Aldergrove

[tango234]

The EGA1 AFD fits almost perfectly with the UK2000 Belfast scenery, only a small amount of work needed!

I suspect a bigger job for me will be getting the Islanders and Defenders to park somewhere reasonable...

[mage]

Strangely enough I just made a helicopter overlay for Aldergrove as the final UK2K "Xtreme" airport overlay in a long series for FS9. So far it's civilian aircraft only but I was considering making one for the military area.

I'd be interested to know what the operations are for the military there with regard to runway usage and, in the case of helicopters, also the approaches.

Basically, do fixed-wing use the main airport's main runway or put down on the shorter runway when winds permit, and do helicopters conform to angled approaches from the north that avoid overflying the civil airport?

My civilian overlay brings helicopters in from the east to land on a taxiway close to their parking positions close to the freight ramps. Aldergrove has no consistent civilian helicopter procedures since they have no civilian helicopter parking set aside, meaning that rotary arrivals are dealt with case-by-case in terms of where they land and park. So, I improvised. With military ops obviously it's different and I'd like to cook up a military overlay that not only has the parking looking plausible, but also the tracks taken by helicopters to arrive there.

[TimC340]

It's a long time since I was a regular military operator into EGAA, but I doubt things have changed hugely since I left the RAF. The helos generally left the airfield south of the main runway and, if they needed to go north, would cross the extended centreline a few miles out - unless it was an emergency shout, in which case the departure would be as direct as possible. Most milittary fixed wing traffic in those days was from the air transport fleets (C130/VC10), who would operate in accordance with normal civilian procedures. The Islanders/Defenders will land and take off as close to their dispersal as they can, with the minimum of taxi time, so even if using the main runway, they'd land as close to the nearest exit to their pan as possible, and take-off from the same place (in those days, the based military aircraft were all over on the west side).

[mage]

Thanks Tim, that pretty much confirms my assumptions. For obvious reasons details are thin, and I thought about my own flying and how I'd organize things if I was the Master of the Universe (and in FS9, I can be a legend in my own simulator).

I'm making my own version of the EGA1 AFD to minimize interference with the civilian airport (which is the side I'd be flying anyway), so I'm having the military rotary presence using RW17-35, which the civilian airport in FS9 just won't use since it's not the longest runway. If something lands on a runway in an overlay that is superimposed on the main airport the main airport seems to "notice" and force go-arounds,so using the main runway would be problematic. But, based on what you've just told me, at Aldergrove we have the situation where we can legitimately have military rotary aircraft using the other runway. Even though the blocking problem is there, nobody else is using that strip anyway so it's benign.

I'd found some info on operational military helicopter flights and, as you say, they're on a case-by-case basis and mainly off to the west and northwest except for urgent reasons, so although there's not any control I have over departures, I can at least angle arrivals in from the northwest sector for landing at each end of a short helicopter strip. The only way I could also keep departures clear would be to invent an invisible runway that's orientated to avoid conflicts with the main airport that in FS9 only really uses 07-25. I could use the closed taxiway that leads across to the PSNI pads for that, and share it with the PSNI fleet, and angle approaches in from the northwest. Then again, why bother when we could just be simulating an urgent shout. On a regular basis!

The UK AIP mentioned for Belfast that military ops are off in that quadrant and won't get closer than about 250 metres to the main manoeuvering areas.

I believe there is a way (in FS9 at least) to close one end of a runway by creating a fan of x-wind runways around to each side of the main one, twinning the runway with itself, but I've no idea how true that is. Something arcane like that might help keep traffic in the correct quadrant.

What's problematic in a sense is the Islanders. Do we allow for them to use the main airport at all, or make a slightly larger runway 17-35 that Islanders can also use, in the knowledge that they will sometimes create close calls with traffic on the crossing runway. The glitch in that thinking is that an angled approach for the helicopters would also be used by the Islanders, which would be turning final very close in. I used to fly in the Caribbean, so I know Islanders can do that very easily. Question is, did the Army do this with Islanders at Aldergrove, where there's no high terrain to consider and therefore no reason to take unnecessary risks on approach.

