Plane & Pilot
Tuesday, January 26, 2010

Upgrade Your Plane! Part III


Firewall forward—life after TBO


The Options
Each of the five options has its unique attributes; but you may be surprised to learn that the nuances between them are more than semantics. So here they are, roughly in order based on price (from most to least expensive).

• Factory New: If you’ve been squirreling away money in an engine reserve for the last 2,000 hours since your aircraft (or engine) was new, you may opt to purchase a brand-spanking-factory-new engine. The factory-new engine is a new zero-time engine that reflects all of the latest production improvements; it’s compliant with the latest service bulletins and airworthiness directives, and has the longest factory-backed warranty available. It’s also the most expensive of the five options. But if you want an engine that’s 100% new—just like the day the aircraft was first delivered—then this option is for you. All of the remaining options make some sort of concession to lessen purchase price.

• Factory Rebuilt: Sometimes the terms “rebuilt” and “overhauled” get used interchangeably. Adding to the confusion are statements like “rebuilding the engine to zero-time limits” or “to new tolerances,” etc. One key difference between a
factory-rebuilt engine and an overhauled one is that only the engine’s OEM is FAA-authorized to rebuild (i.e., “remanufacture”) engines. Only the OEM can claim that factory-rebuilt engines are zero-time powerplants just like factory-new engines. This primarily is because the factory-rebuilt engine is built anew on the same production and assembly line as factory-new engines, which ensures that rebuilt engines are assembled to the same tolerances and limits as new engines, in accordance with the same quality management and under the same FAA production certificate scrutiny. For these reasons, factory-new and factory-rebuilt engine benefits are virtually indistinguishable. The chief differentiating factor between a factory-new and factory-rebuilt engine is that the rebuilt engine may contain cores (i.e., crankcases, crankshafts, etc.) that have been refurbished to new specifications. The limited use of cores in factory-rebuilt engines is what accounts for the slightly lower price than factory-new engines with brand-new parts.

• Factory Overhaul: Some engine manufacturers (such as Lycoming) also overhaul engines. This has benefits for both consumer and manufacturer. For the manufacturer, it means engine data plates won’t be overhauled by third parties who might not know what they’re doing. For the consumer, it provides an even more price-competitive alternative over a zero-time rebuilt engine.

The chief differentiating factor between a factory-rebuilt and a factory-overhauled engine is engine time—and this is a significant key difference. No company, not even the OEM, can overhaul an engine to “zero time” like a factory-new or factory-rebuilt engine. For those inclined to go the overhaul route, there are two major benefits of a factory overhaul compared to a field overhaul: parts and tolerances.

Because the OEM is overhauling the engine, you can rest assured that only genuine OEM parts are used. Additionally, since the OEM built the engine new, only the OEM truly knows the engine’s manufacturing specs. Granted, most field overhaulers claim to overhaul engines to “factory-new specs,” but the OEM only publishes data based on service limits, not manufacturing tolerances. Thus, it stands to reason that the factory-overhauled engine will conform to a tighter set of tolerances than a field overhaul.

• Field Overhaul: These are performed by third-party engine shops. As you can imagine, there’s a wide range of expertise between shade-tree overhaulers and world-class maintenance, repair and overhaul (MRO) shops, so quality control is something you’ll need to gauge for yourself. Some field overhaulers have built strong reputations for delivering a quality product at a fair price. And while it’s not our intention to convince anyone that one of the above options is better than another, there are key points of differentiation.



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