[matthew_w100]

I've just been practicing ILS approaches at Lydd (on X-Plane, due to lockdown ) Can anyone explain to me the design considerations that led to the Lydd approach going out to 14nm from the threshold, with the glideslope interception at 3,200'? Most others are 10 or less, with the glideslope coming in between 2,000' and 2,500'. Lydd approach has to be over the lowest, flattest land in the country except, perversely, the bit at 14nm. What's special about it?

[AlanM]

Good question....! Just a guess....

Maybe EGD141 is within the danger zone for a 8 mile intercept? It would make sense to be established and stable before 8.5d.

[Iceman]

Like Alan, I suspect it’s due to the proximity of D141 to the final approach track and no possibility of an intercept further in at a lower altitude. It’s certainly makes for an approach where you want to get in first time as that missed approach is one hell of a cross-country (including entering the hold to establish on an outbound course back to the DME arc).



Iceman

[G-JWTP]

I renewed my IMC there last time around.
Direct arrival from the North, a go around, into the hold, once around that then the full procedure.

I think it took about a week.



Nice lunch though in the cafe.


G-JWTP

[Rob P]

Direct arrival from the North, a go around, into the hold, once around that then the full procedure.

I think it took about a week.

Golly! And I thought The Colt was slow.

Rob P

[masterofnone]

I've just been practicing ILS approaches at Lydd (on X-Plane, due to lockdown )

Which aircraft are you using in XP? The C172 don't have a DME in them (so far as I can see)

[Dave A]

Whenever my brother, who's an Instrument Flying Instructor in the USA, wants to give his colleagues a laugh, he pulls out the Lydd ILS plate I gave him. They all fall about in fits.

[matthew_w100]

I renewed my IMC there last time around.
Direct arrival from the North, a go around, into the hold, once around that then the full procedure.

I think it took about a week.



Nice lunch though in the cafe.


G-JWTP

Me too - my IMC renewals tend to alternate between Lydd and Sarfend. It takes most of the morning to do the Lydd procedure! The offset ILS provides additional entertainment - does anywhere else have one? I had thought that would be sufficient to dodge the danger area, but take the point that the long run in lets one be settled properly by the time one is passing it. On the other hand it does mean one is tempted to fly the approach clean and fast and then manage the configuration changes at the bottom, rather than fly the whole thing in landing configuration.

Which aircraft are you using in XP? The C172 don't have a DME in them (so far as I can see)

You are right - the 172 doesn't, annoyingly. When using that I use the GPS distance which is good enough for government work. Otherwise I use the JustFlight Arrow III - a PA28 VP Retractable. The X-Plane Garmin 530 does have an approach for the Lydd 21 ILS you can use, but it bears little resemblance to the real one.

[GrahamB]

The offset ILS provides additional entertainment - does anywhere else have one?

Hawarden 04 is offset by 2.6 degrees, intercepting the centre line about a mile short of the threshold. The glideslope is also at 3.5 degrees, so it's an interesting one all round.

[GT500]

The VOR approach to EHKD to runway 03 is offset by 23 degrees

[rdfb]

Which aircraft are you using in XP? The C172 don't have a DME in them (so far as I can see)

You are right - the 172 doesn't, annoyingly. When using that I use the GPS distance which is good enough for government work. Otherwise I use the JustFlight Arrow III - a PA28 VP Retractable. The X-Plane Garmin 530 does have an approach for the Lydd 21 ILS you can use, but it bears little resemblance to the real one.

Actually the XP 172 does have a DME. It appears on the 430 if tuned in to a VOR/DME. But for some reason it doesn't work on any ILS/DME I've tried. I think it's a bug.

[matthew_w100]

Actually the XP 172 does have a DME. It appears on the 430 if tuned in to a VOR/DME. But for some reason it doesn't work on any ILS/DME I've tried. I think it's a bug.

Oh - I'll try it. I gave up exploring the 172's 430 when I found the OBS function didn't work properly.

On the JF PA28, although you can switch the DME between NAV1 & 2 the ident function only gives NAV 1.

[rikur_]

I've got DME on 172 in Xplane - but I think I edited it to add it. Can't have been that difficult to add.

[matthew_w100]

I've got DME on 172 in Xplane - but I think I edited it to add it. Can't have been that difficult to add.

Easy enough in the 2D cockpit, but I have no idea how you do it in 3D. If anyone can explain, I'd love to hear it.

[MichaelP]

Offset approaches are not unusual in mountainous areas such as in British Columbia where I did my IR.
As an example of mountain procedures here is one in Thailand, a GPS approach I reviewed with my former PPL student there.

It started with the approaches into Phitsanulok and was an investigation into obtaining VNAV indications.
In some GPS systems you can set up your own vertical guidance but this seems not to be possible with an Aspen PFD Garmin 430/530 interface.
I suggested he probably needs barometric connection to the Garmin for this facet to be available?
If anyone knows how to get a form of vertical guidance for a straight in GPS approach I’d be interested to know.

It should be possible to set the minimum altitude on the autopilot and arm the ALT mode with the VS set...

As for the Mae Hong Son approach plate this follows my own VFR descent when I have flown in there though I’m rather lower. It’s one of my favourite places.

Excuse me for the deviation from Lydd. Often these things lead to a wider discussion, and discussing approach plates is always interesting.