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New engine for less money than an overhaul

As per previous post an overhaul for an N-registered aircraft such as Peter’s requires disassembly, inspection to verify compliance with service limits and reassembly as the only specific actions.

Yes, but, engines are sold new with a TBO (Time Between Overhaul). This cannot be misunderstood as “time between factory rebuild”. If inspection shows the engine to be “as good as new” at “overhaul”, then the time until next “overhaul” is still valid.

The elephant is the circulation
ENVA ENOP ENMO, Norway

It doesn’t have to be “good as new” at overhaul only “good enough to operate”. Imagine the lawsuits that would follow if the US Government decided to force owners to improve their completely serviceable property beyond service limits. This is consistent with the manufacturer recommended TBO meaning nothing under FAA regulations, it is only advisory, and if the engine has been given a quickie field overhaul it becomes meaningless. The FAA knows that and has left us on our own recognizance

The perception that engines must be overhauled at regular government mandated intervals, and brought to new service limits at overhaul, is fundamentally incorrect under FAA regulations, and would exceed their legal scope. What the owner chooses to do to protect his own safety and property value is a different matter.

Last Edited by Silvaire at 30 Jul 17:02

It doesn’t have to be “good as new” at overhaul only “good enough to operate”

This is a very peculiar definition. An inspection to assess continuing operation for an unspecified amount of time is not normally known as an overhaul, but simply an inspection. Let’s see what Lycoming say about this:

New and factory rebuilt:
“Lycoming Engines, a division of Avco Corporation (hereinafter “Lycoming”) warrants each new and rebuilt
Lycoming reciprocating engine to be free from defect in material or workmanship under normal use and service for a period
of twenty-four (24) months or the recommended engine time (hours) between overhauls (“TBO”) in accordance with the
latest edition of Lycoming Service Instruction 1009, whichever occurs first”

Overhauled engines:
“Lycoming Engines, a division of Avco Corporation (hereinafter “Lycoming”) warrants each overhauled
Lycoming reciprocating engine to be free from defect in material or workmanship under normal use and service for a period
of twelve (12) months or the recommended engine time (hours) between overhauls (“TBO”) in accordance with the latest
edition of Lycoming Service Instruction 1009, whichever occurs first”

Obviously an overhauled (by Lycoming) engine is not “as good as new”, but it is guaranteed to run until next TBO (which is theoretically possible within 12 moths )

The perception that engines must be overhauled at regular government mandated intervals, and brought to new service limits at overhaul, is fundamentally incorrect under FAA regulations, and would exceed their legal scope.

It is not the FAA or any other authority that specify overhaul intervals. It is the manufacturer of the engine. But this specifications cannot be done without approval of the authorities. A certified engine is not an experimental engine with only a recommended TBO.

The elephant is the circulation
ENVA ENOP ENMO, Norway

It doesn’t have to be “good as new” at overhaul only “good enough to operate”.

I understand an engine which is overhauled has to be wholly to “overhaul limits” – perhaps called “service limits”.

In reality, a 2000hr engine which has no abnormal problems should still be within “new limits” in most parts, with common exceptions being

  • exhaust valve stems
  • camshaft (which can be reground to new limits, believe it or not, and case re-hardening may not be needed)
  • cam followers

By the time I was paying for all that stuff, I would go for new limits every time. Then I have a “new” engine.

Administrator
Shoreham EGKA, United Kingdom

it is guaranteed to run until next TBO (which is theoretically possible within 12 moths )

This is lame. Noone is going to fly 2000h in a spam can (preferably VFR only) in a year. That would be 5.5 hours every day.

Given that corrosion is a major problem, the engine warranty doesn’t cover many real world failure scenarios. My club has had new Lycoming enignes failing shortly after the end of the warranty…

LSZK, Switzerland

By the time I was paying for all that stuff, I would go for new limits every time. Then I have a “new” engine.

As would most other people, myself included However, FAA does not have the legal authority to force the owner to do work beyond that required for airworthiness in terms of measurable criteria, as opposed to arbitrarily dictated procedure that may or may not be necessary to maintain airworthiness. I think all this stuff is very important in its implications to the owner, particularly as not every certified aircraft operates on the same economic or operational basis. A ‘limiting case’ example (that I’m pulling out of thin air) might be that somebody with a Kinner-powered Ryan or Franklin-powered Stinson does not have his aircraft’s FAA certificate of airworthiness removed (i.e. downgraded to some hassle loaded annual permit) because he cannot overhaul the engine to within new specs. He instead puts together an engine that is safe but not new, makes logbook entries to fly on without concern, and then when more parts show up on his doorstep he does it again.

Moving on from that diatribe I noticed a brand new Lycoming IO-320 on the UK AFORS site yesterday for a pretty good price IO-320, and its a variant that would be of direct interest to me if it were closer. Apparently its been sitting in the crate for three years, in the Slovak Republic. That made think of this thread and several others on EuroGA.

Last Edited by Silvaire at 30 Jul 20:57

Apparently its been sitting in the crate for three years, in the Czech Republic.

Let it sit for another 2 years and Socata might be interested in using it for a new aircraft

It is not the FAA or any other authority that specify overhaul intervals. It is the manufacturer of the engine. But this specifications cannot be done without approval of the authorities. A certified engine is not an experimental engine with only a recommended TBO.

I’ve noticed you writing that (or similar) several times in the past, but it is incorrect under FAA rules that regulate most of the world’s certified light aircraft. Under FAA rules the engine manufacturer cannot write law and only the US government dictates legally required maintenance protocol.

Further, FAA regulations do not require overhaul at the manufacturer’s recommended TBO or any special inspection protocol after that TBO. The basis for airworthiness under FAA rules is an annual condition inspection, which is the same every year. The manufacturer’s TBO recommendation, either in terms of operating hours or calendar time, is legally irrelevant.

Last Edited by Silvaire at 30 Jul 21:16

Let it sit for another 2 years and Socata might be interested in using it for a new aircraft

I was going to say more or less the same thing

As would quite a number of TB20GT / TB21GT owners…..

I believe the last 14 of the IO540 engines are still sitting on the shelf at Tarbes, no doubt valued in Socata’s accounts at €50k each or whatever.

An engine crated for 3 years will be about 2 years beyond the storage life. At the 1 year point, an overhaul is mandatory to restore legal airworthiness. At best, there will be fine rust inside the cylinders, so best to not do oil analysis for a year or two

Last Edited by Peter at 30 Jul 21:01
Administrator
Shoreham EGKA, United Kingdom

An engine crated for 3 years will be about 2 years beyond the storage life. At the 1 year point, an overhaul is mandatory to restore legal airworthiness. At best, there will be fine rust inside the cylinders, so best to not do oil analysis for a year or two

Mandatory to who? Not the FAA. I’d pull the cylinders, inspect, hone if required and run it. That opinion might come from living in a much drier climate where engines are regularly stored for a lot longer. A friend just flew his brand new O-360 for the first time after five years of storage. Like a lot of homebuilders (and apparently Socata too!) he thought he’d be finishing up his aircraft faster.

Last Edited by Silvaire at 30 Jul 21:17
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