NDB approach: when to turn outbound?

When making an NDB approach that calls for an outbound turn when I reach the NDB, how do I time that?

If I'm skilled (lucky) enough to fly right over the NDB, the ADF needle swings very quickly and I'm past the NDB before I can even start the turn.

What's the proper procedure here?

• Should I initially aim a little to the left or right of the NDB so that the needle doesn't swing so fast? If so, how far off should I aim?
  
• Go ahead and make the turn once past the NDB and fly parallel to the course marked on the approach plate?
  
• Something else?
  

If you know where this question is already answered, a pointer is appreciated.

So much depends on how the approach is laid out and which way you are coming in to it. Tell us which approach, and what your path is, so we can look at the chart. But is the turn called for exactly at the NDB, and how large a turn?

The approach plate tells all...

For example:

KLFK IAP ILS 7, transition from VOR LFK

You fly 296° from LFK to the IAF at FLUFY (NDB LF)

At FLUFY (NDB LF), you turn left to 253° for your outbound leg.

Now, in this instance, you're transitioning from the LFK VOR/DME and since FLUFY is 6.5 nm from LFK, you could just watch your DME.

Similarly,

KBRO IAP ILS 13, transition from RELAX

Fly 199° from RELAX to IAF at DEPOO (NDB BR)

At DEPOO (NDB BR), you turn right to 312° for your outbound leg. That's a pretty steep turn. Again, you could watch VOR/DME BRO to know when you're getting close to DEPOO (NDB BR).

And,

KUVA IAP NDB 33, transition from SAT

Fly 239° from SAT to NDB UVA

At NDB UVA turn left to 148° for your outbound leg. Again, you could watch your DME distance from SAT.

Is that what you're supposed to do? Look for a nearby (or not-so-nearby) DME, and use it to anticipate your turn to outbound? If so, what if there is no DME? Did pilots use these sorts of approaches before DME? If so, what did they do then?

Did you notice this notation on the ILS/LOC RWY 07 plate?

Procedure NA for arrival on LFK VORTAC

airway radials 245 CW 354

So the procedure isn't usable on that 296º radial The second line means "radials from 245º ClockWise to the 354º radial." "NA" is Not Available, or you could say Not Applicable. So you must come from a different direction. IRL ATC would clear you to come in on an acceptable path.

As for the RWY 13 at KBRO, I'm surprised they don't prohibit the approach from there, since it is a sharp (NOT STEEP) turn. When IFR you do standard rate turns, which are 3º per second, by definition, and that is also the rate at the mark on a turn coordinator gauge where the "wings" match that mark. And that complicates the approach from this direction, since you'll need to be slow enough to avoid crossing into Mexico (IRL, of course). Also, during the procedure turn you need to remain within 10 nautical miles (see profile on chart).

So were it me approaching from there, I'd be sure to turn when the localizer needle hasn't quite centered, perhaps a couple of degrees from center. But I'd be more comfortable using a different IAF.

you could watch VOR/DME BRO to know when you're getting close to DEPOO

At the angle you're coming in, that DME from BRO won't be very accurate -- it'll be not far from the 8.1 mark well before you reach DEPOO. A DME measures distance by the time a radio signal takes to travel the distance, so it's ALWAYS in a straight line to the DME transmitter itself.

Is that what you're supposed to do? Look for a nearby (or not-so-nearby) DME, and use it to anticipate your turn to outbound?

No. If that were to be the case, they'd specify it. They try to leave nothing to chance when designing these approaches.

For the NDB 33 approach to KUVA, SAT is 71.9 miles from UVA, so you may not be receiving it at all once you get close, so you'll be using UVA to get to UVA. So at station crossing, you make that left turn to 148º and go outbound and make your procedure turn, remaining within 10 NM.

Note that tracking a COURSE on an NDB is not the same as HOMING on the NDB, so that 328º is your INBOUND Course, not HEADING.

Again, you could watch your DME distance from SAT.

Nope, at that distance you may not be able to receive it.

I suggest you read the FAA's Instrument Flying Handbook on instrument procedures. There's a lot there.

Of course you may do as you wish in the sim, but the above is how it's done for real.

lnuss, everything you say makes sense to me.

Did you notice this notation on the ILS/LOC RWY 07 plate?

 

Procedure NA for arrival on LFK VORTAC

airway radials 245 CW 354

(That seems logical, too, but I wasn't coming into LFK on 296°; I was coming into LFK on V13 (199°) and then turning onto 296° to go to FLUFY.)

Using the DME seemed fishy to me, which is why I asked; thanks for confirming my gut feel.

But I still have my original question - if or how to anticipate a turn over an NDB. I read Chapter 9 in the book you suggested, and although it didn't directly answer this, I now have a third possible option to the two I mentioned earlier:

1. Initially aim a little to the left or right of the NDB so that the needle doesn't swing so fast
   
2. Make the turn once past the NDB and fly parallel to the course marked on the approach plate on my way to my PT
   
3. Same as (2), but use the technique in Chapter 9 "ADF interception and tracking outbound" to get onto the outbound track as published on the plate.
   

My gut now tells me that real pilots do (3); or am I missing another technique?

but I wasn't coming into LFK on 296°; I was coming into LFK on V13 (199°) and then turning onto 296° to go to FLUFY.)

But that's not what you said in your post above ( #3 ). The only 199º you mentioned was coming in to KBRO from RELAX.