Panel Install Job

During this COVID-19 pandemic, my very limited flying/traveling/socializing has left me with plenty of spare time. Josh has a Van’s RV-9A that he bought from another builder, and he was looking to do a big upgrade of the avionics to something more capable and modern. He decided to pull the trigger and order an Advanced Flight Systems panel with dual AFS-5600 screens, a Garmin GNC355 GPS/COM for IFR, an Autopilot controller, and second COM radio. He asked me if I would get it all installed, and I agreed to take on the job and get it done.

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Freshly assembled by the AFS team and ready to ship.

The AFS system comes as a completed panel, so I didn’t have to cut out any holes for the avionics, or deal with adding switches, painting and labeling. The AFS panel comes with an Advanced Control Module, which acts as the central hub for all of the wiring. It has electronic circuit breakers and a variety of other built in features for flaps/trim control, and things like pulsing the landing lights. Overall, it is very capable and configurable. The biggest benefit is that it is all connected up and mostly configured so that it is fully tested as a unit before it is installed. All that is needed is to bring all of the various wires from the fuel boost pump, lights, control stick inputs, flaps/trim, etc. to connectors that plug into the ACM unit. Future panel updates are made easy by just plugging in new units to the ACM.

AFS also provides an installation document that lays out exactly what you need to do to mount everything (and where), which types of wire are needed, and what connector pin outs are to be connected to your aircraft. It took several nights of reading up on everything in the installation manual to make sure I was aware of the scope and what tasks lay ahead in the installation process.

Josh flew over to Ramona Airport prior to the job so that I could look over the existing panel and wiring to see what needed to be pulled out (almost everything), and what could be reused (almost nothing). I poked my head under the panel and took some photos. It was a real rats nest in there. His airplane had a Dynon D100 EFIS and D120 MFD, so it already had “glass”, but they were the smaller 7″ screens and were several generations old from what is now available. It used standard toggle switches and circuit breakers, had a small audio intercom, an ICOM radio, and a Garmin Transponder. The GPS was a portable Garmin 496 unit mounted on the panel.

I had already planned a quick roadtrip out and back to Kansas City, MO to move my daughter back to San Diego at the end of her residency externship there. After we got back we took a week of quarantine before I started on this job. I figured it would take at least two weeks, possibly three to get it done. That was a bit optimistic! It ended up taking a whole month. I started on April 20 and finished up on May 19. There were a few factors involved with the additional time. It required some more time just waiting for parts, and the scope of the project did creep a bit. During the disassembly process I found multiple “critical to flight safety” sort of issues that the airplane had and needed to be fixed.

As I tore into the wiring I found more and more of the old stuff just had to be replaced. I did reuse a significant amount of wire, but all of the routings from front to back were modified to accommodate the additional wiring. Most of the existing wires went around the sides of the cabin above the arm rests, instead of going down the center tunnel, which is where the wires should normally be routed. I pulled out all of the switches and labeled the wires as I went. The circuit breakers all got removed. There were several local ground points being used on the airplane, and the new ACM box would now act as a central point for all of the various ground wires. I had read in the installation guide that the new AFS units would require that the existing Dynon autopilot servos be updated first with the latest firmware. To update the servos it would require some serial cable connectors be fabricated to talk to the old Dynon units, and I would need a laptop with a serial port. I called Dynon and they said to just send in the servos for them to refurbish. That was a good call, since one of the servos was very sticky in its motion, and the other one had a bent arm. Both servos were also lacking the “range limitation” brackets that keep them from going over center and potentially locking up the controls. Dynon sent them back looking great and the firmware was updated from v0.14 to v5.6. I don’t think they had ever been updated.

I pulled out the interior. One of the seat backs wasn’t even held in by the usual hinge pins. The pins used looked more like a piece of safety wire. The seat pan under the pilot seat was missing most of the rivets that should be holding it in place. The flap cover panels in the baggage area were also not completely riveted in place. I removed the baggage bulkhead cover and got a look at the aft fuselage. The ELT was mounted in the tail under the empennage fairing. The ELT was switched off. It should have been “ARMED”. It also was not connected to the aircraft power and the GPS location data serial wire was not connected. We also later found that the remote ELT switch on the panel didn’t even work because there was no battery in the switch unit. The builder had used clear vinyl tubing as conduit for running wires and they were just laying on the belly skins and not secured by anything. Lots of rubbing and vibration had started wearing out the aluminum belly skins. There was dust, dirt and debris everywhere back there.

