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

"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

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

"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.

"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

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.

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