Bonanza fuel limitations?
 

So I'm safety piloting for a friend today who needs some approach currency. She brought an old (70-something) V-tail Bonanza. On the fuel tanks, the caution area is a good 1/3 tank or so with the annotation "do not take off...etc" next to it.

What's that limitation for? 1/3 tanks seems like quite a bit if you just wanted to go do a local hop, say touch and gos or hop over to another airport to grab lunch. FWIW, the aircraft has 80 gallon tanks I believe, so we'd still be looking at 27 or so gallons. I can't imagine there's anything in the tank design that would be dangerous about taking off with 20+ gallons of fuel onboard.

And no, it's not in the yellow, it's damn near full of fuel. :p

Perhaps it's a precautionary measure where an acceleration with abrupt turns (take off with corrections for gusting winds) could cause momentary fuel starvation by pushing fuel to the back and sides of the tanks. That's just my guess. But whatever it may be.. Heed to the placards!

On second thought that would make flight through turbulence a problem too :o

Never mind!!

Hey your guess is as good as mine. I was going to dig around in the POH while she did some approaches but ended up being much more involved that I thought I would be.

By that, I mean I was watching to make sure I survived a couple of the ILSes/LPVs that took us low...AR if you're reading this I'm sorry, just the truth!

Might have something to do with the type of fuel system, being how it is not a gravity feed like a Cessna. At least it doesn't have a wobble pump like some much older V tails.

The caution area is 13 gallons per side. And yes, it is due to the high pitch angles that sometimes accompany a take off. Below that fuel level, continued fuel supply to the engines can't be assured. Word of warning, if you take off near that level, and make a bunch of traffic patters, you can end up with a fuel imbalance, and with that level of fuel it can create a very real problem. :)

No baffles and unporting. There is also something about making quick turns while taxiing, like clearing the runway after landing. LH tank selected, RH turn can result in unporting and no engine.

FWIW I've flow Bonanzas, Barons, and King Airs, and they all have a min fuel limitaion. You takeoff in the yellow and bend the plane, it isn't Beech's fault. They can wash their hands right off the bat.

I hope you weren't really planning on reading the POH while acting as safety pilot.

Please get off the high horse. It takes all of 30 seconds to flip open the POH and reference something. I'm sure the entire time you're CFI'ing you never take your attention off of traffic scanning and cross checking instruments at the same time, but some of us are not so perfect.

Ah that's what I was looking for. Lack of baffles would do it.

Prior to this job I was flying King Airs and again, knew the limitation, but not the exact reason why (though I remember Beech in the AFM being very explicit about there being no exceptions).

Thanks guys.

If it only takes 30 seconds, why not do it on the ground while they are preflighting?

I'm sorry you think caring about the safety of the people paying you (or expecting you, in the case of a safety pilot) to ensure their safety is being on a "high horse". Obviously, I can't be looking for traffic 100% of the time, but to purposely plan on reading a POH while the other pilot is under the hood is reckless at best.

Having had a few near misses, I realize the importance of looking for traffic.

If my CFI started reading a book while I was under the hood, the hood would come off and it would be their last flight with me.