Engine overhaul, regulatory question

[tspear]

So, a non-pilot friend asked this question and I did not know the answer. Mostly because I never considered it

Assuming you can find an A/P or IA who is willing to oversee and certify, is there any regulatory rule which prevents an owner from performing a tear down and rebuild of the engine?

I know the answer for E-AB, but never considered such an action for certified. Besides extremely difficult to get the A/p or IA blessing, I did not have an answer.

Tim

 

[Capt. Geoffrey Thorpe]

Assuming you can find an A/P or IA who is willing to oversee and certify, is there any regulatory rule which prevents an owner from performing a tear down and rebuild of the engine?

nope. That's one way to become an A&P - work under the supervision...

 

[Clip4]

The regulation requires an AP to supervise your work.

 

[Stewartb]

I’ve done it. Ended up with a great engine. I enjoyed it.

 

[Domenick]

I've done virtually all the work on my Warrior for 20+ years under supervision, including an engine replacement. Learned much about the aircraft.

 

[tspear]

@Stewartb @Domenick

Well, if we never wanted to fly again, I am sure I could take on such a project!
I always go off on tangents on stuff like this, plus I am super slow to avoid mistakes.

For me, this was curiosity since I never considered it.

Tim

 

[Magman]

My interpretation of the FARs is that a person may perform any task for which

the Tech is rated.

Currently the regs require the Tech to be present and available for consultation.

I’m sure there are lots of situations where a Cellphone would suffice but

as often said; “ FAA is stuck in the 50s”.

I always advise young people ( which means anyone other than me) to

document their “ Wrench Time” as they may want the A & P someday.

Of course ; having the Supervising Tech sign your Tech Log is the best way to go.

If you have a somewhat unique aircraft and know more about it than the

AMT life might be frustrating.

 

[Salty]

I did my o-360 overhaul with oversight of my IA

 

[pfarber]

"However, this paragraph does not authorize the performance of any inspection required by Part 91 or Part 125 of this chapter or any inspection performed after a major repair or alteration.”

https://www.faa.gov/documentlibrary/media/notice/n_8900.410.pdf

 

[Magman]

I’m certainly not advocating an inexperienced person overhauling an engine or

splicing a wing spar under cellphone supervision.

There are some Minor Repairs that may require A & P supervision strictly

to meet regulations.

They are often done by “ Hangar Fairies” with zero certificated oversight.

Likely the most common is replacement of brake pads.

Would you want to pay the $150 “ show -up fee” to some Tech to change 1 brake pad?

Or is it better to fly with worn out brakes?


GE remotely monitors the condition of many of their engines remotely.

The decision whether to continue in service is often made by a person

that has not been within a 1000 miles of the engine.


Joe Logie (formerly of Champion /Slick ) told me that all of their

warranty assembly work performed by the women was on video.


Just as in other fields; Technology may change the way some things are done.

Lets hope they get it right.

 

[Jdm]

If you’re trying to find the minimum you don’t even need an A&P. Just a power plant mechanic.

 

[pfarber]

I’m certainly not advocating an inexperienced person overhauling an engine or

splicing a wing spar under cellphone supervision.

There are some Minor Repairs that may require A & P supervision strictly

to meet regulations.

They are often done by “ Hangar Fairies” with zero certificated oversight.

Likely the most common is replacement of brake pads.

Would you want to pay the $150 “ show -up fee” to some Tech to change 1 brake pad?

Or is it better to fly with worn out brakes?


GE remotely monitors the condition of many of their engines remotely.

The decision whether to continue in service is often made by a person

that has not been within a 1000 miles of the engine.


Joe Logie (formerly of Champion /Slick ) told me that all of their

warranty assembly work performed by the women was on video.


Just as in other fields; Technology may change the way some things are done.

Lets hope they get it right.

Maintenance means inspection, overhaul, repair, preservation, and the replacement of parts, but excludes preventive maintenance.

