Io540
 

Most of the GPS units that have a TSO have a databus input/output and the ability to drive the GS indicator on the CDI/HSI at the moment the GS won't work , the whole set up is ripe for expansion aid I see no reason why data from another nav system could not be mixed with GPS in or outside the GPS unit and then drive the CDI for a NP approach OR even (god & CAA forbid) a CAT 1 Approach.

You are right about the GS bar not doing anything when the HSI is in GPS mode, but I've read somewhere that some GPSs (GNS530? - I don't have one) can do vertical navigation to more or less the extent you describe. Unfortunately I don't have more details.

Most King GPS units conections to the GS indicator and spare anunciatior light pins (approx 5 on the KLN89B) however these are not at the moment used.

It is clear that the unit is intended for further development otherwise why go to the trouble of putting all this stuff in ?. King tend to produce Very good kit that will interface with other equipment rather than build things with lots of "showroom performance" so this is the sort of attention to detail that I would expect from a company that is looking to the future.

You'll need WAAS or LAAS to support CAT 1 or better approaches (they are precision approaches since they have vertical guidance). WAAS is due for full USA coverage this year sometime, LAAS will have to be provided by a local provider such as an airfield operator. Which means someone will end up paying for it.

As I understand it, the UK CAA are not against GPS approaches per se. But they won't be the ones that draw up the procedures, they will merely regulate them (not as an EASA organ but as the Directorate of Airspace Policy which is a different sphere of operation). To date, no one has grasped the nettle and designed any overlays or stand alone GPS procedures, then done the safety analysis, then submitted them to the CAA for approval. The main problem being that someone will have to pick up the cost of that work and obtaining the approval. Once the first is done, then it may be simplified and cheaper for others following on, but like somone getting a type certificate for a new aircraft, then until someone with deep pockets makes the effort, everyone will just wait in the wings in hope. So there you go IO540 .. you could blaze the trail here and design a NPA for your local field :ok: Plenty examples in the US to use as guidance, although the US uses TERPS for their procedure design whereas the rest of the world uses ICAO PANS-OPS :(

NATS is doing some work on routes which might, in fact will, use GPS as a possible means of navigational compliance. These will be Precision RNAV routes in the TMA airspaces of the UK around about 2010 onwards. But these will be in pure IFR airspace (SIDs and STARs) and all probably a bit above your average PPL though :ok:

Just for the avoidance of doubt, I like GPS, I like what it offers to someone trained in its use. It offers great accuracy, and potentially (with all the right maps and databases), an electronic nav plog kind of capability which can be used to reduce workload.

My nervousness is that we go on to produce a generation of aviators who can only slavishly follow the line on a moving map, without understanding how to navigate themselves, and will end up in trouble if it goes wrong. They'll probably even have to input the circuit pattern so they can follow that around the airfield too ;)

I also don't buy the 'it never goes wrong' argument. The fact that someone has never seen a problem in 500 hours of GPS operation is neither here nor there. Any safety assessment will have a probability of failure to look at and there is no electronic system which simply cannot be degraded or fail at any time in its life cycle. So you have to allow a fallback which deals with that and the obvious one is for pilots to be able to navigate without any electronic aids. Ensuring they are competent in both is the test for this industry ... in terms of training requirements and ultimately cost. This is being dealt with in the other thread.

Fuji

'GoTo' is good for diversions to airfields which are already in the database. Quick and simple (as long as the line also shows CAS and Danger Areas which have to be negotiated). But these are not the kinds of diversions I see problems with. The ones I see causing problems are those where your original route through CAS (because the pilot only knows how to get a straight line on his GPS between established airfields or waypoints) is refused and you then have to 'divert' around CAS.

That gives 2 options. The pilot can visually navigate around the CAS lines on his moving map. Wouldn't be hard as long as the multiple lines are not misunderstood and there is awareness of stepped bases where appropriate. But still a small element of risk. Or the pilot has to input a lat/long which he didn't do on the ground, since he needs a line to follow. Big thumbs, turbulence, poor vis, high workload .. all can contribute to this having an error input. Interestingly, the top navigational error cause in Transatlantic Gross Navigation Errors are where the crew (2 man professionals and operating in a comfortable well equipped airliner) input a lat/long incorrectly (missing digits, wrong digits, etc). So the odds of an under pressure GA pilot making a mistake must be slightly higher.

