Page 16
VP-X Installation and Operating Manual
Rev. D (August 5, 2020)
Dual Bank technology should be used as a tool to mitigate risk in the case
of a system failure within the VP-X, and not as a tool to mitigate risk of
a larger system failure. Be sure to understand the failure modes you are
solving for. Dual Bank technology provides redundancy if a power supply or
microprocessor in the VP-X itself fails (an extremely rare event). It does not
solve the problem of a failed master switch, battery contactor, or contactor
(main bus) wiring. To solve for these failure modes, install a backup circuit
(Method B or C) as discussed later in this manual.
If you have redundant devices like radios, lights, or displays, then you can
divide those up between Bank A and Bank B so that each bank has one of
each type of device. That way if a VP-X bank fails, the redundant device on
the other bank still has power. Spend some time planning possible failure
modes and divide the devices between the two banks. For example, if you
have two comm radios, put one on each bank. If you have a taxi light and a
landing light, put one on each bank.
ECB
Bank A
ECB
Bank B
Left Landing
Light
Right Landing
Light
Power In
Redundant devices, one on each bank.
Some avionics have two power inputs but each is for a distinct function. Do
not split these power inputs between banks. For example, a Garmin 750
has a nav power and a comm power input. These should be wired to two
separate pins on the same bank.
ECB
Bank A
ECB
Bank B
G750
Power In
Comm Power
Nav Power
Two power inputs to a device should come from the same bank.
If a device has only a single power input, you should use backup Method B
(described later in this manual) to back up this circuit. Do not wire power from
both banks, as this does not provide backup in case of a failure of the battery
contactor or master switch.
ECB
Bank A
ECB
Bank B
Device
Power In
Power Input
Use backup Method B instead of this.
If an avionics device has dual redundant power inputs (most modern EFISs
do), you should use backup Method C (described later in this manual) to
back up this circuit. Do not wire power from both banks, as this does not
provide backup in case of a failure of the battery contactor or master switch.
ECB
Bank A
ECB
Bank B
EFIS
Power In
Primary Power
Backup Power
Use backup Method C instead of this.
