Cirrus SR20, Auto-Pilot, and you.

Mike Wise

Mike Wise

#NewSchool
I've been flying an SR20 pretty often recently, great airplane and real fun to fly. Not a fan of the Avidyne PFD, and the Garmin 430 seems to have some weird connectivity issues. No rudder trim on the airplane is wack-sauce but oh well.

While flying the aircraft, I've noticed that (just like every other aircraft I've flown), when the AP is manually disconnected, the airplane clearly lets you know - that it has been disconnected. HOWEVER, when the GPS fails and loses signal (which has been happening at least a few times per flight, not sure why) the AP in NAV mode will disconnect and not notify me that has done so....I've seen other AP's revert to HDG mode if the AP fails in NAV mode, but today it just displayed AP FAIL and nothing else. Obviously in VFR low work load situation, its not a big deal, however I can imagine being in IMC, in the Mountains, on an approach etc, things can get weird real fast.

Any of you cirrus guys ever experienced any of this before?, and has anyone ever experienced an AP FAIL of this nature?
 
Having flown the G1000 in the chickenhawk (sans autopilot) and the Avidyne in multiple Piper products, one with the S-TEC autopilot, I have to say I liked the Avidyne more. Avidyne was more intuitive, far less fumbling around wondering where you put that last Softkey, could do everything the G1000 could do. That being said, our S-TEC was the 55x, that had a glideslope capture. Not sure if the SR20s did though I heard they did not.

But I could see how you could get suckered into the problem you are referring to. The GPS goes into a "Dead Reckoning" mode and the autopilot is still technically working and in NAV mode, so it isn't a disconnect per se. Although I agree, it needs to have more flashy thingies to tell you it ain't working right.
 
hook_dupin said:
Why? Not knocking you as I've never flown an Avidyne airplane... Just looking for the arguement to back up your opinion.
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I thought it was easy to use and the screen seemed larger then the G1000 I liked the Garmin's separated as it allowed me to have more info up while flying with the two additional screens. Didn't have a backup PFD and did have it fail once but landed and reset on the ground before returning to local airport.
 
gotWXdagain said:
Having flown the G1000 in the chickenhawk (sans autopilot) and the Avidyne in multiple Piper products, one with the S-TEC autopilot, I have to say I liked the Avidyne more. Avidyne was more intuitive, far less fumbling around wondering where you put that last Softkey, could do everything the G1000 could do. That being said, our S-TEC was the 55x, that had a glideslope capture. Not sure if the SR20s did though I heard they did not. But I could see how you could get suckered into the problem you are referring to. The GPS goes into a "Dead Reckoning" mode and the autopilot is still technically working and in NAV mode, so it isn't a disconnect per se. Although I agree, it needs to have more flashy thingies to tell you it ain't working right.
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04 SR20's had the 55x. Might of been an option but mine did.
 
The mid 2000's SR20's I got my PPL in had the STEC 55x...don't recall that issue however...but this 8 years ago.
 
Mike Wise said:
I've been flying an SR20 pretty often recently, great airplane and real fun to fly. Not a fan of the Avidyne PFD, and the Garmin 430 seems to have some weird connectivity issues. No rudder trim on the airplane is wack-sauce but oh well.

While flying the aircraft, I've noticed that (just like every other aircraft I've flown), when the AP is manually disconnected, the airplane clearly lets you know - that it has been disconnected. HOWEVER, when the GPS fails and loses signal (which has been happening at least a few times per flight, not sure why) the AP in NAV mode will disconnect and not notify me that has done so....I've seen other AP's revert to HDG mode if the AP fails in NAV mode, but today it just displayed AP FAIL and nothing else. Obviously in VFR low work load situation, its not a big deal, however I can imagine being in IMC, in the Mountains, on an approach etc, things can get weird real fast.

Any of you cirrus guys ever experienced any of this before?, and has anyone ever experienced an AP FAIL of this nature?
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Oh you rich people. The Cherokee Cruiser I learned on had no GPS, an ADF that was inop, and just one VOR. I flew around cross-dialing to identify position. Then I stepped into a plane with *two* VORs and holy cow now I don't have to cross dial. Then I flew a plane with a GPS, a Garmin 430, and I was King.


