Reporting mechanical irregularities

This regulation requires Part 135 operators to maintain an aircraft maintenance log on board each aircraft to track mechanical problems and their resolution.

As pilot in command, you must document any mechanical irregularity you notice during flight in this log. Before every flight, you're required to check the log and determine the status of any problems recorded after the previous flight—whether they've been fixed, deferred, or remain open.

When maintenance personnel or others take action on a reported problem—either fixing it or deferring it under approved procedures—they must document what they did in the same log following applicable maintenance requirements.

The certificate holder must establish procedures for keeping copies of these logs accessible in the aircraft and include those procedures in their operations manual. This system ensures continuity of mechanical issue tracking between flights and crews, preventing problems from being overlooked or forgotten.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*