Owner/operators can only perform preventative maintenance, which is clearly defined in Part 43 Appendix A

Is it retarded that an owner operator can change a tire, fill the brake hydraulic reservoir and grease a wheel bearing but not change a disk brake pad? Yes.

 

[Stewartb]

Airplane engines are crazy simple. The sticking point for me where I appreciated guidance was in the accessory case.

 

[Capt. Geoffrey Thorpe]

Is it retarded that an owner operator can

Overhaul the engine and return it to service if the airworthiness certificate is pink but

but not change a disk brake pad

if the certificate is on white paper?

Geoff "Pink Certificate" Thorpe



(Note: Apparently all certificates are now printed on white paper, but you get the idea.)

 

[NordicDave]

Airplane engines are crazy simple. The sticking point for me where I appreciated guidance was in the accessory case.

Our air cooled engines are simple but they have peculiarities. Shocking how many A&P's are "certified", but not competent to overhaul an engine. Experience matters greatly.

Seems like too many mechanics make startling decisions on what parts are acceptable for reuse. Example, Cylinder through studs have a maximum stretch that sometimes doesn't get measured. Those same studs are torque rated based on stretch, zinc coating, and lubrication for Continental engines. I've met more than 1 A&P unfamiliar with proper cylinder installation, let along building an engine.

There are many very competent A&P's who have overhauled a ton of engines without issue, frequently any savings is more than recouped on resale from a well known shop.

A thought seriously about a local IA overhauling my engine. He overhauls about 3-4 engines a month and has his own cylinder shop with a 20 year experienced machinist working the cylinders. He was $10K cheaper than the big name shop who performed the O/H. For me, tipping point was the engine was run on a dyno test stand for over an hour with full instrumentation before I would fly it.

The thought of being a test pilot on an untested engine was beyond my risk factor. Sometimes unseen risks are blinded by cost savings.

 

[Salty]

I was on the fence about doing my overhaul myself. My IA was encouraging it. I spent a day at one of the more reputable engine rebuilders watching them work. Doing that solidified my decision to do it myself. I know I was far more focused, detailed, and careful than they would have been based on watching them work for a day. By a long shot.

The bench run is a nice perk for sure. But it's really overkill. I'd rather spend the money paying someone to fly the first few hours with it installed on the plane. I'm over 350 hours since OH now and very happy I did it myself.

The real killer is the paperwork. Sourcing parts and finding people to service the parts to be reused, researching AD's and documenting everything took me a lot longer than the time spent working on the engine.

 

[bradg33]

Owner/operators can only perform preventative maintenance, which is clearly defined in Part 43 Appendix A

This isn't really true anymore. The FAA Chief Counsel has somewhat recently explained that the list in Appendix A of preventive maintenance items is just a set of examples, not an exhaustive list.

See the middle paragraph on Page 2:

https://www.faa.gov/about/office_or...2009/coleal - (2009) legal interpretation.pdf

 

[Stewartb]

Our air cooled engines are simple but they have peculiarities. Shocking how many A&P's are "certified", but not competent to overhaul an engine. Experience matters greatly.

Seems like too many mechanics make startling decisions on what parts are acceptable for reuse. Example, Cylinder through studs have a maximum stretch that sometimes doesn't get measured. Those same studs are torque rated based on stretch, zinc coating, and lubrication for Continental engines. I've met more than 1 A&P unfamiliar with proper cylinder installation, let along building an engine.

There are many very competent A&P's who have overhauled a ton of engines without issue, frequently any savings is more than recouped on resale from a well known shop.

A thought seriously about a local IA overhauling my engine. He overhauls about 3-4 engines a month and has his own cylinder shop with a 20 year experienced machinist working the cylinders. He was $10K cheaper than the big name shop who performed the O/H. For me, tipping point was the engine was run on a dyno test stand for over an hour with full instrumentation before I would fly it.

The thought of being a test pilot on an untested engine was beyond my risk factor. Sometimes unseen risks are blinded by cost savings.

