Hawker 800A Fuel Questions (LJ60 hourly burns as well)

[fly4kix]

Ultra, would you mind going into a little more detail and explain what your theory is behind that. sounds like you'r eon to something and I'd like ot know more about it. Thanks and I look forward to hearing more.

I think what he's getting at is this, you let the wings burn down, the outboard sections are going to cool faster than the relatively fatter and larger chord inboard section. So now you've only got fuel in the inboard 1/3 or perhaps abit more, now turn on gravity, the warmer(again relatively) fuselage fuel keeps the wing warmer...
I believe the AFM calls for that procedure if it's below -65 ambient??
oddly enough, I don't believe the 55 has that requirement, and I wish I knew if the 31 did as well
I too have heard letting the wings burn down does away with the rumble, but I've experienced it many times both heavy and light

 

[ultrarunner]

Ultra, would you mind going into a little more detail and explain what your theory is behind that. sounds like you'r eon to something and I'd like ot know more about it. Thanks and I look forward to hearing more.

LR, fly4kix pretty much summed it up. And I believe he is correct on the AFM reference. There is a touch more to it than that however. And that has to do with the fuel temp compenstating probe in the left wing.

If that probe get's too cold, all heck breaks loose on the fuel quantity guage, in that it pretty much becomes worthless. By burning wing fuel down to 700 or so before going to gravity, you insure a constant supply of warmer fuselage fuel flowing into the wing, thus keeping that little compensating probe happy. And the fuel quantity guage indicating properly.

There you have it.