I continued the disassembly process by taking out the fuel boost pump. I found that the insulation on the floor under it had soaked up a lot of gas and it was very oily and sticky. I spent a bit of time just scrubbing down the floor with soap and water so I could get myself down there to unhook stuff and not come out all greasy and grimy. I took off the engine cowling and started taking a good look at all of the firewall forward wiring. I had to disconnect the throttle, mixture, cabin heat and parking brake controls to get the panel out. I found the throttle cable sheathing completely melted under the engine by the exhaust pipes. The main ground wiring for the airframe was also done incorrectly. It had a stiff and heavy #2 gauge wire going from the battery terminal directly to the engine, then from the engine to the engine mount bolt. On the inside of the fuselage there was a ground wire coming from the engine mount bolt, but it wasn’t connected to anything. I ordered the correct engine ground strap and a new Buss Bolt from SteinAir, along with a new ANL fuse for the aircraft. Previously it had a 60 Amp circuit breaker on the panel, but the new panel didn’t have a spot for that breaker and the ANL fuse is a much better way to protect the entire aircraft from a power surge. You probably don’t want to be resetting a 60 Amp breaker if it pops on your airplane.

I determined from the AFS installation drawings where to mount all of the new avionics. They give specific locations for the Van’s RV-9A and it worked out great. I made an initial order to Van’s Aircraft for the ADAHRS, ELT and ADS-B mounting bracket kits. I also bought a bunch of other hardware that was needed, along with the Flap position sensor kit from the RV-14. The collection of screws holding all of the seat pans and bulkheads was all a big mish-mash of screw types, lengths and materials. The rudder stops on the fuselage were set too low and were scraping against the rudder cables. The rudder cable connections are also supposed to be castellated nuts with a cotter pin. This airplane had regular nylock nuts, which could have come unscrewed with normal rotations of the rudder.  I also did an order with Aircraft Spruce for a bunch of wires, coax cable, connectors, nutplates, firesleeve, new grommets for the control cables, and supplies to do an oil change for the airplane.

The next week was primarily spent getting all of the new avionics boxes and several new antennas mounted. There was the ACM unit, a new Engine Management System box, a new Dynon transponder, a new Dynon COM radio, a remote audio panel, manifold pressure sensor, and a backup battery for the screens. All of these were placed on the subpanel or just forward of the subpanel. I spent a lot of time laying under the panel drilling holes, riveting in new nutplates and fabricating various brackets. I had to cut some of the subpanel out to make way for the deeper mounting bracket for the Garmin GNC355. In the rear of the fuselage I mounted the ADAHRS, moved the ELT forward, added the ADS-B box and got the Outside Air Temperature probe all installed. Josh came by at the end of the week and helped me get the antennas screwed down tight. It takes a person on the inside and one on the outside to get this done.

At the start of the third week I finally had most of the supplies that were ordered in hand. I started by hooking up the EMS wires. The EGT/CHT harness had the same pin outs from the old Dynon unit to the new one, so it just plugged right in. The rest of the wires had to be routed to the other connector on the EMS. I ran a couple of new wires for this, since some of the old wires were too short. The next step was to get all of the rear fuselage wires run through a single conduit. I got all of the new coax antenna cables cut to length and run from the antennas (GPS on the top fuselage, ADS-B and COM’s on the belly) to the front of the airplane. The new AP servo wires had to be run back from the ACM unit to the rear pitch servo location. I spent quite a bit of time running the new AP servo wires out to the roll servo in the right wing. That was frustrating trying to fish the new wires out there. The old vinyl tubing in the wing was really a tight fit for the new AP wires. I also installed a new heated pitot tube in the left wing. We had to get a new pitot mast for the tube, then drill it to match the new pitot tube and get it mounted in the wing. The heated pitot tube has a small controller box that also needs to be mounted out in the wing, along with a couple of wires back to the cabin. The Pitot and Angle of Attack tubes then needed to go back from the wing to the ADAHRS in the rear fuselage.

I spent most of a day just redoing the flap attachments. The control rods for the flaps needed to be shortened up since the rod end bearings were totally bottomed out in the rods. The bolts for the flaps were also installed backwards.  I also trimmed up the holes in the fuselage since the flap control rods were rubbing the fuselage skins. I had to mount a new flap position sensor and get that wired up. The flap motor has a Service Bulletin that requires some safety wire be added to the actuator arm. There was some safety wire on there, but it was completely broken off. The wire was too thin and it broke!

Week number four looked like I might actually get to start hooking up the wires. I had most of the wires run to the front floor, but still had a few more to do. I ran the landing and taxi light wires, and ran wires to the fuel pump. The wires for the pilot stick buttons were still mostly untouched. There was a big connector under the pilot stick with 17 wires coming out, so I disconnected it and used my multimeter to determine the functions of each wire. The Infinity control stick grip had a hat switch for trim, a switch for flaps up/down, and a push to talk button. The other buttons didn’t appear to be hooked up. I found that these other buttons on this Infinity grip were not the “normally open”, momentary type needed by the ACM. One was a “normally closed”, momentary switch and the others were latching on/off buttons. As I got this all sorted out, I found buried under the pilot seat a flap/trim relay controller box. Another unneeded item, since all of that functionality is now in the ACM.