Running-in field overhauled engines on the airframe has been done since airplanes were invented. Not a big deal.

 

[bnt83]

Running-in field overhauled engines on the airframe has been done since airplanes were invented. Not a big deal.

Very true.

On a side note, how many in-service engines don't pass a preflight run-up? That seems like a pretty definitive test IMHO.

 

[NordicDave]

Running-in field overhauled engines on the airframe has been done since airplanes were invented. Not a big deal.

Very true. On a side note, how many in-service engines don't pass a preflight run-up? That seems like a pretty definitive test IMHO.

@bnt83 Spot on.

Running in an engine in on the ramp without proper cooling or instrumentation was beyond my risk factor for a $35K engine. I have little appetite paying to R&R a newly overhauled engine due to a 1st run issues. We used to fly without radios, satellite weather forecasts, GPS of some kind, or an EFB too. People flying factory stock 1947 Champs acknowledged.

 

[Magman]

Local FSDO interprets Lycoming O/H Instructions mandating use of a Test Cell

with complete instrumentation as essential if o/h signed as

“Overhauled i/a/w Lycoming Service Data”.

That’s why there are a couple engines our there with Overhaul crossed out

and Cam Replacement inserted above.

Your fiefdom may feel otherwise.

 

[Dan Thomas]

If you're going to overhaul it, get the overhaul manual for that engine and use it. Study it first. Manuals are full of warnings and advice, and many A&Ps don't know those details; even the "knowledgeable" guy that supervises you might not have a good handle on it.

There are tables for maximum wear limits. Tables for gear lash and piston clearances. Tables for ring clearances in their lands. Tables for valve stem/guide clearances. Table for torques. And stuff like Continental's demand that connecting rod bolts be replaced with new bolts every time they come apart. There are reasons for all of it: that engine is working hard, all the time, and is lightly built so it will fly. It's not built like a bulldozer's diesel engine. All those specs matter, greatly. You need the measuring tools to do all this stuff.

Your mortal body is relying on it. Maybe your family's bodies are, too. Take it seriously. It's not a lawnmower engine.

 

[pfarber]

This isn't really true anymore. The FAA Chief Counsel has somewhat recently explained that the list in Appendix A of preventive maintenance items is just a set of examples, not an exhaustive list.

See the middle paragraph on Page 2:

https://www.faa.gov/about/office_org/headquarters_offices/agc/practice_areas/regulations/interpretations/data/interps/2009/coleal - (2009) legal interpretation.pdf

Well the FAR and the counsel differ, and it depends on what part you fly under. And since that opinion is quite old, new counsel/staff my not have the same opinion. Lastly, the FAA is kinda famous for not following its own rules.

I would bet a warm diet cola that no Pt 91 pilot is properly logging the tire pressure check.

SS 43.5 and 43.9a clearly list preventative maintenance requiring logging.

So, does the owner/operator have the proper documentation and tools to perform the air pressure check? Pilots can't properly check the fuel and oil levels, so there's that, also.

 

[pfarber]

If you're going to overhaul it, get the overhaul manual for that engine and use it. Study it first. Manuals are full of warnings and advice, and many A&Ps don't know those details; even the "knowledgeable" guy that supervises you might not have a good handle on it.

There are tables for maximum wear limits. Tables for gear lash and piston clearances. Tables for ring clearances in their lands. Tables for valve stem/guide clearances. Table for torques. And stuff like Continental's demand that connecting rod bolts be replaced with new bolts every time they come apart. There are reasons for all of it: that engine is working hard, all the time, and is lightly built so it will fly. It's not built like a bulldozer's diesel engine. All those specs matter, greatly. You need the measuring tools to do all this stuff.

Your mortal body is relying on it. Maybe your family's bodies are, too. Take it seriously. It's not a lawnmower engine.

If you think you're gonna start mic'ing journals and bores and have anything close to an accurate reading without a TON of experience I have a bridge to sell you.

