View Full Version : WAAS In OZ..........
Ex FSO GRIFFO
11th Nov 2008, 00:53
"WAAS Approaches Outnumber ILS
The FAA recently commissioned its 1,333rd WAAS approach (technically known as Localizer Performance with Vertical guidance or LPV) and that means there are now more of them than ILS approaches. The agency calls it a milestone in the transition to universal space-based navigation. The system is in use at 833 airports and the agency says it's planning to add 500 approaches a year until every qualifying runway in the U.S. has one. "This is clearly a turning point for aviation and the way pilots navigate," the agency said in a news release.
Something the agency doesn't mention but which is undoubtedly a factor in the rapid deployment of LPVs is they cost of a fraction of the millions of dollars that ILS systems cost. WAAS, or Wide Area Augmentation System, was commissioned in 2003...."
Note the last para re the cost......
And OZ has how many? I wonder why?
11th Nov 2008, 01:57
it's planning to add 500 approaches a year until every qualifying runway in the U.S. has one.
Do that here and we would have most airports covered in a year!:ok:
Would be much simpler than trying to workout which waypoints I am between and how many miles there are to go!:rolleyes:
11th Nov 2008, 05:00
AsA can't make any money out of it. Therefore you can't have it.
11th Nov 2008, 05:25
And there JM you have succinctly, but unconciously, summed up what's wrong with the approach to aviation in this country. Airservices should not be a bloody "business"!! This is not about making money; this is about investment in infrastructure (WAAS) that benefits all Australians. Having said that, I agree your point on ensliting the wider users. However, ultimately our taxes should pay for the myriad of benefits that would be delivered and "business" shouldn't come into it.
12th Nov 2008, 05:36
Thanks JM. If there is an alternative, read cheaper, means of augmentation on the horizon then we should keep an open mind. Provided, of course, that whatever the gurus come up with is not a unique fix.
My main point, however, is that whatever form of augmentation is decided, it needs to service the widest possible range of applications if we are to derive maximum benefit as a nation. Hence my comment on the "aviation business case" vs the fact that if we get a system that has universal application then the expense should not come out of the hide of aviation exclusively. And the only way to ensure equity right across the range of potential users is for the money to come out of federal taxation.
From a purely aviation, and selfish point of view, I want to see a system that has the potential to offer precision approaches into anywhere, provided that the destination has an appropriate plate. From where I sit, that was the failure of GRAS.
12th Nov 2008, 06:26
What's it cost to put a satellite up? Its already cost me $5k for the WAAS upgrade - be happy to chuck in a few $$ to be able to use it fully!
12th Nov 2008, 10:38
Being such an avid researcher see if you can find out the cost of Missed Approaches at aerodromes around the country by the regional airlines alone. Then add to that the RFDS and some charter.Then add to that some Private ops, which would be a small amount.
See how the numbers add up (assuming the difference in minima.
Now the safety benefit probably works the other way, Private then Charter, RFDS etc, then RPT. Add the value of that in.
Now that we have done aviation over, lets get to the bigger end users being Agriculture and mining and shipping.
I am convinced without the numbers, but get the numbers and I bet its a no brainer!
12th Nov 2008, 19:16
The real value of WAAS is not in aviation at all. It's in mining, agriculture and transport.
BTW, JM, the mathematics of handling the relativistic effects in the GPS system are so complex as to be unpredictable. It's all to do with the clocks. The relativistic effects include the different velocities of earth and satellite. Tangential velocity depending on your latitude, then the relativistic gravitational redshift which depends in part on the position of the Sun and Moon. Each satellite gets sent corrections once a day otherwise the system's accuracy would degrade to useless very quickly.
WAAS allows receivers to make some of the corrections on a local basis.
12th Nov 2008, 19:58
Sunfish: Check your PMs please!
13th Nov 2008, 00:01
Also told that it increases the chances of the big bang for those who push minima.
How can that be???
If so we should shut down all the ILS systems at major airports.
13th Nov 2008, 01:07
Also told that it increases the chances of the big bang for those who push minima
I guess it stands to reason that if you put technology in place that allows minima to be lowered - busting those minima comes with an increased risk of ending one's life cycle.