It's how to reduce the risk involved in navigating in these kinds of operations with GPS that need to be tackled and a suitable 'warm feeling' given to the authorities.

Yes you can indeed make all the listed errors with a GPS but it's even easier to do them with the old methods. This is the great fallacy underpinning the anti GPS position; they chuck out the baby with the bathwater.

Let's say you have a carefully prepared plan, wind corrected and all that, through CAS. You ask for clearance 10 miles out or whatever, get refused and now you have to dogleg around it, using compass, stopwatch, together with trying to identify some villages down below. All the way round you will be in need of fresh underpants because you know what that one little mistake will cost you.....

I am talking about doing this in unfamiliar territory, not in one's back yard which is where most anti-GPS pilots stick to (understandably).

There is no way round this. I am sure INS has severely degraded the ability of your British Airways ATP to use a sextant.

As for direct coordinate entry, that is almost never done in GA, if the pilot knows anything about flight planning. In 5 years I have had to do it twice; once to enter an airfield in Spain (which got put into the Jepp data the following year), and the other to enter some gliding site in Kent which a passenger wanted to take pictures of. If airline ops need nav to ever varying waypoints (to get the best winds) they have to pay the price for that, and check their numbers twice :O There is nothing particularly "airline pilot" about checking coordinates; single pilot IFR pilots are supposed to do it for every waypoint, as are airline pilots; that's why the lat/long is printed next to every waypoint on the IFR charts.

Ha BEagle :ok:

IO540

I think these 'anti GPS' pilots you keep going on about are a figment of your imagination. Lots of people use GPS in a different way than you, that doesn't mean they are wrong. Some of the best pilots I know don't tend to leave the local area. Firstly because their planes don't carry enough fuel to go more than 100 miles, secondly they find cross country flying exceedingly boring. Most will have a GPS in their flightbag (one of those hand helds you treat with such contempt)

Wasn't there a study done using 737s which looked at the amount of time pilots spent looking outside during various phases of flight. A comparison was made between 737s with traditional instruments and the variant with a highly computerised flight deck. During the approach and landing phase the pilots on the computerised model spent more time head-in-cockpit as they were spending more time managing the electronics. I'm not saying it proves anything, and I'm sure the engineers took this on board and looked at improving the computers, but interesting stuff.

Beagle

I agree with you; I was just picking up a point made by the person I was responding to.

SS

I never treat handhelds in any comtempt, don't be ridiculous. Some handhelds are brilliant, and because you can load a flight plan into them from a laptop, in some ways much better than IFR approved panel mounts.

I just think the £100 camping-shop handhelds, which need manual waypoint entry using lat/long coordinates, have two big problems:

1) they introduce sufficient scope for gross errors in data entry

2) they don't give you the situational awareness of a decent moving map unit

Your 737 scenario isn't relevant to typical GA. Usually, a 737 is lined up on the runway, up goes the power, climb straight ahead for a bit, then get radar vectors (forget the SID), more radar vectors, climb at 2000fpm+ straight through all the icing layers (and with a TAS high enough to make airframe icing barely relevant), more radar vectors, then DCTs (under radar control) all the way to destination, vectors through descent (forget the STAR), vectors onto the ILS, coupled autopilot landing. CAS is a complete and total non issue, as are danger areas, en route notams, weather except in terminal areas and high level en route. I've flown European airways myself and even at FL150 it is sufficiently different to what we are talking about here to be irrelevant to the debate. And BRNAV GPS is mandatory ;)

Not sure what the joke is, Beagle.

The normal procedure is

1. Plan the OCAS route

2. Plan the more direct route

3. File an ICAO flight plan (if applicable) using the more direct route; abroad this does tend to get distributed "properly" to the proper controllers along the route

4. On the flight, ask (in a very firm tone) for every direct clearance you can ask for, giving the immediate route as IFR waypoints so they can see you are navigating using some proper means and not fishing for villages and ponds which CAS ATC units hate because it makes their life hard

What tends to frustrate the above a bit is the determination of some UK ATC units to send a VFR flight to VRPs when they can see perfectly well you are navigating via radio. This happens abroad too, but isn't a big deal because the official VRPs near airports tend to be in the GPS database. I am not sure of the legal position; I believe a VFR pilot is entitled to navigate by radio when en-route, and in fact some countries (Greece being one) WILL expect VFR navigation by VORs and airways intersections.

