DME arcs and autopilots
 

A question which a student asked me earlier today which I did not know the answer to: can the autopilot on a transport jet fly a DME arc, or does it involve some level of involvement from the pilots?

The question is not specific to any particular manufacturer, type or series, so I'd be interested to hear a variety of answers. Specifically, I'd be interested to hear about different manufacturers, and also about different levels of cockpit automation (for example, based on my knowledge of light aircraft autopilots, I would guess that it is extremely unlikely a steam-driven autopilot could fly a DME arc, but maybe it's more likely in a glass cockpit where an HSI bar or similar can automatically be set to the desired track???)

Thanks!

FFF
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Type aircraft, L1011.
Yes, it can reliably fly a DME arc provided it is in the FMS or GPS database or, if it is not, it can be manually inserted by the pilots (with a fair amount of button-pushing).

Once on the localizer, it can then fly the nicest autoland you ever did see, bar none.

Lockheed TriStar, simply the best.
Still a few around, and I still fly one.....ahhhh, Lockheed!

Well even the autopilots on light aircraft these days can fly you round a DME arc - eg G1000 and Bendix autopilot on a DA42 can fly you round an ARC DME.

Next generation autopilots on light aircraft - eg Garmin GFC 700 can even fly you round a hold pattern - take a look at this little film if you want to see the Garmin 1000 and GFC700 Autopilot in action in a Cessna 182.

On the 737 you can fly perfect DME arcs if they are in the database. If not you can either approximate them close enough with custom made waypoints (radial/distance) or simply fly them with the heading bug.

Yeah they can and they do it with a slight constant bank all the way round to the lead-in radial. :)

Only to programme the FMS. If its already in the database then its just a matter of going to the arrivals page, line selecting the arc procedure and hitting enter.

You could always put it in HDG mode or even hand-fly it I suppose. :ok:

Hmmm, more rounded.
Lets see...

DC-3
DC-4
DC-6B (nice!)
DC-7
1649 Constellation
Fokker/Fairchild F.27/FH227
Lockheed JetStar
Lockheed Electra
Boeing 707
Lockheed TriStar

Seems pretty 'rounded' to me. Not all that interested in an AirBus, however....a Gulfstream V would be nice.:ok:

The Douglas B717 will fly a nice arc if it's in the database as part of an STAR or Approach, as mentioned for other types above.

Similarly one can create WPTs at the appropriate spacing to approximate the arc, and then fly a series of short straight sectors, or, use TRK/HDG to stay within tolerances.

punkalouver you are wasting your breath.

A320/1 will do it with its eyes closed so long as its in its database as an official procedure for an airport. All based on GPS navigation with dme updating just to be sure. Although some of the STARS we fly have a DME arc to bring you onto the localiser in reality we never fly them. Nice to see in training I guess but I wouldn't get hung up on them. Like most training you do such as full procedural turns/timed turns etc ATC will give you a vector onto the localiser to ensure the sequencing and flow of traffic is as efficient as possible. The only time I could think that you would do a full procedure and possibly fly a DME arc anyway is during a loss of comms and then again it would depend on what the Jeppesen manual says is applicable for the destination airport.

Alicante r/w 10, DME arc from Vilna. Pretty much every time I've been there, I've flown it.

Thanks for all the useful input, everyone - it has been passed on to my students, who were most grateful, and I've learnt something new too.Absolutely true in the real world. But as an IR instructor, the procedural stuff is my bread and butter, and although we do plenty of radar vectored approaches, I rarely get to see an autopilot, and the GPS is always disabled for approaches, whether vectored or procedural! It's really handy for me to learn more about how you guys work in the real world, so that I can pass the information on to my students, and, where possible, adjust the training I give to suit real world flying.

Thanks again!

FFF
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Actually not quite true. :p I have to fly DME arcs, procedures, circling approaches and even NDB's quite regularly, there are still many parts of Europe (and the world) without radar and ILS on every runway.

FFF it's good to hear from an instructor who cares about the job, I've met too many over the years who don't and I'm sure it will show in your students. :ok:

Many 'newbys' that only fly within Europe are unlikely to appreciate DME arcs, and the very many destinations in (for example, Africa) which don't have radar.

I suspect they might have a fit without radar vectors...OMG!, I actually have to navigate and fly the aeroplane...what a nightmare!:ugh::ugh::ooh::rolleyes:

I call it fun personally and I'm glad in this day and age were still allowed to do it. :8 :ok:

Yo can fly a Dme arc depends on the database of FMS or GPS. Anyway if you maintain a constant speed (Vapp) with the heading bug of the autopilot you should do the Dme arc without problems.
Cheers!:)

Cabin baggage
 

Just a quiestion!
What is the best baggage with wheels for pilots or flight attendant ?
Thanks!!

Plenty of DME arcs in France. Perpignan and Ajaccio spring to mind. Ajaccio is a nice one - IAF on an NDB, then a nice long DME Arc, interception on a VOR QDM, then another intercept on the ILS, with another NDB as FAF. Loads to do for the pilot identing all the navaids involved - did my IRME test there!

I'm wondering how that question relates with this thread....?:rolleyes:

The best size is the one that fits in a 2.5nm DME arc, with the wheels being 0.1DME arc (and even better if it is a complete arc, else you'll have some trouble moving it). The most expensive come with an autopilot too.:}

You are in UK, potkettleblack? Well, there's plenty places north of Aberdeen without radar, but fully IFR. I teach Procedural IF, too, and I can assure you it is NOT just a training thing.

Please avoid the more obvious "barbarians north of the wall" in your responses!

And a lot further south too - Norwich has a DME arc to ILS that I've had to do a few times when radar vectors not available.

On the contrary 411A - I love the challenge and the chance to engage brain rather than twiddling a heading bug to follow vectors. (and yes I am a 'newbie')