Archived

This topic is now archived and is closed to further replies.

n4gix

Mooney Bravo nav1 autopilot

Recommended Posts

I'm flying a 215 radial to a VOR. The arrow on nav1 in the centre of the HSI is pointed to 215, the white pyramid is pointing up, the TO position. The yellow line is to the right. Looking at GPS I'm left of my desired track.Now if I engage autopilot to nav1 I'm expecting it either to continue on 215, or turn right to intercept the track and then straighten back up to 215. Instead what it does is to turn left something like 45 degrees.Does this make sense? Bug?

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Something doesn't make sense here. If you were really on the 215 radial attempting to fly toward the station your position would be southwest of the station and your course arrow should be set at 035 (215-180). But from your other description it sounds like you are in fact attempting to fly the radial 035 inbound - you are northeast of the station and your course is set at 215. Assuming that this is the case (and that you are to the left of the course - your deviation bar is to the right) you should point your aircraft to a heading from which you can intercept radial 035 - for example heading 260 and engage NAV when you get nearer. So you really should be in the AP's heading mode first. I don't know particulars o this autopilot in the Mooney whether it can automatically switch from HDG to NAV mode so you have to figure it out on your own.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg

Share this post


Link to post
Share on other sites

>I'm flying a 215 radial to a VOR. The arrow on nav1 in the>centre of the HSI is pointed to 215, the white pyramid is>pointing up, the TO position. The yellow line is to the right.>Looking at GPS I'm left of my desired track.>>Now if I engage autopilot to nav1 I'm expecting it either to>continue on 215, or turn right to intercept the track and then>straighten back up to 215. Instead what it does is to turn>left something like 45 degrees.>>Does this make sense? Bug?Does your next waypoint in the GPS correspond to the one your flying to or did you overshoot the previous waypoint by any chance? I fly the mooney alot and havent had any probs with it.

Share this post


Link to post
Share on other sites

It was definitely in nav. I was heading generally towards the VOR beacon but the needle was off to the right.

Share this post


Link to post
Share on other sites

>Something doesn't make sense here. If you were really on the>215 radial attempting to fly toward the station your position>would be southwest of the station and your course arrow should>be set at 035 (215-180).I can't remember the exact particulars now, but it was an IFR flight and TO was indicated on nav1, with the needle to the right.Also a couple of times over about a year, with Cessna 172, as I recall, and the Mooney when I've turned off either hdg or nav on autopilot, leaving just alt the controls haven't responded. I've had to turn off autopilot completely.

Share this post


Link to post
Share on other sites

It sounds like you need to learn a little more about the autopilot and VOR's. Try Rod Machado's VOR lesson under private pilot. A radial extends out from the station. You can not fly to a station on a radial out of the station. You fly to the station using the reciprocal of the radial you are on. Therefore, your heading flying to the station on the 215 radial would be 035 and that would be your OBS setting. Your heading flying from the station on the 215 radial would be 215. The autopilot usually will not track the radial in NAV mode on the autopilot if the CDI needle is fully deflected, it has no way of knowing where you are. You also need to make sure that you are using Nav1 and the GPS/Nav toggle is in the Nav position. A good way to tell if the autopillot "knows" where the radial is located is to use the heading mode to get the plane headed in the right direction to intercept the radial, then press the nav button on the autopilot. If the heading mode button stays lit the autopilot is maintaining the heading bug direction until it "knows" where the radial is, then it will enter nav mode and the heading mode lit will go out.I would also suggest you take a look at the GPS or map to determine your position. If you are using a flight plan you can also change the GPS/Nav toggle to GPS and use the autopilot on nav and that will get you on track.By the way on the HSI it is possible to be heading 215 with the CDI set to 035. This would cause the autopilot to turn away from the CDI because of reverse sensing. If we knew which heading you are suppose to be flying it would be easier to determine the problem.

Share this post


Link to post
Share on other sites

>Also a couple of times over about a year, with Cessna 172, as>I recall, and the Mooney when I've turned off either hdg or>nav on autopilot, leaving just alt the controls haven't>responded. I've had to turn off autopilot completely.The default behavior of the FS autopilot is to turn on the "wing-leveler" function whenever only the ALT HOLD mode is engaged.You merely need to turn off "wing-leveler" (Ctrl-V) to enable turning when in ALT HOLD mode.

Share this post


Link to post
Share on other sites

>You merely need to turn off "wing-leveler" (Ctrl-V) to enable>turning when in ALT HOLD mode. That isn't something I would have thought of. Thanks.

Share this post


Link to post
Share on other sites

>It sounds like you need to learn a little more about the>autopilot and VOR's. Try Rod Machado's VOR lesson under>private pilot.To be perfectly honest, I didn't find those lessons on VOR as useful as they should have been. I couldn't find mention of how to enter a VOR frequency and had to ask here. It's buried somewhere else in the learning centre. I understand VOR, I just lose track of correct terminology sometimes. And there's plenty of it. ;)

Share this post


Link to post
Share on other sites

I just started a flight from Nice to Barcelona. It was an IFR flight and ATC had directed me towards it but not on the exact right heading. No DME so I couldn't tell the distance. As I approached the VOR - that's with hindsight, I was looking at DME from the next VOR at an upcoming intersection for a position fix - the needle started to centre. I switched from HDG to NAV with the OBS set to 244. It just required a slight correction. Then as I passed over the VOR with the arrow at 244, triangle in the FROM position, instead of making a left correction to line up with the needle it turned right, and continued right. It kept turning right and never straightened out, completing two 360 turns before locking up when I tried to turn off full screen to post here.I was expecting it to continue on 244, centering the needle, flying FROM the VOR.

Share this post


Link to post
Share on other sites

>Does your next waypoint in the GPS correspond to the one your>flying to or did you overshoot the previous waypoint by any>chance? I fly the mooney alot and havent had any probs with>it.It's been a while since I flew that, so I can't recall. Autopilot was set to NAV and the VOR was set in NAV1. I just remember it pulling in the opposite direction I was expecting, deviating completely from the course I expected it to follow.The error might well be with me, of course.

Share this post


Link to post
Share on other sites

>I'm flying a 215 radial to a VOR. The arrow on nav1 in the>centre of the HSI is pointed to 215, the white pyramid is>pointing up, the TO position. The yellow line is to the right.>Looking at GPS I'm left of my desired track.>>Now if I engage autopilot to nav1 I'm expecting it either to>continue on 215, or turn right to intercept the track and then>straighten back up to 215. Instead what it does is to turn>left something like 45 degrees.>>Does this make sense? Bug?Next time you try that open up the gps and check the localizer line on the bottom to see if your left or right of your course. If you happen to be 10 miles off either way you can expect a 30-45 degree turn while it tries to center you back on course. To the left on the bottom you'll see a x.xx .

Share this post


Link to post
Share on other sites