Doesn’t DCT ENT ENT do something entirely different than the “Activate leg” function? A direct is from present position, whereas “activate leg” activates a given leg on a flightplan, i.e. between two coded waypoints.
Yes DCT ENT ENT and DCT DCT ENT do do rather different things, as you describe.
(Anyone want to book one of my seminars? It’s all in there 
)
I think it rather proves the opposite, Timothy. These generic ground courses are quite useless. Devices are simply too different. One has to get very specific guidance for his particular navigator.
Alexis wrote:
Isn’t the best way to simply always load the complete approach and then – if you get a vector – go into the list of app waypoints and make a DCT to that point? Is that what you mean, Timothy?
I have found in my many seminars to now thousands of IFR pilots that it’s dangerous to nominate a “best” way. Our brains work differently and we are comfortable with different ways to skin the same cat.
The choices come down to DCT, Activate Leg, Activate Approach, Activate VTF and deleting the waypoints before the next fix. I have heard cogent arguments for each method and I think that it is more important that each of us has an SOP than that we try to press that SOP onto others.
One thing that I do think, though, and was saying at the PPL/IR PBN conference at the weekend, is that once ATC offer you VTF, you are in your rights to hold them to that contract. So if they say “Vectors to RNAV RWY 03 at Bigtown” and then later say, “Route direct XYZ” after you have removed XYZ from your sequence, it is perfectly reasonable to demand ongoing vectors, rather than start scrabbling around putting the procedure back in the GNSS box.
The advantage of Activate VTF once you have been given VTF is that you have a big beautiful magenta line stretching 30nm back from the FAF, so you can keep a very good SA of where you are, where you are going, when you are going to be turned, and you get a neat GNSS turn on.
Alexis wrote:
PS: Do you maybe mean DCT-ENT-ENT (and not DCT-DCT-ENT)??
:sigh: No.
A slide from the seminar. It is dynamic in PPT, so you see it one answer at a time, but if you can see through that, you’ll get the point:
Yes DCT ENT ENT and DCT DCT ENT do do rather different things, as you describe.
OK, didn’t catch that immediately.
I wil try that on the next occasion. But these occasions are rare, since one doesn’t get vectored inside the FAF (on GPS approaches) very often.
The best solution is obviously to decline any offered “shorties” on GPS approches. But still, sometimes, despite there being no such agreement with ATC, they will still vector you inside the FAF. And for these cases, it would be good to have a solution to “save” the approach rather than calling it off and requesting new vectors.
Still, this “activate leg” probably really just a workable workaround, but not a good solution. In the normal procedure, the reduction from 1NM to 0.3NM is gradual, whereas after “activate leg” past the FAF, I assume it will be immediate, which carries the risk of a pegged needle if one wasn’t perfectly on track when doing this.
Also, I agree that fiddling with the navigator in this phase of flight is far from ideal… it’s super-high workload: turning final, calling established, starting the descent at the right time, reconfiguring the aircraft…
I think that every pilot will, sooner or later, develop his own SOP … depending on his equipment
For myself this is:
1. I do not accept a vector to the FAP (ILS) or FAF (RNAV) if in IMC, because in both cases the approach cannot be flown coupled
2. If I am in VMC I will accept it and if I am too high, low, whatever, I will use the Flight Director to get on the Final track/Localizer/GS …
3. Intercepting an ILS I always switch the CDI manually from GPS to VLOC and also set the Final Course manually …
RNAV approaches I mostly fly the complete procedure, especially in IMC. It’s just two or three minutes longer, normally – but I know exactly how the navigator and autopilot will behave.
Other than bosco I have not understood the difference between DCT-DCT-ENT and DCT-ENT-ENT … I mean: I am at a certain position and I get a vector to xyz, so i press DCT and confirm that I want to go there …