Autopilot-coupled-to-dual-GPS airplane with a parachute? Mind = Blown
 
We just got our SR20 a couple of months ago. Like you, we're getting used to the electrical system and its anomalies. I feel like a better trouble-shooter or mechanic than a pilot at times. Do you have the DFC90 or STEC-55 autopilot?

Do you receive a yellow "NAV INVALID" message on the PFD or just "AP FAIL"?

The DFC90 abnormal procedures state it "..will command a wind corrected course hold and, if sufficient power is available, the flight path angle at the time the system displayed 'NAV INVALID'". No clue on the STEC.
 
Itchy said:
Antenna's for $400 Alex.
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There are multiple reports out there that at least with the GTN series GPSs a single antenna going out can cause it to radiate on GPS frequency and knock out reception to ALL GPS units on the aircraft. Bad news. Not probably related to this situation but interesting.
 
I was told there was a grounding issue when the GPS was upgraded to WAAS. Actual an issue that caused the ELT to activate now and again too.
 
ComplexHiAv8r said:
Are the Garmin's WAAS? If so are both? Which AP?

I prefer the Avidyne over the G1000. But that's me.
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No WAAS on either unit unfortunately.

gotWXdagain said:
Having flown the G1000 in the chickenhawk (sans autopilot) and the Avidyne in multiple Piper products, one with the S-TEC autopilot, I have to say I liked the Avidyne more. Avidyne was more intuitive, far less fumbling around wondering where you put that last Softkey, could do everything the G1000 could do. That being said, our S-TEC was the 55x, that had a glideslope capture. Not sure if the SR20s did though I heard they did not.

But I could see how you could get suckered into the problem you are referring to. The GPS goes into a "Dead Reckoning" mode and the autopilot is still technically working and in NAV mode, so it isn't a disconnect per se. Although I agree, it needs to have more flashy thingies to tell you it ain't working right.
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I agree, while my preference is with the G1000 only because it was the first system I had learned after my initial flight training, the Avidyne is easier to use, simple and straight forward.

Roger Roger said:
Good on you trying to learn the airplane, but you really need to take the thing to a good avionics shop not a bunch of dudes on the internet.
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Agreed, I've let the owner know a few times over the past few weeks, hopefully he gets it checked out soon.

CFI A&P said:
The easy solution is to not fly a Cirrus.

The real solution is to discuss it with the avionics shop.
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Haha, I do have to admit though, the cirrus is one of the more comfortable single engine airplanes I have flown.

Cherokee_Cruiser said:
Oh you rich people. The Cherokee Cruiser I learned on had no GPS, an ADF that was inop, and just one VOR. I flew around cross-dialing to identify position. Then I stepped into a plane with *two* VORs and holy cow now I don't have to cross dial. Then I flew a plane with a GPS, a Garmin 430, and I was King.

Autopilot-coupled-to-dual-GPS airplane with a parachute? Mind = Blown
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Lol I know what you mean! If I could afford an airplane, I would go with a clean simple piper cub or a Citabria personally. I guess the owner of this aircraft has a preference for the fancy fancy - I hate to say it, but after an incident with a cirrus owner taking off on a taxi way directly over me, its hard for me not to be judge mental when I meet a cirrus pilot/owner.

I'll tell you what though, the first 40 hours of my flying experience was shared in a c152 cockpit at 100 degrees with @CFI A&P , so I'm not mad at it! lol


FlyingSieve said:
We just got our SR20 a couple of months ago. Like you, we're getting used to the electrical system and its anomalies. I feel like a better trouble-shooter or mechanic than a pilot at times. Do you have the DFC90 or STEC-55 autopilot?

Do you receive a yellow "NAV INVALID" message on the PFD or just "AP FAIL"?

The DFC90 abnormal procedures state it "..will command a wind corrected course hold and, if sufficient power is available, the flight path angle at the time the system displayed 'NAV INVALID'". No clue on the STEC.
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STEC-55, and I get the yellow AP FAIL message on the display and nothing else. In a few other cessna's and archer 2's (Even though its different equipment I would have assumed the AP logic would be the same) I've seen situations where it would revert to HDG mode and notify you, or completely disconnect altogether with a disconnect alarm should the GPS/NAV function fail. This situation though beats me!

We should start taking bets on the problem and I'll have the owner get his mechanic to take a look hah!
 
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