I noticed last night that while I was flying at a fairly low altitude at a moderately low power setting (68%) the plane tended to porpoise. Not that great from an altitude deviation, but significant pitch changes. Any suggestions?
Andy
I noticed last night that while I was flying at a fairly low altitude at a moderately low power setting (68%) the plane tended to porpoise. Not that great from an altitude deviation, but significant pitch changes. Any suggestions?
In one of the other groups I read, someone with an STEC 55 was having that problem and was told it is an adjustment on the STEC.
Andy,
It’s also possible because you were low and a bit slow that you were riding thermals. Your altitude indication would not show much of a change but an increase or decrease in the air pressure would force the autopilot to make pitch changes that can be significant.
I’ve had this happen many times in the desert with my Archer and an STec30. Catch a downdraft and the plane pitches up so significantly the stall horn comes on!
Chris
I noticed last night that while I was flying at a fairly low altitude at a moderately low power setting (68%) the plane tended to porpoise. Not that great from an altitude deviation, but significant pitch changes. Any suggestions?
Andy
In one of the other groups I read, someone with an STEC 55 was having that problem and was told it is an adjustment on the STEC.
I have had this problem with my 260SE. It doesn’t take much to go wrong for you to have a wild ride. A bad servo or servo switch. In my case it turned out to be a bad trim switch. One minute I’d be in level-flight, the next minute the osciliations started and got worse.
I strongly suggest you take a few flights, try to induce the problem. Then carefully record whatever is going on. Do you have autotrim? Maybe your plane is trimming instead of pitching… etc. Would the plane recover from the porpoise or do you disconnect the AP and do it yourself?
You do not want your AP to be unreliable. It could kill you one day.
My new SR22 A/P works fine until I transmit. While the PTT is depressed the autopilot commands nose down trim. A definite incentive to keep transmissions brief!
Any ideas about this one?
George Savage
N747SJ
In one of the other groups I read, someone with an STEC 55 was having that problem and was told it is an adjustment on the STEC.
I have had this problem with my 260SE. It doesn’t take much to go wrong for you to have a wild ride. A bad servo or servo switch. In my case it turned out to be a bad trim switch. One minute I’d be in level-flight, the next minute the osciliations started and got worse.
I strongly suggest you take a few flights, try to induce the problem. Then carefully record whatever is going on. Do you have autotrim? Maybe your plane is trimming instead of pitching… etc. Would the plane recover from the porpoise or do you disconnect the AP and do it yourself?
You do not want your AP to be unreliable. It could kill you one day.
My new SR22 A/P works fine until I transmit. While the PTT is depressed the autopilot commands nose down trim. A definite incentive to keep transmissions brief!
Any ideas about this one?
George Savage
George you may be putting back presure on the yoke with your finger causing a nose down trim. Try your thumb and your finger and squeeze the yoke…Ed
Okay, on this one I can be a help!
This happened on my plane when it was new, whenever I transmitted on com 2. It was a shielding problem. Chris Dixon (of Cirrus) talked my local avionics person through the fix, and it works perfectly.
My experience is that this is definately fixable, and worth the effort!
Andy
My new SR22 A/P works fine until I transmit. While the PTT is depressed the autopilot commands nose down trim. A definite incentive to keep transmissions brief!
Any ideas about this one?
George Savage
N747SJ
In one of the other groups I read, someone with an STEC 55 was having that problem and was told it is an adjustment on the STEC.
I have had this problem with my 260SE. It doesn’t take much to go wrong for you to have a wild ride. A bad servo or servo switch. In my case it turned out to be a bad trim switch. One minute I’d be in level-flight, the next minute the osciliations started and got worse.
I strongly suggest you take a few flights, try to induce the problem. Then carefully record whatever is going on. Do you have autotrim? Maybe your plane is trimming instead of pitching… etc. Would the plane recover from the porpoise or do you disconnect the AP and do it yourself?
You do not want your AP to be unreliable. It could kill you one day.
