Page 23 - Volume 13 Number 5

Ask the Expert
King Air Crossfeed Basics
by Tom Clements
My aim in writing this article is not to present anything new but rather to simply review some of the fuel system information that you should have already received. I am sure the fuel system was covered extensively in your initial King Air training course and, if you have been flying King Airs for a while now, I am sure it has been reviewed in some or all of your recurrent training courses.
Regardless of the particular King Air model you operate, three things must exist for fuel crossfeed to take place. Before I present those three things, let’s remember this important fact: Fuel never flows from a tank on one side to a tank on the other side ... unless we do something wrong and unusual. The term is not
“CrossFLOW.” We are not flowing fuel from tank(s) on one side to tank(s) on the other side. The correct term is “CrossFEED,” since we are taking fuel from a tank on one side and feeding it to the operating ENGINE on the other side. (Sadly, I believe the switch we will be discussing, in some King Air models is, in fact, labeled “Crossflow.” That’s a demerit for the Beech switch labelers!) Additionally, never say “transfer” when you mean “Crossfeed.” In a King Air, transfer refers to moving fuel from the auxiliary tank into the main tank on the same side.
Back to the three things we need for crossfeed. They are: (1) An operating electric boost pump on the feeding side, (2) An open crossfeed line and (3) No opposing electric boost pump pressure on the receiving side.
King Air 350 fuel panel.
MAY 2019
KING AIR MAGAZINE • 21