So I own a completely lovely 27 year old TB20, except that much of the avionic devices are original, including:
The rest of my panel comprises:
I need to get my plane to be 8.33 kHz-compliant, so I have to replace the KY196A:
→ The cheapest thing I can do now is to replace the KY196A with a modern 8.33 kHz radio and live with the rest of the panel until something worse breaks, but then I don’t get a nice GPS display in my plane, nor ADS-B out or an audio panel that does all the nice things that the modern ones do.
→ The most expensive thing I am thinking of doing is to replace all the above with a GTN750, with a hidden GMA 35 audio panel, a hidden GTX 335R ADS-B Out transponder, an overhauled DME unit, and a new (second) panel-mounted nav/com from Garmin such as a GNC225.
The first option costs about £4k. The second option costs about £30k I guess. (I haven’t got a detailed quote yet) That’s a fair chunk money on an aging plane, and I doubt very much it will add very much to the selling price if I sell the plane in a few years’ time. (It will doubtless help it to sell when in competition with planes of similar era that have older avionics.)
I should add that the plane has a KAP150 autopilot that I don’t intend changing, and old steam dials in front of the pilot including a mechanical HSI and an ancient KR87 ADF which I’ll keep if I need to.
I’m looking for some sound advice or some Man Maths or a three word quote from Nike’s marketing department, the last of which is “it” 
Help!
Howard
Howard wrote:
That’s a fair chunk money on an aging plane, and I doubt very much it will add very much to the selling price if I sell the plane in a few years’ time.
I think you’ve answered your own question there. If you plan to sell it in a few years’ time (what’s a few years?), you might be better off just keeping it as is. It’s the same with every asset – you always have to look at the cost of improvements vs. the effect said improvements have on the sales price. In many cases, you will find a negative outcome. Of course, if you intend to keep this airplane for a longer period of time, then the answer comes straight from the Nike marketing department, and you know what it is 
If you really plan to sell the plane in a few years’ time then don’t upgrade it. But your next plane now
If OTOH it meets all the requirements for now and the foreseeable future i.e.
then upgrade it as you wish. I am looking at spending more than you on my TB20 in the next year or two… and for exactly the three reasons above.
Peter,
I don’t really have a “mission profile”. Flying is just a hobby into which I pour cash! More seriously, my TB20 does what I want/need perfectly, but I do hanker after an old twin – something like an Aztec or this Beech 95-B55 for sale. The trouble is I’d have to pour about twice as much money into such a thing as I do the TB, and I can’t justify that at 50 or so hours each year and my advancing years. I need to find someone as mad as me and whose flying I trust and who I got on well with like a brother, in order to buy such a plane. (Have you noticed that that old Beech also has a KNS80. lol.)
I do love my TB. They are really super planes. Occasionally I worry about there being just the one propeller…
p.s.. thanks to 172driver too for the sensible reply.
Doesn’t the GNS530 have a 8.33kHz comm? Pretty sure it does, so why do you think you need a second 8.33kHz unit? IIRC wigglyamp posted a CAA letter saying private ops are fine with just one.
Correct – only one 8.33 radio needed for Part NCO, and an existing second radio can remain on 25kHz for retained frequencies such as the emergency channel.
@tmo @wigglyamp thank you. Someone I know emailed me off board to say the same thing as you and it is very interesting and not well publicised. However, having two radios is very helpful in terms of redundancy and for monitoring e.g. ATIS broadcasts, and I haven’t ever flown a plane with just one radio, although I’m sure there are many. I would only really feel comfortable with two.
I have always discounted to zero my mental “book value” of my aeroplanes the moment I buy them.
I have always had old aeroplanes and, as a rule of thumb, they cost me their insured value every year. If I do sell them (or, in one case, get an insurance payout) then that is an unlooked-for bonus.
If you adopt that philosophy, and completely forget about asset value, it makes this kind of decision much easier. Even more so if your “advancing years” allow you to think in terms of your flying mortality. How many more years have you realistically got?
The only answer then is “how much am I going to enjoy my aircraft over the coming years if I leave in the 530W and KNS80, and how much joy will I get from a GTN?”
For example, if you calculate that you have ten years left (I have no idea how old you are, this is illustrative) then you are going to fly 500 more hours. A £30k bill is therefore going to cost you £60 per hour. Effectively that is going to take your TB20 run rate from (say) £180 ph to £240 per hour. Is the joy you are going to get going to justify a 33% hike?
Indeed, in your position I would be thinking also of an Aspen. Is that worth a further £20 an hour? It would be for me, which is why I have a fantabulosa panel, but no-one can answer that for you.
Is that the kind of man-maths you had in mind?
But do think seriously about the Aztec. They are really lovely to own and fly.
Howard wrote:
A KMA 24 audio panel with a few faults (the marker beacons don’t work and the panel refuses to drive the plane’s speaker)
Did you find out if this in the wiring or in the unit? A replacement KMA-24 wouldn’t be that expensive. For sure newer audio panels are more capable. Do you need / want this new functionality, or are you satisfied with a working KMA-24?
Howard wrote:
A KNS 80 RNAV navigator, which used to be the bee’s knees in the 1980s and which works perfectly, but nowadays I only use it as a normal NAV/DME. I don’t use its clever move-the-VOR function at all. It’s also very bulky in terms of the panel space it takes up. Some people love these things.
If it is working fine, I wouldn’t recommend to replace this, unless you need the panel space. Buying another VOR / DME would add cost, without many true benefit, other then panel space, when needed.
Howard wrote:
A worn out Bendix-King KY196A 25kHz radio with an LED display that’s partially invisible, especially when cold. This radio is of course outlawed in the UK as from 1st January 2018.
As others informed, there is no need to replace is. If you want to replace it, the Trig TY-96 has the same size and is a quality radio.
Howard wrote:
That’s a fair chunk money on an aging plane, and I doubt very much it will add very much to the selling price if I sell the plane in a few years’ time. (It will doubtless help it to sell when in competition with planes of similar era that have older avionics.)
Altough it might help selling it, you will never get the investment back. It seems your comparing doing almost nothing against a major upgrade. I think the most important question for yourself would be, would you want to keep you aircraft on long term. You current know the status of your aircraft. If you upgrade it, you could / should enjoy it for years to come. When you buy another aircraft, you might be faced with hidden defects, which can result in additional cost.
Timothy wrote:
If you adopt that philosophy, and completely forget about asset value, it makes this kind of decision much easier. Even more so if your “advancing years” allow you to think in terms of your flying mortality. How many more years have you realistically got?The only answer then is “how much am I going to enjoy my aircraft over the coming years if I leave in the 530W and KNS80, and how much joy will I get from a GTN?”
With experimental aircraft, a wise and well known saying is: “build the aircraft YOU want !”. It’s all too easy to get entangled into thinking about what to do to increase re-sale value. This ends up in a plane that is not exactly as you would like it to be, and lots of lots of work, and there is no way of knowing what the re-sale value will be 10 years from now anyway. Better to forget all about re-sale value, the airframe is “worth” €10k tops. But, a used GTN750 and other modern Garmin equipment, is likely to be in high demand for the foreseeable future, is easy to sell, and the price is fairly well known. I would also set the value of the aircraft to zero, especially a 27 year old one, but I would include the re-sale value for any equipment on board having a real re-sale value.
