Power for portable GPS. 337 needed?

RotaryWingBob

RotaryWingBob

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We would like to have a local avionics shop (Penn Avionics) install wiring terminating in a standard Garmin plug which can then be plugged into a Garmin 496 which is temporarily mounted with an adjustable clamp. The avionics shop says a 337 is not needed and that all that is required is to tie the wiring into the bus through a fuse and then to make a logbook entry to that effect. Under this scenario, the 496 is easily removed at will.


Penn Avionics says they were explicitly instructed by the both the Allentown and Philly FSDO's that they would not process 337's for this kind of minor alteration.

Our local A&P-IA says that he will not sign off on an annual if this work is done without a 337. Are we missing something here? Does he possibly know something we don't?

Any help would be appreciated!
 
Have a cigarette lighter plug installed (easy and routine), it need not be in a convenient location. Use Garmin plug w/ same. Done.
 
RotaryWingBob said:
We would like to have a local avionics shop (Penn Avionics) install wiring terminating in a standard Garmin plug which can then be plugged into a Garmin 496 which is temporarily mounted with an adjustable clamp. The avionics shop says a 337 is not needed and that all that is required is to tie the wiring into the bus through a fuse and then to make a logbook entry to that effect. Under this scenario, the 496 is easily removed at will.


Penn Avionics says they were explicitly instructed by the both the Allentown and Philly FSDO's that they would not process 337's for this kind of minor alteration.

Our local A&P-IA says that he will not sign off on an annual if this work is done without a 337. Are we missing something here? Does he possibly know something we don't?

Any help would be appreciated!
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I'd look for a different IA or find a way to educate him. There's been disagreement for a long time as to whether or not a 337 is required to replace avionics with upgrades, but I can't imagine that a simple GPS power cord should require a 337 as that's about as far from a major alteration as you can get. Seems to me that drilling a hole in your panel is a bigger change.

Perhaps a letter from the FSDO stating that such a modification is a minor alteration and needs no 337 would solve the problem for you.
 
i think ken ibold did something similar with his citabria. 337'd in a power supply for a solid state gyro which he would use when doing acro. the gyro was technically portable as it did not screw in to the panel, IIRC. hopefully he will chime in.
 
tonycondon said:
i think ken ibold did something similar with his citabria. 337'd in a power supply for a solid state gyro which he would use when doing acro. the gyro was technically portable as it did not screw in to the panel, IIRC. hopefully he will chime in.
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Ha, in fact I did just that. The aux plug was behind the panel, mounted on a fuselage cross tube, but the panel environment was open enough underneath to allow easy access on the ground. It was properly fused and there was a secondary connection in the power line that would allow me to unplug the unit in flight if necessary. Then I DualLock'd the thing to the backside of the panel and it looked "installed" but it was technically a portable installation. There were some FSDO guys who occasionally used the airplane, and they agreed it was kosher.

My semi-official interpretation from the FAA folks in DC was that portable avionics have evolved to the point that plug in power and velcro is OK, hardwired power and screws are not. Antenna plug ins and plugs that link to other avionics are OK, as long as they require no tools to attach and disconnect.

I suspect your IA is thinking of the world 10 years ago, when airplanes were grounded for having a GPS plugged into an aux plug by overzealous FSDO guys.

I agree with Spike. Have them mount an aux plug and use the 12V power plug. It's another set of connections, and carries with it the slight chance of malfunction, but look at it this way. In 2 years you're going to want to upgrade, and you don't necessarily want to rewire that connection. Plug out, plug in.
 
The bottom line is that adding a power tap is not a "change to the basic design" of the electrical system, and thus is not a "major alteration" requiring documentation/approval on a 337. It is merely a "minor alteration" requiring documentation in the airframe log over the signature of any mechanic with an Airframe rating (not even an IA needed).
 
There has been some new guidance for FSDO Inspector on this isused in the form of an AC. The bottom line is it can be installed and signed off by an mechanic and it does not require a 337. The problem is most IA's are not educated on the AC. If I can remember the AC number I will post it.

Both Allentown and Philly FSDO's are correct in not requiring a 337 if installed correctly inaccordance with the AC.

Stache
 
Stache said:
There has been some new guidance for FSDO Inspector on this isused in the form of an AC. The bottom line is it can be installed and signed off by an mechanic and it does not require a 337. The problem is most IA's are not educated on the AC. If I can remember the AC number I will post it.

Both Allentown and Philly FSDO's are correct in not requiring a 337 if installed correctly inaccordance with the AC.

Stache
Click to expand...

Can you post the AC number (or the AC itself)?
 
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