Cracked lifter bodies on my C-145

[Bruce Fenstermacher]

My intent was to keep us from re-defining the terms.

Good catch. Of course when I typed Major I was thinking in terms of what wasn't a minor repair. Of course a Major repair on an engine would not be an overhaul.

Neither plan would meet the definition of " overhaul"...

We intentionally did not list all the requirements of an overhaul. We simply stated that once the inspections Thad planned to carry out where done, he was closer to an overhaul than not so why not complete the overhaul.

...if the cylinders (or any other time-in-service component) was merely
inspected and not returned to overhauled condition.

One of the most common errors found in logbooks is the
confusion and mis-use of those terms. The vast majority of
engines returned to service after major teardown (despite the logbook
entries), are neither overhauls nor rebuilds...but instead are "repairs".

Yes I agree the word overhauled is many things to many people and not understood by many. So there it is. What is overhauled condition? The word overhaul is not defined in FAR 1.1 how ever it is defined in FAR 43.2 Records of overhaul and rebuilding.

• § 43.2 Records of overhaul and rebuilding.
  
  (a) No person may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being overhauled unless—
  
  (1) Using methods, techniques, and practices acceptable to the Administrator, it has been disassembled, cleaned, inspected, repaired as necessary, and reassembled; and
  
  (2) It has been tested in accordance with approved standards and technical data, or in accordance with current standards and technical data acceptable to the Administrator, which have been developed and documented by the holder of the type certificate, supplemental type certificate, or a material, part, process, or appliance approval under part 21 of this chapter.
  
  (b) No person may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being rebuilt unless it has been disassembled, cleaned, inspected, repaired as necessary, reassembled, and tested to the same tolerances and limits as a new item, using either new parts or used parts that either conform to new part tolerances and limits or to approved oversized or undersized dimensions.

So a cylinder inspected and found not to have any defects outlined per the overhaul manual and also within the serviceable dimensions IS in overhauled condition. It requires no new parts or new tolerances.

So bottom line an overhaul is nothing more and nothing less than a Disassembly, Cleaning and Inspection (Chapter 10 OHM). Repair and Replacement (Chapter 11 OHM). Reassembly, Final Assembly, Timiing and Testing (Chapter 12).

Those parts that can not be repaired to at least serviceable limits or those parts required to be replaced by the manual are the only new parts required. Of these steps the testing is probably the one most flagrantly not followed. How many have a 4 bladed test club (not a flight propeller) and ground run the engine with no baffling installed?

The biggest misunderstanding with the word overhaul is folks think it means the engine or its part are new or like new. That can be pretty far from the truth. And log book entries don't help lots of times as the overhauler is not required to list the discrepancies found and how they were repaired or to what tolerances the components were found, possibly repaired to, and used. They are only required to say the engine was overhauled per the overhaul manual and that leaves some pretty wide latitude.

Here is a link to an excellent article I found on this subject: http://www.aviationpros.com/article/103 ... rhaul-myth

[GAHorn]

Also, be aware that new, approved oversize/underside....does not equate to"serviceable".

[Bruce Fenstermacher]

Also, be aware that new, approved oversize/underside....does not equate to"serviceable".

I'm not following that statement.

[GAHorn]

"Serviceable limits" are suitable for continued service....but may not meet "new, or approved oversize/under size" specifications.
An engine which has not met ALL the specifications of the mfr s overhaul specs....is not an
overhaul ed engine...it's a repaired engine...it has"zero hours since REPAIR....not since overhaul...
and should not be represented as SMOH.
Example: TCM Overhaul Manual requires complete replacement of thrubolts.
An A & P disassembles, cleans, inspects, measures and finds the used bolts meet the same dimensions as new bolts and reuses them. ALL other parts are replaced with new parts, and
the engine is reassembled, test run, and approved for return to service.
This is now a REPAIRED engine....not an overhauled engine.
The practice of signing off such work as an overhaul is one which is widely abused,
often with many parts being returned to service which do not meet the definition
of the rules.

[N2255D]

Also, be aware that new, approved oversize/underside....does not equate to"serviceable".

I'm not following that statement.

They are not serviceable because they are only oversize on the underside.

[c170b53]

Aside from a debate on what is an overhaul and what is a repair

[GAHorn]

Aside from a debate......

