I know that YOU know this, Eric, but just to keep things in perspective: There are two reasons to pay for any STC. 1- You don't have to go to all the expense of engineering data acquisition, extensive testing (and subjecting your airplane to that testing, or pay for all the fuel and aircraft engine time to perform those tests) and liabilities without insurance while your airplane is on an experimental certificate and; 2- you are assured of getting all the necessary operating information to use the modification safely (whether or not you actually perform the necessary precautions, ...with the STC purchase at least you are assured of having the data available to you.) Without an STC, you are merely riding along in an experiment with your own airplane, whether or not the modification has been performed on other airplanes seemingly identical.zero.one.victor wrote: Why do we have to pay $145 for a cargas STC for our 170's to make cargas use legal? The airplane doesn't know if I have the paperwork or not. Same kind of deal.
Eric
The legal option available to you otherwise is to submit for a "field approval", which I dare say for most owners will likely end up costing the same $145 for all the time, trouble, and Form 337 submission fees from an IA. (I know, I know, ...the counter-argument is that the IA will spend the same amount of time filling out the STC paperwork as he will a 337-field approval, but that is not correct. Try it. If you have an IA apply for field approval, he will have to submit either approved data (from an existing engineering study...which will cost you) or acceptable data (from an airplane already approved for the identical mod. This is not possible since field approvals have not been made for autogas useage....only STC's....which means you'd be copying an STC and then the FAA will deny the field approval because it is essentially copying an existing STC that you should be purchasing, a-la patent infringement.)
And that's why not only is it fair to pay an STC holder for his work product and his liability exposure, but also it's usually the less expensive route to go anyway.