1
$\begingroup$

Maybe a dumb question. I've seen a few places where a VOR approach doesn't have an obvious (to me) way to get lined up inbound without radar vectors.

Say you don't have GPS and you're navigating with VORs. You'd like to do the VOR RWY 18 approach to KDEC, and you're coming from somewhere north of the AXC VOR the approach is based on, like the BMI VOR for example. How would you get yourself established on this approach without radar help?

It seems reasonable to me to fly (off-airway) R-180 outbound from BMI and intercept the approach course of R-349 inbound to AXC. However I'd heard (though don't have any regs to back it up yet) you can only transition from enroute to an approach based on a fix that appears on both charts. So I suppose you can't essentially vector yourself this way with the off-airway R-180. Is this true? If so, I'd be super grateful for a FAR/AIM reference if you know it!

So then what fix appears on both the enroute chart and the approach plate? Only AXC is on both. But if you fly directly to AXC from BMI then you're facing the wrong direction. You'd be incoming on roughly R-352 and then need to turn around and fly outbound on R-349. A HILPT would be just the thing on an approach, but here we wouldn't be on an actual approach yet and I haven't heard of them being used outside approaches. Would you do a HILPT at that depicted hold, or just hang a uey here, or is neither really right?

As I said, maybe a dumb question, but it's stumping me. Thanks for the help!

approach plate

enroute chart

$\endgroup$
1
  • $\begingroup$ Approach plate added now. I had it linked so it wouldn't be such a long post. But it's easier this way, you're right :) $\endgroup$ – Cameron Jul 5 '20 at 2:20
1
$\begingroup$

I would expect to receive radar vectors to final if I was coming from the north into Decatur, IL. However, we do not plan on radar vectors when we flight plan because we could lose our ability to communicate with ATC.

I would fly the victor airways to AXC. I might plan on coming in on the 029 radial (V191) to AXC. I am hoping for a clearance for the approach by the time I get to AXC. When I hit AXC, I would them make a right turn and proceed outbound on the 349 radial on the approach plate.

With a proper clearance, I would maintain my cleared altitude till TRACS and then descend to 3100 FT and finish the approach using the procedure turn to line up with the runway.

You are more than welcome to fly off routes provided you remain within the service volume of the navaid you are using. For AXC the service volume is from 1000' AGL to 40NM (for low altitude flight). There are no restrictions to the service volume in the Chart Supplements. If you are going to do this (and ATC clears you), you will fly the OROCA as a minimum altitude. The off-route obstacle clearance altitude (OROCA) for this quadrangle is 3200 FT MSL. You could file BLM direct AXC and only be one degree off the final approach course. (See AIM 5-4-7(f))

However, you are still required to cross an IAF before you start the approach. You will fly over AXC and then turn around to fly the procedure turn... you cannot just cross TRACS and descend for the landing.

A procedure turn is always required if it is depicted on the chart with four exceptions (AIM 5-4-9)

  • Receiving radar vectors to final approach course
  • On a route marked "NoPT" on the approach plate
  • Received a clearance for a straight-in apporach from ATC
  • Performing a timed apporach
$\endgroup$
3
  • $\begingroup$ Thanks for your response. Would you plan on the 029 radial inbound just to keep that turn to 349 outbound not as tight, or is there another reason? $\endgroup$ – Cameron Jul 5 '20 at 14:26
  • $\begingroup$ Yes. That is the reason. You can also do a smart turn and not necessarily have to fly over AXC on the turn outbound. $\endgroup$ – wbeard52 Jul 5 '20 at 14:57
  • $\begingroup$ I disagree rather strongly with "you will fly the OROCA as a minimum altitude". That's not what OROCAs are for. OROCAs, are advisory only, and are not good minima generally (think an approach on the plains in a quadrangle with a tall but far away mountain). AIM 5-4-7 does, however, say "ATC will, except when conducting a radar approach... assign an altitude to maintain until the aircraft is established on a segment of a published route or instrument approach procedure." The correct altitude to fly is the one assigned by ATC until reaching a published route or the IAF. $\endgroup$ – Dave-CFII Jul 6 '20 at 11:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.