In setting up for an ILS approach at KBOS for example, Runway 4R.. Source www.airnav.com Magnetic bearing: 036 True bearing: 020 Magnetic variation: 16WWhich is the correct value to enter as Course for the ILS 4R Approach?As you can see there is a 16W degree variance between true and magnetic.Thanks!Barry

The course on the approach chart would be the correct one:In this case-036http://mywebpages.comcast.net/geofa/pages/rxp-pilot.jpghttp://forums.avsim.net/user_files/91017.jpg

Hi Geof,Thanks for your reply.So you would use magnetic, or specifically what the chart says?Thanks again!Barry

You would make sure your heading indicator matches your magnetic compass in straight and level flight sometime before the approach and then fly 036 degrees (and add wind correction to keep the needle centered).Hope that answers it. :-)http://mywebpages.comcast.net/geofa/pages/rxp-pilot.jpg

APP on the A/P, Course setting would be 36 degrees.So is it always magnetic? The course you dial in that is..Barry

Off topic, but can you tell me what the reference to RADAR in "RADAR or DME required means"? As far as I'm aware(but what do I know? :-)), the only radar on board an aircraft is SS Radar, which allows ATC to identify you on their screens and read your speed and altitude(if you have a Mode C Transponder). Of course, there is weather radar, also, but I don't think.....:-)?Thanks,Frank

It means that Approach Control radar must be working OR the aircraft must have DME equipment aboard. Note on the IAP the approach fixes prior to FAF/LOM are radar ones OR through the use of the ILS DME facility. And YES, all courses are magnetic. For an instrument approach of any kind, fly the published course(s). Paul

Thanks, Paul.I'm puzzled, though...? Don't all approaches require radar in that sense(for IFR flights, at least)?BR,Frank

compass roses on charts and indications on plates regarding navaids are always referred to as magnetic orientation. v and j routes in regard to navaids are mag.wind direction in metars are true (I'm prestty sure) but from tower/atc are given as magnetic.this is mostly because your aircraft guidance depends on magnetic sensing instruments.it also appears that the gps displays mostry display an "m" after any bearing/tracking readouts indicating mag as well.in small aircraft when using vfr plotting not involving navaids but dead reckoning i always in this instance had to apply mag correction to develop mag heading for compass/gyro bearing. if using airways then of course this is already accomplished. vfr flight planning charts show both headings when you fill them out.

some approaches due to terrain, equipment outages, etc. are not radar scannable by atc. you can be vectored if at all as far as possible but may be required to do all nav on your own from some point. you can even maintain seperation with atc guidance by using navaids and position and altitudes reports to atc at required checkpoints so they can maintain seperation.if a plate states radar required your transponder must be in order (though it can if allowed be not functional and you fly an identifying pattern to atc radar if they accept the deviation). DME is required for accurate positioning in dense areas along the published course to maintain altitude points as opposed to the more complex intersection method by using multiple navaids. generally this applies to dense traffic areas.

Thank you, ronzie!Great to have all this info.BR,Frank

I meant to ask....Does identifying, say, NARBO as a Radar Fix mean that ATC will tell me when I cross it? If so, I would need to be radar identifiable to ATC, hence the need for a working transponder Mind you, I doubt you could get anywhere near KBOS airspace without a functioning transponder!I note that another Radar Fix WINNT has a collocated NDB, so I could find this on my own, assuming I have an ADF receiver.Now it's okay to tell me I've got it all wrong....again! :-)Thanks,Frank

Thanks Ronzie!Everything I searched for on the internet came up empty on this particular question.There are many really good "engineering" breakdowns of navigation including ILS, but none of the articles I read mentioned the Course and how it relates to magnetic bearings on setting up for the ILS.Thanks again!Barry

In IFR flying you get aligned with the final approach course in two ways: 1) radar vectored, or 2) you fly the full approach from the initial approach fix (identified with the symbol IAF on the plate), a course reversal, then the final approach fix or glideslope intercept, then the missed approach point or decision height.Thirty years ago there were still chunks of USA not covered by radar but IFR flights were still made. (Who needs stinkin' radar vectors?) ATC provided separation by calculating when you will be in a given airspace for how long at what time, and restricts other traffic from occupying that same airspace at the same time at the same altitude. These calculations are based on information provided by the pilot in the pilot's IFR flight plan (that is, airspeed, route of flight, altitude), and are still done each time a pilot files an IFR flight plan.In MSFS, if you are on an IFR flight plan, the program will always radar vector you to the final approach course, as if ATC radar service were everywhere. But I think it is just plain more fun to fly the entire procedure as if you were outside of radar coverage. Looking at the approach plate, the course to be flown is represented with a heavy black lines with an arrow. Minimum altitudes for each segment of the approach is depicted in the profile view of the approach plate.

Without looking at enroute or a plate for the moment, I can't tell you how NARBO is located but there are several ways you might determine when you are over it. ATC will not tell you when you arrive - it is your responsibility to know your position ATC only telling you where to go, how fast, how high, what heading (if vectored).NARBO is a published waypoint. These can be locate via GPS, usually. An intersection waypoint is the intersection of two VOR radials or perhaps a VOR radial and NDB bearing (unusual and not as precise). It can also be a DME reading from a VOR (or TACAN) (and in some final approach cases DME from a DME equipped localizer) along a specified course. You use the most appropriate method available to define your arrival.When colocated with a navaid, such as an NDB, it makes it easier to determine arrival as noted by the change in the instrument reading as you cross it.A caution when using DME is slant range error as you near the specified position. If you are close to the DME source, you will get slant range error which means altitude becomes part of the distance caslculation. As an example if you cross a VORTAC at one nm high the DME will read one nm. This is not normally a problem with published points at expected altitudes but be aware of this if you are using DME to determine arrival at a VOR.