Engine Break-in

[JOhnH]

Is it common for a casual (for lack of a better word) pilot to do their own new-engine (reman/oh) break-in them self. Or is this something that is best left to "professionals"? My wife is 53 yrs old. She took her fist lesson about 2.5 years ago and got her ppl about 1.5 yrs ago. She is good for a 200hr pilot, but engine break-in seems a little scary. Especially that first flight.

She is ready to go for it herself. I am the one that is being a little cautious. At a minimum, I would like her to have a better co-pilot next to her than me. How do you go about finding a "test pilot"?

 

[poadeleted20]

As long as she's familiar with the break-in procedures and stays right over the airport initially, there's no reason she can't do this herself.

 

[ScottM]

I see no reason any current pilot could not do the break in if they have been briefed on the procedure. I would also recommend that you take the mechanic up on the first flight to monitor performance and stay above the airport. I have had to do two break in and each time I spend the first hour just staying in the vicinity of the airport. Basically flying the pattern but at an altitude of at least 1000' above pattern altitude.

 

[Steve]

Lycoming Engine Break-in recommendations

http://www.lycoming.com/support/publications/service-instructions/pdfs/SI1427B.pdf

Continental Engine Break-in recommendations

http://www.tcmlink.com/fiddefault.aspx?cgroup=MATTITUCK&cpagename=BREAKIN

If she feels competent to follow the guidelines it shouldn't be an issue. If not, find someone with dependable experience. From a risk mitigation standpoint I'd want only one individual in the plane for the first 20 or so hours. Just my perspective.

 

[sba55]

From a risk mitigation standpoint I'd want only one individual in the plane for the first 20 or so hours. Just my perspective.

Or even the first 100 hours, ideally. New engines have MUCH higher failure rates for the first x hours. I don't recall what exactly x is; maybe someone here has the chart.

-Felix

 

[Dan Thomas]

Or even the first 100 hours, ideally. New engines have MUCH higher failure rates for the first x hours. I don't recall what exactly x is; maybe someone here has the chart.

-Felix

If it was that bad there would be regulations controlling such operations, and there aren't. I break in our new engines on a three-hour flight, following Lycoming's procedures, check the filters, run it up, and let it go back to work in the flight school but instructing them to run it only on cross-countries for at least 15 hours at 65-75% power. No circuit or low-power ops, or the rings won't seat properly and the engine will use too much oil the rest of its life. We've never had any problems doing this.

Dan

 

[sba55]

If it was that bad there would be regulations controlling such operations, and there aren't. I break in our new engines on a three-hour flight, following Lycoming's procedures, check the filters, run it up, and let it go back to work in the flight school but instructing them to run it only on cross-countries for at least 15 hours at 65-75% power. No circuit or low-power ops, or the rings won't seat properly and the engine will use too much oil the rest of its life. We've never had any problems doing this.

Dan

Well, nevertheless, it is "that bad" - whatever that means. If you look at a plot of failures vs. engine time, you'll see that those failures rates are very high for the first x hours. Like I said, I forget what exactly x is, but it's certainly more than 20 hours.

Of course, failure rates after 1500 hours are probably still lower than rates at 500 hours, but it's not really practical to break in new engines for 1500 hours. So you have to decide at which point you reach a point where the failure rate is acceptably low.

-Felix

 

[RotorAndWing]

Well, nevertheless, it is "that bad" - whatever that means. If you look at a plot of failures vs. engine time, you'll see that those failures rates are very high for the first x hours. Like I said, I forget what exactly x is, but it's certainly more than 20 hours.

Of course, failure rates after 1500 hours are probably still lower than rates at 500 hours, but it's not really practical to break in new engines for 1500 hours. So you have to decide at which point you reach a point where the failure rate is acceptably low.

-Felix

Where are you getting your statistics from? Please cite a credible source please.

 

[gismo]

Well, nevertheless, it is "that bad" - whatever that means. If you look at a plot of failures vs. engine time, you'll see that those failures rates are very high for the first x hours. Like I said, I forget what exactly x is, but it's certainly more than 20 hours.

Of course, failure rates after 1500 hours are probably still lower than rates at 500 hours, but it's not really practical to break in new engines for 1500 hours. So you have to decide at which point you reach a point where the failure rate is acceptably low.

-Felix

From the data I've seen, I wouldn't say that engine failure rates are "very high" at any point in their early life. The failure numbers are indeed elevated during the first hundred hours or so but in this context I think "elevated" means the chances go from very, very slim to just very slim, especially if reasonable attention is paid to an occasional thorough preflight inspection and the overhaul was performed by a reputable shop. For that matter I'll bet there's a similar uptick in failures following almost any maintenance work including annual inspections. If you avoided passengers for a hundred hours after every repair or PM, you might as well get a single seater. It's certainly not something I've ever worried about beyond the first hour or two.

