WRB asked:
Does an A&P or IA have the authority to replace a failing non-TSO 
Altimeter with a used or new functioning non-TSO altimeter with only a log
book entry and without the necessity of FSDO review and/or approval?


Bill, et al:

First, let's separate out the TSO issue.

FSDO review and approval is only required for major repairs and major
alterations not supported by other approved data.

Major repairs and major alterations are defined in part 43 appendix A.  

Approved data includes STC's, Type certificate data sheets and aircraft
specifications, AD's, FAA approved manufacturer's maintenance manuals, work
product of a DER, and field approvals (this is where the FSDO comes in).  In
addition, for unpressurized aircraft under 12500 lbs for which there is no
FAA approved maintenance manual, AC43-13.1C and .2B constitute approved
data.  (I may have missed one, and I may have gotten the 1C-2B stuff mixed
up a little, but you get the idea....)

All major repairs and major alterations must be recorded on a form 337 and
supported by approved data.

By (their) definition, anything that is not a major repair or major
alteration is a minor repair or alteration and can be returned to service by
an A&P with a log book entry.

Replacement of an approved altimeter with another approved altimeter is a
minor repair, hence an A&P and log book entry is sufficient.

Now, we're back to "what constitutes an approved altimeter"?  I still feel
that the field is not unlimited.  I would be comfortable with a used or
overhauled altimeter of the same make and model as the original, or a
similar make and model used in another approved application, i.e. from a
Cessna, Piper, Beech, etc.  I think the non-TSO'd UMA unit previously
mentioned would probably be acceptable as would any TSO'd unit. I am still
not comfortable with the "Chin Wah" unit, the Timex watch, or the unit from
Sharper Image.

There was an interesting comment by someone else earlier that a TSO'd part
still has to be approved for a particular airframe.  If I may cite an
example to clarify this:  Most aircraft tires are manufactured to a TSO.
The Aircraft specification or TCDS calls out a specific size and ply rating.
Hence, a TSO'd tire of 600-6 2 ply is acceptable on an Erccoupe but another
tire manufactured to the same TSO but of a different size is not approved,
assid from the fact that it wouldn't fit...

An aside:  Chin Wah Tire Works LTD manufactures a 600-6 2 ply wheel barrow
tire marketed through Harbor Freight. Is that approved for the Ercoupe?  Not
in my book...

TMSAISTI!

John Cooper
Skyport Services
www.skyportservices.net



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