ah battery in less than a couple weeks. Can somebody confirm this?
One option is to use a DP switch for my Magneto, and have one side also switch the power on from the battery bus to the ELT. Concept is to leave the mag live all the way through the crash.
Alternatively I coiuld put in a separate switch for the ELT power, and put it on the startup/runup/shutdown checklists.
Any other ideas?
I have heard all the arguments regarding whether ELTs are worthwhile or not - don't want to rehash that stuff again. Given the ELT is required I intend to make the most of whatever limited value it has.
This is a bit of a conundrum, as it is easy to envision an emergency situation where the master gets shut off well before the crash (think electrical fire). If I connect the ELT power to the main bus, then the GPS advantage is potentially lost as the ELT will not send GPS position if the master was shut off more than a minute before the crash. (edited)
I could connect the ELT to the battery bus, however this connection pulls 40 mA, and to my simple electrical mind this will kill my little 17 Ah battery in less than a couple weeks. Can somebody confirm this?
One option is to use a DP switch for my Magneto, and have one side also switch the power on from the battery bus to the ELT. Concept is to leave the mag live all the way through the crash.
Alternatively I coiuld put in a separate switch for the ELT power, and put it on the startup/runup/shutdown checklists.
Any other ideas?
I have heard all the arguments regarding whether ELTs are worthwhile or not - don't want to rehash that stuff again. Given the ELT is required I intend to make the most of whatever limited value it has.
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