Is oil counted weight?

[Jim Hann]

To throw a little more mud on the subject. Just weighed my Pacer. The form I used contains the EMPTY WEIGHT and the BASIC EMPTY WEIGHT along with the AIRCRAFT AS WEIGHED number. Because we had no good way to drain the airplane (i.e. I'm not throwing 20 gallons of gas away) we topped it off, verified the capacity with the dipstick, and weighed it that way. I also did not have full oil, so that was mathematically corrected also.

Everybody confused now?

Oh, and the FAA does define BASIC EMPTY WEIGHT in their Weight and Balance Handbook FAA H-8083-1A and EMPTY WEIGHT and you'll find that the water just got a little muddier.

Well, I don't know where to start but here goes. There is no CAR 23 certification rules. I think what you mean is CAR Part 3, which was the certification regs for light planes during CAB days. From the CAR Part 3, Subpart B regulations for "empty weight" (not "standard empty weight" or "basic empty weight" because those are not regulatory terms) it states:

§ 3.73 Empty weight. The empty weight and corresponding center of gravity location shall include all fixed ballast, the unusable fuel supply (see § 3.437), undrainable oil, full engine coolant, and hydraulic fluid.

So that means no oil except residual oil.

Under Part 23, full oil is included in the empty weight. The applicable regulation is:

§23.29 Empty weight and corresponding center of gravity.

(a) The empty weight and corresponding center of gravity must be determined by weighing the airplane with—

(1) Fixed ballast;

(2) Unusable fuel determined under §23.959; and

(3) Full operating fluids, including—

(i) Oil;

(ii) Hydraulic fluid;

Hopefully we are in agreement now when oil is and is not included in empty weight.

In CAR 3 airplanes, manufacturers invented a term called "Basic Empty Weight" (or equivalent) which they published in the pilot handbook or owner manual to facilitate weight and balance computations for pilots. The BEW includes full engine oil, but don't confuse that with the FAA term "Aircraft Empty Weight." BEW is not a regulatory term.

The diagram you pasted above (#16) shows how to get "empty weight" when weighing the aircraft with full oil. They use a complicated mathematical operation called "subtraction" where the weight of the oil is subtracted from the scale weight to get empty weight. Empty weight is what goes on the Aircraft Weight and Balance Report.