DME Arc question

AggieMike88 said:
Bryan, In addition to learning how to hand fly this and get it Wong, make sure you get a chance to fly one using automation and autopilot.

1) to practice setting up the system correctly, and 2) verifying your system can do it without any surprises.

And if you need/want me as a safety pilot, I have lots of availability up to January 17.
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We're somewhat grounded for the moment. Cirrus is getting a new Transponder and possibly a bit of glass depending on MX availability.
that Sandel HSI is trash so we are going to add dual G5s. We plan to begin flying with our CSIP 3rd week in January.

I am just about ready to take the written again. I'm really glad I let that thing expire. Soooper fun test.
 
Walboy said:
I just looked in my old The Instrument Flight Training Manual by Peter Dogan which was the gold standard instrument instruction manual for many years. Yep, sure enough, the turn/twist technique is in there for DME arcs.

The advent of moving maps with widespread use of GPS sort of represented a paradigm shift IMO. I bet a lot of the over 50 crowd that has had their instrument rating for a long time are pretty comfortable with situational awareness just looking at CDI/ADF needles. They had to be.
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Actually, that's where I read it and rejected it when I began to teach myself DME arcs. I used the book in my own instrument training.
 
denverpilot said:
The reason it’s in every book is someone had to come up with a building block technique that was teachable vs saying “Just turn enough to stay on the arc.” :) After doing a few most folks just “get it” but for those who don’t, step by step instructions are needed.

As far as the over 50 crowd goes, I’m not and flew plenty prior to GPS and even remember a few folks who had money to blow buying LORAN. I continued to fly a /A airplane for a long time even after GPS was available. And there’s a lot of old ass working airplanes out there for those who go commercial that still don’t have a GPS, but it’s slowly fading.

Only one thought comes to mind though. If you’re flying something with an OBS you’d still better know how and be comfortable with using it by itself for SA. Crap fails. And most of us oldsters will cover your moving map and your iPad to make sure you know how to use everything on board to the fullest. Before you really need it one day when all of the automation in something you’re flying goes insane and you’re down to raw data and your brain is going to save your butt today. :)

Get comfortable with it if you aren’t. It doesn’t take too much practice but it does take a little. Evil CFIs will happy arrange practice sessions if you don’t ask for them. Hahaha.
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No idiot left behind shall be he death of us all.

Later idiot does idiot type thing at work, handwringers cry to gov to “do something” and all our lives are a little worse, yet we still can’t leave a idiot behind.
 
Why do you care where you are on the arc?

I also never understood the turn and twist 10 thing as it just seems to add workload and complication.. fly a steady turn based on the DME and when you get to your radial you're done
 
Walboy said:
I think that book was a staple with the PIC training folks. I picked it up thinking I might go that route back in the day. My instrument instructor taught twist and turn and it seemed to make a lot of sense to me. :dunno:

This thread has been an eye opener. I didn't know twist and turn was so despised.
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It's not about despising it. Just that is is more work than necessary. Situational awareness along the arc can be maintained without twisting every 10 degrees. Distance can be maintained without automatically turning 10 degrees by rote.
 
Tantalum said:
Why do you care where you are on the arc?
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Other than knowing where to get off and finish the approach?

I suppose you don’t need to and if you’re above MSA you can make 10 mile circles around the airport all day if you like. LOL.
 
denverpilot said:
Other than knowing where to get off and finish the approach?

I suppose you don’t need to and if you’re above MSA you can make 10 mile circles around the airport all day if you like. LOL.
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Well sure, just dial in the last radial so you know when to leave
 
Tantalum said:
Well sure, just dial in the last radial so you know when to leave
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Usually you need to lead that turn a little. Probably work okay in something slow.

Kinda moot point in the real world these days. Unless there’s no other option it’s pretty rare to fly one anyway.

But on a checkride...
 
denverpilot said:
Kinda moot point in the real world these days. Unless there’s no other option it’s pretty rare to fly one anyway.

But on a checkride...
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I was playing around with the AATD the other day and noticed that there's what seems like a ton of them in Oregon.
 
denverpilot said:
Usually you need to lead that turn a little. Probably work okay in something slow.

Kinda moot point in the real world these days. Unless there’s no other option it’s pretty rare to fly one anyway.


But on a checkride...
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“course alive” should work in just about any airplane because you should be slowed down at this point.
 
Dave Theisen said:
“course alive” should work in just about any airplane because you should be slowed down at this point.
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Should be. LOL. :)

In the end teaching them and actually flying them end up different for most folks. Step by step paint in between the lines vs technique and just staying ahead of the airplane, eh.
 
midlifeflyer said:
90 degrees is a pretty big intercept without a lead. Notice what GPS does fir a fly-by waypoint?
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Depends on the size of the arc...at 15 miles, course alive is 2 1/2 miles from the final course. At 10 miles, it’s still over 1 1/2...plenty for most airplanes.
 
MauleSkinner said:
Depends on the size of the arc...at 15 miles, course alive is 2 1/2 miles from the final course. At 10 miles, it’s still over 1 1/2...plenty for most airplanes.
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LOL. I guess I just like lead radials. Nice with a tailwind. As often, I'm in the middle somewhere between, "I like twist 10 to track my position along the arc" and "I don't care about my position along the arc."
 