 

[azure]

From the data I've seen, I wouldn't say that engine failure rates are "very high" at any point in their early life. The failure numbers are indeed elevated during the first hundred hours or so but in this context I think "elevated" means the chances go from very, very slim to just very slim, especially if reasonable attention is paid to an occasional thorough preflight inspection and the overhaul was performed by a reputable shop. For that matter I'll bet there's a similar uptick in failures following almost any maintenance work including annual inspections. If you avoided passengers for a hundred hours after every repair or PM, you might as well get a single seater. It's certainly not something I've ever worried about beyond the first hour or two.

Where are the data on this, though? I've never seen anything solid. In all truthfulness, at 30 hours now on my new engine (it was zero time at installation and I've put on ~23 of those hours) I have yet to carry a non-pilot passenger and I was more nervous than usual a couple of weeks ago flying over Lake Erie to KLPR (stayed high and threaded the islands, though I'd have done that even with a tried and true engine), and again on Saturday flying over Lake Michigan to/from (especially from) KSJX.

The engine is still carrying "straight mineral oil" though it gets about 9-10 hours/qt and seems stable. I think it is as broken in as it's going to get and expect to switch over to ashless dispersant at the next oil change, in another 5 hours or so.

 

[gismo]

Where are the data on this, though? I've never seen anything solid. In all truthfulness, at 30 hours now on my new engine (it was zero time at installation and I've put on ~23 of those hours) I have yet to carry a non-pilot passenger and I was more nervous than usual a couple of weeks ago flying over Lake Erie to KLPR (stayed high and threaded the islands, though I'd have done that even with a tried and true engine), and again on Saturday flying over Lake Michigan to/from (especially from) KSJX.

The engine is still carrying "straight mineral oil" though it gets about 9-10 hours/qt and seems stable. I think it is as broken in as it's going to get and expect to switch over to ashless dispersant at the next oil change, in another 5 hours or so.

First of all, we're really talking about infant mortality which isn't really related to engine break-in beyond the fact that both occur in the first portion of an engine's life. Second, as I was trying to indicate, while failure rates of aircraft engines (like virtually all electrical and mechanical devices) generally follow some form of the "bathtub" curve, I think you'd find that failure rates under 100 hrs but beyond the first hour or so are only marginally higher than they are in the second hundred hours of use. In addition, mechanical engine failures, particularly catastrophic ones account for a fairly small percentage of the GA fatal accident pie so even a doubling of risk doesn't amount to much in the whole picture.

Here's a little related info from Mike Busch:

tinyurl.com/bathtub-curve

 

[gprellwitz]

For some info, see Mike Busch's article The Savvy Aviator #53: The Dark Side of Maintenance

Dr. Ulrich's analysis of NTSB data proves conclusively what I've long believed to be true: By far the highest risk of catastrophic engine failure occurs when the engine is young -- during the first two years and 200 hours after initial manufacture, rebuild or overhaul -- due to what we refer to as "infant-mortality failures" involving defects in materials and/or workmanship in assembling the engine. (Since replacing, rebuilding or overhauling the engine is a maintenance task, such infant-mortality failures are MIFs [Maintenance Induced Failures - GP].)

 

[Tom-D]

The engine should have been properly tested prior to being placed in service, There should be no problems during the first flights.I see no reason a properly rated pilot should not be able to handle the flights.

 

[swingwing]

There should not be a problem breaking in a new engine. When I did mine, I was more concerned with getting the rings seated than having it fail.

Make sure it gets un-cowled after the first hour and every nut, bolt and screw is checked. Something will be loose or rubbing. Be vigilant at checking for drips during your preflights and do a through inspection during the first couple oil changes.

 

[Marfa Gliders]

There ARE regulations about the first flight after maintenance.

See FAR 91.407

Generally, the first flight after major maintenance must be SOLO. If you carry non "crewmembers" and you have a problem resulting in an accident, you will need to answer to the FAA, and worse yet, to your insurance adjuster. Your mechanic or buddy along in your single pilot aircraft (all categories) is probably not viewed as a crewmember.

The Reg does allow for determination if the maintenance alters the flight performance, but solo might be the best bet for that first flight. Note that the pilot must make a logbook entry in aircraft logs.

Interpret any Reg however you wish, but always ask yourself how the NTSB / FAA, the insurance adjuster and the injured passengers' lawyers will twist it against you.