I won't take your "playing airliners" bait.

PPruneRadar


Your posts begs the question with your familiarity with recent GPS moving maps.

The only times I can remember inputting a lat long co-ordinate is when going to a grass strip not in the database. Yes there is plenty of potential for error and you would want to check before you set off that the position on the moving map is roughly where you expected the strip to be.

However to your example of an unplanned diversion round CAS. It is simple. Personally, I would follow the boundary until reunited with my original track. Not too demanding and whilst you make the point of the need to ensure you follow the correct boundary on a colour moving map the boundaries are in my opinion far better defined that on a chart.

Alternatively, and this is where I wonder about your familiarity, move the cursor to a suitable spot outside CAS (any where you like really) it takes a few seconds, hit GOTO and there is the new course. When you reach that point pull up the flight plan and hit GOTO again for the next point you would have gone to outside CAS on the original “flight plan” and there it is.

Finally I don’t recall anyone saying GPS was infallible, what I do recall are pilots observation that the reliability of GPS compared with radio navigation aids is very favourable.

So what do you do if it fails. If you can, use the radio navigation aids in the cockpit, use dead reckoning from your last know position and / or use visual navigation. Depending on the individual the skills might be a bit rusty BUT if they are get a steer or two from D and D. They will oblige, it is not a drama, and if the failure rate is once in 10,000 hours I don’t suppose they will be too over worked.

Hang on a minute, are you IFR or VFR? If you are VFR then is it not implicit that you might be expected to enter CAS at a VRP?

Slim Slag's point about 737 drivers illustrates the concerns I have voiced on the other GPS thread running at the moment.

IO540,

I think you have some very valid points relating to the form of aviation you seem to do, ie A to B for a mixture of business and pleasure. You obviously get your kicks from flying as efficiently as possible, using all the kit available to you. I have no issue with that. But it is my belief that many PPLs are quite happy bimbling about enjoying the view, doing burger runs or what ever. Sure they might want to go from A to B but like the flexibility to "go and have a look over there" along the way. GPS moving map - fantastic, ideal. But I can do that without a moving map GPS and so can many other people. We manage that because we have learnt how to read maps and charts. Hell, I actually enjoy navigating visually, it is far more satisfying (and flexible) than beacon or waypoint hopping. We don't all need GPS and new pilots should be able to choose for themselves how they navigate. They should also be taught how to read maps and charts more thoroughly.

Droopystop

That is the best and most refreshing post I have heard from the "anti GPS" lobby.

I enjoy navigating visually as well. I particularly enjoy the precision flying type events. Pilots should recognise traditional navigation as an enjoyable skill to perfect and do well. In my view what they certainly should not do is claim it is better / safer / easier than using a GPS which it is not :ok:

Anyone who claims to be able to navigate well traditionally should take part in one of these events. They are demanding and of course will encompass an area with which you are not familiar. I accept they are far harder than traditionally navigating long cross country legs but they do give you a good appreciation as to whether your skills are up to navigating through a small corridor between CAS with which you are completely unfamiliar.

When my engine failed at 3000' over LA in solid IMC ,I instantly pulled back until the speed tape indicated best glide speed and went through an unsucessful restart, then I pressed the GOTO NEAREST on the right hand MFD. I instantly knew I was not going to make any airfield, so I zoomed the map display in, found a highway and lined up on it. 500' I popped out of the cloud and made a perfect landing on the road.

Not a real life situation thank goodness, but it was done in an FAA approved Garmin 1000 simulator. They really are that good that you could even determine which side of the road you want to land on.

The benefit of a good GPS in the aircraft outweighs any perceived disadvantages. In fact the FAA now say that paper charts are not required in the new generation of glass cockpit light aeroplanes, and although I'd probably always carry one as it was "the way I was taught" you really do not need one. Last time I was flying a glass cockpit aeroplane VFR I refered to the paper chart for preflight purposes only, entered all the VRPs into the flight plan in the screen and flew using the moving map.

In this generation of avionics, IF gps is lost a) you know about it straight away, and b) it switches to DR mode.

thanks alot for all the replies, you all have great points and it's been very helpful to me. didn't mean to cause a discussion that would lead to a few arguments, but these things will happen when blokes have too much spare time on their hands!!

thanks again, b bear

Wouldn't that be a rule 5 infringement? :}




I Know off to the naughty step for five hours :O