Six Big Mistakes of Aircraft Maintenance - Savvy Aviation In this webinar, GA maintenance expert and owner advocate Mike Busch A&P/IA discusses the six most common blunders he sees aircraft owners make in dealing with their shops and mechanics. These range from allowing mechanics to decide what maintenance needs to be done (which is the owner's job) to failing to obtain written cost estimates to allowing problems to be "shotgunned" instead of diagnosed systematically. These errors often result in the owner losing control of the maintenance process and winding up profoundly unhappy with the outcome.