Maintenance Our shop at Midstate Aviation can maintain Part 91 and Part 135 aircraft to include annuals, 100-hours, and routine maintenance. We have a limited repair station for IFR bi-annual checks as required by CFR 91. Our maintenance staff includes three full time A&P mechanics, 1 full time IA, and Piper fleet operator status. Ed Beeson, Director of Maintenance, has over 20 years of hands on experience and was awarded WA State Division of Aviation: Mechanic of the Year in 2000.