There’s no end to the troubles when you have an antique A/P.
Last it was in for Aspen install as PFD. I was told by installer, Aspen and everyone else that it could run the old A/P. After install, it turns out it can’t, after all. They spent weeks trying to make it work, but in the end had to re-install my old Sperry/Collins analog HSI.
I just also know that when I get it back, there will be some sort of messup because the HSI has been in and out and it probably won’t speak to the A/P correctly. Every time I’ve had avionics work done, something in the interface between the two gets out of whack. I’m willing ot bet money on that it will be exactly the same this time around.
Sigh.
I have rarely flown a plane with a fully functioning autopilot I trusted.
My least confidence building experience was a maintenance check flight in a Bellanca Viking (which has awesome flight controls, and is highly responsive!). I set the heading bug, selected “heading” and turned it on. The plane promptly rolled hard right, so I turned it off, and righted the plane. Hmmm… How bad is this? So I repeated, with more preparation for a loss of control this time. I selected the autopilot off rolling through 120 degrees of bank angle (who says you can’t have some fun on a maintenance check flight?). I took it back and made my report….
“Take the avionics guy for a flight, he’ll get it working.” So I took the avionics guy. He really wasn’t buying my report, he just saw me as the nuisance pilot who kept reporting snags during maintenance check flights. He took the face plate off the autopilot, and got his special screwdriver ready. So I warned him that the auto pilot had a sharp right roll when I turned it on… Yeah… yeah…. Okay, I warned you….
The Viking, being a steel tube fuselage, has a tube running down and forward from the ceiling to the glare shield at each side of the windshield.
I trimmed it up, took my hands off the control wheel, and counted: 3…2…1… and turned the autopilot on. Well somewhere between 60 and 90 degrees of roll, I saw his hand rapidly grasp that tube in the windshield, (yes, his knuckles were white!) as he loudly proclaimed: “Okay, okay, I believe you!!!”. He couldn’t fix it, and had very little interest in me reaching for the “ON” switch again. I landed, he took the unit out, and send it to Century. I checked the new owner out in the plane with no autopilot. When it returned, I reflew it, and it worked.
In my opinion, an autopilot which could roll a plane inverted at all, let alone how quickly this one did, gives me zero sense of safety, were I actually in IMC! I like hand flying….
Just wondering, is this a function of the age?
A colleague spent a fair amount of time as PIC on a Lear 35 spanning the globe. It had the Punch and Judy analogue FD with sticks for moving the wings (like my KFC200), and no altitude capture. It was a Bill Lear design and worked very well. I have similar hopes for my KFC200 and plan to sink the usual AMUs in overhauling servos when required. If Honeywell/Bendix King ever improve the availability and serviceability of the AeroCruze 230 upgrade may consider this in due course. On a previous aircraft I had an antique Altimatic Vd which worked smoothly and reliably, flying good coupled approaches.
I did most of my IR training, first time around, in a twin with Piper’s version of a Century 3 autopilot. For the vast majority of the time it did strange things (banking large angles etc). It would get fixed, work perfectly including with Garmin’s 155 (I don’t remember whether it was GTN or GNS or whatever). 2 flights later the strange things would start again. One quickly lost faith in it. Then an old school avionics guy suggested that we put a dehumidifier in the cockpit if the plane was not going to be used for more than a day or 2, even though it was hangared. We did but were not totally convinced so we bought one of those cheap household dehumidifiers which is basically a plastic box in which you put a bag of crystals which soak up the humidity. I have to say the autopilot worked for many more flights before having to go back to the engineer, and it seemed to me that there were no violent reactions, just a slow, steady decline. I was quite surprised how much water was in the dehumidifier despite the aircraft being hangared when it wasn’t being used. And despite it being a shared hangar in which a few did their own maintenance so the doors were often open all day with good air circulation.
I think I’ve only flown two planes with a working autopilot: the Piper Arrow we had in our club in Houston, which had an ancient but still functioning Piper Autocontrol. The other was the Apache I did my MEIR in, that had quite a nice S-Tec unit which worked perfectly.
All the other aircraft I’ve been in with some kind of prehistoric autopilot, it’s either not worked at all or has been completely useless.
I didn’t learn anything about the AP in PPL flight school. I trained in an Aquila 210 and a Piper PA28, both had no autopilot. After I got my license, the planes I rented, predominately that PA28 and a DA20, didn’t have APs either. I can only guess, but probably one half of the problem is broken APs and the other half is people who didn’t learn how to use them ?
I think US pilots that fly single pilot IFR are much more likely to keep the autopilots in working condition. For many pilots, this is a go/no go item for IFR.
I have not yet come across a rental plane which had an AP which did not work.
I’ve come across a large number of pilots who CLAIM their AP does not work because they never found out how to use it and expect things of it which it doesn’t do. Sort of after the infamous tech log entry:
Autoland very rough on this plane
to which the avionics guy entered:
Autoland is not installed in this airplane!
But fun aside, I’ve worked with a good number of AP’s over the years. KFC150/200 being the ones I did my IR on at the time. I still think they are very good AP’s.
Then I flew a Seneca I which had the original Altimatic III. Nobody in that ATO used it or knew how to use it. The same went for the Rajay Turbos that plane had. Well, this being me I read up on it and tried it. It worked flawlessly, even the kind of altitude preset it had. I’d have no qualms buying a plane which has that one installed provided it works.
Right now, I fly behind a S-TEC 55X which has had it’s gremlins. One AP computer changed, 2 servoes overhauled, all in all less than 200 hours since new. It works after a fashion but keeps you on your toes.
Some years ago, a friend of mine bought a lovely Cherokee which had a Century AP installed which was labled inop for decades. When the avionic guy went to check it, he found it working perfectly and could not find out why it had been labled inop, there was no tech log entry either. Turns out an owner 2 times grand to the current one could not figure it out so he labelled it inop just to forget all about it.
To me it is staggering why people don’t learn about the equipment they have and how to use it.
Maybe my club is the odd one here, but we have five aircraft to rent to our members. (Three that we own and two that we lease.) Four of them have autopilots and they all work. There are two KAP140’s and two Piper Autocontrol IIIB’s.
