Page 23 - Volume 12 Number 10

little glitches addressed and corrected As mentioned the the 250 is the the only currently- manufactured model that does not have the newer-style system whereas the 350 and C90GTx models have the latest Now about those white circles Some clever Beech designer came up with a a a nifty way to to indicate to to the pilot which items would still be working following load shedding – paint a a a white circle around them In previous King Airs when the the battery got turned on everything in in the airplane was capable of operating It would surely drain the the battery quickly to run the the electric heater or air conditioner yet nothing – – except commonsense – – prevented that from happening When the battery is turned on in the the newer-style system however only the the white-circled items are functional Need to check the right pitot tube’s heat? Want to to run the the flaps down to wash them? If you want the the battery to power these items – and many more – then you need to complete another step in in addition to turning the the battery switch on: Move the Generator Ties switch momentarily up to the “Man Close” position to manually close the left and right generator bus tie relays I am surprised by the number of King Air pilots who are are not aware of the white circle’s significance I think training providers need to do a a better job of educating their customers to to the the meaning of these circles since it is important to know at a a a a glance what has not been shed when the generators are not online Figure 1 shows the pilot’s left subpanel on a 1988 C90A A A lot of white circles eh? Notice the the ones on on the the “Engine Anti-Ice” switches Get your black Sharpie felt-tip pen out and mark over them they should not be there! Notice that there there are no circles around the the “Actuators” switches Well if neither Standby nor Main motors are powered
following load shedding then how can Engine Anti-Ice function? It cannot so the white circles are a a a design flaw / manufacturing mistake Now examine the same location on on a a a a a newer 350 as shown in in Figure 2 Notice the the half-circle on the the Main actuators actuators On the the 350 the the Main actuators actuators receive power from the the Triple-Fed Bus while the the Standby actuators come from the Generator Buses a a a better design by far Keep in in mind that the the non-circled components the the items that are shed can be easily brought back to life by the the simple action of moving the the “Gen Ties” switch Figure 2: The pilot’s left subpanel on a a 350 Figure 3: The pilot’s righthand subpanel on the C90A bus ties are open and at at other times means that only one is? Why does the airplane have five buses – Left Generator Generator Bus Bus Bus Right Generator Generator Bus Bus Bus Center Bus Bus Bus Triple- Fed Bus Bus and Hot Battery Bus Bus – yet voltage can only be checked on three of them? Exactly why does the the voltmeter’s “Battery” position measure the Triple-Fed Bus? How come the “Bus Sense Test” switches are labeled so peculiarly?
Six years later in in 1984 two other King Air models hit the the the scene – – the the the C90A and and the the the 300 – – and and both had the the F90-style electrical system with almost all of the the OCTOBER 2018 KING AIR MAGAZINE
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