Ils approach at GCFV

[Julioviana]

Hello I am a Spanish ATC working at Canarias control. I would like to comment what happened in my afternoon shift yesterday.
A 737 proceeding from the east to Fuerteventura is cleared for the ils approach before the iaf. He is number one for approach. I see that he descends to 3000´. The procedure starts over FV at 4000´and I tell them why have they done that. The captain says that they can descend to the msa which in fact is 3000´. The mva is 4000´, the approach procedure starts at 4000´. The SID´s are designed so as to be separated from a traffic starting the manouvre at 4000´. Do you think it is necessary to remind the pilot to maintain 4000´until leaving FV ?.
Thanks in advance

[OzExpat]

I don't know what your AIP says about it but it occurs to me that, if the chart shows a mandatory minimum altitude of 4000FT prior to the IAP, the pilot must observe that. If it does not show that as a mandatory altitude, a pilot would seem to be at liberty to descend to your MVA of 3000FT for a more convenient start to the ILS approach.

If the procedure is predicated on separating departing traffic from arriving traffic, I would have to say that it would be up to the Air Traffic Controller to tell the pilot of an arriving flight not to descend below 4000FT until passing the IAP, due traffic.

As I said at the outset, your AIP might say something different but, in absence of that, the above is my interpretation. Maybe there are others who can comment in the next few days?

[Knold]

If it is like you say then he's not allowed to descend off the profile. He's been cleared ILS-Approch then that means he should follow that procedure. Of course you can allways ask for a change but that's a different story...

[Duke of Burgundy]

Buenas tardes Julioviana - having looked at the ILS/DME chart for Runway 01 at GCFV, it is easy to see how the B737 captain misinterpreted the altitude at which he should have commenced the procedure.

He was obviously misled by the MSA diagram on the chart which shows the MSA to the east of the FTV VOR/DME as 3000ft.

Because of this potential for confusion and because traffic separation is involved I would agree with your suggestion of reminding or instructing pilots to maintain 4000ft until leaving the FV NDB.

:) :)

[Julioviana]

Thanks all of you.
Does anyone of you know a site where charts of English airports are published?.
In Spain we have http://ais.aena.es where you can find charts of all the Spanish airpors.

Saludos from the Canary islands

[chiglet]

Julio,
Try www.ais.org.uk
Just "might" help
we aim to pleasae, it keeps the cleaners happy

[bookworm]

To me the IAP chart (http://ais.aena.es/img/ad2/gcfv/gcfv-iac1.pdf) looks even more confusing than Duke of B suggests.

Two racetrack shapes are depicted at the FV. The northern end 180 degree turn is common, but two southern ends are depicted. Inside the shorter racetrack shape, it says "MNM ALT 4000". South of that, outside the shorter shape but inside the longer one it says "MNM ALT 2800" and "IAS MAX 220 kt". Outside the longer shape it says "HIPODROMO Cat A&B 3 min, Cat C&D 2 min".

Presumably the shorter racetrack shape is the holding pattern, and the longer one is the racetrack course reversal itself, as labeled by HIPODROMO.

My interpretation would be that the MNM ALT 4000 refers only to the holding pattern, and the MNM ALT 2800 refers to the racetrack course reversal that is the first part of the IAP. If not, why is the MNM ALT 2800 there at all? It's not unusual to have a higher minimum holding altitude than minimum altitude for commencing the approach. That's how I would expect it to be depicted.

I suggest that you not only remind pilots to maintain 4000 ft where required, but also encourage your AIS charting section to add a note to the effect that the minimum altitude for commencing the procedure is 4000 ft until reaching the IAF at the FV.

[Mister Slot]

I don't see where the confusion lies. To me it is quite evident from the profile view that the min. hold alt. is 4000' and that the procedural approach commences at 4000', ONLY descending to 2800' once outbound in the procedure.