It's not as though the Islanders would have to use it, they could just be flightplanned into EGAA and taxy to parking over in the military area, which is something I'll need to do for transports etc, since I assume C-130/A400M and such will head over there to park, and I'll have those using EGAA.

For the moment I'll work on a helicopter-only overlay that shares ramp space with EGAA-bound military aircraft and mesh the taxiway systems together as best I can to integrate the two destinations (EGAA/EGA1). If Islanders typically made approaches to avoid the main airport also, then I can enlarge the runway to accommodate those too, add their parking, and suggest that people flightplan their Islanders to EGA1 rather than EGAA.Trouble starts when an overlay's runway gets bigger, since it gets harder to integrate into the main airport. I'll make my FS9 AFD available along with the EGA1 AFD, and also with my XGAA AFD that accomodates civilian helicopters landing on a short stretch of taxiway over by the cargo ramp. So, in my sim, Belfast will have potentially 4 overlays, maybe even 5!?!

The others would serve the PSNI base off in the NW sector of the airfield, and the fifth would be for those 3 helipads slightly further away still, whose purpose isn't obvious. They're not Medvac since those are based at Long Kesh and St Angelo, so I believe. I'm wondering whether they are support aircraft for Op Helvetic, supplementing PSNI. Seems likely.

[TimC340]

In my day, the NW area was Learjet/Bombardier, so I've no idea what goes on there now. The area to the SE of the intersection was still the WW2 spectacle dispersals, and would be where we (C130) and the VC10s would park. The helos (Gazelle, Scout, Lynx, Wessex and Puma) would all be over on the west side. I don't remember if the Army had any fixed wing assets there back then (I was a regular there 1980-98) but the RAF had a couple of ELINT Turbine Islanders that were quite frequent visitors. They would be hangared whenever they were on the ground, and I assume that would be in the secure area on the west side.

In reality, the airline traffic almost exclusively used the main runway. A crosswind strong enough to mandate using 17-35 would be very unusual, though perfectly reasonable for the majority 737/A320 traffic. The RAFAT traffic would be told which runway to use by ATC, but that was in negotiation with the ground security teams who would be clearing the MANPAD areas under the selected approach. I'm quite sure that a similar protocol would be in use for notified helo and Islander ops, but that all other ops would rely on random arrival and departure routes to minimise the threat. Deconfliction with civil AT movements would be fairly critical - no-one wanted to risk a potshot being taken at a military aircraft, missing and hitting Aer Lingus!

Obviously things are rather different now, and it will be a much more conventional operation with military traffic obeying civilian protocols where appropriate. I'm sure a study of Flightradar 24 or FlightAware will reveal some interesting and useful info for constructing your traffic patterns.

[mage]

I've realized that in my conversations I've been casually referring to the orientation of the AFD as I've been working on it and gotten the quadrants mixed up. Northwest, nothing goes on, and my AFD has helos arriving from just south of west, just to the south of the main runway axis, and turning sharply onto final just fine when landing on RW17. They arrive angled onto the other end but not nearly as 90-degree angled as they are onto 17, basically from the southwest with a 45-degree turn onto final (using fake ILS approaches, so anything IFR will fly those while anything else will fly a typical US-style traffic pattern with a 45-degree turn onto downwind and the usual pattern thereafter.

The helicopter AFD is really only suitable for helos. I have a bunch of aircraft heading out at 30-minute intervals for a local flight (2 flights in a 1-hour plan), all Gazelles but for one Islander. The Islander flies the angled approaches but lands on the grass and fumbles its way over to the runway for taxy to its parking spot. It was just there for testing and comic interludes. If I change the Islander to fly VFR it'll land on the runway just fine, but will cross the touchdown zone of the main runway up at that end.

Google maps (and the other mappers, many just using the same images) shows helicopters parked on the large ramp area southeast of the intersection, so I've put the helicopter parking there. I'm still working out the best access to the mini-runway to avoid head-to-head deadlocks. Overlays seem to make these head-to-head moments more frequent since there might be moments when taxying that AI cannot hear their airport's controller because they're passing through an area where the main airport's controller is active and not their own, and can't be warned to hold position to avoid a conflict.

