May 15, 2008
By Ian J. Twombly
Refurbishing an instrument panel is a unique task. Not only does the installer have to be current on all the popular avionics and how they interact with each other, but he or she has to also understand basic electronics, including voltage, amps, ohms, and power. The Get Your Glass Sweepstakes Piper Archer was an even harder job for Penn Avionics because it involved a piece of equipment they had never installed before, the Aspen Avionics EFD1000 primary flight display.
According to Chris Vincigureo, the installer at Penn doing the work, the Archer was pretty straightforward, except for the Aspen. But making things more difficult was the fact that Vincigureo had less than a month from when the airplane first arrived until when we had to take it away to make it to Sun ’n Fun in early April. In that time, we wanted to have both Garmin GNS430Ws, the Avidyne EX500, the P.S. Engineering PMA 8000 audio panel, the Garmin transponder, and the Aspen PFD installed. Vincigureo was up to the task but these things are never easy.
Ideally, the entire job would have been completed in one visit. But since we wanted to show off the Aspen at Sun ’n Fun, Vincigureo had to double his effort and only install these initial items. The first series of work was almost completely flawless. As in any job, Vincigureo started on the outside. “I do all the antennas first,” he said. So even though the Avidyne TAS 600 traffic system won’t be installed until later, the antenna went in on the initial round. The reason is because when you’re working with a new interior and the entire headliner has to come down, it makes sense to only do that once. Along with the antennas, Vincigureo replaced all the coaxial cable in the entire airplane. Aviation coax is similar to what you would see in your house, except that it is all 50 ohm, whereas video coax for TVs and other devices is 75 ohm. Also, aviation coax is often double-shielded to impede interference, Vincigureo said.
After replacing the antennas, Vincigureo pulled out all the old radios, the VSI, the attitude indicator, and the directional gyro. At this point, all the work was still contained within the old panel structure, as if a customer decided not to replace the old plastic overlay with a solid, one-piece metal panel. The new GPS units, audio panel, transponder, and EX500 multifunction display went in predictably, with no issues, according to Vincigureo. The process for these installs is well known at this point, but it basically entails building a wiring harness, setting in the radio trays that come prefabricated from the manufacturer, and hooking everything together. The hard part comes when it’s time to program the boxes and make sure they’re talking to each other. We’ll have more about that in coming weeks.
This being Penn’s first Aspen install, and one of the first ever, we were worried there would be problems. Because the Aspen uses a magnetometer to obtain its data, proper placement of that antenna is the first step. Aspen Avionics has identified certain places where the antenna can’t go, and these include some predictable locations like next to a GPS antenna, or next to a light. But in testing, some other interesting observations have cropped up. One company representative said that they found it couldn’t go directly above the pilot or copilot seat in some airplanes because metal on the occupant’s headsets altered the readings. In the case of the Archer, the magnetometer ended up on the back of the fuselage, next to the dorsal fin that leads to the vertical stabilator.
After Vincigureo installed the magnetometer, he had to get the ACU, or auxiliary control unit, in. The Archer has limited space behind the panel, so Vincigureo decided to put the ACU under the rear seats next to the spar. That’s also where the autopilot servos reside. Aspen’s ACU is a complex, interesting piece of equipment. In some cases it won’t be necessary, but because our unit will be interfacing with two GPS units and an analog autopilot, it was required. Customers only trying to get one Garmin GNS430 to feed in to the Aspen probably won’t need the ACU.
After the ACU came the unit itself. “In general I like to finish my work in the panel,” Vincigureo said. “After the antennas come the boxes, then the work in the panel itself.” With that systematic philosophy in mind, he installed the Aspen last. And because the Aspen simply slips in to the space left by the vacant attitude indicator and directional gyro, that is easy and logical to do. Stay tuned for how the Aspen install came together.
Next week: Installing the Aspen and interfacing
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