Empty CG question...

[pmccand]

All right shortwingers... here's a headscratcher for y'all.

When an I/A mechanic measures the empty weight and calculates the new CG after adding equipment, is he supposed to make the weight measurements with full oil (2 gallons) and unuseable fuel in the tanks?

The Piper Type Specification Data Sheets state for the PA-22 105 reads: "2 gallons oil at -29 (arm)"

The main question is:
As a pilot making weight/balance calculations with FULL (2 gallons) oil in the crank case, do I disregard the oil corrections listed in the TSDS in my W/B calculations because I am assuming that it has already been included in the empty data, or should I add the data for oil as listed in the TSDS anyway?

[Kenneth Aasand]

If I remember correctly and I may just go back and look. Aircraft certified under CAR 3. are weighed with no oil. On my orginal W&B for my colt and I believe my tripacer is the same way the plane was measured with oil but then the actual empty weight was calculated by mathmatically subtracting the oil weight.
So when I did a weight and balance I had to add the oil back in.
I believe Planes certified under the FAR's are weighed with full oil.
The real trick and the FAA has put this out in an advisory circular on weight and balance is that when a plane is measured the measurments need to be repeatable, that is you need to have a listing of all installed equipment including the flight manual on board as well as if you are measureing the plane with full oil or no oil etc.
So to answer your question you should at time of weighing have a listing of what is installed. And if the plane was weighed with or with out oil. With out this info I would go the most conservative route and add the oil in each time you do a weight and balance.

[Kenneth Aasand]

Phil
Look at FAA handbook FAA-H-8083-1A page 3-2. You can get the handbook online

[pmccand]

Kenneth

That's what I thought...CAR 3 vs FAR's. I am assuming that the mechanic who did the repairs that he had NO idea that the W/B was anything different than current FAR's. There is no note in the WB sheet, nor would I expect one if it was done per current FAR specs. Everyone would assume that full oil is calculated in the empty WB...

hmmmm.

Phil