Review of structure of avionics and essential bus

Previous posts

https://webuildplanes.com/adam-dickson-sling2/p/7175/review-of-master-and-alternator-bus-breakers

and

https://webuildplanes.com/adam-dickson-sling2/p/7174/review-of-standby-bus-breaker-ratings

outline the structure and current draw of the essential and avionics bus

In more detail there is an essential bus, which can be switched between the main bus and the IBBS battery output.

On this bus there are currently two breakers

EFIS - which then feeds the (main) EFIS toggle switch

AVNCS - which then feeds the AVNCS toggle switch

On the switches side of the AVNCS toggle switch are currently the following CBs

• comms
• xponder
• flarm
• backup efis
• flaps
• cabin light
• trim
• headset

Clearly some of these items are no longer avionics but nonetheless essential

So these CBs will be redeployed as follows:

The main bus will feed the following circuit breakers

• REG - regulator
• BK CHG - IBBS charge input
• START - start solenoid
• TAXI LT - taxi lights
• LDG LT - landing lights
• AP - autopilot servos
• BOOST - boost pump
• STROBE - strobe lights
• NAV LT - navigation lights
• USB - USB/camera power supplies

The "essential" bus, which can be switched between the main bus and the IBBS battery output, will have multiple breakers:

• EFIS - which then feeds the (main) EFIS toggle switch
• AVNCS - which then feeds the AVNCS toggle switch
• FLAPS - flaps
• CB - cabin light
• TRIM - trim

The switched side of the AVNCS toggle switch will now power the "avionics" bus, on which the following circuit breakers will reside

• COM - com radio
• XPNDR - transponder/ads-b in
• FLARM- flarm
• BK EFIS - backup efis
• HDST -headset

There is of course two remaining CBs

• BK OUT - output of IBBS backup
• MAIN BUS - feed to main bus from firewall forward