SixPapaCharlie said:
We're somewhat grounded for the moment. Cirrus is getting a new Transponder and possibly a bit of glass depending on MX availability.
that Sandel HSI is trash so we are going to add dual G5s. We plan to begin flying with our CSIP 3rd week in January.

I am just about ready to take the written again. I'm really glad I let that thing expire. Soooper fun test.
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What don’t you like about the sandel?
 
SixPapaCharlie said:
Too dim, cant be seen from any angle except straight on, glitchy as hell. If its not spinning wildly, it is 30 degrees off.
Fix it, and it goes tits up again.
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Huh, I’ve been really happy with my 3308, though I don’t instruct in my plane so can’t speak to side viewing it.

Thing for me is it’s actually a grown up eHSI with overlays, RMI etc, the G5 and even the AV eHSI are just digital versions of a basic mechanical HSI
 
@SixPapaCharlie - I too was surprised to read about the Sandel HSI issue. We never had issues with the one in the Cardinal.
 
SixPapaCharlie said:
Too dim, cant be seen from any angle except straight on, glitchy as hell. If its not spinning wildly, it is 30 degrees off.
Fix it, and it goes tits up again.
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Adding to that: the colors wash out, the linkages and joints make the buttons/knobs feel mushy, resolution isn't great and the refresh rate can be a little slow at times. It was far ahead of its time, but that time has passed.
 
asicer said:
Adding to that: the colors wash out, the linkages and joints make the buttons/knobs feel mushy, resolution isn't great and the refresh rate can be a little slow at times. It was far ahead of its time, but that time has passed.
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Haven’t had those issues, minus field replacing one little ujoint for the OBS which was easy and cheap, but the sandel still seems way ahead of the pumpkin spice basic G5 and AV HSIs

Resolution wise it shows everything I need...I mean not like we’re streaming pornhub...oh I mean Netflix on it ;)

Having a digital eHSI with that screen and not being able to populate it with overlays, or even a simple RMI just seems like lots of opportunity tossed in the trash.
 
SixPapaCharlie said:
Too dim, cant be seen from any angle except straight on, glitchy as hell. If its not spinning wildly, it is 30 degrees off.
Fix it, and it goes tits up again.
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I’ve had two checkrides cancelled by a flakey Sandel. Not a fan. Old tech.
 
James331 said:
Haven’t had those issues, minus field replacing one little ujoint for the OBS which was easy and cheap, but the sandel still seems way ahead of the pumpkin spice basic G5 and AV HSIs

Resolution wise it shows everything I need...I mean not like we’re streaming pornhub...oh I mean Netflix on it ;)

Having a digital eHSI with that screen and not being able to populate it with overlays, or even a simple RMI just seems like lots of opportunity tossed in the trash.
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Well, I wouldn't rip one out for the sake of ripping one out, but if it needed more than a little bit of time/money then it'd be gone.
 
asicer said:
Well, I wouldn't rip one out for the sake of ripping one out, but if it needed more than a little bit of time/money then it'd be gone.
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Only issue I’d have is what to replace it with, a G5 or AV is no where near the same level of instrument
 
Walboy said:
This thread has been an eye opener. I didn't know twist and turn was so despised.
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I think it was a practical way to fly an arc with a display like the one here, the needle vibrating to the beat of each power stroke:

NarcoDME.jpg

http://www.vintageavionics.info/DME/html/NARCO UDI4.html​
 
Walboy said:
I just looked in my old The Instrument Flight Training Manual by Peter Dogan which was the gold standard instrument instruction manual for many years. Yep, sure enough, the turn/twist technique is in there for DME arcs.

The advent of moving maps with widespread use of GPS sort of represented a paradigm shift IMO. I bet a lot of the over 50 crowd that has had their instrument rating for a long time are pretty comfortable with situational awareness just looking at CDI/ADF needles. They had to be.
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I'm over 50, but have been flying IFR only 16.5 years. The DME arc was one of the easiest procedures I ever flew (for practice and for real). I enjoyed it.

Moving maps and GPS have been available the whole time I've flown, and I appreciate being able to glance at them once in a while as a sanity check, but they're a distraction if you're relying on them--instead of a heading and the CDI--for your primary navigation. I think panels in general are getting a bit too busy for safe flying, because the information you need is buried in a lot of clutter you don't need (most of the time): we used to have to train IFR pilots how to fly with too little information; now we have to teach them how not to get distracted by too much. I think they're both potentially deadly situations.
 
David Megginson said:
I'm over 50, but have been flying IFR only 16.5 years. The DME arc was one of the easiest procedures I ever flew (for practice and for real). I enjoyed it.
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We do this a lot, but DME arcs is one of the best example of an incredibly easy procedure we do our best to make difficult.
 
midlifeflyer said:
We do this a lot, but DME arcs is one of the best example of an incredibly easy procedure we do our best to make difficult.
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Yes, the elaborate instructions in the Canadian instrument procedures handbook always puzzled me, and I suspect it was the same for the US FAA guides. How could they make such a simple procedure seem so hard?

