I'm trying to decide what to do about the autopilot in my 1977 Arrow III. I'm interested in getting opinions from other owners.
My Arrow is equipped with the factory-installed Piper Autocontrol IIIB, otherwise known as a Century IIB. It rolls slowly from side to side constantly. We've tried to tune this out and have been able to minimize this, but have been unable to eliminate it. The roll is worse at low speeds, like during a climb, but is still present in level cruise. Aside from that it works pretty well. It tracks nav sources (heading bug, GPS, VOR/LOC) pretty well, albeit with the constant, annoying, slow rolling back and forth.
The attitude source is a vacuum AI. This was replaced with a freshly overhauled unit a few years ago after the previous one failed. The heading source is an Aspen EFD-1000 Pro. Nav sources include a GTN-750 and a KX-155 with GS.
My other issue is that this autopilot lacks altitude hold. Aside from the occasional $100 hamburger run, my flights tend to be several hours in length and flown single-pilot under IFR. Altitude hold would really help reduce my workload. The ability to capture and follow an ILS and LPV glideslopes would be a real plus.
Years ago it was suggested that I add an S-TEC 30-ALT altitude hold unit and keep my current autopilot. I was quoted $10K, installed. But it won't capture a glideslope, and I'd still have the roll issue. So that's a non-starter.
When it was first announced I lusted after the S-TEC 3100, but the PA-28 isn't on their certification schedule. They say that if they get 15 no-cost, non-binding orders they'll put it on the schedule, but last I checked they hadn't received e a single order for a PA-28. Not one. So scratch that off the short-list. (Yes, I've read about the teething problems in other airframes.)
I've been watching the TruTrak Vizion since it was announced. I consider it a good unit for the VFR pilot, but it lacks the electronic circuitry to take input from any analog sources such as a VOR, LOC, ILS, or mechanical heading bug. At the moment it can't even track the electronic heading bugs on a G5 or Aspen, though I understand they're hoping to announce that at Oshkosh. It's not certified for use in approaches or other coupled procedures. So scratch that off too.
Aside from doing nothing, I see two realistic options:
One option is a Garmin GFC-500. The website says they're actively working on the STC for the PA-28R-201 now. However, the GFC-500 requires a G5 AI, and for coupled navigation it also requires a G5 HSI with the nav coupler. That means replacing my Aspen EFD, which I really love, with a pair of G5s. The rather large GFC-500 control box won't fit in my center radio stack, and I'm not sure it'd fit in the right stack even if I removed the DME.
The other option is an S-TEC 55X. I can get a factory-refurb kit for $8,200. I think the 55X computer will fit in my center stack; if not, then it will fit in the right stack by removing the DME. It would integrate amazingly well with my Aspen, and the Aspen obviates the need for a remote annunciator or FD display. But it's a rate-based autopilot. Reportedly one of the best rate-based autopilots available, but rate-based nonetheless.
People here and elsewhere seem to be divided on the S-TEC 55X. Some people really love them. Others say they roll and bobble and are costly to maintain. I'm tempted to use gymnastics scoring (throw out the highest and lowest scores, and average the ones in the middle), but is that realistic? Are the nay-sayers exaggerating the issues with the 55X? Or would I hate myself for installing one?
Finally, am I overlooking another viable option?
What sayeth the peanut gallery?
My Arrow is equipped with the factory-installed Piper Autocontrol IIIB, otherwise known as a Century IIB. It rolls slowly from side to side constantly. We've tried to tune this out and have been able to minimize this, but have been unable to eliminate it. The roll is worse at low speeds, like during a climb, but is still present in level cruise. Aside from that it works pretty well. It tracks nav sources (heading bug, GPS, VOR/LOC) pretty well, albeit with the constant, annoying, slow rolling back and forth.
The attitude source is a vacuum AI. This was replaced with a freshly overhauled unit a few years ago after the previous one failed. The heading source is an Aspen EFD-1000 Pro. Nav sources include a GTN-750 and a KX-155 with GS.
My other issue is that this autopilot lacks altitude hold. Aside from the occasional $100 hamburger run, my flights tend to be several hours in length and flown single-pilot under IFR. Altitude hold would really help reduce my workload. The ability to capture and follow an ILS and LPV glideslopes would be a real plus.
Years ago it was suggested that I add an S-TEC 30-ALT altitude hold unit and keep my current autopilot. I was quoted $10K, installed. But it won't capture a glideslope, and I'd still have the roll issue. So that's a non-starter.
When it was first announced I lusted after the S-TEC 3100, but the PA-28 isn't on their certification schedule. They say that if they get 15 no-cost, non-binding orders they'll put it on the schedule, but last I checked they hadn't received e a single order for a PA-28. Not one. So scratch that off the short-list. (Yes, I've read about the teething problems in other airframes.)
I've been watching the TruTrak Vizion since it was announced. I consider it a good unit for the VFR pilot, but it lacks the electronic circuitry to take input from any analog sources such as a VOR, LOC, ILS, or mechanical heading bug. At the moment it can't even track the electronic heading bugs on a G5 or Aspen, though I understand they're hoping to announce that at Oshkosh. It's not certified for use in approaches or other coupled procedures. So scratch that off too.
Aside from doing nothing, I see two realistic options:
One option is a Garmin GFC-500. The website says they're actively working on the STC for the PA-28R-201 now. However, the GFC-500 requires a G5 AI, and for coupled navigation it also requires a G5 HSI with the nav coupler. That means replacing my Aspen EFD, which I really love, with a pair of G5s. The rather large GFC-500 control box won't fit in my center radio stack, and I'm not sure it'd fit in the right stack even if I removed the DME.
The other option is an S-TEC 55X. I can get a factory-refurb kit for $8,200. I think the 55X computer will fit in my center stack; if not, then it will fit in the right stack by removing the DME. It would integrate amazingly well with my Aspen, and the Aspen obviates the need for a remote annunciator or FD display. But it's a rate-based autopilot. Reportedly one of the best rate-based autopilots available, but rate-based nonetheless.
People here and elsewhere seem to be divided on the S-TEC 55X. Some people really love them. Others say they roll and bobble and are costly to maintain. I'm tempted to use gymnastics scoring (throw out the highest and lowest scores, and average the ones in the middle), but is that realistic? Are the nay-sayers exaggerating the issues with the 55X? Or would I hate myself for installing one?
Finally, am I overlooking another viable option?
What sayeth the peanut gallery?
