FAA approval of A/RFM(S) for GPS not needed?

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skipnsb

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skipnsb
I read AC 20-138A again. I am still convinced a follow on gps install in an unpressurized non-commercial se Cessna is not a major alteration for:

Garmin 300xl gps connected to KI202 cdi with generic lights/switches.

After re-reading page 11, I believe that it is legally sufficient for the installer to prepare the A/RFM(S) based on the generic one provided in the Garmin installation manual, since this installation is "nothing special".

Steps: 1. basic equipment install 2. ground checks, placquard vfr only
3. fill in generic FMS 4. installer makes appropriate log entry and approves return to service 5. at a later time, complete flight tests, installer makes log entry and removes vfr restriction.

So, if the installer uses the sample FMS, does he simply sign it at the end "Prepared by John Doe, as installer pursuant to AC 20-138A based on the provided Garmin sample flight manual supplement"?

Disagreement?

Thanks for help understanding the FAA. Skip
 
In all honesty it depends upon the installer and the way the local FAA interprets it.

If it was me I would go about the way you stated and submit it for approval. The worst that can happen is to be denied, then at that point ask "So what do you want to see to make this legal"?

Good luck.
 
I agree with R&W -- if you don't know, ask the FSDO, because the consequences could be serious if you guess wrong.
 
I'd also think that your tech should be able to obtain or copy the generic flight manual supplement from Garmin, insert the pages after putting the a/c serial number on them, and be good to go.

That's how the Baltimore FSDO has handled IFR GPS installs from the late 90s to 2008 (based on my experience doing the flight testing portion for some shops in that area).
But, as everyone has noted - each FSDO is an independent fiefdom. It may be worth your while to find a shop that's done a lot of this stuff in the past and knows exactly what the FSDO wants, and taking your airplane to a more distant shop where it's "not" a major alteration may be cheaper than taking it to a local shop where it "is" a major alteration.

And if you're doing it yourself, then a phone call to the FSDO now will save rage/tears later.

As far as "understanding" the FAA goes - if anyone ever does I think they get declared an enemy combatant and picked up for processing.
 
The big misconception is, the installler makes the decision if it is a major or minor alteration. When the decision is made to be a major, the 337 is filled out, if there is approved data, the local A&P-IA signs off on the return to service on the 337. and the local FSDO never sees the 337. it is sorted and sent to OKC and filed with no review.

If the installer feels it is a major, and no approved data is availible, they request for field approval is made on the 337 with a cover letter. then and only then will the local FSDO see it.

I do not do avionics installs, but during the annuals I do with GPS installed I do not see a 337 stating a major occured when it was installed.
 
skipnsb said:
I read AC 20-138A again. I am still convinced a follow on gps install in an unpressurized non-commercial se Cessna is not a major alteration for:

Garmin 300xl gps connected to KI202 cdi with generic lights/switches.

After re-reading page 11, I believe that it is legally sufficient for the installer to prepare the A/RFM(S) based on the generic one provided in the Garmin installation manual, since this installation is "nothing special".

Steps: 1. basic equipment install 2. ground checks, placquard vfr only
3. fill in generic FMS 4. installer makes appropriate log entry and approves return to service 5. at a later time, complete flight tests, installer makes log entry and removes vfr restriction.

So, if the installer uses the sample FMS, does he simply sign it at the end "Prepared by John Doe, as installer pursuant to AC 20-138A based on the provided Garmin sample flight manual supplement"?

Disagreement?

Thanks for help understanding the FAA. Skip
Click to expand...

I agree it is not a major, UNLESS the instrument panel is modified to except the install. And the instrument panel is structure.

next issue would be weight and balance.
 
Whether it's major or minor, the A/RFM Supp is required, and if you don't know how to do that, it would be unwise not to ask the FSDO Airworthiness folks for help, since they're the ones who'll be involved if an issue ever arises about it.
 
Tom-D said:
I agree it is not a major, UNLESS the instrument panel is modified to except the install. And the instrument panel is structure.

next issue would be weight and balance.
Click to expand...

The problem becomes when the IA fills out the 337 he must also submit the A/RFM Supp to the local FSDO for approval. The FSDO at that point can approve the A/RFM Supp and return it (as it should be) or return the A/RFM Supp unapproved and demand the installation be feild approved before they approve the A/RFM Supp.

Just depends upon the individual FSDO.
 
Tom-D-on your annuals, have you noticed who prepared the FMS for the minor install gps? I thought weight and balance recalculation was an AP function as long as you stayed in the approved envelope?

I did call my FSDO a while back, unfortunately my project has sat for quite a while since then. I wanted to get some other's thoughts before calling again. The FSDO response then was basic avionics including (follow on) gps was a minor install, dummy. "As long as the avionics are TSO'd" she said, don't start :)

Thank you all again for your insights. Skip
 
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