VOR/DME via arc possible?

[ryanbatc 12,836]

It doesn't appear to work with the approach selected in the FMS. I can hand fly it using the old twist ten turn ten method but it doesn't appear to function from an automated standpoint, is this correct? I tried starting via the DLH288015, arcing NE for the vor/dme ry 21 apprch at KDLH. The FMS only draws a straight line from the IAF to the turn inbound. Is this a navigraph function? I've seen other addons fly this approach.

[VLJ510 16]

Mine has worked fine, I've done the HNL Arc onto 4R @ PHNL a few times and today LAS Arc into KLAS on RW 1L. All I did was pick the right IAF and the DME arc was on the ND. I'm no expert but from your approach onto were the arc starts off the 288 radial to fly a arc would need a hell of a turn. Looks like you could have came on the approach at heading 152 to intercept CHERL INT and the DME arc not even needed. You would have to turn almost 165 -170 degrees to start a proper arc and maintain the 15 DME. Looks like the arc is for approach from the opposite direction that your approaching from. You have no need to fly it as for whatever reason the arc exist the natural direction your approaching from already would have you clear and as said should just fly heading 152. Pretty much looks like your spending a dollar to save a dime with that flight path. Even if the ND drew/displayed the proper arc it would be a funky flight path that I think would/is surpassing the logic.

[CrashEd 8]

Mine has worked fine, I've done the HNL Arc onto 4R @ PHNL a few times and today LAS Arc into KLAS on RW 1L.

I didn't think they were in the current nav database? I'd love to see a tutorial on DME arcs if they are possible (properly)?

[bpcw001 22]

I've read somewhere in these forums that DME ARCs are not supported because Navigraph doesn't feature them in their procedures.I'd be interested to learn otherwise and/or see how DME ARCs are done properly.

[trisager 2]

The Navigraph data does have DME arcs in approaches, although the one that Ryan was trying to fly is not correct incycle 1108. I'd suggest taking the issue to the Navigraph forum, maybe they can fix it for 1109. I've flown a procedure with a DME arc into GCLP in the NGX. By the way, Navigraph defines DME arcs the same way you would fly them manually, as a sequence of short, straight segments.

[Tabs 2,790]

Arcs are not in our navdata format - should be there when we do the new navdata format. ie you'll see "ARC L" and stuff like that on the LEGS page.

[Flexman 30]

The Navigraph data does have DME arcs in approaches, although the one that Ryan was trying to fly is not correct incycle 1108. I'd suggest taking the issue to the Navigraph forum, maybe they can fix it for 1109. I've flown a procedure with a DME arc into GCLP in the NGX. By the way, Navigraph defines DME arcs the same way you would fly them manually, as a sequence of short, straight segments.

I've done that arc many times in the old NG. What I would normally do is, while onroute, draw the arc myself with points 2 or 3 miles apart. I know that drawing over terminal procedures is not accepted by the regulations, but oh well... Everybody does it at GCLP as the vectors they will give for approach are almost always the same and have become a very predictable procedure.

[PaulKent 0]

easy way to fly a DME arc... go to the fix page, type the name of the fix around which the ARC is based. In this case, DLH. Just below this you can enter radial and distance info. Type /15 and enter it using LSK3L (i think). This draws a 15nm ring around DLH. If you want you can add specific radials, eg you might want R095. Enter 095 below /15 entry. It will show the 098 radial from DLH. I use this method all the time flying in to sumburgh, it has a direct arrival via a 10DME arc.

[Flexman 30]

easy way to fly a DME arc... go to the fix page, type the name of the fix around which the ARC is based. In this case, DLH. Just below this you can enter radial and distance info. Type /15 and enter it using LSK3L (i think). This draws a 15nm ring around DLH. If you want you can add specific radials, eg you might want R095. Enter 095 below /15 entry. It will show the 098 radial from DLH. I use this method all the time flying in to sumburgh, it has a direct arrival via a 10DME arc.

but that will only give you a representation of the arc... and so would your RMI. For hand flying an arc, there are instument flying methods already. The thing is that in order to fly an arc on LNAV today, the only thing you can do is to draw that arc as good as you can, point by point. DLH095/15 (your IAF)DLH105/15DLH115/15DLH125/15DLH135/15DLH145/15DLH155/15DLH165/15DLH175/15DLH185/15

[VLJ510 16]

I might have been wrong above about the NGX arc itself, but here it surly looks like to me the on the ND that's attempting to draw a arc while not perfect. It has placed D172N witch is not on the approach chart for this RW as if is wanting to do so and has not provided me with a straight line as shown by the original poster.. Chart: http://204.108.4.16/d-tpp/1108/00662ILD1L.PDF

[ryanbatc 12,836]

Arcs are not in our navdata format - should be there when we do the new navdata format. ie you'll see "ARC L" and stuff like that on the LEGS page.

Appreciate the information Ryan.

[ryanbatc 12,836]

Pretty much looks like your spending a dollar to save a dime with that flight path. Even if the ND drew/displayed the proper arc it would be a funky flight path that I think would/is surpassing the logic.

No it's really not that difficult. The only thing that changes is when to start the turn. I use this quick math to determine turns to final when I'm working IRL... Aircraft's ground speed divided by 100 = distance from localizer/final app course/etc to turn them on. I then have to adjust the formula for any wind and the angle of the turn (if not perpendicular), but it works most of the time. Example, aircraft is 200 kts, south of final on a 360 heading. The ILS 27 is active. 2 miles south of the localizer I turn the aircraft to a 300 heading - in a no wind condition it works perfectly. The arc is about the same but all I need to do become parallel to the VOR by the time the DME reads 15. My initial setup is usually turn 90 degrees off my current heading (if I'm perpendicular to the arc), and turn the course knob another 10 degrees left or right. I keep centering the cdi needle, then turn another 10 degrees, and so on.

[VLJ510 16]

Even still it dose not answer why you want to fly the DME arc when the approach chart shows the 152 heading to enter the approach @ CHREL from your original heading. Your flying past all that to fly a arc when you could just have flown 152 heading shown on the chart. All the fancy computations are of no need as your (IMO) doing more then you need to approach the RW at least from the direction your approaching from shown above in your picture.

[ryanbatc 12,836]

It's for practice... that's the whole point. Sure I could get radar vectors to final approach course but that takes zero skill.

[ryanbatc 12,836]

I'm going to dig up this old topic because I have a similar question... I'm flying SAN - BUR via ZLA's TEC route MZB293R SLI148R SLI V23 LAX LAX316R SILEX. Interestingly enough, the intersection of the first two radials is PEBLE, but I'm not flying the DP. What is the best way to input MZB293R into my FMC? I tried MZB293/39 (which is the point where the radial intersects SLI148R) but it said invalid entry.