An antipodean asks
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An antipodean asks
Here in Auntie Podea at Norfolk Island to be precise we have a non-controlled airport served by F100, 737-300 and 747-400 aircraft seating up to 140 pax in the case of the 400. YSNF/NLK are the identifiers. Non-controlled with an MBZ up and working HO, but no ILS but a VOR and NDB, PAPI and soon (yeah, pigs fly!!) an SLS2000 certified for SCAT 1. NLK is domestic as far as Brisbane is concerned but Auckland despite being nearer is International. Now, and here is the tickler, what do you say should be the airspace category etc etc when the remote Island of St Helena gets its airport? (Typically would be served by 737NG and A318/319). And what navaids would you want... MLS, GPS???
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St. Helena is in the South Atlantic, about six days' boat ride from S. Africa. No airport due difficult terrain/lack of space. But one hears on the grapevine that it may happen oneday.
A former Governor's Staff Officer from a certain British Overseas Territory in the Caribbean was posted there a couple of years ago. He was much involved with aviation issues and has developed an interest in making it happen for St. Helena also.
Can obviously only be a large airport capable of handling longhaul flights as it is too far from anywhere to have small traffic.
All or nothing.
Until recently the Royal Mail Steamers did the round trip from Britain via Ascension, Tristan da Cunha, S. Africa for about 3,000 pounds. It didn't seem to be profitable anymore so I think that there is now a regular service from S. Africa for those that want to spend a little time without the joys of weeks at sea.
A former Governor's Staff Officer from a certain British Overseas Territory in the Caribbean was posted there a couple of years ago. He was much involved with aviation issues and has developed an interest in making it happen for St. Helena also.
Can obviously only be a large airport capable of handling longhaul flights as it is too far from anywhere to have small traffic.
All or nothing.
Until recently the Royal Mail Steamers did the round trip from Britain via Ascension, Tristan da Cunha, S. Africa for about 3,000 pounds. It didn't seem to be profitable anymore so I think that there is now a regular service from S. Africa for those that want to spend a little time without the joys of weeks at sea.
Last edited by el dorado; 4th Oct 2004 at 16:35.
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Thanks for that el dorado, it'll be interesting to see who comes up with the money for such a project. By the sound of it, if there's enough space (somewhere) for a decent length of runway, probably won't be enough space to install ILS/MLS, let alone a VOR on runway centreline. And, without any of that, not a lot of scope for a DME either.
Might be the ideal location for a SLS2000 Scat 1 Precision GNSS approach system... just like YSNF...
Well, I suppose that it has to start somewhere. I for one would certainly like to see this Scat 1 system in operation as I have more than a passing interest in it.
Might be the ideal location for a SLS2000 Scat 1 Precision GNSS approach system... just like YSNF...
Well, I suppose that it has to start somewhere. I for one would certainly like to see this Scat 1 system in operation as I have more than a passing interest in it.
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More than a passing interest in it? Then you're surely aware of Norway implementing SCAT-1 on all of its STOL-ports, starting next year. I'll be flying the approaches. Have you tried flying SCAT-1? Does it work? What's the deal? Feed me!!! :-)
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My interest in Scat-1 is strictly from a procedure design perspective Crossunder. I'd like to be able to implement it in this small corner of the planet. To answer your question, yes, I knew that Norway was working on it, but didn't know that they'll be ready to implement next year.
There's a lot of complexity involved in designing and establishing the procedure - and in flight checking too, of course. But, if they've got all of that under control, I daresay you'll find that it'll work very nicely for you. I'll be watching Norway with much renewed interest now, thanks!
There's a lot of complexity involved in designing and establishing the procedure - and in flight checking too, of course. But, if they've got all of that under control, I daresay you'll find that it'll work very nicely for you. I'll be watching Norway with much renewed interest now, thanks!
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Hi Guys!!
If you read www.shelco.sh you'll have a pretty good site to read up on.
The airport stalled a bit with GIC Ltd being the first consultants pulled in by DfID and now it has gone to WS Atkins.
After a lot of delay it looks like UK Govet has come around to realising pretty much that Shelco were right all along only they have wasted 3 years and half a mill faffing around.