You'd be in close to $1000 for measuring tools alone if you want to check all the limits on your motor. And no, that uncalibrated $20 dial indicator is not going to cut it.

 

[Salty]

If you think you're gonna start mic'ing journals and bores and have anything close to an accurate reading without a TON of experience I have a bridge to sell you.

You'd be in close to $1000 for measuring tools alone if you want to check all the limits on your motor. And no, that uncalibrated $20 dial indicator is not going to cut it.

Where did he say anything about mic’ing journals and bores?

 

[Dan Thomas]

Where did he say anything about mic’ing journals and bores?

You have to mike them to determine the wear. There's no getting around it. So you need a full set of micrometers, up to cylinder bore size, and you either need a dial bore indicator or a set of snap gauges or inside micrometers. I use my micrometers and snap gauges. And feeler gauges. And a dial indicator or two. I spent 12 years as a machine shop foreman and got used to working to within a tenth of a thou (.0001").

 

[Salty]

You have to mike them to determine the wear. There's no getting around it. So you need a full set of micrometers, up to cylinder bore size, and you either need a dial bore indicator or a set of snap gauges or inside micrometers. I use my micrometers and snap gauges. And feeler gauges. And a dial indicator or two. I spent 12 years as a machine shop foreman and got used to working to within a tenth of a thou (.0001").

I wouldn’t recommend doing that yourself. I sent mine out and had it inspected for cracks, reground (if necessary, and it was) and re-nitrided. Measurement is the easy part of all that, but why bother when practically nobody can do the rest of it?

 

[Dan Thomas]

I wouldn’t recommend doing that yourself. I sent mine out and had it inspected for cracks, reground (if necessary, and it was) and re-nitrided. Measurement is the easy part of all that, but why bother when practically nobody can do the rest of it?

I presume you mean the crankshaft. Yes, if it needs regrinding it can be sent out, reground and renitrided. Unless it's an A-65 or -75, whose cranks were never nitrided.

If I had a crank grinder I could grind it myself. I spent thousands of hours doing that in the machine shop, along with resizing cylinders. Shops like that are almost gone now. People buy new stuff instead of rebuilding. Even the aircraft engine shops buy new cylinders instead of resizing them, unless the used cylinders have little wear and only need rehoning to establish a crosshatch for break-in, and some valve work. Even then, the labor costs can almost outweigh the new costs.

I think some field overhauls are little more than new rings, bearings, seals and gaskets. Not the sort of overhaul you get from the factory or a decent overhaul shop. Probably no NDI on anything, no runout checks on the crank, no parallel checks on the rods. Nothing.

 

[bnt83]

So, a non-pilot friend asked this question and I did not know the answer. Mostly because I never considered it

Assuming you can find an A/P or IA who is willing to oversee and certify, is there any regulatory rule which prevents an owner from performing a tear down and rebuild of the engine?

I know the answer for E-AB, but never considered such an action for certified. Besides extremely difficult to get the A/p or IA blessing, I did not have an answer.

Tim

If you do end up going down this road, I'd take a picture of every packaged, bolt, nut, gears, bearings, oil pump, cylinder etc. Could save you a lot of trouble down the road when you need to figure out if an AD applies.

Save all the paper they come with.

Make sure the paperwork matches the parts and repair/overhaul services you contracted out.

Inspect every part you buy as soon as it arrives. I had two brand new cylinder assembles that had corroded barrels right out of the box. Fortunately I looked at them as soon as they came off the delivery truck and I called them same day, so the retailer knew it was their responsibly.

Take care of all your parts and don't let them go bad laying around waiting for assembly. Stuff can corrode quickly.

 

[tspear]

@bnt83

Good info. But not me. I highly doubt I will ever take on such a project.
A friend asked about flying costs, and I showed him an older budget I had, which included engine reserve. He thought the engine reserve was crazy and how come owners do it themselves.
Hence this discussion.

