What is the legality of installing a panel mount system for a Skymap 3, but removing the Skymap itself nightly. The unit would not be “hard wired” to the aircraft’s electrical system, but the mount itself would be permanently attached.
Response credit to Bob Steward:
It’s generally accepted that owner/Pilots can remove and install the SLIDE-IN radios, that have trays and some sort of latch (usually an Allen wrench). This DOES NOT include DME, Radar and Transponders. These are not even supposed to be R&R’d by A&Ps, unless they have an FCC license with Radar endorsement.
If your Skymap has provisions to be released from its tray, I see no reasons why you can’t pop it in and out at will on the ground. You’d need proper paperwork for the initial installation, per AC 43.13-2A. This would include weight an balance revisions for installed and uninstalled, should you ever plan to fly with the Skymap out for service, etc. In my region you’d need a 337 filed showing the installation, but NO FIELD APPROVAL if the installation is done I/A/W the Advisory Circular listed above.
Addendum by Mike Rellihan:
It sounds like the above described mounting will be screwed or riveted to some cockpit structure, most likely the instrument panel itself, and will involve some form of permanent changes to that structure (different fasteners, newly-drilled holes with screws or rivets, etc.). That is what understandably drives the paperwork requirement.
I have to qualify the following by saying other opinions may differ. Perhaps Bob S will view this and weigh in on it, as the BAC A&P-IA resident expert.
So far, all the A&P-IA’s I have worked with have accepted “temporary mountings” and “portable devices” without any paperwork requirement. An example of a temporary mounting might be a RAM or Garmin yoke mount, or a clamp-on mount for an approach plate or map holder. This same perspective has been extended to things such as GPS snap-in mounts that are clamped to the windshield corner braces using rubber-padded Adel clamps. The local rule of thumb has been that if the attachment is readily removable, adds no significant weight to the portable device, poses no safety hazard beyond the usual norm, does not affect any structure and uses none of the original structure’s fasteners or fastening points, and does not involve any modifications to any original structure, then it is considered a temporary, removable accessory.
It is very easy to make up a nice, small aluminum mounting plate for something like a Garmin snap-in mount. The plate can be powder-coated, the plastic snap-mount fastened to it, and the plate clamped to the corner braces with the padded Adel clamps. With the new horizontal GPS format, there is little cabin impact hazard versus a yoke mount (probably less, in a forward impact), the unit is readily viewable from both front seats, and the integral antenna is positioned where it works just fine, right on the unit.
This approach becomes even more attractive if you can take one more step, somewhere down the road. If you ever have any panel electrical or radio stack work done by a shop that has a Repair Station license (such as Gulf Coast Avionics), you can add something to the work order at relatively little additional cost. Ask them to install a 12V panel jack power outlet on the upper right and left sides of your panel. In the case of GCA, they use a nice, compact, and TSO’d helicopter headset jack, with the receptacles labeled “12V” on the panel. You can then use the male portion of the jack to make a power cord that will legally connect most portable devices to ship’s power. Since the jacks will be fused (or on a breaker), the electrical system can’t be overloaded by connecting an inappropriate device. The repair station will include this installation on the 337 for the rest of the work, making it all legal. Note that while the helicopter jack approach probably has enough pins to use for the purpose, I doubt you would be able to talk them into providing autopilot feeds this way (from a handheld GPS). More regulations would come into play, and I doubt they would be willing or able to do it.