RNAV initial offset onto ILS

[alphacentauri]

Can anybody point me to an ILS approach that has an offset initial RNAV segment? I am not looking for an RNAV STAR onto ILS, I'm specifically looking for instances where the RNAV segment is part of the approach. Does such a thing exist?

Thanks in advance

[FlightPathOBN]

OK,

I dont think that qualifies as RNAV to ILS, it is simply a Point in Space Navigation, with a vector to the ILS capture.

There have been a few trails looking at this. The issue tends to be the terminator for the procedure in the coding. We have been looking at RNP transitions to an ILS final for sometime, but the transition to capture tends to be more abrupt than acceptable.

According to Airbus, they were successful in a trial, once, but have not seen or heard of any use.

[Zeffy]

http://i202.photobucket.com/albums/aa92/zeffy_bucket/JACILSZ19_zps752f3282.png (http://s202.photobucket.com/user/zeffy_bucket/media/JACILSZ19_zps752f3282.png.html)

[FlightPathOBN]

I was wondering about this one...it was the original test procedure started by AVN/AFS back in 2004, didnt realize it went live...would really like to see the coding...especially the IAF, if it is coded as the IAF or PiN..

Interesting to see the result after 9 years...

Looks like they end the procedure at 8700, with 2.7 miles to intercept at 8000

Thanks for finding that...

[M609]

ILS 01R ENGM (https://www.ippc.no/norway_aip/current/AIP/AD/ENGM/EN_AD_2_ENGM_5-1_en.pdf)

Same deal on all 4 runways

[FlightPathOBN]

M609,

Sorry, but I am gonna have to cry BS on that procedure, even with a flyby waypoint at VABSO...

Curious charting...the MAPt is fixed at DME 1, and CAT IIIB approved??

[Cough]

FPath - VABSO isn't the FAF...Whats the issue?

The MAPt is for LOC approaches...

[M609]

Well FPObn, it's used every day without problems.

And do study the chart more closely before you comment next time. :ugh:

Oslo have used RNAV from IAF since april 2011 to all runways, with a tweak to the linked style since april this year.

We vector less and less aircraft for final, IAF is "fed" from a PRNAV point merge system on each side.

ENGM aip page (https://www.ippc.no/norway_aip/current/AIP/AD/ENGM/engm.html)

[FlightPathOBN]

MAPt-A pilot must execute a missed approach if a required visual reference is not in sight upon reaching the MAP.

[alphacentauri]

Thanks for the response guys, that what I was looking for.

We are investigating inplementing an RNAV to ILS solution for an aerodrome here in Australia. We can't find anything that indicates it can't be done, but there isn't alot of guidance out there on how to do it.

Like FPOBN, I would be interested to see how it is coded and any issues in the mode change from RNAV to ILS. For example is the mode change prior to LOC intercept or do you bring them on the final approach track under RNAV and then do the mode change.

From the plates shown above I am going to assume the Norway plates are PANS-OPS and the Jackson Hole plate is TERPS? I notice the TERPS plate doesn't give much of a level segment to intercept the GP. PANS-OPS requires 2nm, what does TERPS require?

I had been told this type of procedure is also utilised at some locations in Asia, anybody know where?

Again thanks for the responses, very helpful

[FlightPathOBN]

alpha,

If you are in AUS, then you know that this has been thought of.

It really does come down to a coding issue, and then switching modes.

The RNP procedures have a 250 min HAT, while the ILS is 200, so we were trying to get the lower DA and go precision. You have to think about setting up the RNP or the RNAV in the box, then disco over to the ILS approach.

The box doesnt like to terminate that way, especially when it understands and sets up when encountering the IF coded waypoint and then starts looking for a coded FAF.

[Oktas8]

MAPt-A pilot must execute a missed approach if a required visual reference is not in sight upon reaching the MAP.

Did you have the wrong brand of cornflakes this morning OBN? There's nothing third world or odd about the Oslo chart above, not even the MAPt.

Interesting thread, please keep it going guys.

[Zeffy]

alphacentauriany issues in the mode change from RNAV to ILS. For example is the mode change prior to LOC intercept or do you bring them on the final approach track under RNAV and then do the mode change.


The mode change methods may vary from one type of equipment to the next.

Many avionics have an automatic "nav-to-nav" transfer capability, but that functionality is not strictly specified by AC 90-108 (http://www.faa.gov/documentLibrary/media/Advisory_Circular/90-108.pdf), paragraph 10.
10. SPECIFIC REQUIREMENTS TO FLY RNAV SEGMENTS PUBLISHED ON ILS PROCEDURES. In order to fly RNAV transitions to an ILS final approach or RNAV missed approach segments of an ILS procedure, pilots must comply with the operating requirements of this AC. RNAV systems used for this type of operation must allow for a means to become established on the ILS final approach course with minimal overshoot or undershoot.