Last I heard it was to be about 1900m more or less into the ESE trades for takeoff with two runways joined to form a Vee-shape. The second runway is only 1500m or so with a cross-wind component ffor landing only Reason? Topography and glide-slope. So you get enough to land on and a decent approach. No one in their right mind would land on the long runway as a) over a misty moun tain and b) not 3 deg or anything like!!
As to VOR if there is one its at the vee intersection at a guess but who is going to install obsolescent gear and then rip it out before the paint is dry?
It would a 180-min ETOPs place and by all input a 737NG/A319 would be 70 tonnes gross. BBJ can do Orly and also Stansted in one lash. I dont think the A319 can take enough ACTs and might have to run 5 tonnes lighter.
Difficulty with this SCAT1 is this... is it enough and what happens if the DGPS throws a wobby? You know, degrades and says it has been a bit poorly for the last 2-3 mins. Okay you have a 2hr island reserve but wouldn't MLS be better but has anybody bought one yet??
If you read www.shelco.sh you'll have a pretty good site to read up on.
The airport stalled a bit with GIC Ltd being the first consultants pulled in by DfID and now it has gone to WS Atkins.
After a lot of delay it looks like UK Govet has come around to realising pretty much that Shelco were right all along only they have wasted 3 years and half a mill faffing around.
Last I heard it was to be about 1900m more or less into the ESE trades for takeoff with two runways joined to form a Vee-shape. The second runway is only 1500m or so with a cross-wind component ffor landing only Reason? Topography and glide-slope. So you get enough to land on and a decent approach. No one in their right mind would land on the long runway as a) over a misty moun tain and b) not 3 deg or anything like!!
As to VOR if there is one its at the vee intersection at a guess but who is going to install obsolescent gear and then rip it out before the paint is dry?
It would a 180-min ETOPs place and by all input a 737NG/A319 would be 70 tonnes gross. BBJ can do Orly and also Stansted in one lash. I dont think the A319 can take enough ACTs and might have to run 5 tonnes lighter.
Difficulty with this SCAT1 is this... is it enough and what happens if the DGPS throws a wobby? You know, degrades and says it has been a bit poorly for the last 2-3 mins. Okay you have a 2hr island reserve but wouldn't MLS be better but has anybody bought one yet??
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The advent of GPS pretty much signed the death warrant for MLS, enicalyth, so I doubt that there's much of a market for it these days. If this place is 180-minutes ETOPS, that's a worry. Are there any adequate/suitable aerodromes nearby?
And, if the shorter runway is operationally necessary at the time, what happens if it's blocked by an aircraft involved in an incident or accident? The longer runway would be needed and, by the sound of it, the weather would need to be favourable. This is startng to look like a real nightmare.
Sounds like a 737 mightn't be able to carry enough fuel for the requirements of this place.
And, if the shorter runway is operationally necessary at the time, what happens if it's blocked by an aircraft involved in an incident or accident? The longer runway would be needed and, by the sound of it, the weather would need to be favourable. This is startng to look like a real nightmare.
Sounds like a 737 mightn't be able to carry enough fuel for the requirements of this place.
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No worries ozexpat
Gee ozzy no sweat!! This is an airport for two flights per week or one per day. Not even as busy as Norfolk!! If you look at a topo or talk to Shelco/CAA they'll explain better than I can that N->S there is only 1700metres economically and ecologically okay land that will accommodate a 3 degree glideslope. So 1700m less 300m RESA is 1400m LDA. But trade winds being trade winds and the island being where it is Auty's Law gives you a fine ESE prospect and 2200 metres in which to construct a take-off runway; if you fancy a 9 degree glideslope, mist and turbulence then you can land on it too! Careful about aircraft fuel... the 180-mins is essential because it is an island with no suitable diversionary (ASI is 800nm away) but a wetahre corrected range circle based on a 2000nm still-air geodesic of 2000nm takes in Rio, Recife, Sal and Cape Town. With a love puff it takes in Durban.