Minima will usually be pushed where ATC are not watching
Hmmmm! We do not seem to have a problem in Oz with aircraft pranging off ILS approaches by busting the minima - although these types of events appear to be not uncommon in the USA. Is it because the majority of our ILSs are associated with primary control zones?
How many prangs have we had that clearly occurred because someone busted the minima off an NDB approach into Woop Woop? Very few that I can recall.
As for unqualified pilots pushing their luck in aeroplanes full of fancy equipment like the G1000 generation of Cirruses, Cessnas Mooneys, Bonanzas etc. That sort of thing has been going on for years - and quite a few life cycles have ended as a consequence.
None of the above is justification for denying those who are appropriately qualified and experienced access to technology that will enhance utility, flexiblity and safety.
13th Nov 2008, 01:58
Would be much simpler than trying to workout which waypoints I am between and how many miles there are to go!
Hear Hear! :ok:
it increases the chances of the big bang for those who push minima.
Well, at least you'd be in the landing config and clobber the threshold given the minima is so low... :D
WAAS? Couldn't think of anything better, myself. Except ADSB.:}
Oh oh. Here comes Binghi!
13th Nov 2008, 05:29
I could almost hug ya Bloggs...........:D but I am not quite sure of your gender so lets just say........ Love ya work!:ok:
13th Nov 2008, 06:53
Having vertical guidance enhances safety several fold, that on it's own should be enough to sell the advantages of WAAS for aviation uses.
GPS approaches without vertical guidance are more dangerous than your normal VOR/DME or NDB/DME approach due to the fact that there are two countdown distances on the GPS approach compared to just the one distance on the VOR/DME NDB/DME approaches.
Profile monitoring on a GPS approach is nowhere as simple as it is for the other approaches. You cannot run the 3 times profile in your head when you are outside the final fix. Also it would be easy for a pilot to read off the wrong distance particularly in difficult conditions and descend below profile.
JM: "....just tell me how to make a business case for WAAS for aviation in Oz. I always used to ask my sub-managers "Would you do this if it was your business"Couldn't agree more.
Implementing WAAS capability in Oz is not simply a case of just equipping aircraft with the required functionality and pilots using it.
Just like with CAT II/III ILS installations, in order to maximise the lower minima (LPV) benefits afforded by the WAAS equipment, a holistic systems approach would be required to implement WAAS LPV procedures and create the necessary operational/airspace environment to allow pilots to operate safely to the lower minima.
In particular, Australian airports would be required to significantly upgrade their airports in terms of runway width, approach/runway lighting, standby power supplies and runway security. Unless airports put these infrastructure upgrades in place, WAAS could not offer any improved operational benefits as the approach minima would essentially have to be the same as the existing minima afforded by our conventional NPAs.
Notwithstanding the above, I acknowledge that there are some safety benefits to the pilot in terms of improved descent profile management but I doubt whether these benefits would justify the cost of national WAAS implementation considering the generally good (VMC) conditions that many airports experience throughout the year.
13th Nov 2008, 22:21
Unless airports put these infrastructure upgrades in place, WAAS could not offer any improved operational benefits as the approach minima would essentially have to be the same as the existing minima afforded by our conventional NPAs.
To my knowledge, no extra/improved infrastructure has been put in place for RNP approaches at regional airports, but the minimas have come down to around 250ft AGL from the GPS NPA average of 400ft AGL. Why wouldn't the situation be the same for WAAS approaches?
I assume you are referring to RNAV(RNP) approaches (ie the ones requiring SAAAR approval)?
As you would be aware, precision approaches are normally only approved onto runways classified as precision instrument runways. As I understand it WAAS (LPV) approaches are classified as precision approaches and, therefore, I would assume the associated terminal airport infrastructure to support these approaches would have to meet the relevant airport design standards listed in MOS 139. Airport design standards for precision runways provide additional specific dimensions, facilities and requirements to compensate for the reduced time a pilot has to visually acquire and align the aircraft with the runway after becoming visual at the DA. Many regional runways in Australia currently do not meet precision approach design standards.
I'm no expert here (I don't work for CASA or Naverus) but I would assume that the reason why some aircraft operators are approved to operate RNAV (RNP) approaches onto NPA instrument runways in Australia is because of the very high navigational accuracy and automation capabilities offered by the approved aircraft which has the potential to relieve a lot of the pilot workload involved in visually acquiring and aligning with the runway; hence the lower minima.
