DME Arcs

[Back_Course]

When flying dme arcs and you've been given an intercept from ATC and cleared for the approach, do you have to fly to the IAP or can you join up with the arc? A student of mine claims his friend was asked this in an interview and told he had to fly the ENTIRE arc even when given an intercept. Doesn't seem correct to me, but any ideas?

[CapnJim]

Comes down to a question of common sense to me-- if ATC has sequenced you for the approach, what is the sense in flying completely around the airport? I've heard "If it's a bold black line you have to fly it..." , but a GPS approach may have 3 IAFs (ex., GPS RWY 5 at Malone-Dufort NY) ; can't fly 'em all... so what gives? I'm thinking that your student's friend may not have his facts straight.

[MikeD]

[ QUOTE ]
When flying dme arcs and you've been given an intercept from ATC and cleared for the approach, do you have to fly to the IAP or can you join up with the arc? A student of mine claims his friend was asked this in an interview and told he had to fly the ENTIRE arc even when given an intercept. Doesn't seem correct to me, but any ideas?

[/ QUOTE ]

If cleared to commence the approach at the IAF that begins at the arc, you'll fly the arc in lieu of any procedure turn. If receiving vectos from ATC, you fly the vectors and no procedure turn is required. If I'm reading your question correctly, your buddy claims to be receiving vectors while on the arc; which wouldn't normally happen, unless ATC wanted to vector you off the arc and to the final approach course via radar. Then, the arc would be "cancelled" so to speak with the radar vectors overruling the published course.

[Eagle]

[ QUOTE ]
If I'm reading your question correctly, your buddy claims to be receiving vectors while on the arc;

[/ QUOTE ]

I thought he was saying he had been vectored to the arc, and the claim was he needed to go to the IAF and fly the procedure. (even if the IAF was behind him)

which is nonsense.

If you are vectored to the arc or even to the inbound radial like in a VOR app, you do not need to do the entire gig. it is a nice short cut.

Of course that is assuming he is cleared for the approach, I've been vectored to intercept without being cleared to shoot..

NY App... 65R, am I cleared for the VOR Alpha?

oh yeah sorry, 65R you care cleared for the VOR A, you are familiar with the canx procedures blah blah blah

[Doug Taylor]

My biggest goof on DME arcs, was that I was so amazed that I was performing it correctly, I'd totally blow my final approach course! D'oh!

Riddle would have us hold on the DRK 259/15 fix for a while, and then transition from a hold to an arc.

Alas, I haven't done an arc in real life, nor training since 1997. I hope the DAL training department isn't reading the forums today!

[PA44]

Once your on vectors, thats it. They want you on the ground as soon as possible in order to deal with other a/c.

[E_Dawg]

I would ask if there was any ambiguity whatsoever. Barring that, if they give you vectors to the FAC... why would you want to bother with the DME arc (even if it WAS legal)!?

[MikeD]

[ QUOTE ]
I would ask if there was any ambiguity whatsoever. Barring that, if they give you vectors to the FAC... why would you want to bother with the DME arc (even if it WAS legal)!?

[/ QUOTE ]

You wouldn't. Agree on query ATC if you feel there's any ambiguities.

[Josh]

Ok, so here is my little input from my arc experiences.

One of the local approaches is VORDME-A (WVI if anyone wants to look it up) that is kinda backwards. Since the VOR is at SNS and you are heading out on the arc to WVI. And also did the arcs down at PRB. Anyhow, since the WVI one is local, I flew it a lot. Not used it other than the test, and training, but I would if I was flying in from that direction. Good thing about it is you are brought in around a regular 45degree entry for 20, which is the normal runway at WVI. And with all the yahoos out who love to skirt under the clouds when it is around 1000-1500' overcast, and not use the radio, it is nice to come in from where you are expected. Rather than the LOC2 at WVI which is opposite the normally used runway 20.

Anyhow, in every arc flown, I was vectored. A couple of times, requested vectors from a different side, but always vectored. For the 20 or 30 I did at WVI VORDME-A, I think every time, vectored to intercept the arc. Then fly that, and on the turn out (remember this WVI one is backwards since it is away from the VOR) or shortly before that turn began, cleared.

Guess the point is, you are getting vectored to make things faster. As stated above, they wanna get you on the ground first and free up the space for the next person. The approach means going from the place you are on through the procedure. So if you are cleared, and vectored to the arc, then you execute the approach from where you are put by ATC. They will not expect, or want you to turn to the IAP (which will likely be the other way than they expect if you are getting vectors (again vectors are usually used to shorten things up- unless they give a "vectors for spacing" as I've often got on busy days).

Just as if vectored into say, and ILS. You do not fly to the IAP, and execute a procedure turn (unless of course for some odd reason, ATC vectors you with those instructions). Point of vectors, and radar control is to clean up the spacing and that is usually always to mean shorter for everyone.

[MikeD]

[ QUOTE ]
Point of vectors, and radar control is to clean up the spacing and that is usually always to mean shorter for everyone.

[/ QUOTE ]

Yes. ATC vectors is one of the number of times when NoPT is flown

[seagull]

U.S. Department of Transportation
Federal Aviation Administration

Nov 28 1994

Mr. Tom Young, Chairman
Charting and Instrument Procedures Committee
Air Line Pilots Association
535 Herndon Parkway
Herndon, VA 22070


Dear Mr. Young:

This is a clarification of our response to your letter of August 23, 1993.
In that letter you requested an interpretation of Section 91.175 of the
Federal Aviation Regulation (FAR) (14 C.F.R. Section 91.175). 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.

Section 91.175(a) provides that unless otherwise authorized by the
Administrator, when an instrument letdown to a civil airport is necessary,
each person operating an aircraft, except a military aircraft of the United
States, shall use a standard instrument approach procedure prescribed for
the airport in Part 97.

First you ask whether an arriving aircraft must begin the SIAP at a
published Initial Approach Fix (IAF). A pilot must begin a SIAP at the IAP
as defined in Part 97. Descent gradients, communication, and obstruction
clearance, as set forth in the U.S. Standard for Terminal Instrument
Approach Procedures (TERPs), cannot be assured if the entire procedure is
not flown.

You also ask whether a Distance measuring Equipment (DME) arc 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.

Finally, you ask whether a course reversal segment is optional "when one of
the conditions of FAR section 91.175(j)is not present." Section 91.175(j)
states that in the case of a radar vector to a final approach course or fix,
a timed approach from a holding fix, or an approach for which the procedures
specifies "no procedure turn," no pilot may make a procedure turn unless
cleared to do so by ATC.

Section 97.3(p) defines a procedure turn, in part, As a maneuver prescribed
when it is necessary to reverse direction to establish the aircraft on a
intermediate or final approach course. A SIAP may or may not prescribe a
procedure turn based on the application of certain criteria contained in the
TERPS. However, if a SIAP does contain a procedure turn and ATC has cleared
a pilot to execute the SIAP, the pilot must make the procedure turn when one
of the conditions of Section 91-175(j)is not present.

It you have any questions regarding this matter, please contact Patricia R.
Lane, Manager, Airspace and Air Traffic Law Branch, at (202)267-3491,


Sincerely,

/s/ Patricia R. Lane

for

Donald P. Byrne
Assistant Chief Counsel
Regulations Division

[El_Cid_Av8or]

Is it just me or do DME arcs only exist at airports that have a military installation at them? Take CHS - Charleston AFB/International Airport for example.

[EatSleepFly]

Its just you.

There's plenty of 100% civilian airports out there with DME arcs.