In the case of the JAC ILS, the WOMRU waypoint is on the centerline of the LOC and the course change at WOMRU is less than 20-degrees, so there should be no problem with intercepting the LOC, even without automatic nav-to-nav transfer -- or even without a Flight Director <gasp!>. :) Obviously, the Final Segment is flown by reference to the LOC and GS.

Please remain mindful that this procedure can be flown by any IFR-rated pilot. The airplane doesn't have to be built by Boeing or Airbus... it doesn't even have to be a transport category aircraft. A light single engine airplane equipped with an IFR GPS and an ILS receiver would be eligible.

Hope this clarifies a bit -- it's not necessary to "over-think" and make the procedure more complex than it actually is.

[FlightPathOBN]

The MAPt is for LOC approaches...

Interesting, from the chart the altitude at the Missed Approach Point is 990.

and the LOC minima is 970....

this is exactly why we dont fix a MAPt.

Yes, the JAC transition both horizontal/vertical at 2.7nm can be hand flown...

[Oktas8]

Following alphacentauri's post, the timing of the mode change is actually a minor issue for aircraft I fly. All the approaches listed above look quite easy to fly (much like YSCB Rwy 35 off the Bungo 9 STAR for that matter), but we cannot identify LOC or DME beacons until after the RNAV display has been removed from the HSI.

So the mode change on an RNAV - ILS approach involves about 30 seconds of manual flying, or HDG-VS modes, as we turn onto the approach. A stick-and-rudder non-event, certainly, but the pilots must think ahead to manage navaids as we turn onto the ILS, given that other things will also be happening at that time. With more modern aircraft, it would go from "takes thought, but no big deal" to "do nothing".

it's not necessary to "over-think" and make the procedure more complex than it actually is
You obviously don't work for my employer...

OBN, you're embarrassing yourself with this talk about MAPts and LOC approaches. Slide your seat back a couple of notches and relax!

[Cough]

FP - Your original quote...

Curious charting...the MAPt is fixed at DME 1, and CAT IIIB approved

Implying the CATIIIB MAPt was 1d...Which it isn't.

[bfisk]

@FlightPathOBN: As you can see, the chart is for ILS or LOC.

The ILS has a DA/DH. The LOC has a MAPt and an MDA. There is nothing counterintuitive about this.

Most operators are required to fly CDFA these days, so a strip with DME-Distance and altitudes is produced for reference. This would result in going around at the MAPt from 990', which is correct for a 3 degree glide to the runway.

If you are not required to fly CDFA, you may very well use non-CDFA ("Dive and Drive"), and descend to 970' once inside D4.0.

The fact that MAPts do not always coincide with MDAs for CDFA-type approaches is well known. Mostly it's by a significantly bigger amount than in this example.

Ahhh....these 3rd World Country charts....

Some might find that to be quite offensive.

[FlightPathOBN]

ok ...(I removed the comment)

as noted, the timeframe for the system (the 30 or so seconds) made it difficult from a human factors perspective, and others (especially the RNAV purists) to set the waypoints, etc

In the US, there is the 8260.54A which specifies criteria for obstacle clearance evaluation of area navigation (RNAV) approach procedures; e.g., Localizer Performance with Vertical Guidance (LPV), Lateral Navigation (LNAV), Lateral Navigation/Vertical Navigation (LNAV/VNAV), and Localizer Performance (LP).
These criteria support adding an instrument landing system (ILS) line of minimums to an RNAV (GPS) approach procedure using LPV construction criteria at runways served by instrument landing system.

This may be of some help in the criteria and calculations behind this. ( I am not sure where .54 is with its use in the US)

In appears that the military has been using the RNAV to ILS for some time...

http://flightaware.com/resources/airport/NKT/IAP/ILS+Z+OR+RNAV+(GPS)+RWY+23R/png/1

[Natstrackalpha]

If I remember correctly - that might be the case at . . Innsbruck LOWE or LOWW . . ?

[Natstrackalpha]

The box doesnt like to terminate that way, especially when it understands and sets up when encountering the IF coded waypoint and then starts looking for a coded FAF

Not arguing, just learning . . .

but does not the pressing of the ILS pb (after tuning and id`ing ILS and setting up hdg for the runway) disable the RNAV?

(eons later) - so has everyone finished with this thread then . . .?

It seems a tad inconclusive to me - or have I missed a fundemental point . . ?

To jump the next response . . . could you not hard tune an ILS on the RMP and . . . := Could you not force tune the ILS on the RAD page, then hit the ILS pb . . . hopefully flashing . . .and recycle app pb?