Be prepared to lose useful load. I’ve helped weigh 3 planes this year, and the best gained 10 pounds and the worst gained nearly 50. I’m convinced the factories lied about empty weights when they came out of the factory. Most of the stuff we install nowadays is much lighter than what came out.
A couple points: if the aircraft must be configured in a certain manner for empty weight and balance it will be stated in the TCDS and/or the OEM manual. If none exist then most follow the W&B Handbook, AC43.13-1B, or other acceptable guidance to configure/perform the actual weight and balance. As to what is residual fluids/draining. Part of the wt/bal process is to level the aircraft. Once leveled drain all needed fluids and what remains is considered residual.
while you’ve got the seats out, scrub the airplane down well, inside and out.
oblivious isn't the word I'd use. I did a thorough scan and removed every little thing that wasn't part of the equipment list.
How much you want to bet they took the stuff out, weighed it, and then put it all back in, with the owner still not adding it into his flight weight?
The quickest way to get a 5-10% price reduction on a pre-buy is to grab the weight/bal report and equipment list and point out the errors. Fortunately while empty weight/bal is one of the most misunderstood features on a aircraft it is one of the easiest to physically correct. Unfortunately I've seen some radical departures from the norm by both mechanics and pilots which in some cases didn't end very well.
Curious, then who? Your only option is an A&P or repair station.
My interpretation is that he won't have it weighed at all.
But they can't change the W&B without an A&P
Airplanes do tend to gain weight over time. Orphaned wiring, a radio or two that wasn’t originally installed, an electrical system.
Unfortunately, in my experience that is the easiest way to throw off the empty CG especially on aircraft with any type of gravity feed header tanks. You can never calculate exact weight/arm/moment of the fuel for a number of reasons. I've always found going through the hassle of draining everything required gave the best results for me and the owner.
FYI: just by going through the weight/bal calculation process over time can alter your empty weight as the "moment" is only a mathematical product and not related to anything physical like weight or arm. As you round off, things change and over time add up which is why certain aircraft require reweighs every 3 years to "reset" the record. Throw in one missed decimal and it can easily add 90 pounds over that length of time.
That definitely can happen.
Yes. Until the next actual weight and balance is performed.
I agree, but its usually close (at least MUCH closer than the old w&b with additions over the years), and if anything, coming out slightly lighter than actual, due to old planes gaining weight, but loosing fuel capacity. Over time tanks have a way of slightly caving in on themselves, and tend to seem to hold more fuel than they actually do.
I’ve found at least a dozen bad ones over the years...bad math on the calculations, bad arms for the scales a couple of times.
Well, aren’t you supposed to not drain the unusable fuel?
