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Major Overhaul



 
 
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  #1  
Old June 6th 04, 04:47 PM
Jim Weir
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Default Major Overhaul

There have been a few questions in this ng lately about a "major overhaul". We
all have TSMOH (time since major overhaul) as an annual inspection calculation
in the logbooks.

Let's say that I tore an engine down to the last lockwasher, inspected each
component by whatever approved standard I wished, replaced each part that did
not meet service limits with an approved part, reassembled the engine in
accordance with approved data and techniques, ran the engine up and checked each
parameter for proper operation (oil pressure, temperature, fuel flow, etc.), and
returned the engine to service.

Could I sign off that engine as a "major overhaul".

Probably not. The work, if it to be signed off as a "major overhaul" must be
done in STRICT accordance with the manufacturer's overhaul procedure.

1. If the manufacturer's overhaul manual specified dye penetrant inspection and
I chose the much better and more conclusive X-ray inspection of a part, it is
not a major overhaul.

2. If I chose not to replace a part that had not reached service limits (or new
limits, for that matter) and the manual specified that the part had to be
replaced at each overhaul, it is not a major overhaul.

3. If I reassembled the engine in accordance with approved data and techniques
and they differed from the manual, it is not a major overhaul.

4. If I ran the engine up and measured each operating parameter and the manual
specified a different method of testing and break-in, it is not a major
overhaul. (This is the one that gets most would-be overhaulers...if the manual
specified a test stand and a propeller club and I used the airframe and a real
propeller, it is not a major overhaul. If the manual specified a Rootytooty
Model AJ3 flow meter and I used the AJ4 version, it is not a major overhaul.)

STRICT accordance with the overhaul manual.

Jim
Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com
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  #2  
Old June 6th 04, 05:35 PM
jls
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Default


"Jim Weir" wrote in message
...
There have been a few questions in this ng lately about a "major

overhaul". [...]
STRICT accordance with the overhaul manual.


And what is the current overhaul manual? Do service letters constitute
supplements, as well as the supplements themselves?

Jim
Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com



  #3  
Old June 6th 04, 06:29 PM
Jim Weir
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Default

Anybody can write a service letter, and you could argue both ways as to whether
a service letter is a part of the current o/h manual.

An approved supplement is, by definition, part of the manual.

My opinion only, YFSDOMV.

Jim





-And what is the current overhaul manual? Do service letters constitute
-supplements, as well as the supplements themselves?

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com
  #4  
Old June 6th 04, 06:56 PM
John Kunkel
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Default


"Jim Weir" wrote in message
...
There have been a few questions in this ng lately about a "major

overhaul". We
all have TSMOH (time since major overhaul) as an annual inspection

calculation
in the logbooks.

Let's say that I tore an engine down to the last lockwasher, inspected

each
component by whatever approved standard I wished, replaced each part that

did
not meet service limits with an approved part, reassembled the engine in
accordance with approved data and techniques, ran the engine up and

checked each
parameter for proper operation (oil pressure, temperature, fuel flow,

etc.), and
returned the engine to service.

Could I sign off that engine as a "major overhaul".

Probably not. The work, if it to be signed off as a "major overhaul" must

be
done in STRICT accordance with the manufacturer's overhaul procedure.


And then you get into the old argument about the word "major" and whether
the use of that word constitutes a major repair needing a 337.



  #5  
Old June 6th 04, 07:09 PM
Jerry Kurata
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Default

Good points. Another reason a buyer should ensure somone in the know
reviews the logbooks as part of the pre buy activities.


"Jim Weir" wrote in message
...
There have been a few questions in this ng lately about a "major

overhaul". We
all have TSMOH (time since major overhaul) as an annual inspection

calculation
in the logbooks.

Let's say that I tore an engine down to the last lockwasher, inspected

each
component by whatever approved standard I wished, replaced each part that

did
not meet service limits with an approved part, reassembled the engine in
accordance with approved data and techniques, ran the engine up and

checked each
parameter for proper operation (oil pressure, temperature, fuel flow,

etc.), and
returned the engine to service.

Could I sign off that engine as a "major overhaul".

Probably not. The work, if it to be signed off as a "major overhaul" must

be
done in STRICT accordance with the manufacturer's overhaul procedure.

1. If the manufacturer's overhaul manual specified dye penetrant

inspection and
I chose the much better and more conclusive X-ray inspection of a part, it

is
not a major overhaul.

2. If I chose not to replace a part that had not reached service limits

(or new
limits, for that matter) and the manual specified that the part had to be
replaced at each overhaul, it is not a major overhaul.

3. If I reassembled the engine in accordance with approved data and

techniques
and they differed from the manual, it is not a major overhaul.

4. If I ran the engine up and measured each operating parameter and the

manual
specified a different method of testing and break-in, it is not a major
overhaul. (This is the one that gets most would-be overhaulers...if the

manual
specified a test stand and a propeller club and I used the airframe and a

real
propeller, it is not a major overhaul. If the manual specified a

Rootytooty
Model AJ3 flow meter and I used the AJ4 version, it is not a major

overhaul.)

