Definition
A 100-hour inspection is a comprehensive maintenance review required by the Federal Aviation Regulations (14 CFR Part 91.409) for any aircraft that carries passengers for hire or is used for flight instruction for hire. The inspection must be completed before the aircraft accumulates 100 hours of time in service since the last 100-hour or annual inspection. The scope of work is essentially identical to an annual inspection, covering the airframe, engine, propeller, and all installed equipment. The inspection must be performed by an FAA-certified Airframe and Powerplant (A&P) mechanic or a certified repair station. The mechanic follows a detailed checklist that covers structural integrity, engine condition, control system rigging, avionics functionality, and compliance with all applicable airworthiness directives. Any discrepancies found must be corrected before the aircraft is returned to service, unless the mechanic determines they do not constitute an airworthiness issue and documents them as deferred items. For flight schools, the 100-hour inspection cycle is a critical operational constraint. Training aircraft accumulate hours quickly — a busy trainer can log 100 hours in as little as three to four weeks — so schools must carefully plan maintenance windows to avoid pulling aircraft out of service during peak training periods. Missing or delaying a 100-hour inspection is a regulatory violation that can result in enforcement action against both the operator and the pilot who flies the aircraft.
Why It Matters for Flight Schools
Flight schools and Part 135 operators deal with 100-hour inspections far more frequently than private owners, who only need annual inspections. The inspection cycle directly impacts fleet availability, scheduling, and revenue. A school with five aircraft might have one in the shop for its 100-hour inspection at almost any given time, making fleet rotation and advance scheduling essential to maintaining student throughput. Beyond the direct maintenance cost, 100-hour inspections often uncover squawks — minor discrepancies that require additional parts and labor to resolve. Schools must budget not only for the baseline inspection cost but also for the unpredictable follow-on repairs that can extend downtime from a day to a week or more.
How Aviatize Handles This
Aviatize tracks cumulative Hobbs hours for every aircraft in the fleet and automatically flags airframes approaching the 100-hour threshold. Operations managers receive advance warnings so they can schedule maintenance windows during low-demand periods, minimizing the impact on student training and revenue. The platform also logs inspection completion dates and hours, feeding that data back into the scheduling engine so dispatchers cannot inadvertently book an aircraft that has exceeded its 100-hour limit. This closed-loop approach eliminates the manual spreadsheet tracking that leads to oversights and regulatory exposure.