ILS nav and approach mode

[mrfuni 0]

>I always prefer the RNAV approach because they usually mirror>the ILS approach very closely.>>A lot of VOR approaches will be "Circle to Land". That's an>extremely useful technique to learn, especially if you fly GA>sized aircraft.>>Also remember just because you are flying a RNAV or VOR>approach, you can still use the ILS on final for the landing.What are the specific differences between RNAV and ILS? I remember reading that RNAV is really about precision, but then again so is the ILS right? Or does it have something to do with CATIII landings, which I don't think every airport supports?Thanks

[RFields5421 1]

First - we are talking about a FlightSim 2004 practice - not the real world - so we can forget about CatI, CatII, CatIII because FS only has one type ILS localizer and all ILS landings use the one process / routine of code. (Yes FS has a label, but does nothing with it - something for the next version ??)Second - the ILS and RNAV approaches in FS2004 were written from the Jeppsen data in the fall of 2003, so some of the data might be out dated.But - in almost all cases the RNAV approach matches the ILS approach turn for turn - distance for distance. This is just pure speculation on my part - but it appears that RNAV/GPS approaches for the real world were initially written to mirror the ILS approach, or VOR, or NDB - which ever was the most precise approach for the airport. Again just a guess - and really based on US approach plates - not much comparison to the rest of the world.Also understand the purpose of using an RNAV approach (or other type) in Flight Simulator is because the FS ATC engine assigns AI traffic to ILS approaches. Those approaches are simplified by the ATC because of the way the AI flies - even if you don't have AI aircraft in your sim.Choosing an alternate approach with the appropriate transition will give you a relative realistic approach without having to be sequenced back in line behind five AI aircraft - 50 miles out at ILS intercept height.That's all - and the main reason to choose a different approach.

[Guest wheelsup]

>question is, which do i want to click, Nav or approach?>from what i've read they both seem to do the same thing. or>does the approach mode track both the localizer and glideslope>and the Nav button only tracks a localizer? thanks, williamThis may be too late (old topic) but -When cleared to intercept the loc, hit nav. If cleared for the approach, hit appr. Nav mode = loc tracking only on ILS and VOR tracking if freq is tuned inApproach mode = loc tracking followed by GS tracking, will capture automatically.I wouldn't mess with switching modes on an approach unless ATC specifcally clears you to intercept the loc and then cleared for the approach (on ILS). Normally they'll just say "fly heading xxx, maintain x,xxx until established, cleared for the ILS xx"". If this is the case, arm approach mode - don't bother with nav.~wheelsup

[N562Z 4]

Hi William:On final, I use APP mode with NAV1 set to the ILS, OBS set to the inbound approach course, and NAV2 set to the local VOR, if available. That NAV 2 needle helps me time my turns in the heavy jets I typically fly, usually a 5 to 8 degree lead assuming 200 KIAS on base leg and a turn to final anywhere from 90 degrees to 30 or 40 degrees. On final I slow to approach speed and drop flaps accordingly, aiming for 140-160 KIAS just as the aircraft captures the glide slope, gear down, setting my desired pitch attitude with airspeed. I only do this in weather at or approaching minimums, or on a tight parallel approach with lots of traffic nearby. Most of the time, however, I fly the approach manually, save for airspeed hold to help ease the workload a bit, which I then disarm once I know I've made the runway.Regards,http://images.google.com/images?q=tbn:GuIf...omestead/imagesAlex ChristoffN562ZBaltimore, MD

[Guest william273]

yea, i'm still checking the threads just in case, LOL. thanks guys and you're not to late. always hit the forums when i get home from work. settle down with a few cups of coffee while seeing what's going on here. just like everyone else, i hope. william

[Guest BobLee]

The specific difference between an RNAV approach and an ILS is that the ILS has electronic vertical guidance -- the glide slope -- while an RNAV approach for FS9 purposes has no electronic vertical guidance. Basically it is the same in the real world for most folks until WAAS enabled GPS boxes become more prevalent and more approaches are designed for them. An ILS is always preferable to any other kind of IFR approach if one is available.