I have an issue with my TT ADI PII wrt the altitude hold mode (it hunts ? see below). I have been working with Lucas and finally got to the point of sending my unit to him to bench check. Before sending it to him we tried several configurations. One that did work was to attach the pitot line to the AP static intake. The vert hold worked great (the pitot side was left vented to the cabin). However swapping both lines (pitot to static intake and static to pitot intake) did not work. So I sent it off to Lucas. Lucas just emailed me and said it checks ?OK.? So now I throw it open to any and all suggestions and submit the following relevant data:
Aircraft
Vans RV8 with dual Grand Rapids HX (with internal GPS), SL-30, Garmin 496, TT ADI Pilot II, Static ports aft fuse per Vans drawing.
Aircraft stabilized/trim shot ~ 1 min.
GRT HX: set Autopilot mode to Hdg
TT: Press right button once, TRK light illuminates no aircraft response. Press right button again both TRK and NAV lights illuminate aircraft follows heading set in GRT PFD or will follow flight plan if GRT is set to ENAV.
Press left button ALT light illuminates. After approx. 3 seconds aircraft begins initial pitch down approx -5o, followed by pitch up to approx 8o then pitch down to -8o followed by a more aggressive pitch up to about -4o then an abrupt stop followed by one or two bumps up then a continuation to approx. 8o. The cycle repeats without going divergent and remains approx. 200? +/- the trim altitude.
Thanks,
Don
Aircraft
Vans RV8 with dual Grand Rapids HX (with internal GPS), SL-30, Garmin 496, TT ADI Pilot II, Static ports aft fuse per Vans drawing.
Aircraft stabilized/trim shot ~ 1 min.
GRT HX: set Autopilot mode to Hdg
TT: Press right button once, TRK light illuminates no aircraft response. Press right button again both TRK and NAV lights illuminate aircraft follows heading set in GRT PFD or will follow flight plan if GRT is set to ENAV.
Press left button ALT light illuminates. After approx. 3 seconds aircraft begins initial pitch down approx -5o, followed by pitch up to approx 8o then pitch down to -8o followed by a more aggressive pitch up to about -4o then an abrupt stop followed by one or two bumps up then a continuation to approx. 8o. The cycle repeats without going divergent and remains approx. 200? +/- the trim altitude.
Thanks,
Don