Coming out of maintenance yesterday I only had 150 lbs/side and discussed running them dry to “calibrate” per above. Kip @ IJSC cautioned that running the engine dry is a hard on the mechanical/engine driven fuel pumps.

It was advantageous to taxi across the airport for fuel and was a good test run prior to departure. At shutdown I indicated 189lbs total, nearly an equal split. Took 402 gallons and now indicated 2804 of 2802 lbs total capacity. I didn’t have them try to pump in a few more gallons after shut off. It’s likely I could have gotten 2-5 more gallons in.


If I did the math right, at near empty I think I’m indicating 50-75lbs high/side. Good to know. And I nearly ran them dry.

Interesting exercise!

By my math you probably indicate about 40 lbs high per side, at least when nearing zero. Here’s the math:

Tank capacity is 418.2 gals usable (I believe the desired gauge calibration should read zero when you hit zero usable, not bone dry).

418.2 gals - 402 gals pumped = 16.2 gal x 6.7 lb/gal = 108.5 lbs theoretically should have been indicated as remaining

189 lbs actually indicated - 108.5 lbs = 80.5 lbs difference / 2 = 40 lbs per side (reading at zero usable).

So once you hit 40 lbs per side indicated, you may want to be on the ground by then.

Do you have any sort of crossfeed? That is, can you run a tank dry without the engine running by moving it to the other side?

The best time to check would be a weighing where you drain the plane of fuel, put back unusable, then check what the gauges read. Its useful to do a weighing every now and then as well, sometimes the numbers are surprising if it hasn't been done for a while. Errors in W&B computations by mechanics happen ALL the time.

You really do need to know what "zero" looks like. On my Citation, "zero" showed 200 lbs/side. I can transfer side to side using boost pumps, so I can check this without running an engine dry.

Mike C.

CrossFEED yes, transfer no.

For pilot controls this is true. When in the shop, I am told (don't know exact details) that one of the pump outputs can be attached to a hose to pump to somewhere else (e.g. the other side) to drain a tank.

Oshkosh bound! 365 knots 90 gph and a full boat of guys!

Did warbird arrival. So much fun and less chaotic than the other ones I have done.

Neat, wish I'd known other P180 drivers were going into OSH proper. I'll be landing ATW on Wed morning. We are driving down and will stay for the night airshow, walk around Thursday and go to the SPA corn roast then home Friday. I'd love to meet in person if anyone is still around later in the week.

Anyone know the Avanti that landed at LaCrosse around the B2OSH departure ?

Someone filmed our osh departure - https://youtu.be/vB_HIIxshXM

4:45 mark.

I get 2800 ft ground roll.

Basically, a bit before pink dot to a bit before white dot on runway 27.

Mike C.

Found myself in good company at ATW this morning.

I get 2800 ft ground roll.

Basically, a bit before pink dot to a bit before white dot on runway 27.

Mike C.

Got your arrival. Camp TwinBo is abeam the approach end of 36L.

Does that increase tire wear?

What does that do for runway length required to abort at 120 KIAS? Or do you consider going past 106 KIAS to be committed to flying, like V1 in a jet?

What is Vmc?

Mike C.