In my day, the NW area was Learjet/Bombardier, so I've no idea what goes on there now. The area to the SE of the intersection was still the WW2 spectacle dispersals, and would be where we (C130) and the VC10s would park. The helos (Gazelle, Scout, Lynx, Wessex and Puma) would all be over on the west side. I don't remember if the Army had any fixed wing assets there back then (I was a regular there 1980-98) but the RAF had a couple of ELINT Turbine Islanders that were quite frequent visitors. They would be hangared whenever they were on the ground, and I assume that would be in the secure area on the west side.

There's mention online of a couple of BN Defenders based at Aldergrove, and the fact that they were normally inside. There are hangars both sides of runway 17-35 and the default AFD for the UK2000 scenery shows parking in both areas, so I'm a bit fuzzy on whether they were parked on the large southeastern ramp or up in the small area just south of the main runway's western end. I'm leaving all that parking "as is" and coding the spots on the large open ramp as AAC (and recoded JY's Gazelles the same, Army Air Corps), so that the Gazelles will prefer that patch - as per Google images.

The spectacle dispersals close to that large ramp are used by the EGAA AFD for fixed wing military coming into Aldergrove on the main runway, quite separate from the helicopters. From what you just said, that was the right guess.

In reality, the airline traffic almost exclusively used the main runway. A crosswind strong enough to mandate using 17-35 would be very unusual, though perfectly reasonable for the majority 737/A320 traffic... Deconfliction with civil AT movements...

Since the AI system forces things to get set in stone I've decided to make EGAA live without the secondary runway. It's still there, but I've made it into a stubby little runway to get it out of the way of the military traffic (it's in a UK2000 scenery addon with its own ground textures, so this isn't a problem). It's a PITA to delete it altogether. It gives me a free hand to redevelop that area south of the main runway for the overlays, and only the military transports arriving into the civilian runway will encroach onto there.

Obviously things are rather different now, and it will be a much more conventional operation with military traffic obeying civilian protocols where appropriate. I'm sure a study of Flightradar 24 or FlightAware will reveal some interesting and useful info for constructing your traffic patterns.

For military I tend to go to ADS-B Exchange, who are less keen on blocking. That said, I can only find a couple of military over western Europe today, an Irish Air Corps PC-12 at FL280 over the North Sea, and a C-5M steaming westward just past Frankfurt at FL380, presumably up from the sandpit (the ADS-B trace ends and restarts over Romania, I guess because no landing was recorded). Oh, and an RAF A330-KC2 heading northwest just past Belfast.

[TimC340]

If you're using a shortened 17-35 as a separate AFCAD for mil traffic only, using ADE you should be able to create complete IFR approach routings from well away from the airfield that achieve the exact flightpath you want to achieve (I'm assuming approach construction in FS9 works the same as in FSX/P3D). VFR traffic will, of course, do whatever FS9 wants it to.

[mage]

If you're using a shortened 17-35 as a separate AFCAD for mil traffic only, using ADE you should be able to create complete IFR approach routings from well away from the airfield that achieve the exact flightpath you want to achieve (I'm assuming approach construction in FS9 works the same as in FSX/P3D). VFR traffic will, of course, do whatever FS9 wants it to.

I've done just that. EGAA has a vestigial 17-35 up near the intersection, just to save me from having to deal with any problems relating to the ILS for that runway, while EGA1 has its own 17-35 closer to the dispersals and AAC ramp. It has made life easier because runways tend to reserve a bit of space around them (for the purposes of ATC) and having them overlaid or even quite close, can cause overlays to become unreliable, either in themselves or in their effects on the main airport's layout.

The EGA1 overlay has angled ILSs at each end that bring any IFR traffic in from the west/southwest according to which end they're going into. VFR traffic just flies the pattern, and there's not much we can do about that. The Gazelles get a bit "sporty" on arrival though, swooping around in a low arc over the grass but landing nice and square on the AFD runway, or sometimes short of it. Since it's an addon scenery, where the Gazelles touch down looks like the runway anyway, it just means that the arrival gets told to call ground immediately, which certainly improves the flow of my intensive test traffic!

