> just use this off-the-shelf transistor instead" I don't know if it meets the legal definition of fraud, but it will certainly get you in trouble. I imagine

> just use this off-the-shelf transistor instead" I don't know if it meets the legal definition of fraud, but it will certainly get you in trouble. I imagine Aviation is similar to Medical Devices and in that (my) environment, to build a device using a component with a different part than specified in the design, you need at a minimum an evaluation from an EE to see if the suggested replacement is suitable. That's considered a Design Change and the evaluation, criteria to be met, and outcome (possibly including Test Data), along with the peer review will all be documented to create an Engineering Change Order (ECO). Only when that ECO is approved and released, can you then start building the assembly with the new part. Anything else would be Non-Conforming and could cause you to have to recall all the devices that were built incorrectly. Basically, changing a part is not a trivial undertaking. For non-critical parts, the process will be quicker but nothing can be changed without documented justification.