Over a decade ago, I flew a 360° DME arc (so a DME circle, I guess) 3 miles outside the edge of Ottawa Terminal airspace, just for the fun of it.
 
David Megginson said:
Yes, the elaborate instructions in the Canadian instrument procedures handbook always puzzled me, and I suspect it was the same for the US FAA guides. How could they make such a simple procedure seem so hard?

Over a decade ago, I flew a 360° DME arc (so a DME circle, I guess) 3 miles outside the edge of Ottawa Terminal airspace, just for the fun of it.
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I think I saw a copy of an older Canada manual and they were pretty similar. I mentioned earlier I was lucky. I didn't have DME when I got the rating, so I self-taught later and managed to simplify it for myself. Over-complicating the simple is definitely a rant topic for me,
 
midlifeflyer said:
We do this a lot, but DME arcs is one of the best example of an incredibly easy procedure we do our best to make difficult.
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Everyone over complicates numerous things in the old needles books. ADF approaches were always a hoot.

My favorite is holding pattern entries for over complication. All the angle “calculators” and such. The thumb rule. All of it.

An old wise instructor got me straight on those. “Hit the fix and turn outbound.” It works every single time.

The only time you have to think even the tiniest bit is on shallow angles where you might like a bit of room to do a teardrop and even then it doesn’t really matter. Just go through the inbound course in the first turn and keep the turn going and correct it.

Of course we have to teach the official angles and such, but if all you’re doing is trying to stay where you’re supposed to be and not kill yourself hitting terrain or whatever, overloaded, behind the airplane, whatever... just hit the fix and turn outbound. Then turn toward the course and fly it inbound.

Most people can visualize at least that much of where they are. It’ll give them a couple of minutes to decide which side of the course line they’re on.

I laughed the first time I was doing hold entries with a Garmin. Instructor tapped on the bottom corner of the screen and I realized the stupid Garmin was doing it all for me.

Oh look. A little countdown and everything! Nifty! LOL. Cheating. Soooo easy. Cover it up, I don’t care. :)

I think it was more second nature to visualize where you were before the modern toys. You just had needles and no map and you visualized position or you were lost. :)

But hit the fix and turn outbound was a lightbulb moment of simplicity for me. Engineer brain wanted to calculate crap and such. No need.
 
denverpilot said:
Everyone over complicates numerous things in the old needles books. ADF approaches were always a hoot.
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Yes, ADF approaches and holds were my favourite during IFR training. Just one needle to watch, always pointing to the FAF or MAP; way simpler than all the radial twisting.
 
David Megginson said:
Yes, ADF approaches and holds were my favourite during IFR training. Just one needle to watch, always pointing to the FAF or MAP; way simpler than all the radial twisting.
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I didn't understand ADF approaches until I was working on my CFII. I experimented on a friend who was also having difficult. Net result was he flew them better than I did :D.

In my case, the problem was my instructor. Not really. He was great and we are still in contact 25+ years later. But he could just immediately and unerringly visualize where he was no matter where that needle was pointed and couldn't find a way to make it click for me. One night I got so frustrated with ADF intercepts, I took the hood off turned to him and said, "Your airplane."

He was understanding. "I know you are having difficulty with these. Let's call it a night. Take us home."

I replied, "Maybe you didn't hear me. I said 'YOUR AIRPLANE!'" He flew us home.
 
When I was teaching DME arcs to aviators who had never had a TACAN on board, I would start them off with "DME Stopsigns." As long as they stayed within the standards for maintaining the arc, they were OK and would usually tighten up their tracking by themselves. Having a recording of the ground track for a debriefing review usually meant they needed no further instruction and would fly nice arcs out of self-discipline...
 
I don't remember ever doing the 10 thing. The allowable tolerance on the arc is +/- 1 nm. We'd simply enter the arc, set the display to time to station and hold that at 0. Check the distance now and then. Set the OBS to the inbound radial. When the needle started to deflect, turn to the inbound course and fly. DME arcs are really simple. It helps that we have one to my home drome, too.
 
I can barely remember doing arcs in my training back in the early 1990's. I sorta remember getting wrapped up in ident and minutia multi-task maddness... I don't recall if I had to do one on my checkride or not.

David Megginson said:
Yes, ADF approaches and holds were my favourite during IFR training. Just one needle to watch, always pointing to the FAF or MAP; way simpler than all the radial twisting.
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I agree. I loved the simplicity and I have often said I feel like they shouldn't go away.....EXCEPT I didn't so much love them the time I failed on my 1st instrument checkride on one. I got myself disoriented... maybe in the procedure turn I suppose it was. Anyway, I just remember my examiner...and old WW2 C-47 pilot.... tapping the RBI (ADF) so hard I thought for sure the glass was going to break while simultaneous very loudly yelling in a gruff and condescending Marine Corps Drill Sgt demeanor..."Sir, What are you Doing?...Sir, What are you doing?...."
I did better (well good enough anyway) the following weekend...but I'm still rattled when i think of it.
Regardless, I wish I'd struck up a conversation with that guy about his service and experience. It was an honor Mr. Watson.
 
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