I've experimented with the ARP/reference point positioning to improve reliability in the overlay. I found that moving EGA1's ARP closer to the military area gave it (EGA1) control over comms for the whole ramp area, meaning that even badly parked Gazelles could get departure clearance/authorization to taxy at the ramp area and runway clearance. Normally an overlay's parking spot with the main airport's ATC all around it requires an AI aircraft to park within the limits of the spot if it is to get clearance reliably, because it's only by being in the spot that they can talk to the correct controller, moving the ARP to give the overlay overall control even around the spots gives us some wiggle room for AI that can't turn neatly into position.

In the military area (large ramp space) the helicopters park facing out from the buildings and need to execute a smart turn if they're to end up in that orientation. My nine test Gazelles would all end up getting stuck in the clearance phase until I moved the ARP closer. I've also needed to make two routes to the runway since the obvious single route is a huge cul-de-sac that brings all sorts of problems with AI stuck waiting for a new arrival to find its spot before they can continue taxying.

I've a persistent problem getting the Gazelles to turn into the correct orientation but then to taxy straight out from there without a pushback (this is FS9, lest we forget). I can do this in my sleep for larger aircraft, but the small radius of the Gazelles seems to make the whole thing hit & miss, and I may end up just having to accept pushbacks after all.

With the approach coding, there's really only one important aspect for AI, and that's the heading from the Initial Fix, and only that heading and fix position are in play for AI. FS assumes that the IF is on the extended centerline and the heading is the one we fly to the threshold (and ADE makes that assumption too, but we can override it). To angle the approaches we just move that IF away to wherever we want the aircraft to be vectored for approach, and then pick a heading that intercepts the runway centerline at whatever point we want the AI to suddenly realize that it's not aligned with the runway and execute that turn to actually land. I tend to code two legs for the approach, from IF to FF and from there to the threshold, but I wouldn't mind betting that I could leave out those approach legs entirely and still have AI fly the approach using just the IF and the heading I tell it to use from there. It's great to have it simplified by ADE, remembering my early ones from 2005, all hand-coded in XML and taking ages to test and change!

The problem with putting the IF out too far is that AI can claim the runway while still quite far out, which can leave the runway unavailable for longer than is ideal. In extreme cases the approach (with the prior vectoring that goes on even further out to bring AI to the IF) can leave AI out of radio coverage entirely, particularly if there are a string of arrivals that the AI engine is spacing out with a few miles between them.

With the Aldergrove helicopter overlays (there are two, with civilian helicopters directed to land on a taxiway near the cargo ramp) the track distance from IF to threshold is .6 of a mile - 0.4 to arrive at the extended centerline, and then 0.2 mile to touchdown, really close in.

[TimC340]

You've obviously done a lot if work on this - it's a shame it's for FS9 (from my PoV obviously!). Constructing approaches is great fun, IME, though having to reload FS after each change to see how it's working is a pain. I used to keep a 'vanilla' installation of FSX to make it as quick as possible, but that's got a bit bloated (like me) over the last couple of years. Anyway, it'd my interesting to have a look at what you've done when you're happy with it - I do have FS9 installed in a backwater HDD on my machine for checking out non-P3D addons.

[mage]

Well, I've put a lot of time and effort in, but most of it won't make any difference, sadly. While the AI works fine on the overlay it wouldn't do the last thing that I wanted, which was to park the right way around and not perform any pushback. I've tried the "sharp turn" approach that I have used for larger aircraft in the past, no dice, and I made an AFD using the "plumbing system" that a friend of mine, "Matthew Ministry" proposed about 15 or more years ago, but that ended up unwieldy and unreliable as well, fine on standard sized runways but awfully hit & miss on a tiny overlay runway that the AI won't always land squarely on.

