Friday, December 01, 2006

Avionics Upgrade - Part 2

What makes a technically advanced airplane (TAA) technically advanced? I'm sure there are different opinions on this subject, but in my opinion a TAA airplane has systems that talk to each other in order to share information whereas traditional aircraft systems are stand-alone. To expand on this, a TAA would have to have a minimum of an IFR Certified GPS, Multi-function Display (MFD) and other systems that exchange information between units.

Integration is the key to achieving the TAA goal, so what should I get? There are a million and one systems you can stuff in an airplane. The key is to minimize weight and get the biggest return on the investment.

Decision 1, GPS? There are a lot of GPS's on the market, but in reality only one manufacturer -- Garmin. The choice is relatively easy with this one. Get a GNS-430 or GNS-530. Garmin also sells the Apollo GNS-480, but they aren't going out of their way to enhance it. Stick with the tried and true 430/530. They are easy to use, powerful and naturally train you to jump to a G1000 system. The UI of a G1000 is very similar.

Decision 2, WAAS. Wide Area Augmentation is an absolute now days. The FAA is adding LPV (Localizer Performance with Vertical Guidence) virtually every day. What does this mean? You can get ILS minimums with a glidelsope like bar off of your GPS! At some point if you don't have WAAS you won't be able to fly IFR. It is too costly to maintain legacy navaids. It is only a matter of time and they will be gone forever. The simple choice is if you are putting in a GPS -- put in a WAAS unit. If you have a GPS, upgrade it to WAAS.

Decision 3, the GPS decision is easy, the WAAS decision is easy, which one should I get? A 430 or a 530? From a capability perspective the GNS-430 & 530 are basically the same units. The only difference is the 530 has a bigger display. It is nice having a big display, but the resolution is nowhere near a dedicated MFD. A MFD is designed to maximize screen real estate and the 530 also takes up a lot of potential screen area due to the com/nav knobs. I wanted a TAA and I wanted an MFD. If I had a Bonanza I could do it all, but a Mooney simply does not have the panel space to do a 430/530/MFD. I decided to go with the 430/MFD combo. At the time the MX-20 was the only Garmin option. Now they have the GMX-200. If I were doing this project today, the GMX-200 would be the best choice.

Decision 4, should I get 2 430's or just one and keep the KX-165? A lot of people install two 430's or a 430/530, but to me this doesn't make since if you already have a solid IFR nav/com. To be legal to fly IFR, you have to update both radios. Jeppesen gives a discount for the second radio in the same plane, but this is a pain to do every 28 days. Why update the MFD & two GPS's when in most cases you can do everything you need with the MFD/GPS? It does add redundancy, but it also add material cost to the project. My decision was to update the KX165 by adding a glideslope card and change the indicator to a KI-206 (w/glideslope). The KX165 is a solid radio that provides redundant IFR capabilities. I decided to keep it, but I will allocate space when I designed the panel to swap it out later if necessary.

Decision 5, what should I do with the transponder? I have a perfectly working KT-76A transponder. The unit had no problems, but at some point it would need to be replaced. The 76A's have a tube in them that must be energized for the unit to work. These tubes eventually fail and it costs more to replace than a new unit. It also takes the tube awhile to charge up before the unit will work. At some point we will all need Mode-S to fly into busy airspace. I live in Chicago, so I decided to install a GTX-330 Garmin Mode-S transponder with TIS. The Traffic Information Service is going to eventually be phased out, but it will be several years before Chicago gets downsized. I figure I can benefit from TIS as long as it's around and move to ADS-B when they get better coverage in the states. I will design the panel to enable me to remove the transponder when it becomes obsolete/replaced. For now, however, the GTX330 is the best choice.

Decision 6, what audio panel do I need? I actually made this decision right after I got the plane, but it was a decision that had to be made. The plane originally had the standard KMA-24 audio panel installed. This was a very good unit, but didn't have an intercom. I like taking long trips so audio quality is important. The PS Engineering line has the best audio quality of any intercom. They hold many patents on their technology. This decision may take me away form an "all Garmin" stack, but PSE is the best choice if sound is important to you. Radios, music, voices, etc. are better with PSE than anything available. They have a couple of different versions, but I landed on the PMA-7000b. I picked this one originally because it had the same wire connector as the KMA24, which made my initial retrofit easier. The PMA-8000 is also a very solid unit. If I were doing the wiring from scratch I would have picked the PMA8000.

Decision 7, weather... No question we want weather. XM Weather has changed the GA world. It isn't going to help you navigate through a line of T-Storms, but it most certainly will keep you out of them. The power and freedom that WX in the cockpit adds is the second best innovation in GA (just behind the GPS) in my near 20 years as an aviator. This was an easy decision. Garmin makes a rock solid GDL-69(A). The A is for Audio. Pay a bit more and you can get XM Radio stations piped down to you. Of course, I went with the GDL69A, which is fully integrated with the MX20. You can change radio stations, select weather, etc. directly off of the MFD.

Decision 8, Should I keep the KR-87 ADF, WX-900 Stormscope and other legacy radios. Nope. This equipment adds weight. Why keep it? The ADF will soon be a boat anchor and the WX900 is nice, but it is a one-off stand-alone unit. It cannot be integrated with the MFD or GPS. I decided that XM Weather is all I need for now, but I will allocate space on the Avionics shelf in the rear of the plane to add a WX-500 later. The WX500 fully integrates with the MX20, so it doesn't take up precious panel space.

The fun part is complete. The decision has been made about what I want. I will remove the old equipment, but keep the HSI, Flight Director, Auto Pilot and upgrade the KX165. I will add a WAAS GPS, MFD, Mode-S Transponder and XM WX/Radio.