As a pilot who flies VFR in an aircraft which is fitted with moving-map GPS, but who would rather the GPS wasn't there, I feel like I should comment on this.

There is no doubt at all that GPS can be a navigation and safety aid, providing extremely accurate positional information. The thing which concerns me about it, from first-hand experience, is that it makes the concious part of your brain less aware of your location.

When I fly using only a chart, I am always able to point at my location on the chart within a few seconds of being asked. In other words, I know exactly where I am, all the time. I don't often use VORs or NDBs, but the few times I have, I've still been able to pinpoint my position on the chart. A VOR radial simply isn't enough by itself - you need to be able to transfer the raw data from your VOR onto you chart in order to be able to navigate.

When I have flown with the GPS turned on, though, I can't honestly say that I've been able to pinpoint my position so easily. I've known I'm "somewhere south of Newbury", but if you wanted anything more precise than that, it would have taken me a minute to spot landmarks and locate them on the chart. Unfortunately, I can't turn my GPS off, since it doubles as a radio. However, I now switch the GPS to a mode which doesn't show me any navigational information. It's comforting to know that it's there if I manage to get myself completely lost, but I won't use it any other time, because I don't like the effect which it's having on my situational awareness.

The last time this was discussed here, someone (sorry, I forget who) suggested that it's useful to program your route onto the GPS, but then set your display so that the only thing it shows is your planned track. That way, you can't use it to get navigational information, but it serves as a nice check that you're on track. This sounds like an excellent idea, and one which I plan to try, but a combination of bad weather and non-flying commitments means I haven't had a chance to try it yet.

This is all IMHO, of course!

FFF
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Interesting. I'll extend the debate, not because I believe there's a right way and a wrong way to do it -- clearly how you use the tools at your disposal is entirely up to you -- but because we can learn from different techniques.

DTK is static. It can be checked against your PLOG before flight. There doesn't seem to be much point in displaying it. I like to have BRG (which gives the bearing to the waypoint) and TRK on display.

I find TRK the single most useful output from a GPS, as it takes away all the uncertainty of drift. As you say, DTK and TRK is not a lot of use, but BRG and TRK aligned can tell you that you're going the right way, and, if you diverge from your intended track, what you need to do to get back there sensibly.

I've never understood why anyone with the choice of a CDI or a moving map would choose the CDI, but I realise there's not the luxury of a map with all equipment.

I don't think that the anti GPS stance of the CAA has anything to do with it being an USA system, as has been suggested, after all VORs and ILSs came from the states. There MAY be an issue that the USA can downgrade the accuracy (or even switch it off) at any moment.

However, I think that the real problem is that it is very easy to jam the very weak GPS signals over a small area, i.e. the approach path to a major airport. I guess the tests that were carried out this weekend were to access the threat.

Also I would hate to do an approach to the minima with a display that only updates once a second!

Its very easy to block an ILS....just park another aircraft in an ILS critical area, and there you go :D

If the GPS signal fails or is switched off then an aproach aproved GPS unit will put up a nav fail flag just like if the signal fails on an ILS or VOR ,this is more than we can say for the CAA aproved NDB aproach !.

'BRG' and 'TRK' will get you to your turning point if you're off track - not necessarily back to your planned track. You may as well just press 'Direct to' if that's all you want to do! 'DTK' and the CDI bar remind you of the original planned track and show relevant cross-track information relative to it.

I specifically asked my radio shop to source a GPS150 and 2 GNC250s rather than something with a moving map to reduce 'head-in' time - and to stop student pilots being seduced by GPS. We train our students to be able to read off GPS range and bearing from their home aerodrome if they need it to help ATC find them quickly (the default waypoint is user-defined as our home aerodrome). We do not teach 'GPS for naviagtion' to non-licence holders

However, that was before the advent of kit like the Garmin 430 which is in a rather different league!

A difficulty with trying to use the built-in database in a 430 or 530 to check a procedural Instrument Approach is that the database only contains the Cat C/D procedures. The outbound track for Cat A/B is frequently different. Does anyone know if the GPS approaches in the states have the same tracks for all aircraft cats?

