View Full Version : Dynon Skyview Autopilot ILS Lateral Offset

Dan Langhout
02-02-2020, 06:50 PM
So - flew my instrument cross country with my instructor today. It was decided to make the 3rd approach an autopilot coupled ILS. The Skyview autopilot flew a perfect glideslope (at least down to the last 100 feet or so) but it also flew the localizer with precisely a 1 dot offset to the right on the HSI (aircraft was right of course). There was a pretty strong crosswind from the right on the approach, but the autopilot maintained exactly the 1 dot offset all the way from before the FAF to the MAP with no apparent attempt to correct the deviation. Guidance is from an Avidyne IFD440 interfaced to the Skyview via ARINC-429.

Anybody observed this behavior before?

02-02-2020, 08:17 PM
By chance, have you not updated your SkyView firmware since last April or May 2019? Dynon issued a firmware update to correct the big GPS clock update that usually created errors similar to a left quartering tailwind (regardless of the actual winds).
Not quite what you had, but I know the experienced errors varied.

02-02-2020, 09:20 PM
Check you didn't have an "off-set" dialed into the Avidine unit. I know you can put in an "off-set" into the Garmin units and the SkyView tracks it perfectly. BTDT! :o

02-03-2020, 04:20 PM
Dan, Do you have the Nav antenna mounted in the wing, the localizer will be following that so it will be off the length of the wing.

Dan Langhout
02-03-2020, 04:52 PM
. . . . . for all the suggestions! The Dynon software is all up to date, no offset dialed in, and the Nav antenna is a "V" cat whisker mounted under the tail.

I tried it again today (KMDQ ILS 18) and also tried KMSL ILS 30 twice. Had an 11 kt crosswind from the right at MDQ (like yesterday) and an 18 kt crosswind from the left at MSL. Both very bumpy. AP did a great job keeping the needles pretty well centered. The GS struggled a bit at MSL in the bumps but was never off more than 1/2 dot. Bottom line: still have no idea why it worked the way it did yesterday. Eric Bale suggested I could have centered it manually with the rudder and then see if it held. Didn't occur to me to try it yesterday :mad: