Page 27 - Oct24

Models C90 and E90 right subpanel
groups: “Subpanel Feeders.” When an operator wants to designate a particular one of these four, he must say, “The far left one” or “The second one from the right,” etc.
In the 100 series, however, to keep following the loop concept, the four breakers are now labeled from left to right: LH #1, RH #1, LH #2, and RH #2. The first and third of these are the first and second feeders for the LH Loop, and the second and fourth are the first and second feeders for the RH Loop. The first feeder for both loops comes from the left main bus and the second feeder comes from the right main bus. Until this unusual CB labeling is explained and understood correctly, it can be very confusing: How come a CB labeled “RH” originates from the left main bus?! However, clarity is achieved when it is recognized that the LH and RH labels refer to the loops being fed whereas the #1 and #2 labels refer to the source side.
To let you in on a surprising and weird little piece of design sadism that took place, guess which subpanel
CB has the branch going to the left fuel panel? The correct answer is RH #1. Vice versa, the LH #2 CB feeds the right fuel panel! Although this is not as crazy as it first seems when one associates the #1 label with the left side and the #2 label with the right side, the designer could just as easily have used LH #1 to feed the left fuel panel and RH #2 to feed the right fuel panel. The labeling mismatch would have been avoided. Oh well.
200 Series
In 1972, Beech started working on the first Super King Air, the wonderful model 200 that has become the bestselling of all the King Air models. In addition to the obvious improvements of more power, more fuel, a longer wingspan and more pressurization capability, the engineers were also tasked with improving all systems and making the airplane more maintenance- friendly.
One system improvement was eliminating the fuel panel bus weakness of the 90 and 100 series. Namely, the items were not dual-fed for redundancy but received power from a single subpanel feeder CB. To correct this, Beech went from two to four subpanel buses, with the names of, not surprisingly, Dual Fed Bus #1, Dual Fed Bus #2, Dual
Fed Bus #3 and Dual Fed Bus #4. To keep the left-right thing as logical as possible, all left-side items are now associated with an odd-numbered bus and all right-side items with an even-numbered bus. Dual Fed Buses #1 and #2 have all of their CBs and/or CB-switches on the cockpit’s right sidewall or on the instrument subpanels; #3 and #4, however, are exclusively located on the left sidewall, where the fuel panel is located. Unlike in the past, the CBs on the left sidewall would include some items not associated with the fuel system, flaps and ignition, for
example.
Models C90 and E90 right sidewall
OCTOBER 2024
KING AIR MAGAZINE • 25