Don't spend much time looking for loopholes and exceptions. Pilots who waste my time seeking exceptions which may shortcut training, safety and proficiency kinda creep me out. Just my 2 cents . . . make your own determination as YOU are the PIC.

Burt (soloed 1967.) CFI / DPE
Marfa, Texas USA

 

[Bob Noel]

There ARE regulations about the first flight after maintenance.

See FAR 91.407

Generally, the first flight after major maintenance must be SOLO. If you carry non "crewmembers" and you have a problem resulting in an accident, you will need to answer to the FAA, and worse yet, to your insurance adjuster. Your mechanic or buddy along in your single pilot aircraft (all categories) is probably not viewed as a crewmember.

The Reg does allow for determination if the maintenance alters the flight performance, but solo might be the best bet for that first flight. Note that the pilot must make a logbook entry in aircraft logs.

Interpret any Reg however you wish, but always ask yourself how the NTSB / FAA, the insurance adjuster and the injured passengers' lawyers will twist it against you.

Don't spend much time looking for loopholes and exceptions. Pilots who waste my time seeking exceptions which may shortcut training, safety and proficiency kinda creep me out. Just my 2 cents . . . make your own determination as YOU are the PIC.

Burt (soloed 1967.) CFI / DPE
Marfa, Texas USA

hmmm...

It would appear that the requirement "No person may carry any person (other than crewmembers)" applies if the maintenance "appreciably changed the flight characteristics or substantially affected the flight operation of the aircraft."

and there is also subparagraph (c)

"(c) The aircraft does not have to be flown as required by paragraph (b) of this section if, prior to flight, ground tests, inspection, or both show conclusively that the maintenance, preventive maintenance, rebuilding, or alteration has not appreciably changed the flight characteristics or substantially affected the flight operation of the aircraft."

Does rebuilding an engine constitute substantially affecting the flight operation of the aircraft?

 

[RotorAndWing]

There ARE regulations about the first flight after maintenance.

See FAR 91.407

Generally, the first flight after major maintenance must be SOLO. If you carry non "crewmembers" and you have a problem resulting in an accident, you will need to answer to the FAA, and worse yet, to your insurance adjuster. Your mechanic or buddy along in your single pilot aircraft (all categories) is probably not viewed as a crewmember.

The Reg does allow for determination if the maintenance alters the flight performance, but solo might be the best bet for that first flight. Note that the pilot must make a logbook entry in aircraft logs.

Interpret any Reg however you wish, but always ask yourself how the NTSB / FAA, the insurance adjuster and the injured passengers' lawyers will twist it against you.

Don't spend much time looking for loopholes and exceptions. Pilots who waste my time seeking exceptions which may shortcut training, safety and proficiency kinda creep me out. Just my 2 cents . . . make your own determination as YOU are the PIC.

Burt (soloed 1967.) CFI / DPE
Marfa, Texas USA

I reviewed the Regulation you cited (91.407) and can't see where it would apply to an engine overhaul if it was removed, overhauled and reinstalled as per the overhaul manual and aircraft maintenance manual.

Sec. 91.407 - Operation after maintenance, preventive maintenance, rebuilding, or alteration.
(a) No person may operate any aircraft that has undergone maintenance, preventive maintenance, rebuilding, or alteration unless --
(1) It has been approved for return to service by a person authorized under §43.7 of this chapter; and
(2) The maintenance record entry required by §43.9 or §43.11, as applicable, of this chapter has been made.
(b) No person may carry any person (other than crewmembers) in an aircraft that has been maintained, rebuilt, or altered in a manner that may have appreciably changed its flight characteristics or substantially affected its operation in flight until an appropriately rated pilot with at least a private pilot certificate flies the aircraft, makes an operational check of the maintenance performed or alteration made, and logs the flight in the aircraft records.
(c) The aircraft does not have to be flown as required by paragraph (b) of this section if, prior to flight, ground tests, inspection, or both show conclusively that the maintenance, preventive maintenance, rebuilding, or alteration has not appreciably changed the flight characteristics or substantially affected the flight operation of the aircraft.

Paragraph (c) says it does not apply provided alteration has not appreciably changed the flight characteristics or substantially affected the flight operation of the aircraft. A removal and installation along with an overhaul should not change the flight characteristics or would it effect flight operation.

I did some research and cannot find anyone who has been violated using this Regulation because they did not flight test an aircraft after engine overhaul in the manner you described.

