How To Intercept and Fly DME Arcs

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Note: This lesson uses a 2-4 degree rule of thumb for adjusting heading and radial. I know that the often taught method is "twist 10 turn 10" but for this lesson I chose to use the method outlined in the Instrument Flying Handbook just for standardization.
DME Arcs may seem scary to new instrument pilots, but given a few quick and easy tips they can be as easy as tracking any course.
A DME Arc is just another way to intercept a final approach course. Most approaches use procedure turns or vectors to get a pilot on the final approach course. However, sometimes due to rising terrain and other obstacles it isn't always possible to safely make a procedure turn.
In this lesson we'll explore how to intercept a DME Arc from both the inside and outside of the arc. We'll also look at the simple way to keep on course while flying an arc and how to slightly adjust for drift. You will also see how keeping situational awareness is key while flying the arc.

[@fernando13e]

Isnt it easier to look for your RMI instrument, dial the VOR frequency and fly the arc trying to maintain the needle pointed 90 degrees towards the VOR station?

[@twister8310]

Why make a 90 degree turn to join the ARC? I was taught and always do turn 100 or 80 degrees to intercept the ARC. If for example outbound on a radial FROM the VOR to intercept the arc, you turn 100 degrees about 0.5NM prior to reaching DME ARC (In an airplane flying around 100/ 120 Kts this works perfectly, in light wind conditions at least). If inbound TO the VOR you turn 80 degrees to intercept the ARC and again about 0.5NM prior to the DME ARC. This way you pretty much always end up right on the desired DME ARC (20NM in this case), and thence just smoothly turn with the ARC to keep the correct distance all the way .

[@petermerry6123]

When you first establish on the arc your heading will be around 033 but the Cdi should be about 123 to center. You’ll be flying a long way if you’re on a 033 at exode waiting with obs on 033 too.

[@firepots]

Good lesson. Thanks

[@RIDGELzraizaa]

Walker Brian Thomas Ruth Rodriguez Robert

[@TWhite94]

This sounds like such a pain in the ass to actually do while flying, especially in IMC

[@Klaviation]

20PhantomRegiment09 It isn't too bad with a few minutes of practice in the airplane. Flying arcs with an RMI is much, much easier.

[@FindingSkidoo-l1q]

Jones Mark Davis Donald Martin Eric

[@tonymontana5753]

Your voice tone makes me sleepy.

[@chubakabrah]

Tune 10 turn 10 is much easier than messing with 2-4 degrees. If your .5 miles off your desired DME then use tune 10 turn 20.

[@Hedgeflexlfz]

yea

[@azcharlie2009]

Turn 10 twist 10 is the way my IFR instructor taught me. May God bless his soul. He passed away last month.

[@David-jk7ot]

the narrater Sounds like Tina from Bob's Burgers

[@berndl]

At 7:15: Why did you pick an example not related to the approach plate, that you showed before? Would be easier to follow.

[@denniskitainik5501]

7:12 The CDI should be on NAV, not GPS!

[@DavidDyck]

I am curious why you drew the procedure turn when outbound from JIVDO as a turn to the left ( I'm a student, but I thought we turned right after flying outbound on the 345 bearing for one minute

[@danielvanwormer5551]

What happens if ATC has you fly direct to one of the IAF i.g. GUSSE. More than likely you are not going to fly the radials identifying the IAF. You can approach the IAF from any direction.

[@dicktracy2453]

Arc is hard to maintain unless guided by DME. Why not intercept the arc left and then fly a right pattern to final. Tune to localizer if IFR.

[@wills2954]

You got to talk louder...Say again plzz...

[@bimayadesilva9432]

how is R-301 outbound equal to R-121 inbound? Do you mean heading 121 on the R-301? Please explain.

[@Mrlownly2]

At Embry-Riddle, they teach 1/2 a percent of our ground speed as the distance from the published DME to intercept the arc. (i.e if your ground speed is 120 knots, then you'd turn to intercept the ark at 14.6 on this ark)

[@nevadaair1270]

the twist 10 turn 10 is lot easier to explain and understand.

[@abbieamavi]

Great video as always, and your voice is so calming it helps! The red drawings too(: if you’re an instructor, you’ve got to have the most calming voice ever I think and your voice is!

[@DavidDyck]

When flying the Pendleton arc, you mention the 250 radial - but while one would be flying 250 inbound, wouldn't the outbound radial that the VOR would be tuned to be something like 070? ( did I miss something? )

[@happysawfish]

Excellent. I really like the format. Your explanation combined with the overlay notes is perfect. Thank you and hope you keep making these. I would like to see also a 'interactive' format, where the viewer is given the option to think through the scenario at various intervals as you go along, and then you provide solutions that could be chosen.

[@MarkParker-z1d]

Rodriguez Helen Moore Richard Thompson Paul

[@NicholasAguilar-s5o]

Jones Eric Young Thomas Jackson Elizabeth

[@FelisaSteuber]

Walker Cynthia Perez Steven Davis Timothy

[@TheCanreme]

I have a dout every ten radials you have to change the heading to intercet the other radials or what is the best way keep the arc with the correts headings !!

