AMT question: Approved Data
"Mark" wrote in message
...
Hello.
I am studying for my O&Ps and I have a question about "approved data" and
"acceptable data."
I understand that the manufacturer's maintenance manual is only considered
"acceptable data," and is therefore not approved for use in making major
repairs or major alterations.
So let's suppose I want to overhaul some big nasty Lycoming with an
integral supercharger and a planetary-type prop reduction gear. Per CFR
Part 43 Appendix A, this is a powerplant major repair. What is my approved
data? Is the Lycoming overhaul manual a source of approved data? If so,
what is the difference between this overhaul manual and a "maintenance
manual" as defined in CFR Part 43 Appendix A?
Second question:
Suppose I crumpled some skin on the wing of my Cessna 172. Assuming that
it is economically feasible to undertake a major repair to correct this
damage, where would I find my approved data? A Cessna 172 Structural
Repair Manual seems like the obvious choice, if there is such a
publication. Again, would this not be considered a "maintenance manual?"
Thanks
-Mark
Mark,
It can be very confusing between acceptable data and approved data. Some of
the data in the manufacturers maintenance manual is likely "approved" data,
but most is "acceptable." AC43-13 is also considered "acceptable" data.
On a major repair "acceptable" data is acceptable! It becomes "approved"
when they accept the 337. Approved data is required for major alterations.
For this purpose the data provided with the STC or on the TCDS is approved
data. The difference becomes important on a "field modification." Then you
write up the 337 explaining what you are going to do and how you will do it
referring to what approved data you have and acceptable data where you do
not have approved data. Make sure you include all sixteen points of the
ICA even if you only put down N/A for most of them. Then you send it off to
the FSDO before you do any of the work. They will put their stamp and
signature in Block 3 of the 337 and when they do all of your writeup becomes
approved. Then you perform the work exactly like you said you were going
to, and have the IA do the "return to service."
A major overhaul is "minor" maintenance and does not require a 337 form.
Welding up a crack in a seat frame is a "major" repair and does require a
337. :-) In my FSDO replaceing any factory part is minor maintenance and
just requires a logbook entry unless the part is something like a skin panel
that requires rivits to attach. Then it becomes a "major" repair because of
the rivits and requires a 337.
Putting in any avionics that is not listed on the TCDS, which these days is
virtually all avionics, requires a 337.
If ever you are not sure about something, call you PMI at the local FSDO and
talk it over. They will be glad to tell you what they will require from
you. If you give them what they need, all should go smoothly. I has worked
well for me over the years.
Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )
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