It seems the DME arc is going the way of the dodo.  Based on the NextGen document put out by the FAA last year, the only reason the VOR's are still around is there is still GA without RNAV/RNP capability. Once that changes you can expect most of the old VOR/DME stations to be decommissioned.

I agree,  and it should as it requires lots of work to stay oriented , and it easy to get things the wrong way. I had little time with it while doing my IFR rating and I don't think I will use use those VORs in real life the way I was trained especially IMC.

Yep, I mentioned that in my original post. However, the main motivation for my question was just to learn how the airlines typically fly DME arcs, although I'm beginning to think they don't have to do it very often -- probably get vectors instead.

 

Appreciate all the comments and info.

Al

 

As far as how to real world airline pilots fly DME arcs?

 

First, it's rare to actually fly a DME arc, other than a few simulator events, I think I've only flown one real world with paying passengers on board - although I've flown lots of DME ARCs during instrument pilot training.  But in the event you needed to fly one, we'd normally set it up so the automation will fly it, as it's not a common thing, a majority of airline pilots probably would be uncomfortable or be really rusty hand flying it or using the HDG turn 10/twist 10 method that is taught during GA training.

 

To properly do the DME ARC using the automation, you have to select and load the approach and the DME ARC transition from the nav database.  You can't modify the approach or build your own DME ARC the way you would jury rig the sim e.g. ABC130/10, ABC140/10 - the arc has to be loaded from the database.

 

Once it's loaded, you sequence the FMS and then have the autopilot join the arc from heading (with nav armed) or by flying directly to the arc's IAF, depending on the approach clearance.   Or you can hand fly it using the flight guidance (from the flight director) from the FMC.

 

The last time I flew a DME arc under scheduled passenger 121 operations, it was about 9 years ago, in a non-autopilot, non-FMC turboprop.  The FO wanted to fly the full procedure, arc and all real world, just for kicks, so we just requested it, the controller was kind of surprised, but cleared us for the approach via the arc.   So that was my one real-world DME ARC with paying passengers on board.  - They didn't know any different and were just as happy to get to their destination.

 

Steve W.

Here in Brazil we still same a good number of them even at our main airports. But with RNAV kicking in it's probably going to change

As far as how to real world airline pilots fly DME arcs?

...

The last time I flew a DME arc under scheduled passenger 121 operations, it was about 9 years ago, in a non-autopilot, non-FMC turboprop.  The FO wanted to fly the full procedure, arc and all real world, just for kicks, so we just requested it, the controller was kind of surprised, but cleared us for the approach via the arc.   So that was my one real-world DME ARC with paying passengers on board.  - They didn't know any different and were just as happy to get to their destination.

 

Steve W.

 

Thanks for the RW input.

 

Al

And a reason pmdg need to seriously consider updating the nav data and capabilities so RF and other rnav capabilities are achievable. But not holding my breath on that coming anytime soon - the fslabs airbus is rumoured to have that capability

To fly an RNP approach that has an RF leg you need to have TOGA/LNAV capability. It requires a software update and aircrew training. I can't remember from reading the 777 manual does the PMDG 777 have TOGA to LNAV or is it TOGA to HDG?

We do it it in the Airbus quite frequently, but the older A330s required a quite expensive software update.

If you look at the approach charts for one it's going to require SA (special aircrew) approval, and it will also state that that TOGA to LNAV is required. I just can't remember if the PMDG NG and or the 777 is TOGA to LNAV.

Look at the RNP 13L in JFK it's one of the more simple RNP approaches, but I think the chart is airline specific and requires administrator approval.

 

TOGA to LNAV is required in the event of a missed approach, because of the RNP approach criteria the aircraft can not go into HDG mode when TOGA is selected because the aircraft will not continue the turn in the RF leg and could fly into an unprotected area.

 

Paul M.

DME arcs are easy as you have a HSI!

 

Fly towards the beacon until you're close to the desired distance. Make a turn as necessary to put the station on the beam.

 

Let's say you're flying a 10 DME arc at 250 kts. To keep the station off the beam, maintain a roll angle of about 3 to 5 degrees. If you find the distance increasing, then turn in the appropriate direction by 5 degrees heading, then resume your constant roll angle of 3 to 5 degrees.

 

Taking cuts may be a way to learn how to fly an arc, but harder work IMHO, and unprofessional.

 

Best regards,

Robin.

Taking cuts may be a way to learn how to fly an arc, but harder work IMHO, and unprofessional.

 

Please explain? What "taking cuts" means?

Please explain? What "taking cuts" means?

Using roundabout methods other than the "official" way as he's described. Honestly, putting the fix on the FIX page and setting the DME in so it creates an arc to follow makes a ton of sense. Legally, you'd still need the raw data up (otherwise you'd need to have an overlay RNAV RNP approach with an RF segment), but using the fix page for monitoring makes a ton of sense.