To fly to a VOR, you rotate the OBS until you get a zeroed bar and a TO flag, then you read what the OBS says and make that your new heading.
;-) We know that one
That has nothing to do with intercepting a different radial. Let’s say you’re on r-180 inbound and you get the instruction to intercept r-150 inbound … That’s what I meant.
I’ve generally had the instruction in the Middle East although you tend to get a “Route to XXXXX and intercept the YYY radial inbound” where XXXXX is handily an RNAV waypoint on the specified radial.
When I used to instruct PPL students, I always dedicated an hour or so to teaching radial intercepts, using that D+30 method. My experience is that it does confuse students at first, even though it’s rather simple. I attribute that to the fact that at that point, they haven’t really grasped the concept of radials and flying along those radials of some station yet.
Like so many things, it’s quite useless in practice nowadays, but is a good exercise to develop an understanding of navigational tasks and situational awareness.
Today i use the D+30 concept to intercept a bearing I set with the either the OBS or the Direct to Feature of the GNS430W. It helps me estimate a good intercept heading. What I want to say: Understanding these concepts can help you a lot when navigating by GPS too!
Flyer59 wrote:
There’s actually many correct ways to intercept a radial, the one i prefer is what they teach at Lufthansa: “D+30”, meaning that you add 30 degrees to the difference between the radial you are on and the one you want to intercept.
Let’s say you’re on r-180 inbound and you get the instruction to intercept r-150 inbound ….
I haven’t heard the term “D+30” before. Does it mean that you should turn right 180-150+30=60 degrees in this case?
Let’s say you’re on the 180 radial inbound and ATC wants you to intercept r-150 inbound.
Difference between the radials is 30 plus 30 = 60. Which means the intercept angle is 60 degrees (which is also the maximum)
Now you add the 60 degrees to your present course of 360. The intercept HEADING is 060.
Other example: You’re on r-180 inbound and want to fly on r-170 inbound. Difference is 10+30 = 40. Use a intercept heading of 040 to intercept radial 170 inbound.
In the Northeast US around NY approach I would get that flying on a radial. ATC would give instructions to leave the airway to intercept Example POU 153 R upon reaching they usually start with radar vectors.
I usually use my Collins 351 backup for this because it is just easier to use since Im not heading to a fix. I guess I should practice using my 430w just in case.
Today I would make a direct on the GPS, enter the course i want and fly to that magenta line with HDG+NAV and the autopilot would intercept “virtual radial” … I could also confirm that with the second blue pointer in the HSI set to the VOR frequency
In Israel they have a full radar environment, but will not give you vectors. Instead they tell you to intercept a radial of a VOR. I found that strange. Why would they do that if they have you on radial. Did another night flight from the Golan Heights to Sde Dov airport near Tel Aviv and again, instead of giving vectors all instructions were related to flying inbound or outbound radials, entercepts, etc.
When we were drafting the EASA AMC for PBN, which sets out default operating procedures, we were very mindful that there is no equivalent for conventional navigation.
So the AMC will say e.g.:
“For parallel offset operations enroute (in RNP 4 and Advanced RNP), transitions to and from the offset track should maintain an intercept angle of between 30 and 45° unless specified otherwise by ATC”
But I know of no equivalent regulatory material that tells you how to intercept a specified radial, other than on the present heading. Come to think of it, I can’t even find the instruction to intercept a radial in PANS-ATM phraseology.
