DME Arc IAF Entry

[CloudyIFR]

From what my training has told me is that you may turn onto the DME upon any radial within the arc. Just make sure you're at or above ATC's MIA/MVA, airway minimum altitude, MSA etc....

I've been hearing the airline folks who come into our airport stating that the only place that you may enter the arc is at the very end of the arc.

Is this a Part 121 rule or someone's has interpretation?

Thanks for any insight.
Curtis

 

[DC8 Flyer]

Looking through the AIM and the Instrument Flying Handbook (FAA-H-8083-15) I find nothing that says you can, or can not, start an arc from a point other than the beginning.

Common sense would say if you are under radar control and told to fly a heading and intercept the published arc, that is ok, just like vectors to final.

Something to think about, the Bendix 89b (I think thats the right number??) allowed you to "move" the arc based on your ground track. This is an IFR certified GPS so I would venture a guess that if the FAA didn't want pilots intercepting the arc from anywhere but the initial point this wouldn't be a feature on the GPS units???

Maybe someone with a little more terps knowledge could answer the question...

Also one I have always wondered about is, how wide is the protection area on the arc, 1 mile or 4 miles?

 

[partypilot1]

You can enter the arc at any point along the arc, if under radar control. EX..You would be told to fly heading 340 and intercept the 12 dme arc to the ILS7L. If not, you would have to proceed to the IAP along the arc. Lots of shooting ARC approaches in Dominican Republic (Santago).

 

[MauleSkinner]

You can enter the arc at any point along the arc, if under radar control.

...

If not, you would have to proceed to the IAP along the arc. Lots of shooting ARC approaches in Dominican Republic (Santago).

You wouldn't happen to have a reference for that, would you? I've read the second part several times in periodicals (sorry, I can't think of specific articles offhand, but search articles by Wally Roberts), but I've never seen the vector part in print. It makes sense, just wondering.

Fly safe!

David

 

[Andy Neill]

Here's the word from the lawyers at the FAA. Sorry I don't have a date for this letter.


FROM OFFICE OF DONALD P. BYRNE, ASSISTANT CHIEF COUNSEL, FAA REGUALTIONS DEVISION.

“You address the necessity of executing a complete Standard Instrument Approach Procedure (SIAP) in a non-radar environment while operating under Instrument Flight Rules (IFR). Our response assumes that each of the specific scenarios you pose speaks to a flight conducted under IFR in a non-radar environment….
...You also ask whether a Distance Measuring Equipment (DME) initial approach segment can be substituted for a published IAF along any portion of the published arc. A DME arc cannot be substituted for a published IAF along a portion of the published arc. If a feeder route to an IAF is part of the published approach procedure, it is considered a mandatory part of the approach.”

​

 

[100LL... Again!]

Expect the arc to eventually go the way of the NDB with gps becoming more common.

I like flying arcs, but teaching them sucks.

 

[CloudyIFR]

Expect the arc to eventually go the way of the NDB with gps becoming more common.

I like flying arcs, but teaching them sucks.

I think it will be quite awhile though, we're still flying NDB approaches at many airports! Great fun!

Curtis