In answer to your question...yes, nearly all do have the same tracks for the various aircraft catagories.

Was just quoted an install cost for a Garmin 530 of $13,200...very tempting indeed. Puts my King KLN89B to shame.

Have done over 50 GPS approaches to date...all 'spot on'. The FAA releases approximately 6 new GPS approaches per month.
And...are now considering LORAN approaches as well, as a back-up for GPS.:D

I'm not going to vote either for or against - the GPS is an amazing piece of kit if used correctly .

First scare I had with it was listening to an R22 helicopter, which was talking to London Information.

Pilot asked for weather at Gloucester, FIS read it to him - it was cr*p. Fog. When asked for his position and intentions, pilot (term used loosely) informed FIS that he would "have a go at finding Gloucester" - but was not 100% sure of his position due to being IMC (in an R22)....but the GPS was telling him that he was tracking down a valley between mountains.

Second encounter was hearing a Bonanza, talking to Miami Center. I had heard the aircraft come on frequency and declare his route as Ft. Pierce to North Palm Beach - a magnetic track of approx. 170 degrees.

Miami later called the Bonanza and asked for confirmation of destination and heading. Aircraft confirmed "North Palm Beach - heading 224 degrees". When Miami pointed out that 224 degrees would not get him to North Palm - the pilot (?) argued that the heading shown on the GPS was 224. 54 degrees of drift?

Helicopter pilot (British Army Air Corps - in the Gulf War), turned on GPS whilst aircraft was on the ground at base camp. GPS put their position as 180 kilometers further East than where they were.

Was working with the FAA at a safety meeting and heard two FAA inspectors discussing a previous flight they had taken together. GPS went blank - for forty minutes.....they were grateful it was during the cruise, not on an approach.

Last encounter worth recalling was that of John Steurnagle (Senior bunny with AOPA, USA). His passenger (also a pilot) pressed the magical "direct" button. Read off the track and distance and suggested turning that way......which would have taken them straight into a mountain.

The truly scary thing with GPS is that people simply believe it - with little or no mental picture of what it should be showing.

AOPA (USA) say their main fear is that there is no standardisation of display and controls - even on different models from the same manufacturer.

A truly magical piece of kit - if used correctly.

411A
 

Having used the King KLN 89B and both the Garmin 430 and 530 you may well find that the 89B is a lot more practical to use in the air than the 430.

The 530 with the bigger screen is a lot better as more can be put on the screen and this saves a lot of knob twisting.

If I was re fitting an aircraft avionic stack now I think that I would go for the GNS 530 and a nav/com rather than two 430 units the main reason being that the 530 has the screen space to interface with a lot of kit such as data linked real time WX imformation ,stormscope ,TCAS and may be soon real time data linked trafic imformation.

I,m keeping my 89b in the aircraft for a year or two just to see what happens the 430 from garmin was a big step forward but was very much a MK 1 box the 530 has shown that.

New displys are on the way from King some will interface with the 89B so this may be the way for you to go rather than to rip the whole fit out .

Many thanks A and C, I was going to keep the 89B regardless, 'tis a nice unit (and paid for). The rest of the radios are King Gold Crown and are still working fine after all these years. As you mention, some very nice units in the pipeline, especially multi-function displays.

Well nice to see I have got a bit of a debate going with even a few comments from the day-to-day pilots.

I tend to file IFR for most flights now and even though I am navigating mainly via VORs or under direct vectoring from ATC I still carry a handheld GPS. This weekend was a prime case, 3-up over to France and a cloud base of 700' we were running a handheld linked to a laptop running moving map software, it is actually very accurate. It was also very useful afterwards to checkout track , alt holds, etc during the flight afterwards. It gave us a useful secondary indication especially after we lost the VOR signal and were waiting for the next to come in, we were holding a mag heading.

