Reverse sensing, localizer, Aspen, SL-30

Clark1961

Clark1961

Touchdown! Greaser!
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Flew a bit yesterday. First time in a couple months. Landings were smooth and right on the thousand foot marks. After two landings and three take-offs I left the airport vicinity for a little airwork. As is my usual practice I set up the nav radios for the ILS on the way back to the airport. Lots of folks flying so eyes needed to be out of the cockpit. I quickly set the course on the Aspen without bothering to check it.

I set course to intercept the localizer on nav 1 then switched the Aspen to nav 2. It showed I should turn 90 degrees to intercept. Nav 2 also has a CDI and it agreed with what nav 1 had shown on the Aspen. I muttered under my breath that I haven't had a problem with nav 2. I did recheck the tuning and station id on nav 2. I should have rechecked the course setting on the Aspen but didn't. Nav 1 is a 430w and nav 2 is a SL-30.

I rechecked the setup today and found that I had set the course wrong by 180 degrees on the Aspen. That setting caused the apparent reverse sensing on nav 2. The 430w handled it without a problem. Somewhere an avionics tech and/or designer is laughing at me I'm sure.

So I thought I'd share this story so other folks using an Aspen may be aware of this little bit of unfortunate display behavior which may occur if the nut behind the yoke is 180 degrees off.
 
I thought this was going to be about the localizer at Aspen, ASE, not about that thing in your panel that confuses me....
 
I don't think the Aspen has anything to do with it, that's how the SL 30 works. You have to hit SEL and ENT to enable BC sensing, it doesn't just do it automatically like the 430W.

Same thing applied to my GTN 650 and my SL 30 when I had them. GTN 650 just handled it, SL 30, not so much.
 
Caramon13 said:
I don't think the Aspen has anything to do with it, that's how the SL 30 works. You have to hit SEL and ENT to enable BC sensing, it doesn't just do it automatically like the 430W.

Same thing applied to my GTN 650 and my SL 30 when I had them. GTN 650 just handled it, SL 30, not so much.
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Interesting point. It seems contrary to the old saw that reverse sensing is not possible with an HSI.
 
Everskyward said:
I thought this was going to be about the localizer at Aspen, ASE, not about that thing in your panel that confuses me....
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Everything in my panel confuses me apparently...
 
Ravioli said:
With a correctly set HSI it is not possible. Is that what you meant?
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Not sure what you mean by "correctly set". If you are doing a BC, "correctly set" means with the arrow on the front course. But I don't think Clark was attempting a BC approach. Now I'm really confused...
 
Clark1961 said:
I rechecked the setup today and found that I had set the course wrong by 180 degrees on the Aspen. That setting caused the apparent reverse sensing on nav 2. The 430w handled it without a problem. Somewhere an avionics tech and/or designer is laughing at me I'm sure.
Click to expand...

Everskyward said:
Not sure what you mean by "correctly set". If you are doing a BC, "correctly set" means with the arrow on the front course. But I don't think Clark was attempting a BC approach. Now I'm really confused...
Click to expand...

Well, the OP said the aspen was set incorrectly.
 
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