I would hope a discussion such a this not be misconstrued with a "debate".
The very point is to learn from each other and to preserve accuracy in our vocabulary. It's often the miscommunication that creates hardship/injury....which never mightnt
have occurred if matters had been accurately represented in the beginning.

[Bruce Fenstermacher]

"Serviceable limits" are suitable for continued service....but may not meet "new, or approved oversize/under size" specifications.
An engine which has not met ALL the specifications of the mfr s overhaul specs....is not an
overhaul ed engine...it's a repaired engine...it has"zero hours since REPAIR....not since overhaul...
and should not be represented as SMOH.

I agree that the overhaul has to meet the standards of the overhaul manual . That includes oversized or undersized parts as allowed by the overhaul manual or other approval for overhaul. An overhauled engine with a legally ground .010 under crank and .010 over bearings, .15 over cylinders, .005 over rocker shafts, longer push rods and other things I can't think of at the moment is overhauled if the manual allows it and in many cases it does.

Example: TCM Overhaul Manual requires complete replacement of thrubolts.
An A & P disassembles, cleans, inspects, measures and finds the used bolts meet the same dimensions as new bolts and reuses them. ALL other parts are replaced with new parts, and
the engine is reassembled, test run, and approved for return to service.
This is now a REPAIRED engine....not an overhauled engine.
The practice of signing off such work as an overhaul is one which is widely abused,
often with many parts being returned to service which do not meet the definition
of the rules.

This is a bad example George because the overhaul manual (C-145) does not call for the replacement of the thrubolts. In fact it does not call for the replacement of a lot of things one might replace at overhaul such as main or connecting rod bearings. TCM SB 97-6 1997-04-07 MANDATORY REPLACEMENT PARTS calls for the replacement of the thrubolts as well as a lot of other parts. As we know we do not have to comply with SBs for part 91 flying and it is not called for in 42.3 where the term overhaul is defined.

Ok then why are overhaulers replacing thrubolts at $134 a pop. Because there is case law where a mechanic was found to not have followed the Lycoming Overhaul Manual (OM) by the NTSB because in part he did not follow a Lycoming SB that called for a person performing the magnetic particle testing to be certified. Appearently the Lycoming OM says that any SBs subseguently issued by Lycoming are part of the OM. Here is an article with analysis of that case: http://www.aea.net/AvionicsNews/ANArchi ... wsHill.pdf

I haven't read the Continental C-145 OH from cover to cover lately. But a recent quick review did not show the manual contains any wording that would include any subsequent SBs as part of the manual. So in my opinion SBs including but not limited to TCM SB 97-6 do not have to be complied with in order for an Continental C-145/0-300 engine to be considered by the FARs to be overhauled.

BTW- The danger of course with the decision in the case law is that with some simple wording in overhaul or maintenance manuals, manufactures can supercede the FARs and in effect require everyone to comply with ALL SBs issued. Beware, this is one reason we do not want TCM or Cessna rewriting or up dating any overhaul or maintenance manuals for our aircraft.

[GAHorn]

"Serviceable limits" are suitable for continued service....but may not meet "new, or approved oversize/under size" specifications....

I agree that the overhaul has to meet the standards of the overhaul manual . That includes oversized or undersized parts as allowed by the overhaul manual or other approval for overhaul. An overhauled engine with a legally ground .010 under crank and .010 over bearings, .15 over cylinders, .005 over rocker shafts, longer push rods and other things I can't think of at the moment is overhauled if the manual allows it and in many cases it does. .

A part which meets "service limits" may be out-of-spec for new, oversize, or undersize limits...but may continue for time-in-service. Therefore, it cannot meet "overhaul" defn'. The engine utilizing such parts is a "repair".

Example: TCM Overhaul Manual requires complete replacement of thrubolts.....

...This is a bad example George because the overhaul manual (C-145) does not call for the replacement of the thrubolts. In fact it does not call for the replacement of a lot of things one might replace at overhaul such as main or connecting rod bearings. TCM SB 97-6 1997-04-07 MANDATORY REPLACEMENT PARTS calls for the replacement of the thrubolts as well as a lot of other parts. As we know we do not have to comply with SBs for part 91 flying and it is not called for in 42.3 where the term overhaul is defined.....