[@charliefoxtrotthe3rd335]

I would think that once you got to that 14.5 mile mark and made your 90° turn, just keep a slight right hand turn and using the DME to keep that 14 mile arc, adjusting your turn. Eventually you will determine the perfect amount to hold the turn and just keep your eyes on that 14 mile. Is that too simple of a procedure? It sure would be easier than trying to keep it centered on the dial...

[@mattbowers3541]

Situational & Spatial awareness are primary. I just make the first turn. Then check the DME and start a 1/2 rate turn. Then set the CDI and HdInd for the inbound. Now, vary my turn rate while cross-checking the DME. Watching for the CDI to come alive. At 1/2 deflection, start the inbound. Notice there is NO turning knobs, calculating, etc. Just awareness of what I'm doing now (DME) and the goal (turn inbound). Simple! But, as stated, staying INSIDE the DME distance is way easier. ie, 13.7-14nm for this arc. CFI,CFII,MEI,AGI,IGI... eieio.

[@Bloblobloblown]

I forgot how it was supposed to be...long time I don't practice it

[@JonathanDuchesne-g6o]

White David Perez Angela Anderson Cynthia

[@BloomerVicky]

Martin Donald Brown Michelle Garcia Kimberly

[@HusOoius]

Garcia Melissa Taylor Kenneth Thompson Charles

[@MrChoclas]

Isn't a radial (VOR) always the same regardless if we are inbound/outbound? In this case we would be always intercepting R301, and when inbound following course 121 to the station.. (no wind).

[@WingAce5]

That is right, he would have been inbound on the 301 radial on a heading of 121

[@oliviawhitefera9237]

Gonzalez Mary Jackson Robert Young Mark

[@johnrobert7107]

Thanl u

[@malcolmhand3631]

Very good, thanks !! Would like to see a tut describing how to do a visual arc at low altitude (1000 ft agl)

[@VincentAnnabelle-l4l]

Smith Lisa Wilson Nancy Robinson Jason

[@barbarablomfield2125]

Anderson Eric Taylor Brenda Hall Helen

[@Jl3d8]

Too much talking with Little bit of knowledge

[@brhelodrvr]

Just ran across this. This approach to RWY 21 is one of my favorites.

[@JennyMitchem-e3u]

Lee Lisa Lewis Kevin Davis Timothy

[@reponrepnation3004]

After turning 90 degrees to join the arc, afterward why can't you just watch for DME distance, if the DME distance is increasing, meaning you are flying away from the arc so you better start turn towards inside a bit vice versa or even easier way keep your VOR always 90 degree of your current heading eh . wouldn't this work out better ?

[@WobblyLawbaby]

Nobody knows what are you talking about ......... I think

[@WobblyLawbaby]

Thankyou I'm sorry !

[@ArmandoLasseter-h3i]

Moore Brian Lee Betty Lee Ruth

[@SlantAlphaAdventures]

I know this video is a few years old now, but, if you'd like to see a simulator pilot fly this approach in X-Plane 11 using radio navigation only (no GPS) and compare the theory to the execution, check out kzbin.info/www/bejne/f2KZlI2ne8qNgck -- I made a few altitude deviations during the approach, but the navigation of the arc itself was pretty successful. Just take everything there with a slight grain of salt, as I'm a sim pilot with 30+ years in, but no real-world experience. Most of the procedural execution of the approach should be pretty solid, though, minus the aforementioned altitude issues.

[@SlantAlphaAdventures]

Here's another attempt, finally, in which I flew the altitudes correctly, and in which my end-title screen didn't pop up halfway through the approach. Again, it's this same DME arc, the ILS 21R into Pasco. kzbin.info/www/bejne/fqSZlHufedyAZrs

[@CreepinCreeper145]

This is why I like flying with RMI.

[@SpankyMcGician]

why can't you say '14 miles' from vor on first part, turning left onto arc, if you have dme?

[@solomonpilot2510]

thanks will very informative thanks again !

[@MrHustleme]

thankyou so much ! learnt alot

[@patrickmollette15]

Now when you showed the OBS indicator, should it have been in VLOC mode or GPS mode like it was? I imagine if you were flying Radials it should be on VLOC right?

[@masterpilot321]

It should be in VLOC mode because you are tracking the station using your CDI. You are not tracking the arc using your GPS.

[@suradmister3694]

Does the plane have to have DME to fly this arc? If not, do you just estimate 14 miles from the VOR?

[@berndl]

Surad Mister Of course the plane must have DME equipment - that's why this approach is called "DME arc"!!!

[@kpunroy]

Thanks a lot, it really helps!

[@alexisesparza7773]

What means NoPT.

[@farayidarlingtonchaparadza20]

No Procedure Turn

[@kevinkim18]

This is different than what I have learned. Aren't you suppose to twist the nob 10 degrees away from the center and track the course until CDI is centered? When CDI is centered, turn 10 degrees to the course and twist 10 degrees again and so on.

[@3pilot]

+Kevin Kim just different techniques.. not mandated. you only need to stay at +/-1nm on the arc.. everything else is just whatever you need to do to keep that dme (hopefully a lot closer than 1 off)

[@capncrunch9313]

Go teach something else my friend. Total confusion for a simple maneuver.

[@airliner27]

why not just plug it into the fms?