George you may be putting back presure on the yoke with your finger causing a nose down trim. Try your thumb and your finger and squeeze the yoke…Ed
I don’t think so. The Wings Aloft instructor we brought along had the same problem from the right seat. However, next time I fly I’ll try your technique; if you’re right, my next post will include the sound of me eating crow :>)
(The plane is, of course, fantastic overall. I flew ~15 hours in two days and, due to fatigue, never wanted to see it again when we finally got through the “enhanced Bravo” to home base on Sunday night. I stopped by again yesterday just to sit in it and I’m very much looking forward to my next flight. Sleep is a wonderful drug!)
George Savage
N747SJ
I’m missing something here.
Why are squawks like this not handled before delivery? Why does it have to be fixed in the field? I don’t get it. Is this unique to the SR22 only?
Okay, on this one I can be a help!
This happened on my plane when it was new, whenever I transmitted on com 2. It was a shielding problem. Chris Dixon (of Cirrus) talked my local avionics person through the fix, and it works perfectly.
My experience is that this is definately fixable, and worth the effort!
Andy
I’m missing something here.
Why are squawks like this not handled before delivery? Why does it have to be fixed in the field? I don’t get it. Is this unique to the SR22 only?
The problem did not occur on the acceptance flight. However, the EHSI behaved erratically in one turn and the CD team elected to replace the flux gate gyro behind the rear seats. They then tested the EHSI in ground runs and we departed…with the A/P problem. I speculate that some shielding was disturbed while they were working on this fix.
BTW, Tx on both comms causes the problem.
George
In my case, the test pilot discovered the problem on the acceptance flight, and suggested I have it fixed. With all that was going on, I forgot to mention it to the Cirrus people at the end of the day. My fault, not theirs.
Andy
I’m missing something here.
Why are squawks like this not handled before delivery? Why does it have to be fixed in the field? I don’t get it. Is this unique to the SR22 only?
Okay, on this one I can be a help!
This happened on my plane when it was new, whenever I transmitted on com 2. It was a shielding problem. Chris Dixon (of Cirrus) talked my local avionics person through the fix, and it works perfectly.
My experience is that this is definately fixable, and worth the effort!
Andy
Oh thanks that makes sense.
In my case, the test pilot discovered the problem on the acceptance flight, and suggested I have it fixed. With all that was going on, I forgot to mention it to the Cirrus people at the end of the day. My fault, not theirs.
Andy
I’m missing something here.
Why are squawks like this not handled before delivery? Why does it have to be fixed in the field? I don’t get it. Is this unique to the SR22 only?
Okay, on this one I can be a help!
This happened on my plane when it was new, whenever I transmitted on com 2. It was a shielding problem. Chris Dixon (of Cirrus) talked my local avionics person through the fix, and it works perfectly.
My experience is that this is definately fixable, and worth the effort!
Andy
In my case, the test pilot discovered the problem on the acceptance flight, and suggested I have it fixed. With all that was going on, I forgot to mention it to the Cirrus people at the end of the day. My fault, not theirs.
Did you have to provide your own test pilot? If he worked for Cirrus as a test pilot, why didn’t he report the problem Cirrus so it could be fixed before the plane was released?
Art, it was their test pilot who discovered the problem on my acceptance flight.
The problem was on Com2, which I don’t use too often to transmit in the air so I wasn’t that surprised that they didn’t discover it sooner.
My observation was that the test pilot was truly trying to find out what wasn’t perfect and get it resolved, not to just get me to take the plane.
I feel that with my SR20 being new technology, there were more problems than I would have liked. At the same time, I have found Cirrus to be zealous in working with me to get problems fixed.
Andy
In my case, the test pilot discovered the problem on the acceptance flight, and suggested I have it fixed. With all that was going on, I forgot to mention it to the Cirrus people at the end of the day. My fault, not theirs.
Did you have to provide your own test pilot? If he worked for Cirrus as a test pilot, why didn’t he report the problem Cirrus so it could be fixed before the plane was released?