LPFR ILS 28
 

Hi everybody, I have a question that so far I have not been able to get an answer that everybody agrees. I have attached a chart for ILS 28 in LPFR (Portugal), as you may notice the outbound radial to be flown after passing VFA, is either 114 or 134, depending on your aircraft category. My doubt is the following, at what point do we switch to the ILS frequency (only one NAV radio installed) after starting the left turn at the 8 DME mark, That is, do we continue with the VOR frequency until established on final, and then switch frequancies? or do we switch to the ILS one suring the turn in order to intercept the ILS localizer directly?
Your help is greatly appreciated. Thanks

Once you start the turn at 8D you no longer seem to need VFA it so tune the ILS.

I do agree with that, in my opinion that is what makes sense. What knd of brings some doubts to some people is the fact that the 8 DME mark is also placed on the localizer line, making it look like that is the reference point for interception, and since that pount is based on VFA, I see how that brings some questions.

Thank you

Interesting for me. I have always flown IFR under jurisdictions that required at least two NAV receivers, which in this case i would personally view as the minimum to legally fly that procedure as the reception of the VFA DME is required.

Now, one could argue that it is no longer required after the start of the inbound turn as all DME distances inbound are both given for IIF and VFA, however the note doesn't make that distinction and therefore reception (or a legal substitute) of VFA DME throughout the whole procedure seems to be required.

I guess in the real world nobody would really care, but then, bobody would fly the whole procedure anyway, always got a clearance direct GEBTI from about 100NM or so out and flew it from there.

Look carefully and you will see that 8D VFA on the centreline equates to 7.2D on the ILS DME

LPFR ILS 28
 

I guess after all is acceptable to complete the turn with both versions, either with VFA tuned in or the ILS one. In my way of seeing things it makes more sense to switch to the ILS frequency in order to have the final course set in in the HSI, for example, and guarantee that you are a bit more ahead in everything to be set up. One problem I do see with the VOR frequency version is the final course you have to set in, we would assume is the ILS one, but clearly the VOR is not aligned with the localizer, so we would have a slight difference thant in the moment we switch to the localizer frequency would translate in a bit of a localizer jump. I know I am being picky, but we do fly this approach with a helicopter in our company and at those reduced speeds (compared to airliners) you have a lot more time to "enjoy" this differences.....

I agree that the time to flip navaid would be after starting the turn inbound. I am not sure why anyone would disagree with that, do you know?

Also, I don't see a note requiring dual receiver so it must be perfectly legal to fly this procedure with one receiver. But you need DME for the course reversal.

Curious enough the ones that disagree are mainly active or retired Portuguese Air Force pilots, it seems they always did perform this proceedure with the VOR tuned all the way in. In my humble opinion it makes no sense, but better be safe than sorry :-). In regards to having one NAV only, it also seems to be completely legal, at least for this procedure. Thanks for your reply.

The VFA 8.0 DME is the same fix as the IIF 7.2 DME. The VFA 8.0 DME is charted for pilots coming straight in from GEBTI on the VFA 274 Radial.

For those flying the base leg there is no further use for VFA once starting the base leg turn at VFA 7.2 DME. The ILS should be tuned and identified starting the base leg turn. If flying the LOC (GS out) procedure then the IFF DME is also required.

Thanks for the reply. I am going to speculate here - maybe if equipped with an old basic CDI (pre HSI) it was less confusing to carry out the turn using the VOR, thereby avoiding 'reverse sensing' during the first half of the turn, before flipping to the ILS once pointing 'the right way'.

Actually coming from GEBTI I seem to think that the point IF ( 9 DME IIF ), that is before VFA 8 DME, is the one charted for pilots coming from that point.

Actually your point makes a lot of sense, if I am correct some of the aircraft still used today by the Portuguese Air Force are pretty old in terms of cockpit equipment, specially the helicopters. I have flown with some retired pilots coming from the portuguese AF and HSI was definitely not an equipment they were so familiar.

Rotordan:

Good point. Since IFF D7.2 (and VFA D8.0) are in the profile as well as the plan view, I can only speculate that the procedures designer added that as an aid in rolling out of the base legs.

Certainly not the best design I've seen. There is no note about DME being required when the GS is out.