Tim

Sent from my HD1907 using Tapatalk

 

[JAWS]

Lycoming Service Instruction 1427C.
Field overhaul break in recommendations.

 

[pfarber]

Unless you do motors regularly, I would not try to overhaul one. Not only do you need the proper tools, but there are some pretty critical operations like the through bolts that can easily be done wrong and wreck an engine.

My opinion of 'under supervision' is that you hand me tools, do the cleaning and organizing things. How many shade tree mechanics know how to exercise a torque wrench? Have a calibration program etc.

 

[JAWS]

Where is Tom D? This is right up his alley.

 

[Capt. Geoffrey Thorpe]

How many shade tree mechanics know how to exercise a torque wrench?

Or, how many A&Ps for that matter:

I went down to my mechanic to ask how he does it and whether I could borrow his tool. No need, he just uses a screwdriver and a ball peen hammer for removal or installation. Yeah, it buggers the nut but just use a new one each time. Of course his hammers and his hands are calibrated.

 

[BoButt]

The “Coleal” letter and the ‘08 letter defining “current” gave heartburn to many sky is falling purists in the field and at the FAA! However both provide documentation for the defense in front of the Administrator, Whether they like it or not.Both are amazing displays of reasonableness from a fear mongering tunnel vision FAA.

When anyone claims in writing they have performed an operation “IAW”, no exceptions are acceptable. It must be all or nothing. So do not use that statement. It only opens one to possible prosecution by ones own inadvertent admission. There is no standard for claims of Overhaul. Why create one?

 

[Gary Ward]

So, a non-pilot friend asked this question and I did not know the answer. Mostly because I never considered it

Assuming you can find an A/P or IA who is willing to oversee and certify, is there any regulatory rule which prevents an owner from performing a tear down and rebuild of the engine?

I know the answer for E-AB, but never considered such an action for certified. Besides extremely difficult to get the A/p or IA blessing, I did not have an answer.

Tim

Like said above, yes it can be done in your hangar with the help of a power plant certified mechanic. MY AP/IA suggested we could do it in my hangar since we have both overhauled engines in the past. He airplane engines and me only car/truck engines.

In the end I decided to order a factory rebuilt engine and swap the old one out. That way my plane was only down for a week for the swap and I felt I have a better resale value plane with factory rebuilt engine and warranty. Lot's of variables and no one answer is best for everyone.

 

[Magman]

At one time Penn Yan Aero had something called the “ Home Pack” or similar.

They would perform all NDT and dimensional checking of all components.

You then had to buy or repair components as needed and then reassemble.

I’ll guess and say the practice was phased out.

 

[unsafervguy]

yes it is legal, is it a good idea? that's hard to say. I hold an A&P with IA. when my warrior engine needed overhaul after I priced all the parts, machine shop work, shipping, supplies I called a well know shop in florida I trust and got a quote. in reality, his quote was only a few grand more than what it was going to cost me. I assume he was getting better pricing than I would ever get so his profit margin was more than that. for those few grand, I got his knowledge, and skill, and a ready to hang engine that was test run properly with a warranty. It was a no brainer to me in the back of the truck it went and off to him.

 

[mondtster]

yes it is legal, is it a good idea? that's hard to say. I hold an A&P with IA. when my warrior engine needed overhaul after I priced all the parts, machine shop work, shipping, supplies I called a well know shop in florida I trust and got a quote. in reality, his quote was only a few grand more than what it was going to cost me. I assume he was getting better pricing than I would ever get so his profit margin was more than that. for those few grand, I got his knowledge, and skill, and a ready to hang engine that was test run properly with a warranty. It was a no brainer to me in the back of the truck it went and off to him.

I’ve done quite a few aircraft engines and have always found the same thing. When comparing apples to apples between the overhaul I would do and the overhaul I would want an engine shop to do the price difference is negligible.

Whether it is a good idea or not to overhaul your own engine is debatable. The only reason I continue to do them is because I sleep better knowing what’s inside my engine.