When shutting down the Longitude, when I turn off the second (final) battery, I get an audible “GPWS System Failure” alert. What is the root cause, seems like I could be missing something in the orderly shutdown. I don’t think the order of turning off the batteries affects this issue.
Asked ChatGPT and it said try to turn off the avionics before turning off the batteries. That should help
No avionics button on the C700, powering up/down avionics is automated with that aircraft I believe.
I believe the root cause is that I was not waiting the required 3 minutes per the checklist after engine shutdown and APU shutdown and such, before shutting off the batteries. When following that guidance, I do not get the audible message.
Well, afraid this was not the solution, it is recurring. Anyone else getting an audible “GPWS System Failure” when turning off Bat 1 at time of shutdown on the Longitude?
I too started having this issue when shutting down the C700. I didn’t have it in the past, but started using a more complete checklist and the issue suddenly appeared. In the past I had never touched the STBY PWR Switch, so it was on throughout my flight and at shutdown. I tried a couple of things, but finally found what worked for me. I now do all the normal shutdown items, but leave the STBY PWR Switch on at shutdown. I then turn off the right battery, wait a few seconds and turn off the left battery. The GPWS warning is no longer voiced. Hope this helps someone else.
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Just flew a leg from EWR to DAY in the C700, My fix above still works. I’ve edited my shutdown checklist to leave the STBY PWR on until the batteries are both off. This seems to be the answer. I haven’t tried reversing the order of shutting down batteries. If anyone wants to try shutting off the left battery first, let me know if this makes any difference. I haven’t bothered to try that. Just happy I no longer have to hear the warning message at shutdown!
I continued to have this problem, despite my above “fix”; I experimented a bit more over the last couple of flights and have refined my approach and it seems to work.
After coming to a stop at my parking spot, I do the following:
Throttles to idle
Parking brakes set
Engine Run/Stop buttons off
Emer LTS Switch to off
STBY PWR Switch to “Off”, then momentarily to Test (New Add)
APU Knob to off if needed (I usually don’t have this on during landing)
Exterior Lights, Seat Belt Light, and Safety Switch to Off
Right Battery Off, then Left Battery Off
This seems to work for me. Before modifying the STBY PWR Switch to “Off, then Test”, I continued to often get the GPSW Failure Warning. Adding the momentary test position, I no longer get the warning. This change seems to work for me. I’d like to hear what other people see. Thanks!
Just flew another C700 flight (DAY to TYS) No GPWS warning on shutdown using this sequence. Let me know if this works for others!