I think it's the PERFECT example, Bruce. Firstly, I did not specify the C145/O300 engine, as I was speaking in generic terms....
HOWEVER, you bring up a magnificent example of this vocabulary problem: YES...you are correct, a Part 91 operator does not HAVE to comply with all SB's. HOWEVER..if the mfr issues a SB which provides instructions for completion of the overhaul, such as the SB 97-6.... it becomes a requirement of that overhaul. (See the article you posted regarding this very matter.)\
BUT, also..as you correctly observe, Pt 91 operators are NOT req'd to comply with that SB... however if they don't...they may NOT call it an "overhaul".... it is a "REPAIR."

[c170b53]

George it's all very good material as you and I know and I'm just having some fun with what I foresaw as the logical path of this thread. And yes maybe I helped it along but I was really counting on some others to get the ball rolling.
Seriously, in aviation it seems that everyone is trying to split the beaver off their nickels.

[twlareau]

Well we got the engine crated up and off to Tulsa for a few weeks of R and R. The cylinders go out next week!

[twlareau]

Update,
I just recieved a call from Aircraft Specialties Services. My crankshaft has a "severe" crack on the flange. Not good news but at least we found it before the prop fell off! I think the airplane will be down for quite some time now. Will keep the updates coming.

[GAHorn]

Update,
I just recieved a call from Aircraft Specialties Services. My crankshaft has a "severe" crack on the flange. Not good news but at least we found it before the prop fell off! I think the airplane will be down for quite some time now. Will keep the updates coming.

That is GREAT (bad) news. I'm glad it was found. It would be a shame to spend a lot of time/money on a "field repair" only to have a crankshaft fail....and perhaps endanger occupants/bystanders as well.

Hopefully a good crank, reasonably priced can be found.

[Bruce Fenstermacher]

After some research I wanted to return to this thread which has morphed into the question, "What is an Overhaul".

Two questions seem to be in contention. 1. What minimum dimension parts need to be used to be considered an Overhaul. 2. Does on have to follow manufacturers Service Bullitens for an engine being flown under part 91.

As for question #1. After speaking with about 6 A&Ps with IA which included one major engine overhauler, one tech rep for a major engine manufacturer and one retired FAA maintenance inspector, the concensise was unanimus. Parts in an engine "Overhaul" only have to meet the Servicable Limit. I then came across AC 43-11 Reciprocating Engine Overhaul Terminology and Standards. Below I've copied the applicable part for this discussion. The emphasis in red is mine.

• AC 43-11 CHG 1
  4. ENGINE OVERHAUL TERMINOLOGY.
  a. Engine Overhaul Facilities.
  (1) Engine overhaul facilities include following:
  • The manufacturer, or a manufacturer’s approved agency
  • Large and small Federal Aviation Administration (FAA)-certificated repair stations
  • Engine shops that perform custom overhauls
  • Individual certificated powerplant mechanics
  (2) These facilities offer various services. Regardless of the type or size of the facility, all are required to comply with §§ 43.13(a) and 43.13(b). In this regard, it is the responsibility of the owner to assure that proper entries are made in the engine records in accordance with §§ 91.405 and 91.417. Engine overhaul facilities are required by § 43.9 to make appropriate entries in the engine records of maintenance that was performed on the engine. The owner should ensure that the engine overhaul facility references the tolerances used (new or serviceable) to accomplish the engine overhaul.
  b. Fits and Limits. Engine overhaul manuals outline the two kinds of dimensional limits observed during engine overhaul as a “Table of Limits” or a “Table of Dimensional Limits.” These tables list the parts of the engine that are subject to wear, and contain minimum and maximum figures for the dimensions of those parts and the clearances between mating surfaces. The lists specify two limits as follows:
  (1) Manufacturer’s Minimum and Maximum. Some manufacturers use the terms “new parts” or “new limits” when referring to these dimensional limits. These are the dimensions and standards that all new parts meet as required by 14 CFR for the issuance of a type certificate (TC). It is important to note that new dimensions do not mean new parts are installed in an engine when a manufacturer, or the manufacturer’s authorized representative, presents zero time records in accordance with § 91.421. It does mean that used parts in the engine were inspected and met the manufacturer’s new specifications.
  (2) Service Limits. Service limits are dimensions representing limits that must not be exceeded and are dimension limits for permissible wear.
  (a) The comparative measurement of parts will determine their serviceability; however, it is not always easy to determine which part has the most wear. The manufacturer’s new dimensions or limits are a guide for determining the amount of wear that has occurred during service. In an engine overhaul certain parts are replaced regardless of condition. If an engine is overhauled to “serviceable” limits, the parts must conform to the fits and limits specifications as listed in the manufacturer’s overhaul manuals and Service Bulletins (SB).
  (b) If a major overhaul is performed to serviceable limits or an engine is top overhauled, the total time on the engine continues in the engine records.
  c. Overhaul. In the general aviation industry, the term engine overhaul has two identifications that make a distinction between the degrees of work on an engine:
  (1) Major Overhaul. A major overhaul consists of the complete disassembly of an engine. The overhaul facility inspects the engine, repairs it as necessary, reassembles, tests, and approves it for return to service within the fits and limits specified by the manufacturer’s overhaul data. This could be to new fits and limits or serviceable limits. The engine owner should clearly understand what fits and limits should be used when the engine is presented for overhaul. The owner should also be aware of any replaced parts, regardless of condition, as a result of a manufacturer’s overhaul data, SB, or an Airworthiness Directive (AD).
  
