Empty weight and center of gravity: Currency requirement

This regulation requires Part 135 operators to weigh their multiengine aircraft at least every 36 calendar months to establish current empty weight and center of gravity values. These actual weighing values must be used for all weight and balance calculations during operations.

Two exceptions apply: aircraft don't need reweighing if they received their original airworthiness certificate within the past 36 months, or if the operator uses an FAA-approved weight and balance system specified in their operations specifications (which may allow calculated weight changes instead of actual weighing).

This matters because aircraft weight and CG change over time due to equipment modifications, paint, repairs, and accumulated dirt or moisture. Operating with outdated weight and balance data could lead to incorrect loading decisions, potentially putting the aircraft outside safe CG limits or over maximum weight. The 36-month requirement ensures operators work with reasonably current baseline data for flight safety.

*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.*