Autopilot on Test day (Vizion TruTrak)

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4RNB

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4RNB
So in the process of trying to learn why my heading turns are slow using my autopilot someone mentioned that my AP is not certified for use on GPS approaches. I know I can't use it above 700'. I was not previously aware that there was this limitation on a TruTrak Vizion AP. At what point should I expect to not be able to use this? Is the 700 feet good enough?

Thank you.
 
I think the certification for GPS approaches has more to do with instrument procedures that spell out coupled aproaches.

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asicer said:
I think the certification for GPS approaches has more to do with instrument procedures that spell out coupled aproaches.

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I'm not sure what you are saying, especially in relation to my question. Can you say this another way?

In other words, it seems to me that you have posted exactly what I have said and asked about.
 
MooneyDriver78 said:
That’s BELOW 700’.
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Oops! Yeah, and perhaps the other person was pointing out that I cant use on any approach, not just GPS.

Still though, at what point do I turn it off? It seems to do the job well when left on...
 
This has been beat to death on another forum. The 700 foot limit is clear. The definition of coupled procedure, not so much. Is an HILPT a procedure? By the letter of the manual you can’t fly an approach at all. This is a certification issue only. Experimentals fly to minimums all day long with this AP.
 
Hang 4 said:
This has been beat to death on another forum. The 700 foot limit is clear. The definition of coupled procedure, not so much. Is an HILPT a procedure? By the letter of the manual you can’t fly an approach at all. This is a certification issue only. Experimentals fly to minimums all day long with this AP.
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What forum? Link?
 
Piper forum. Not sure your allowed to link to another forum on this one. Multiple threads there and some immovable and opposite opinions, just like here
 
4RNB said:
So in the process of trying to learn why my heading turns are slow using my autopilot someone mentioned that my AP is not certified for use on GPS approaches. I know I can't use it above 700'. I was not previously aware that there was this limitation on a TruTrak Vizion AP. At what point should I expect to not be able to use this? Is the 700 feet good enough?

Thank you.
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I'm sorry they didn't make you aware of that before you bought the autopilot, if it's a concern for you. You'll find the limitation in the supplement they provided for your aircraft flight manual:
2.4. Other Limitations
• This autopilot has not been evaluated by the FAA to meet the certification requirements for coupled instrument procedures, including coupled approaches. Therefore, these types of procedures are not authorized without further evaluation and approval.
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On the Piper Forum, someone wrote to the FAA for clarification. The written response from the FSDO was that the AC100 (formerly TruTrak) is prohibited from use coupled to the GPS navigator for any instrument procedure — approach, SID, or STAR. That's a broader limitation than I'd expected:

Steve,

Good morning. We spoke on the phone last week, after you submitted the question below in the email thread to the Scottsdale FSDO.

After researching this in great detail, I have the following answer. Regarding your question, the limitation is very direct, the autopilot has no airworthiness approval for use during either terminal procedures (arrival and departure procedures) nor during any instrument approach procedure.
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That said, while the vast majority of TruTrak /AC100 owners are delighted with it for what it actually is (a fun, affordable autopilot certified for VFR and enroute IFR), you will find a few who will try to convince you that neither the AFMS limitation nor the FSDO clarification really means anything, "coupled" doesn't mean coupled, "procedure" doesn't mean procesure, red is green, up is down, etc. etc.

You have all the information you need now, so I'll drop out of the thread.
 
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I’m sure there’s pilots who use it for approaches and below 700’, probably under nearly ideal conditions. But certification requires performance under harsh conditions:
How quickly the computer/servos can react to wind gusts for example.
Momentary loss of GPS
Voltage drops
Overloading the servos
Etc etc

Above 700’ you have a chance to react and correct…I’m sure this is some standard for an average pilot.
 
The limit is 700ft....however the TT WILL fly it all the way to the ground. Nobody will know outside the plane if you have it on still or not.
 
simtech said:
The limit is 700ft....however the TT WILL fly it all the way to the ground. Nobody will know outside the plane if you have it on still or not.
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Yes, but on checkride day, that is the question...
 
On checkride day I mainly flew by hand except the hold. I definitely didn't use the AP past the FAF on any of the approaches.