I ended up with quite an impressive construction that made absolutely no difference to the outcome so, guess what, I reverted to something so simple that it looks stupidly underdeveloped! At least people will be able to figure out what's going on and, if they have any brighter ideas might make something that works better overall. So over a day and a half of fiddling and tweaking and nothing to show for it but a pretty typical AFD. I went on and made another overlay for the PSNI helipads, EGA2, and will consider Belfast to be as "done" as I can manage.

If you can open AF2 files I can always post those here, or if you can "import from XML" I can simply zip up the XML files instead, if that is a truly portable format that passes between versions. I've been compiling to XML quite often making these overlays since that gives me the ability to edit the water runways out of the file after I'd used the main airport's AFD to create the basis of the overlay. Then they compile and there are no deleted runways lying around. After the edit I simply "open from XML" and get a nice clean overlay to develop. So, I could simply provide the XMLs if they make life easier.

With regard to having to perform sim restarts to get scenery to reload, I found when testing an airport project I was working on 12 years ago (Abu Dhabi for FS9), that I could change locations to other parts of the world twice, and then return to Abu Dhabi for testing, and BGL changes would be immediately available without a restart. Provided I went to quiet parts of the world (in my case it was somewhere in Alaska and then Port Moresby before returning to Abu Dhabi) the process would be a lot faster than a sim restart. I guess that two changes of location was enough to empty out the cache and force the sim to reload the files from disk. It was desperation at the time taken to restart that made me look for alternatives.

What I'd be making available would be an AFD for EGAA (main airport), XGAA for civilian helicopters, EGA1 for the Gazelles, and EGA2 for the PSNI base. And Editvoicepack entries (FS9 only) to allow ATC to say "Aldergrove" for all those new AFDs. The main airport would be taking the military transports and parking them in the "spectacles" and other areas close to the tower. Although this area is partly embedded in overlay territory it seems to work properly

[mage]

Those AFDs I mentioned - for UK2000 Aldergrove in FS9

[TimC340]

Mage, I've just popped in to see what's occurring. RL has, as it tends to, got firmly in the way of any kind of FS stuff over the last few months. I'm not out of that yet - no-one told me that retirement meant that lots of people and organisations assume your time is now all theirs! I'm over-committed for some time yet, but I'm learning how to get that under control and I hope that by the time summer is established I can at least give a few hours a week to FS work. When I do, I'll have a look at your overlays - which I've downloaded in the optimistic hope that I can install them sometime soon!

[mage]

Mage, I've just popped in to see what's occurring. RL has, as it tends to, got firmly in the way of any kind of FS stuff over the last few months. I'm not out of that yet - no-one told me that retirement meant that lots of people and organisations assume your time is now all theirs! I'm over-committed for some time yet, but I'm learning how to get that under control and I hope that by the time summer is established I can at least give a few hours a week to FS work. When I do, I'll have a look at your overlays - which I've downloaded in the optimistic hope that I can install them sometime soon!

Hi Tim -

They're yours to use as and when (or if!) you see fit, and to change as you like. They're just the basis of my setup presently. I'd also been hoping to put more time into just observing how they worked over a longer period but have also been away from the sim for a little while, which was why I posted these the other day. I'd talked it up rather a lot and then, nothing. So I thought the least I could do was put them out there for people to experiment with and improve upon if they like. If anything useful comes from that, they're free to repost!

I understand what you mean about retirement, though. I'm not retired but found the same thing with self-employment! There's some weird assumption that if you manage your own time, you can make time for other people's things, "now that you're home more often...!". If anything, it means having to say "no" much more often and for some of us that's quite difficult, especially if we've been helpful and obliging in the past. For some people it's quite hard to make the transition to saying "no" more often, and quite hard for other people to understand that freedom often means ring-fencing our time quite strictly. In my case it's fair to say that I've never been working harder than at the times when people assume I'm idle - people confuse movement with action. Not that long ago I lazed through several springs and autumns out there in the garden with a book at my side and a laptop nearby, staring at the sky for hours on end. Only I knew that I was studying for an Open University degree. I got quite protective about my precious summers of freedom.

It's like the old saying, "when an author is staring out of a window, he's working".