ATA 73 — Engine - Fuel and Control

Life-limited parts — how engine material is really valued

Engine rotating structure — fan, compressor and turbine disks, spools, hubs and shafts— is life-limited: each part number carries a hard cycle limit published in the engine's Airworthiness Limitations Section. Unlike blades, vanes and seals, which are on-condition and repairable, an LLP is retired at its limit regardless of condition.

That makes cycles remaining, not condition, the value of a used LLP — and makes complete back-to-birth trace records the difference between a saleable disk and scrap. It is why engine teardowns are underwritten on the LLP stack rather than on parts count.

What we do not have:we carry no per-part-number cycle limits and no remaining-life data. Those live in OEM Airworthiness Limitations Sections and in each unit's own trace file — neither is public, and neither can be inferred from registry, SDR or PMA data. Our life-limit tagging covers date- and shelf-controlled classes (oxygen, fire bottles, slides and rafts, batteries, pyrotechnics, tires, de-ice boots, fuel bladders, pressure vessels), not engine LLPs. Always price an LLP off its trace records.