"follow on" field approvals

Before I leave on my Sabbatical, I thought I'd leave this for you to ponder. Anyone familiar with what a "follow on" field approval is? Well worth finding out. Don't know if they are new, or been around a long time but if they have been, I wish I had known about them.

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Interesting. Read about it.
www2.faa.gov/avr/afs/faa/8300/8300_vol2/2_001_00.pdf
See page 2.
SB

Supporting Data

The way I read it is that a follow-on approval is another 337 that is approved due to supporting data from a previously approved 337. Is this correct?

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Progress Report

Has anyone made any progress figuring this out?

I THINK it means that a prior approved 337 can be an acceptable source of data to support approval of a repair or mod, but that it does not automatically guarantee approval for the new instance of the repair or mod.

I asked this question specifically at the recent IA meeting. The ASI said basically what TJ surmised. That the Avionics guys were the only ones getting involved with these. His understanding was that a radio, for example, has the same requirements whether it is installed in a Jetstream or a Citation (oops, let's say a Super Cub or a Husky). Any detailed supporting documentation (like indicating head combos that are shown to be compatible) that is so obviously the same as to not matter WHICH airplane you installed it in would be sufficient for the approval being applied for. He supposed, "let's say you had a field approval to put an automotive voltage regulator on a Pacer, you could use it for a follow-on for a Super Cub." But he also said mechanically (as opposed to electrically), he didn't see any differance or advantage from going the regular route, because there is no "ultimate differance" in how you get -or don't get- an approval. Basically, its "Much ado about Nothing", not an easy way around.

I don't know if this was really a "follow-on", but I obtained approval in the past month for a B&C alternator and voltage regulator in a PA-12, based on prior 337's and the fact that the alternator was similar to equipment used on current production aircraft. Friendly Aviation Administration was very easy to deal with on this one.

I got a fiberglass split nose bowl approved on a PA16 using previously approved 337 from a Super Cub. I think it all comes down to the inspector.