I finally had all of the wires laid out and ready to be fished through the new conduit in the center tunnel of the floor and up to the panel. I barely had enough room to get everything run through in there. I had to leave the control stick wires out of the conduit, but that is probably a good thing in case later a new grip or copilot controls get added. The current copilot stick just had a single Push To Talk button to wire up.

The ACM has four connectors to populate that connect up the rest of the airplane’s electronics. There is the Flap/Trim connector, the Control Stick connector and then a Front Aircraft, and a Rear Aircraft connector. The rear connector has the ELT, heated pitot, nav/strobe lights and landing lights. The front connector has taxi lights, fuel boost pump, cabin lights, power outlets, key switch and starter power. By the end of the fourth week, we were able to plug in all of the connectors and power on the panel. We ended up working the entire weekend and into the next week getting the last few wires for the Electronic Ignition circuit breaker and the Key Switch all wired up. Before we could get the engine started up for testing, I had to reinstall the throttle, mixture, parking brake and cabin heater controls. The parking brake needed a hole drilled into the new panel to hold it, and I had to shorten the cable quite a bit, since it previously was much farther away. The cabin heater control also needed some work. The old mounting location didn’t have a cushion clamp holding the outer sheath stationary, so it wouldn’t open and close cleanly. I got all of the interior vacuumed out and started putting back all of the center tunnel covers. I had to reinstall the fuel pump and put new insulation down on the floor under it. We finally got to do a ground run with the engine to verify all of the engine sensor readings.

We found a couple of issues. The RPM readings were off (too high), and the oil/fuel pressure readings were also wrong. We were able to get some of these fixed by changing the Pulses Per Revolution settings for the Electronic Ignition, and modifying the pressure sender types in the set up menus of the AFS. The flaps and trim also had some issues. The pitch trim was wired up backwards. There are two motor wires going to the trim servo and they are both plain white wires, so you have a 50/50 chance of getting this wrong. We pulled off the empennage fairing and swapped the wires at the connector back by the servo. The Flaps issues were seemingly just software related, and a new version of software was going to be provided for that (we were running some Beta test software, not a production version). We also had some bugs with the Autopilot calibration. The AP calibration requires a dedicated disconnect switch. I wasn’t able to get the existing control stick grip switches to work for this because they were the wrong type of switches. We repurposed the AP disconnect switch that was on the old panel and mounted it on the new panel. Since the engine run warmed up the oil, we finished the day by draining out the old oil.

I was really hoping to get it all done on Monday at the start of the fifth week of work. I finished up the oil change. We did the ELT checks, bled the brakes, and installed all of the interior panels, carpet, seat pans and cushions. We drained the fuel completely and borrowed some scales to do an updated Weight and Balance with the new avionics. Empty weight was found to be 1142 pounds. We added back the fuel to calibrate the tanks and then Josh took it up for a test flight. The weather was starting to degrade and rain was on the way, so we decided not to have him depart for his home airport. We still had an issue with the RPM readings. The next morning the weather was much better. I found that the key switch wire for the left magneto needed a 30K Ohm resistor added in order to fix the RPM issue. I pulled out the Primary Flight Display screen to get access to the correct wire, added the resistor and quickly put it all back together. We did another test flight and that last issue was resolved. Josh took off for his home airport, and I followed in my airplane so I could bring him back to his car that he left at my airport.

We still have a list of items that were deferred to work on later. We have new LED Nav/Strobe lights on order to install. The mechanical tach port on the engine needs a proper cover added (currently it just has a loose fitting rubber cap stuck on there). We are going to add a dimmer to the cabin light strip of LED’s, the rudder stops need to be redone and moved out of the way of the control cables, and there needs to be some restrictor orifice fittings added to the oil pressure and manifold pressure lines from the engine. There is also a forward controls bracket that is missing on the subpanel to support the mixture and throttle cables. We also need to adjust the location of the rudder pedals. Currently they are all the way aft. The slider canopy really needs some TLC. Most of the rivets on the side skirts are badly set. Fixing this now would mess up the paint job, so that might have to wait.

For now, I’m just happy that my airplane can have it’s place in the hangar back. It spent the entire month tied down outside getting dirty. I washed it once during the month, but since then we’ve been rained on a couple of times. The hangar also needs a big clean sweep. I had tools and supplies and wire and boxes piled up everywhere. It was quite a big project, and I was very glad to be able to do this work and to get his airplane in better condition. Hopefully, I can pick up some more of this kind of work to keep me busy.

The full gallery of photos is here.

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