Page 16 - April 25

T O A D V E R T I S E M A G A Z I N E I N K I N G C O N T A C T :
J E N N A A D V E R T I S I N G R E I D ,
D I R E C T O R
J E N N A . R E I D @ V P D C S . C O M
8 1 6 - 6 9 9 - 8 6 3 4
A I R
So, how do we check them? On the ground with
battery power or with a ground power cart hooked
up to the plane, we are going to pull the 50a circuit
breakers one by one and see if we have any dual-fed
bus failures with only one CB pulled.
Let’s walk through the procedure using Dual Fed
Bus #1 as an example. The CBs for Dual Fed Bus
#1 are on the right-side CB panel, along with Dual
Fed Bus #2 (Dual Fed Bus #3 & # 4 are on the fuel
panel CB). First, turn on the battery; ground power
helps but is not required. Pull one of the No. 1 CBs.
Dual Fed Bus #1 items should still be powered; if
not, the current limiter on the opposite side has
failed. Assuming pulling the first CB has had no
effect on Dual Fed Bus #1 items, pull the second
No.1 CB on the right-side CB panel. All Dual Fed
Bus #1 items should go dead, this verifies that the
CBs are disconnecting power from the #1 bus.
Third, reset the first Dual Fed Bus #1 CB and power
should be restored to the #1 bus. If power is not
restored the opposite side current limiter has failed
and will need to be replaced. Repeat the process
for the remaining three dual-fed buses to check all
the 60a current limiters and CBs.
As you can see, protecting our current limiter
during start is not a difficult thing to do. Using a
generator-assist type start will protect the 325a
current limiters in all dual-fed style King Airs.
Occasionally checking the 60a current limiters
protecting our dual-fed buses is a good way to check
that our dual-fed buses are actually dual fed! KA
Zach Cleaver, a Gold Seal flight instructor since 2009, started
teaching in King Airs in 2010. He has worked for King Air
Academy in Phoenix, Arizona, since 2013 and flies all models of
King Airs.
6
26
18
14 •
­ KING AIR MAGAZINE APRIL 2025