This is a document only for Carenado C90 King Air. Do not attempt a real flight based on this document. You should always use certified and official documents.
Every Pilot’s Operating Handbook (POH) for the various King Air models contains a prohibition against using Aviation Fuel crossfeed except when one engine is inoperative. In the case of the A90, B90, and C90 variants, the POH also allows crossfeed when one side’s boost pump is inoperative.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. Why can’t we do this? Why are we prevented from taking advantage of this desirable option in these two cases?The crossfeed prohibition did not exist until after the POHs got revised in the mid- and late-1970s. Prior to that, pilots could and did use crossfeed as needed to correct a fueling imbalance.
The case of a major tank leak is so rare – and probably only of great concern when far from land on an oceanic ferry flight – that I will not address it again in this discussion.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 side’s fuel supply can physically be done, even during periods of maximum fuel flow. Knowing this, it is apparent that the crossfeed limitation did not originate with the engineering designers; instead it came from Beech’s legal team.In June 1974, a Beechcraft BE95 Travel Air – the 180 horsepower Lycoming-powered predecessor to the Baron – experienced fuel starvation to both engines, crashed, caught fire, and killed the four occupants. Investigation revealed that both engines had been drawing fuel from the same tank on one side, the exhaustion of which led to the double engine failure.
The fuel selectors were positioned properly for this crossfeed situation. The pilot never repositioned the fuel selectors such that he could feed the engines from the existing fuel in the other tanks.Although most aviation-savvy people thought this was an obvious case of pilot error, a jury trial found Beech to be liable for a “Failure to Warn.” Huh?