 

[AuntPeggy]

We are getting a rebuilt engine along with the annual my plane is now getting. The mechanic will fly the airplane first before signing it off. Probably about 1/2 hour. Hubby will fly it, too, and check it out. Then the two of us will take it on a 2000 mile trip to get the burn-in over in a weekend. This will be our third engine burn-in. We found problems with various parts that came with the new engine during the initial check-out. We got two cracked carburetors. The brush leads on the starter motor were improperly installed. At every oil change, we had to tighten the bolts on the exhaust clamps. But once that was over with, everything else went fine. The burn-in was only about 20 hours. Run it hard, run it rich, run it low.

 

[gismo]

Run it hard, run it rich, run it low.

Better yet, run it LOP (if the engine is capable of doing that smoothly). You get the same rapid seating of the rings with cool CHTs and don't cabon up the heads and plugs.

 

[Tom-D]

There ARE regulations about the first flight after maintenance.

See FAR 91.407

Generally, the first flight after major maintenance must be SOLO.

Burt (soloed 1967.) CFI / DPE
Marfa, Texas USA

91.407 does not apply to first flights after engine overhaul, because there is no change in flight characteristics.
as per (2)
(b) No person may carry any person (other than crewmembers) in an aircraft that has been maintained, rebuilt, or altered in a manner that may have appreciably changed its flight characteristics or substantially affected its operation in flight until an appropriately rated pilot with at least a private pilot certificate flies the aircraft, makes an operational check of the maintenance performed or alteration made, and logs the flight in the aircraft records.

this rule is mean to cover items such as a flight control rework, where if done wrong could cause the aircraft to fly in a weird manor.

 

[azure]

For some info, see Mike Busch's article The Savvy Aviator #53: The Dark Side of Maintenance

Thanks for the info. I would be surprised if there weren't a pattern of more failures after maintenance. I always test fly for ~an hour over the airport after even minor mx like an oil change. But infant mortality, while related, isn't exactly the same thing and I still wonder what data exists on failures within, say, the first 100 hours of an engine's life vs the second.

Lance, that link isn't even a valid tinyurl... not sure what article you meant to point to.

 

[Henning]

Infant mortality is a fact that in the first 25 hrs catastrophic failure rates are a bit higher than there after, but it's not enough that I would be overly concerned about it. My idea of caution would be to fly with a field made for a 3 hr flight following the recommended power and mixture settings, then change the oil and cut open the filter to inspect and see if the engine is making any metal. Just keep an eye on the instruments and proceed with normal caution. There's no reason she shouldn't make the flights.

 

[gismo]

Thanks for the info. I would be surprised if there weren't a pattern of more failures after maintenance. I always test fly for ~an hour over the airport after even minor mx like an oil change. But infant mortality, while related, isn't exactly the same thing and I still wonder what data exists on failures within, say, the first 100 hours of an engine's life vs the second.

Lance, that link isn't even a valid tinyurl... not sure what article you meant to point to.

Hmmm, it works for me although vBulletin didn't automatically recognize it as a URL. I tweaked the post to make it a real link but the original worked OK if I pasted it into a browser.

The full link is:

http://www.avweb.com/news/savvyaviator/savvy_aviator_48_reliability-centered_maintenance_part_2_195969-1.html

 

[gprellwitz]

Hmmm, it works for me although vBulletin didn't automatically recognize it as a URL. I tweaked the post to make it a real link but the original worked OK if I pasted it into a browser.

The full link is:

http://www.avweb.com/news/savvyavia...ity-centered_maintenance_part_2_195969-1.html

Lance, When I go to that link I get "The page you have requested is no longer available at this location." Perhaps you mean this one:
http://www.avweb.com/news/savvyavia...ity-centered_maintenance_part_2_195969-1.html
(looks like you were short an 'r').

 

[gismo]

Lance, When I go to that link I get "The page you have requested is no longer available at this location." Perhaps you mean this one:
http://www.avweb.com/news/savvyavia...ity-centered_maintenance_part_2_195969-1.html
(looks like you were short an 'r').

Yep, that's the one. I fixed the missing 'r' in the link so it should work now. Apparently when I trimmed the EOL chars that the vBulletin inserted I caught an extra byte. The original tinyURL also works for me as it did even before I tagged it to show up as a clickable link.

 

[azure]

Yes, it works now for me too, must have been a glitch at tinyurl.com.

It's very sobering to see that the bathtub curve for engines doesn't bottom out really even after the first 1000 hours and ~5 years SMOH. It almost makes me wonder if I shouldn't have bought a plane with a "run-out" engine.

It sounds like the take-away lesson here is, tear open that filter and submit your oil samples every time, follow up on anything that doesn't quite seem right (who wouldn't do that anyway?), and service your mags every 500 hours.