Comments on: My new autopilot in instrument conditions

By: Ryan S

Ryan S — Mon, 22 Aug 2011 14:22:26 +0000

Ya, we know the feeling… We were waiting quite awhile to upgrade to the 430/50.

Keep an eye out though, with Garmin releasing the successors to the 430/530, I’m sure the used market on used IFR GPSs will come down.

By: David Megginson

David Megginson — Mon, 22 Aug 2011 14:19:34 +0000

Thanks for the comment, Ryan. The STEC-20/30 does support an interface with a GPSS, but currently, I don’t have one installed in the plane. I had the budget for an IFR GPS or and autopilot, and decided that the A/P would offer bigger convenience and safety benefits, so I’m still using only a portable VFR GPS (Garmin 696 with weather and traffic).

There’s on-and-off talk about implementing an RNAV approach at my home airport (CYRO). If/when that happens, I’ll likely install an IFR GPS and connect it to the A/P.

By: Ryan S

Ryan S — Mon, 22 Aug 2011 14:15:39 +0000

Not sure if your GPS/AP support it, but one of the most worthwhile upgrades for our plane was a GPSS converter to work between the 430 and STEC-50. Before the GPSS, you had to pretty much be lined up with the track line (either VOR or GPS) to keep the AP from oscillating back and forth over the course. Even then, it would drift further off course than I was comfortable with. Once when I was testing it while particularly far out on a VOR radial, ATC queried me as to my distance from the track (was VFR w/ flight following though so no deviations…)

The GPSS is the polar opposite. As long as I’m not 180 degrees off or going too fast for the turn required, the AP will turn to and hold a course perfectly, even through holds, 90 degree turns to final, etc. I will admit though, I haven’t tried it with too many VORs, but I did test it on an ILS. The only downside to it is that its somewhat counter intuitive to need the AP to be in “HDG” mode for the GPSS to work. I’ve had to explain that to a few pilots.

One use I’ve found for the wing leveler is when traveling through small convective clouds. I’m not talking big thunderheads, but the little building clouds w/o precip or lightning but still a little bit of turbulence. I’ve found that when I get hit with winds that want to roll the a/c, the AP can sometimes exacerbate the situation by inducing more roll. In these situations, I’ll flip over to the wing leveler just to keep the AP from leading me into inverted flight.

Ryan