Then again, I hand flew almost all of my IFR training. I'm just crazy like that.
 
The only time I was allowed to use the AP on the check ride was to maintain straight and level while studying PAPER charts (approach plates). Kids today… :-)
 
FWIW, the altitude limitations, specifically the part 2.3, posted from the AFM by asicer, above, are pretty common to most autopilots. Many that are capable of glideslope capture (which is a somewhat different control mode than a selected descent rate), might even have different parameters from altitude hold mode.
And, for some reason, I've always thought of a coupled approach as an ILS or LPV, with both lateral and glideslope signals, rather than non-precision lateral guidance only approaches, that are essentially flown in NAV lock mode. But, I can't find any "official" reference for that, so maybe that's just OWT stuff.
 
asicer said:
Mine didn't "fail" it per se. He simply and politely asked if I could hand fly the approaches.
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NealRomeoGolf said:
On checkride day I mainly flew by hand except the hold. I definitely didn't use the AP past the FAF on any of the approaches.

Then again, I hand flew almost all of my IFR training. I'm just crazy like that.
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MooneyDriver78 said:
The only time I was allowed to use the AP on the check ride was to maintain straight and level while studying PAPER charts (approach plates). Kids today… :)
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I don't remember how it was worded in the old PTS, but for any recent checkrides using the ACS in an airplane with an autopilot, the applicant is required to demonstrate understanding of the autopilot and the ability to use it to at least make course intercepts. And they are "expected" to be tested on its use.

Given the number of people I have flown with in aircraft that have fully capable autopilots, but all they know how to use is altitude hold and heading bug, I think it's very appropriate to test on autopilot use. It is the absolute #1 workload reducer and situational-awareness enhancer in the airplane.
 
RussR said:
I don't remember how it was worded in the old PTS, but for any recent checkrides using the ACS in an airplane with an autopilot, the applicant is required to demonstrate understanding of the autopilot and the ability to use it to at least make course intercepts. And they are "expected" to be tested on its use.

Given the number of people I have flown with in aircraft that have fully capable autopilots, but all they know how to use is altitude hold and heading bug, I think it's very appropriate to test on autopilot use. It is the absolute #1 workload reducer and situational-awareness enhancer in the airplane.
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Right. I probably should have added that I was on autopilot prior to the DPE asking me to hand fly the approaches.
 
RussR said:
I don't remember how it was worded in the old PTS, but for any recent checkrides using the ACS in an airplane with an autopilot, the applicant is required to demonstrate understanding of the autopilot and the ability to use it to at least make course intercepts. And they are "expected" to be tested on its use.

Given the number of people I have flown with in aircraft that have fully capable autopilots, but all they know how to use is altitude hold and heading bug, I think it's very appropriate to test on autopilot use. It is the absolute #1 workload reducer and situational-awareness enhancer in the airplane.
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But be careful of autopilots that try to turn you in the hold before station passage. :rolleyes: I think my DPE liked that after the AP did that with the first turn, I momentarily turned off the AP to allow station passage and then turned it back on to let it make the turn the second time around the hold.
 
NealRomeoGolf said:
But be careful of autopilots that try to turn you in the hold before station passage. :rolleyes: I think my DPE liked that after the AP did that with the first turn, I momentarily turned off the AP to allow station passage and then turned it back on to let it make the turn the second time around the hold.
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Was this a typical light GA autopilot? I assume by it flying the hold you must have had GPSS, and were therefore holding using GPS data but over a VOR (since you say "station passage"). So I'm trying to think of the scenario you were in, where the autopilot would turn early. It shouldn't.

All I can think of is if you were also monitoring the VOR on a second NAV radio, and the autopilot turned at the waypoint, but before the VOR had indicated a TO/FROM flip. (And I don't see why that would be a problem.)
 
For my practical, I was required to do one of the three approaches with the AP to demonstrate that I knew how to use it. The remaining two were by hand.
 
Hang 4 said:
For my practical, I was required to do one of the three approaches with the AP to demonstrate that I knew how to use it. The remaining two were by hand.
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I think that's fairly typical (and appropriate, IMO).
 
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