February 1999 - American Bonanza Society

ITSDEAD,JIM'--../---.-.Tips on anAVIONICSUPGRADEBY GEORGE WILHELMSENThe day has finally arrived. Your favorite Nav/Comm,which has been part of your plane since the day youbought it, has left the monal coil and joined the electroniccrowd invisible. Your avionics technician, looking likethe venerable Dr. McCoy from Star Trek, surveys the piece ofgear and says, "It's dead, Jim."After a radio has been deemed too costly to repair, or it isunable to be repaired and still meet regulations, it's time to lookat your options. The departure of a single radio from the planedoes not mean the end of the world. Still, it is cenainly time totake stock of your current avionics situation to see if changesare either warranted by the age of your equipment, or by thecost savings that might be realized by making more changes atthe same time you replace your failed radio.As an example, if you happen to be a Bonanza owner that isstill trucking around with a couple of Nav/Comms that wereput in at the same time over 15 years ago, then chances are thatPage 5570the second radio's fai lure won't be long behind the first. In theelectronics industry, this principal is described as "the bathtubcurve," and is used to explain the situation when the componentsin a piece of electronics hit the age wall , and begin to failat a very hi gh rate.If this is the case with your aircraft, this would probably bea good time to approach your shop about replacing both Nav/Comm units at the same time. What many aircraft owners seemto forget is that a good quantity of the cost of an avionics upgradeis in the labor of installation. To that end, it is frequentlycheaper in the long run to change out both Nav/Comms whenthe fi rst one fai ls.Consider this: Your avionics shop will have to open up yourplane, remove remote equipment, pull wires, route power, purchasecircuit breakers, and then put the plane back together andtest it. This process can take anywhere from five to 20 hours fornon- pressurized ai rcraft, to up to 40 or more hours for pressurizedplanes like the Duke and 58P Baron. Taking the average ofthe non-pressurized numbers, an aircraft owner can save between$625 and $1,000 dollars by installing both radios at thesame time!More than radiosWhat about the rest of the radio system? Most pilots forgetthat their antennas are an imponant pan of the radio equation.This leaves them in the situation where the shop has to pointout that their 30-year-old Comm antenna isn't compatible withtheir state-of-the-art Garmin GPS-430 unit. The point here issimple: If your radio has died and it is fairly old, in most casesit is not only a good idea but necessary to change your antennaout along with the radio.The avionics shop would like to change out the antenna forone good reason. They want your newly installed radio to work!Old antennas and old, cracked antenna wires can cause problemswith newly installed radios. While some customers arewise enough to understand this, others tend to take their radioproblems and the frustration caused by not installing new antennasand cables on the avionics shop when the work done bythe shop really isn't the problem.The rest of the stackBut what about the rest of the stack? Should you take thisopportunity to replace all the radios or just stop with the secondNav/Comm? The fact of the matter is that the same economy ofscale applies in this case too, and if all the radios are 20 to 25years old, it may be a good idea to change them out.Still, it is important to get some feedback fmm the shop aboutthe radios you have in your airplane. As an example, if you have aplane flying with a KX-170B and a KX-170A, working in concertwith a scratchy, old audio panel, a T-12B ADF and a LORAN, youcan get into some nice equipment these days at a reasonable price.As an example, you could replace the entire stack with alIMorrow stack, which would include two GX60 GPS/Communits, while replacing the audio panel with the llMorrow's SLI 0-ASS February 1999