It wont be class G airspace it has to be 180mins ETOPs despite FHAW/ASI being 800nms away as I say. But having said that as you know Norfolk is non-controlled, no ILS, an uncommissioned SLS2000, an MBZ, 1950 metres ASDA 60 metres RESA (not even 90), the runway ends are pitched up on ramparts, the hospital can't do major trauma, there is no morgue, there are three 40 year old fire engines. Now that is a nightmare.
Back to fuel. A B737 (especially a BBJ) has heaps and heaps and heaps of fuel. A straight 737-800 won't break sweat at 124 pax and 1700nm to Cape Town, nor will an A319... (BRW for these from STH would be 70.5 tonnes off 1850 metres, RESA extra). The B737/A319 with 124 pax and a 2hr island reserve can fly from Recife/Sal Amilcar/Rio/Capetown. Coming and going a A319CJ has range with 50 pax for Orly and a BBJ similar has range for Stansted and Fort Lauderdale KFLL. Young kids and backpackers are not going to be coming for the sun, sun, sun and the business hoteliers planning things have estimated 250 pax per week is a fair go. San Antray this airport is not going to be.
There will be a 300m RESA and two aircraft a week so it isn't ah-tall a nightmare. Talking of RESA 240 metres is enough but BALPA want 300 so 300 it is. (ICAO base their 240 metres on stopping from 90 knots at the REIL with a deceleration of 13ft/sec/sec).
What is a nightmare is having people die there on St Helena for want of surgery because a ship is nowhere near. People always think an airport is for access IN (at least tourists think that way); Islanders look at it for access OUT as well as in.
And no you cannot, absolutely cannot land on the long runway. It is there at 2200 metres (or will be) with 300 metres of RESA purely for take-off straight into the eye of 15 knots trade wind. You cannot land on a westerly approach without becoming a statistic of CFIT. So how do you land?? With a modest crosswind you can enjoy 1700 metres landing of which 300 metres is RESA and believe me 1400 metres is enough for all B737 and A319.
We've been through all this since 1986, the twin runway Vee-shape is Okay with Ove Arup (airfield specialists), Boeing, Airbus, ASSI, CAA and with 300m RESA, Cat 7 fire cover and a decent navaid it will be fine with me.
What is critical is a good landing system and GPS as it stands at hesitant Cat1 just is not it. SCAT-1 was supposed to be on NLK in 1998, then 1999, then 2000, then 2002 and now it is 2004 and it is still a pile of brushed satin poo in a brick outhouse. That navaid couldn't find a skimpy in a Kalgoorlie bar on Saturday night. There is over 200dB of space loss twixt a satellite and your VDU, in L-Band and the receiver/antenna gain has to make this up and receive the broadcast DGPS datastream either or both of which can be suffering precipitation loss, and not degrade below certain "stringent" standards. Sheesh!! And one of those standards is an unsatisfactory bit error rate up to two minutes. Two minutes! At 150kts that is 5nm. Sorry, in my book any landing system that can have that long an outage of precision and may be 30 metres in error for that period is not precision.
The manufacturers say they have xx systems installed. Yeah. Installed in brick huts but how many are actually commissioned and working and how many are Cat 3 capable? Norfolk is a prize example... installed yes, working no and the wrangle goes on.
At this rate we'll just get it built and the oil will run out!
It wont be class G airspace it has to be 180mins ETOPs despite FHAW/ASI being 800nms away as I say. But having said that as you know Norfolk is non-controlled, no ILS, an uncommissioned SLS2000, an MBZ, 1950 metres ASDA 60 metres RESA (not even 90), the runway ends are pitched up on ramparts, the hospital can't do major trauma, there is no morgue, there are three 40 year old fire engines. Now that is a nightmare.
Back to fuel. A B737 (especially a BBJ) has heaps and heaps and heaps of fuel. A straight 737-800 won't break sweat at 124 pax and 1700nm to Cape Town, nor will an A319... (BRW for these from STH would be 70.5 tonnes off 1850 metres, RESA extra). The B737/A319 with 124 pax and a 2hr island reserve can fly from Recife/Sal Amilcar/Rio/Capetown. Coming and going a A319CJ has range with 50 pax for Orly and a BBJ similar has range for Stansted and Fort Lauderdale KFLL. Young kids and backpackers are not going to be coming for the sun, sun, sun and the business hoteliers planning things have estimated 250 pax per week is a fair go. San Antray this airport is not going to be.
There will be a 300m RESA and two aircraft a week so it isn't ah-tall a nightmare. Talking of RESA 240 metres is enough but BALPA want 300 so 300 it is. (ICAO base their 240 metres on stopping from 90 knots at the REIL with a deceleration of 13ft/sec/sec).
What is a nightmare is having people die there on St Helena for want of surgery because a ship is nowhere near. People always think an airport is for access IN (at least tourists think that way); Islanders look at it for access OUT as well as in.
And no you cannot, absolutely cannot land on the long runway. It is there at 2200 metres (or will be) with 300 metres of RESA purely for take-off straight into the eye of 15 knots trade wind. You cannot land on a westerly approach without becoming a statistic of CFIT. So how do you land?? With a modest crosswind you can enjoy 1700 metres landing of which 300 metres is RESA and believe me 1400 metres is enough for all B737 and A319.
We've been through all this since 1986, the twin runway Vee-shape is Okay with Ove Arup (airfield specialists), Boeing, Airbus, ASSI, CAA and with 300m RESA, Cat 7 fire cover and a decent navaid it will be fine with me.
What is critical is a good landing system and GPS as it stands at hesitant Cat1 just is not it. SCAT-1 was supposed to be on NLK in 1998, then 1999, then 2000, then 2002 and now it is 2004 and it is still a pile of brushed satin poo in a brick outhouse. That navaid couldn't find a skimpy in a Kalgoorlie bar on Saturday night. There is over 200dB of space loss twixt a satellite and your VDU, in L-Band and the receiver/antenna gain has to make this up and receive the broadcast DGPS datastream either or both of which can be suffering precipitation loss, and not degrade below certain "stringent" standards. Sheesh!! And one of those standards is an unsatisfactory bit error rate up to two minutes. Two minutes! At 150kts that is 5nm. Sorry, in my book any landing system that can have that long an outage of precision and may be 30 metres in error for that period is not precision.
The manufacturers say they have xx systems installed. Yeah. Installed in brick huts but how many are actually commissioned and working and how many are Cat 3 capable? Norfolk is a prize example... installed yes, working no and the wrangle goes on.
At this rate we'll just get it built and the oil will run out!
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Okay, so the weather, wind, runway, traffic and fuel situations are under control. With so few flights, it's clear that the place doesn't even need ATC, even under ETOPS, so long as there's a way of getting weather information and Notams. Thus, I guess this aspect is also under control, now we're back to the original question in relation to navaids.
I'm still not convinced that anyone would be brave enough to install a MLS because, as I understand it, there's no further development going on for it. There is, however, much more development going on with GNSS navigation technology. I accept what you say about a time-out period of 2 minutes, but I'm not convinced that it's an insurmountable problem.
If the DGPS goes offline for that period of time, exactly how much adverse effect is it really likely to have? I'd suggest that the the total course deviation would not instantly degrade. It would take some time and, in fact, might only reach maximum deviation after that 2-minute period.
In any event, during that 2 minutes, the aircraft will not simply move laterally by 5 NM, in your example. It will still be travelling forward while starting to diverge from the course. I'd suggest that, if it all started to happen just as you reached a point that is 2 minutes from touchdown, you'd reach Cat 1 DA and probably still be within the required lateral tolerances to effect a landing, if visual, or a safe missed approach.
I deliberately use Cat 1 because, to me, it sounds like this place can't meet Cat 2 or 3 precision approach standards. And, of course, with the possibility of a 2-minute denegration of accuracy, the system could never be classified as anything better than Cat 1.
However, it seems to me that if you think the place can accommodate an MLS installation, then it can probably also accommodate an ILS as well. It would have a DME associated with the GP. Despite everything that's been said in the last few years, I don't see ILS facilities being phased out rapidly around the world, so this is probably going to be the approach navaid of choice.
If the place can also have a VOR adjacent to the intersection of the 2 runways, might also be able to use it to provide an alternative approach, for redundancy purposes. Thus, if there isn't much enthusiasm for GNSS approaches, I think there might be an alternative or two that would be useful.
I'm still not convinced that anyone would be brave enough to install a MLS because, as I understand it, there's no further development going on for it. There is, however, much more development going on with GNSS navigation technology. I accept what you say about a time-out period of 2 minutes, but I'm not convinced that it's an insurmountable problem.
If the DGPS goes offline for that period of time, exactly how much adverse effect is it really likely to have? I'd suggest that the the total course deviation would not instantly degrade. It would take some time and, in fact, might only reach maximum deviation after that 2-minute period.
In any event, during that 2 minutes, the aircraft will not simply move laterally by 5 NM, in your example. It will still be travelling forward while starting to diverge from the course. I'd suggest that, if it all started to happen just as you reached a point that is 2 minutes from touchdown, you'd reach Cat 1 DA and probably still be within the required lateral tolerances to effect a landing, if visual, or a safe missed approach.
I deliberately use Cat 1 because, to me, it sounds like this place can't meet Cat 2 or 3 precision approach standards. And, of course, with the possibility of a 2-minute denegration of accuracy, the system could never be classified as anything better than Cat 1.
However, it seems to me that if you think the place can accommodate an MLS installation, then it can probably also accommodate an ILS as well. It would have a DME associated with the GP. Despite everything that's been said in the last few years, I don't see ILS facilities being phased out rapidly around the world, so this is probably going to be the approach navaid of choice.
If the place can also have a VOR adjacent to the intersection of the 2 runways, might also be able to use it to provide an alternative approach, for redundancy purposes. Thus, if there isn't much enthusiasm for GNSS approaches, I think there might be an alternative or two that would be useful.
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good shout ozexpat
Yeah this all really starts to make sense. I'd place a VOR at the intersection too and like you say the old gear is going to be around awhile. CAA/ASSI are not happy about ILS because of this big hill called the Barn which does intrude a little bit into the cone of the approach but I can think of a similar rocky atlantic island with the runway perched above sea-shore, on stilts in places, on the side of a mountain. Needs must when the devil drives. The CAA and CASA might as well be two different beasts and so the get-out has to be a bendy approach. As you say MLS is not favoured (except by me!!) despite being a robust system. You are right of course about gradual degradation of GPS and I wasn't really thinking about a lateral error of 5nm, more like 5nm nearer decision height! But yup, Cat 1 really should be adequate and the 2hr Island Reserve is there, god forbid. Will the CAA sanction an MBZ look-alike like Norfolk NLK? How will they draw up airspace categories? Dunno really but it is taking an awfully long time fo Mr Buggins to put the seal of approval on all the plans. Never mind oil running out, I'll be in my bath-chair.
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I hadn't realised that there's an obstacle penetration on approach to the shorter runway, but no understand why you've been advocating MLS. However, if it's only a slight penetration, an offset ILS might be workable. That'll depend on the amount of offset that's needed, of course.
As for airspace, I don't see the UK CAA opting for anything like a MBZ. However, ICAO provides a minimalist ATC structure called an Aerodrome Traffic Zone (ATZ). Given their well documented track record of conservatism, I think that this would be an option they'd explore in this instance.
An ATC facility could provide real-time weather observations which are always helpful to pilots in assessing the likelihood of a successful Cat 1 approach. So, while a Tower wouldn't be busy at this place, the weather information would be a distinct advantage.
I suspect that the speed with which anything happens at this place will be linked to the degree of interest by airlines in scheduling flights to the place. After all, it's usually the airlines that drive these things and, if they're not pushing it, we probably won't see any developments during our life time.
As for airspace, I don't see the UK CAA opting for anything like a MBZ. However, ICAO provides a minimalist ATC structure called an Aerodrome Traffic Zone (ATZ). Given their well documented track record of conservatism, I think that this would be an option they'd explore in this instance.
An ATC facility could provide real-time weather observations which are always helpful to pilots in assessing the likelihood of a successful Cat 1 approach. So, while a Tower wouldn't be busy at this place, the weather information would be a distinct advantage.
I suspect that the speed with which anything happens at this place will be linked to the degree of interest by airlines in scheduling flights to the place. After all, it's usually the airlines that drive these things and, if they're not pushing it, we probably won't see any developments during our life time.