I can't see how the average GA aircraft equipped with a single WAAS (LPV) receiver can ever hope to achieve the same level of navigation/automation capability offered by SAAAR approved aircraft and, therefore, I believe there will continue to be a high level of reliance on airport infrastructure capability to support the pilot in visually acquiring the runway as early as possible after becoming visual.
14th Nov 2008, 04:56
I can't see how the average GA aircraft equipped with a single WAAS (LPV) receiver can ever hope to achieve the same level of navigation/automation capability offered by SAAAR approved aircraft
My TSO 146 Garmin 430W has a accuracy spec of +/- 1.25 metres! When combined with a good coupled AP why would I not be able to meet the required level of navigation capability?
14th Nov 2008, 07:00
Surely it is more important to get some sort of proper IFR approach to the hundreds of aerodromes that do not have one at all!! Or a better one for Lockhart River.
Are we only interested in Qantas?
The agricultural and survey aircraft have systems that allow them to navigate very accurately, and not just within the J curve.
Why are we only concentrating on lower minima for the major airlines in capital cicties?
14th Nov 2008, 07:55
"Why are we only concentrating on lower minima for the major airlines in capital cicties?"
1. Maybe because QANTAS can make money by paying squillions to NAVERUS to design special approaches that allow lower DA's and special departures that allow a lower TO minima, that only QANTAS can use, thereby gaining a REAL competitive advantage over their rivals by being able to arrive and depart more often in poor weather conditions or carry more pax and baggage because they know they won't have to divert, or can get out of the place more regularly.
2. Maybe because QANTAS has more political pull than your average charter company.
3. Because no-one else can afford to pay squillions to NAVERUS.
Its not just capital cities. Check the AIP SUPPS on the Air No Services website and you will find Broome, Port Hedland, Alice Springs, Cant-berra, (it might be the nations capital but you CAN'T get anything done there.)
And it is not for the major airlines, its only for QANTAS.....or any other airline willing to pay SQUILLIONS.
What was the name of the guy from CASA who pushed the RNP stuff through and then left and now works for NAVERUS?:rolleyes:
14th Nov 2008, 08:06
The fish-tail DOC says:
"My TSO 146 Garmin 430W has a accuracy spec of +/- 1.25 metres! When combined with a good coupled AP why would I not be able to meet the required level of navigation capability?"
Your fish-tail doesn't have triple GPS, IRS, head-up display, and the rest of the gear that the B737-800 has installed especially for the RNP requirements. If it did it wouldn't be able to get airborne.
And the fish-tail driver does not have the integrated training system for himself and his copilot and engineers that keep the thing in spec so that the aircraft can do its thing in an acceptable form of safety which is probably an order of 10 to the minus something safer than flying a 50 year old fish-tail.;)
14th Nov 2008, 08:31
Your fish-tail doesn't have triple GPS, IRS, head-up display, and the rest of the gear that the B737-800 has installed especially for the RNP requirements
And the lighty doesn't have the inertia and delay in engine spool-up that the B737 has, approaches at a slower speed and can climb at a steeper gradient (not a faster ROC, tho') right AT the MAP and thus should be able to handle a lower approach minimum with the current more accurate gear.
I believe this argument had been used successfully in the USA (correct me if I'm wrong) for some lighties with the "usual" gear to do cat II approaches.
14th Nov 2008, 08:56
the fish-tail driver does not have the integrated training system for himself and his copilot and engineers that keep the thing in spec so that the aircraft can do its thing in an acceptable form of safety
... and I'll bet the B737-800 doesn't have "Helga, the talkng cigarette lighter" co-pilot!
PS: For the record the FTDK is only 31 yrs old - like a woman, just coming into her prime!
14th Nov 2008, 09:42
Being such an avid researcher see if you can find out the cost of Missed Approaches at aerodromes around the country by the regional airlines alone
How about the cost of 15 lives at YLHR?
14th Nov 2008, 11:17
I think I covered the safety issue further on but I reckon 15 or so families might agree with you!
14th Nov 2008, 21:35
The Doc might have Helga perform a vital function but the many lassies in the back of the Boeing perform other tasks magnificently. :p