STRICT accordance with the overhaul manual.

Jim
Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com



  #6  
Old June 7th 04, 12:00 AM
Jim Weir
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Default

"Gene Kearns"
shared these priceless pearls of wisdom:


-
-No... you shouldn't sign it off at all. You, as a mechanic or owner
-cannot just arbitrarily decide to "....inspect each component by
-whatever approved standard I wished...."

That is not true. If 43.13.1x or 65-9/12/15 or any one of a number of Advisory
Circulars gives me, as a mechanic, the option of inspecting a particular part by
a number of methods, then absent direct prohibition during a REPAIR, I can use
any one of them. For example, there are four methods by which I am authorized
to inspect a part (magnetic particle, dye penetrant, x-ray, or hydrostatic). It
is MY option in MY professional opinion as to which method I am going to use on
a particular part.

However, if it is to be a major OVERHAUL, then I must use whatever method(s) are
specified in the o/h manual.

-
-If one *must* do business in this manner.... go homebuilt.

Please, don't talk down to me.


-
-Probably not. The work, if it to be signed off as a "major overhaul" must be
-done in STRICT accordance with the manufacturer's overhaul procedure.
-
-
-"major overhaul" is not a defined concept. There are overhaul
-standards clearly stated in FAR 43. An overhaul may be a major
-*repair* or not.... under Part 43.

I'd suggest a brief discussion with your Principal Maintenance Inspector at your
local FSDO. "Major overhaul" is a VERY WELL defined concept.

-
-1. If the manufacturer's overhaul manual specified dye penetrant inspection
and
-I chose the much better and more conclusive X-ray inspection of a part, it is
-not a major overhaul.
-
-
-Clearly under Part 43 you must follow the manufacturers suggestions.
-That doesn't however, prevent you from having your own procedure
-approved by the FAA. The onus of proving that you "chose the much
-better and more conclusive X-ray inspection of a part" is on you.

No sir, I do NOT have to follow the manufacturer's suggestions. Suggestions are
just that, suggestions. And, if I am "repairing" instead of "overhauling" then
I certainly must follow any approved repair procedures. If there is no clear
repair procedure, I may proceed on my own best judgement.

[snip of a whole bunch of nitpicky crap]


-
-Many manufacturers of engines and airframes allow break-in installed
-on the airframe if the proper engine parameters can be monitored. A
-GEM is usually sufficient.

A GEM didn't even EXIST when a C-85 was designed, nor has the service manual
given that as an approved method of testing. Ditto most engines in service
today.


-
-STRICT accordance with the overhaul manual.
-
-
-And service publications, which engine manufacturers consider to be
-supplements and supercedures to the printed manual.

Only if the magic words, "FAA Approved Data" appear on the publication, in which
case it is a true supplement, not a service letter.

-
-
-Again, if the rules contained in FAR 43 are just too intrusive and
-onerous to follow..... the FAA has give you an "out" ... go homebuilt.

Oh, horsefeathers.

Jim

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com
  #7  
Old June 7th 04, 03:30 PM
Javier Henderson
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Default

"John Kunkel" writes:

And then you get into the old argument about the word "major" and whether
the use of that word constitutes a major repair needing a 337.


Since when a 337 is required for a major repair?

Are you confusing a repair that requires a lot of work but doesn't deviate
from the original TC with a major alteration?

-jav
  #8  
Old June 7th 04, 05:31 PM
G.R. Patterson III
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Default



Javier Henderson wrote:

Since when a 337 is required for a major repair?


The title of the form is "Major Repair or Alteration".

See http://www.awp.faa.gov/fsdo/ans_apr3_99.htm

George Patterson
None of us is as dumb as all of us.
  #9  
Old June 8th 04, 05:44 AM
Javier Henderson
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Default

"Gene Kearns" writes:

On 07 Jun 2004 07:30:14 -0700, Javier Henderson
wrote:

"John Kunkel" writes:

And then you get into the old argument about the word "major" and whether
the use of that word constitutes a major repair needing a 337.


Since when a 337 is required for a major repair?


Since almost forever. See FAR 43 Appendix B....
http://tinyurl.com/ytakf


Interesting. Thanks for the URL.

But, if I read it correctly, paragraph (b) tells that the form is not
needed if the repairs are made IAW manual or specs acceptable to the
administrator. Presumably, the overhaul manual is a manul or spec
acceptable to the admin?

-jav
  #10  
Old June 8th 04, 11:19 AM
JohnN3TWN
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Default

That is ONLY for a certified repair station (part 145)

But, if I read it correctly, paragraph (b) tells that the form is not
needed if the repairs are made IAW manual or specs acceptable to the
administrator. Presumably, the overhaul manual is a manul or spec
acceptable to the admin?



 




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