If a GPS was fitted in an aircraft I would have it switched on and in use, I do not see the point of disregarding a piece of kit that is there to help you. I must admit to being a bit bemused by FFF comment on wishing it wasnt there, there is nothing to stop you having it switched on and ready and waiting - you shouldn't be living on the panel as a VFR pilot anyway :D Dont forget FFF that you can use two radials from VORs to find out where you are exactly on the map also if you have DME equipped aircraft you can again find out where you sit on a particular radial.

As stated previously you should make sure you know how to use one first! I think this is pretty self explanatory though as you would not attempt to track a VOR if you had never been shown to do it first - probably a bit suicidal :rolleyes: , who knows where you would end up... Anyone who would just blindly follow a GPS heading without checking first should not really be in an aircraft, you have your charts, you have all the aids to tell you where you are on that chart - think then act !

Quite right, Julian, you can use two VORs, or VOR/DME, to find where you are on the map. And most pilots who use VORs do this at regular intervals, because it's necessary to have any kind of situational awareness.

With a GPS, however, it's possible to have some kind of situational awareness without attempting to transfer the data from the GPS onto a map. Therefore, the pilots I've flown with who use a GPS for navigation - and I include myself in this - tend not to bother to do so. Thus, their situational awareness is well below the standards of a pilot who uses VORs, or ded reckoning/pilotage.

As for why I'd rather it wasn't there, what I really mean is that I don't like to use it, because I notice my situational awareness decreasing when I do use it. Certainly if I was kitting out an aircraft myself, I'd save myself the money - maybe fit a VOR/DME or two instead if I really felt I had to spend some money on nav-aids. Sorry if I bemused you! :D

I should also point out (again) that the above is a generalisation, and is all IMHO. Of course there are some very good pilots out there who are using GPS, and it's possible, with a bit of discipline, to maintain situational awareness with a GPS that's as good, or better, than without. But see GoneWest's post for some excellent examples of where this hasn't been the case. I don't want to be one of the people GoneWest is writing about, which is why I don't use the GPS in my aircraft.

FFF
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Wow:

I really am begining to feel afraid to fly in British airspace knowing there are pilots who do not use every nav aid availiable to them for situational awareness.

To not use, understand and trust the information being displayed on a GPS is truly difficult for me to believe.

I will be flying from Prestwick to Iceland, Greenland and North America in a couple of weeks. If I do not use the four GPS receivers we have on board can anyone please, please explain to me what form of navigation units I should replace them with?

A.D.F.?......Yeh that is what I will do get rid of the GPS units and put in four more A.D.F.'s :) :)

Cat Driver:
...................
:D The hardest thing about flying is knowing when to say no.:D

Chuck,

You can just DR your way across:D

Sounds like an interesting trip, one I hope to make in the future...

Cheers
EA;)

englishal,
Take it from one who HAS DR'ed across the North Atlantic (destination Stansted, B707-138B ferry circa 1975, LORAN & both Bendix Dopplers went kaput) it ain't fun. If it had not been for Clipper and TWA providing drift data, might have ended up in.....France.:eek:

411A:

At least in France you can get good food.:D :D


Cat Driver:

Chuck - Well said mate! I think the US has a much more pragmatic approach to GPS.


FFF - I see where you are coming from and I agree that when VFR its only right to be fully aware of where you are. There are going to be occasions as stated where you cant judge where you are by DR so GPS is the only way really - even if the dreaded 'Men In Black' are out with jammers! I just think we are a bit backward when it comes to GPS, I think it is a very interesting debate though.

Julian.

Chuck my man

GPS.....pish and tish

I've said it before and I'll say it again....small HB with a pink rubber on the end...... a note pad.......and a sextant.......saved me on more than one occasion.....can't patch flack holes at 12,000ft with a GPS system.

Must Fly.....TTFN

Sdn Ldr Handlebar

S.L.H.:

Great, how about flying the ferry trip with us and we will let you navigate with your equipment.

However what do I do if there is no way to see the sky? ( you know about cloud cover I presume? )
:) :)

Cat Driver: