DER or ASI approval for AFMS / 337 data

[mtuomi]

Getting the GX55 GPS in my C150M approved for IFR. Everything else is done for the install, just need to get the flight manual supplement approved and 337 sorted. Should be an easy-ish process, Garmin/Apollo provides the manual template, installation uses a Mid-Continent CDI/annunciator. Everything's TSO'd etc. No STC with AML available for this GPS. Only a generic STC for a Partenavia P68 (can this be used as approved data?)
Flight test was completed i/a/w AC90-138B.

Now, first of all. Is this actually required? My plane was type certified before AFM was a requirement. from 8300.16

"c. The supplemental information may be presented as modified or additional markings and placards in aircraft that were type certificated before AFMs were required."

I still can't find the requirement to get a field approval for a non-approach IFR GPS. I'm sure it's somewhere, just can't find it.

8300.16 says a DER can approve AFMS within their authority. What authority would be the correct one? I would imagine the same DER could approve the technical data provided for the install, removing the need for a field approval? Would this be an easier way to complete this?

 

[flyingron]

Not having a flight manual does not give you an out for having a flight manual supplement when required. I've got a dozen supplements for my non-existant flight manual (tip tanks, IFR GPS, autopilot, tail STC, etc...).

I agree, unless you had to make structural changes to install it, a VFR-only GX55 installation is not a major modification requiring any more than some compliant A&P's signature.

Now the GX55 can be installed and approved for IFR enroute and terminal, so there you'll have to get the STC or other approval.

 

[mtuomi]

Not having a flight manual does not give you an out for having a flight manual supplement when required. I've got a dozen supplements for my non-existant flight manual (tip tanks, IFR GPS, autopilot, tail STC, etc...).

I agree, unless you had to make structural changes to install it, a VFR-only GX55 installation is not a major modification requiring any more than some compliant A&P's signature.

Now the GX55 can be installed and approved for IFR enroute and terminal, so there you'll have to get the STC or other approval.

It is installed as VFR right now, and I'm working to get it IFR'd. The GPS has an STC to another airframe (P68), I understand this can be used as approved data for my install as well?
The installation has everything GX55 installation manual requires for IFR use (annunciator and CDI). Flight test has been done i/a/w AC 90-138B.

I still can't find where FAA says IFR GPS is a major modification. I know it is, but I just can't find a reference for it.

How long is the ASI/DER approval process normally, assuming paperwork is in order? Can I "shop around" for an ASI who knows what they are doing or do I have to use my nearest FSDO?

Technically I think not having a flight manual does give me "an out" (see my quote from 8300.16) , but it seems then the placards/markings have to be approved, and I guess that is harder than just using a template AFMS.