The International Cessna^® 170 Association

Thx. The FSDO will do a field approval, but not w/o a DER.

48RagwingPilot wrote:Thx. The FSDO will do a field approval, but not w/o a DER.

Then they're not doing a field approval. A DER usually has the authority to approve the modification...that's why they are able to charge handsomely for their work-product.
Did you show your FSDO the modification illustrations in the first part of this thread?

I submitted a very thorough proposal, complete with drawings and a DER report from another ragwing owner who, based on that report, received an approved Form 337 from the FAA. Bottom line: No DER, no approval (of any kind).

Why can't you use the other guy's DER paperwork as a basis for your proposal?
If you have permission to use the data, I don't see the issue.

Making you get yet another DER (or even the same one) to make paperwork seems like a forced waste of money as the papers will say exactly what the other paperwork says.

Is the report marked as valid only for the previous aircraft?

The FAA will not accept DER paperwork from another aircraft. I've argued the point for the last year and am to the point where I need to find a DER of my own. Doesn't look like anyone here has a name, so I'll start looking at the list.

I would start with the DER who's name is on the other paperwork.

Already did. He's retired.

bagarre wrote:Why can't you use the other guy's DER paperwork as a basis for your proposal?
If you have permission to use the data, I don't see the issue.

Making you get yet another DER (or even the same one) to make paperwork seems like a forced waste of money as the papers will say exactly what the other paperwork says.

Is the report marked as valid only for the previous aircraft?

Although this seems wasteful and perhaps silly... but it's a matter of "intellectual property". Like a patent, an STC or DER paperwork is intellectual property. Unless an unlimited license is authorized from the owner of that property, it cannot be used for anyone else's purposes. That is why FAA is saying what they are.
Here's an example: My second landing/taxi lighting approval was performed by a DER. He charged $500. It probably took him a day (or two) to gather the information from structural repair manuals and Cessna IPC's, and electrical studies, and FAA AC 43.13 to make himself comfortable with the mod, then to copy and type up all the paperwork and modification instructions necessary to support FAA requirements of his job. He (or his company, partners, successors/heirs, etc.) is responsible forever as to the safety and appropriateness of the work.
That paperwork specified that the engineering was applicable ONLY to my airplane by serial number. Although I have shared that paperwork with others, it is only useful for reference, not authorization to modify another airplane. The DER who performed the study is protecting his intellectual property, and unless someone is willing to contact him and get him to allow the use of the work on another serial number... the paperwork will only apply to my airplane.