  The full AC 43-11

It is pretty clear to me that Overhauled engine parts only have to meet service limits. So one Overhauled engine is likely not the same as another Overhauled engine. A buyer or owner should understand this. And buyers and owners should also understand that in all likely hood they are not going to see much detail exactly to what standard an engine was Overhauled to because that information is not required to be entered into the logs. In my opinion this is a shame really. Note please we are not talking about an engine that is signed of as Rebuilt. Rebuilt engines must have parts that meet new dimensions and if Rebuilt by the manufacterer or their representitive can be set to 0 time with a new log.

As for question #2 I was not able to find a FAR that required part 91 operators to follow manufacturers Service Bullitens during engine Overhaul. In fact most of the A&Ps I spoke to said that in the case of a Continental you probably don't but that was not necessarily their practice or preference.

In the case of a Lycoming Overhaul the Overhaul manual states that all subsequent Service Bullitens become part of the Overhaul Manual. As discussed earlier there is a precident set in court by judge and upheld by the NTSB which involved a Lycoming Overhaul. In it the NTSB determined that if a manufacturer uses SBs to make revisions or additions to it's Overhaul Manual then they become part of the manual.

A call to Teledyn Continental Motors Technical Support confirmed that the overhaul manual for the C-145/0-300 hasn't changed since 1982 except for rev 2 in Aug 2011 (as I recall) which consisted of a change of logo on the cover sheets. I've read it several times and can not find a statement that subsequent SBs become part of the manual. When I asked the tech rep how Continental revised their maintenance manuals he said by revision and he didn't expect any for our out of production engines. When pressed about SBs he said he thought that SBs were in essense revisions of the maintenance manual since they could contain later official manufacturers information. I didn't expect him to say any different.

So what are we left with. Appearently no FAR, that I could find anyway, that requires SBs to be complied with and in fact some to the contrary yet the legal system that backs the FARs has found that we do have to follow SBs in the case of following Overhaul Manuals. This of course is a dangeroius precident as pointed out by the legal brief of this case linked earlier. If a manufacturer writes an SB that states one can only use OEM parts for overhaul, then produces none, we will all be out of business. The brief stated it would expect this decision to be overturned had the case been heard by appellate court for several reasons but it was not.

Bottom line in my opinion. In the case of a Continental Overhaul one does not by FAR have to comply with SBs for Overhauls flown under part 91, but should one be challenged in court for not doing so, one would have an uphill battle they may win with enough time and money.

[N2255D]

As for question #2 I was not able to find a FAR that required part 91 operators to follow manufacturers Service Bullitens during engine Overhaul. In fact most of the A&Ps I spoke to said that in the case of a Continental you probably don't but that was not necessarily their practice or preference.

Looks like it's here Bruce

(2) Service Limits. Service limits are dimensions representing limits that must not be exceeded and are dimension limits for permissible wear.
(a) The comparative measurement of parts will determine their serviceability; however, it is not always easy to determine which part has the most wear. The manufacturer’s new dimensions or limits are a guide for determining the amount of wear that has occurred during service. In an engine overhaul certain parts are replaced regardless of condition. If an engine is overhauled to “serviceable” limits, the parts must conform to the fits and limits specifications as listed in the manufacturer’s overhaul manuals and Service Bulletins (SB).