Knowing this, it is apparent that the crossfeed limitation did not originate with the engineering designers instead it came from BeechвЂ™s legal team. In fact, all King Air models, including the latest 350 variants, are designed and manufactured with sufficient pump capacity and fuel line capacity that feeding both engines from one sideвЂ™s fuel supply can physically be done, even during periods of maximum fuel flow. The case of a major tank leak is so rare вЂ“ and probably only of great concern when far from land on an oceanic ferry flight вЂ“ that I will not address it again in this discussion. Prior to that, pilots could and did use crossfeed as needed to correct a fueling imbalance. The crossfeed prohibition did not exist until after the POHs got revised in the mid- and late-1970s.

Why canвЂ™t we do this? Why are we prevented from taking advantage of this desirable option in these two cases? This prohibition means that we are not allowed to crossfeed (1) to correct a fueling imbalance, side-to-side, or (2) to consume the remaining fuel as rapidly as possible from a side that has sprung a large leak. In the case of the A90, B90, and C90 variants, the POH also allows crossfeed when one sideвЂ™s boost pump is inoperative. Every PilotвЂ™s Operating Handbook (POH) for the various King Air models contains a prohibition against using Aviation Fuel crossfeed except when one engine is inoperative.

737 800 crossfeed