[OzExpat]

Ahha, now we're cooking. For my money that 737 Captain was completely wrong to descend below 4000 FT at the reported stage of flight. The LLZ course is clearly within the 4000 FT MSA/MVA sector so he had no right to assume that the 3000 FT MSA/MVA applied.

Being a procedure designer, I've encountered incidents of confusion in the depiction of a holding pattern and a racetrack pattern. For this reason, I've elected to show the holding pattern as a short fat-ish shape with the racetrack longer and thinner - especially where a speed limit below holding speed is necessary in the racetrack procedure.

I believe it's quite feasible for a racetrack to have a lower minimum altitude than a holding pattern. This is primarily because the racetrack does not provide sector entry protection. The design parameters assume that the aircraft has already completed the relevant sector entry. Thus, the overall area to be protected for the racetrack is usually not as wide and, therefore may eliminate obstacles that the holding pattern must provide protection against.

So, yes, in this case, lowest holding is 4000 FT and this must be maintained until the aircraft is established in the holding pattern and has turned outbound in the racetrack and has reduced speed to a maximum of 220 knots IAS. At that stage, descent to 2800 FT may be commenced. Then, on turning inbound and established on the inbound track of the racetrack procedure, descent may be continued to 2500 FT until overhead the FAP/FAF at glidepath intercept.

The reason this approach seems to convoluted is the location of the FV Locator. It's just too close to the threshold to arrange the procedure any other way. And, as it's obviously impractical to reposition it out in the Atlantic Ocean, there is no other way that this procedure can logically be constructed.

The fact that the flight in question was approaching from the east - ie in the 3000 FT MSA/MVA sector - is irrelevant. The procedure gives him no authority to descend below 4000 FT until he meets the speed and tracking requirements of the racetrack procedure. Thus, he should have maintained at least 4000 FT, as our friend Julioviana was entitled to expect.

[bookworm]

No argument with most of that, OzExpat.

I think a glance at the elevation view makes it clear that the procedure starts at the FV at 4000 ft, to be maintained until outbound in the racetrack. And the MSA is not relevant. The pilot was, without doubt, technically wrong to descend below 4000 ft, but I can see why he was confused.

But I do believe that the plan view is more confusing than it needs to be. Imagine a case where the procedure started at the FV at 2800 ft, but the minimum holding altitude was 4000 ft for separation from departure traffic. Would the plan be depicted significantly differently from what you see on the plate? It's not easy to work out which altitude applies where.

[OzExpat]

bookworm ...

Imagine a case where the procedure started at the FV at 2800 ft, but the minimum holding altitude was 4000 ft

That is, effectively, what this procedure is saying. After completing the sector entry, you can fly a 2 (or 3 as the case may be) minute racetrack at 2800 feet, all day and all night, if you've got the fuel and inclination. The problem lies in how you get to 2800 feet from 4000 feet and this is where the profile view gets messy.

I really can't see how else to show it. Aircraft must be level in the hold at 4000 until established on the outbound leg - and passing FV. This is because an extreme sector 3 entry (ie from 298 inbound to FV) is a very big turn that needs the terrain protection that the racetrack doesn't provide. The sector entry is well and truly complete when you roll wings level on the outbound leg and note that FV has passed abeam.

The only "cleaner" way would be to establish a holding pattern on the Localiser, somewhere further to the south. Depending on whatever other terrain is around, it might be possible to have the holding pattern at 2500-2800 feet, around about 8-10 DME to the south.

About the only problem with this is that it might be a tad messy to get from any given inbound track to that holding pattern, to start the approach. And, if this place uses Procedural ATC, such a procedure would be difficult to manage at peak traffic times.

So, on balance, I'd have to say that the procedure and its' depiction are about as simple as they can be. I'd have thought that a professional aircrew might, on seeing such an apparently convoluted procedure, take some extra time to review it well in advance of their arrival.

This is not the sort of procedure to try to figure out "on the fly", after leaving Top of Descent.