Who else admits to using GPS as their primary means of navigation ???

[Monocock]

We read so many times about how GPS must be used as a back-up to standard methods of navigation and about how unreliable it is.

I am not ashamed to admit that it is my primary means of navigation and I have 2 different types in my aircraft.

Admittedly, I regularly double check my postion with my map and cross check my postion with VOR's and NDB's etc.

I know that GPS can "go down" and I know that they can give unreliable readings but in over 700 hrs it's never happened to me. I have, however, tuned into the wrong nav aid frequency in the past and I have also mistaken many towns and power sations etc. in the past for the wrong ones whilst purely map reading.

Is it that using GPS as a primary means of navigation means we are worse pilots? If we can use a whizz wheel and navaids when needed then surely we can't be that "naughty".


This is not a provoking or reaction-seeking post, I am just curious to find out who else might feel the same way.

Before my Grandfather died he told me how he was ordered by his CO during the war "not to rely on those new fangled radio navigation aids, they were there purely for back-up to dead reckoning and solid map reading skills".

Food for thought.
:hmm:

[Flyin'Dutch']

MC

You best start saving for your defence lawyer if you ever bust CAS!

Very honest answer but by using GPS (the non approved version) for primary navigation you short change yourself a bit.

I suspect there are plenty of peeps who do just that but it ain't legal.

Even IFR approved units sometimes can lead you astray as one of our friends found out when comparing the CAS boundaries in the database with those on the 'real' map.

FD

[Monocock]

Yeah, but this is my whole point.

There are times when flying en route to somewhere in uncontrolled airspace, where the GPS is set up to give a track to steer and once that is cross-referenced with a fix from a VOR etc, then the track made good is much easier to steer.

I'm NOT saying that I don't use navaids and map reading because I do. My point is that flying straight tracks on long trips is made far easier with the GPS than it is with permanent cross checking of a navaid.

Those who "steer" near to and around CAS with their GPS moving maps will undoubtedly get into trouble one day when it goes T**s up.

[Flyin'Dutch']

Phew,

Good to read that.

I think lots of peeps do just that. Makes life a lot easier than the DR method.

There are still those who don't even want to contemplate using GPS as a back-up.

Take it they share the same genetic make-up as your grandpa's CO, won't use electric lightand think leeches are a good cure for a spot of fever.

FD

[Keef]

Good servant, bad master, I reckon.

On a pleasant VFR bimble, I'll look out of the window but have my planned route (assuming there is one) plugged into the GPS so I can see where I am relative to the pink line.

Out in the wilds of East Anglia, the GPS is a great way of knowing where you are. Flying round the busy bits of the South East, it's VOR every time, with the GPS as backup. That way, eyes can be outside for 95% of the time, with the occasional quick glance inside to check all is well.

Electric light and leeches are far too modern. I reckon coming down out of the trees was the mistake.

[drauk]

I have never understood the "eyes should be outside the cockpit" rationale for not using a GPS. Provided the route is entered before departure then why does using a GPS mean that you're eyes are "inside" more often? I'd argue that it means you can spend more time looking outside, because you can get the information you need (course to steer) from the briefest of glances at the GPS. I believe that if you're navigating an area with which you're not familiar you'd spend much more time with your eyes outside if you used a GPS than if you are having to follow your track on a paper map.

In the event that course needs to take you away from your preprogrammed route for some reason I still think a GPS doesn't require any more "eyes in" time than other methods.

I believe that on balance I am more likely to be sure of my position, go where I want to go and avoid places I don't by using a GPS, so I use it quite a lot. I double check it against what I see (when I can see) and a map, and against available navaids. I suppose in this respect I spend more time with my eyes inside than if I ditched the map and the other navaids. Or I could ditch the GPS. But then I could also save "eyes in" time by not looking at my enginge instruments, using the radio, making notes on a log, etc. but I think, as with using the GPS, the benefits of doing these things outweigh the time cost.

As for the legalities of using a GPS in the UK, I don't see that I have any problems. I always always have the appropriate paper map for the flight and I use it. I always use radio navaids if I can't see where I'm going. I'd never conduct a flight with a GPS that I wouldn't conduct without it.

[long final]

Best thing to happen to GA for years. And I believe a great safety tool. I personally always plog the route and draw the lines, do all the pre flight as normal, but use the GPS as Monocock does.

It makes longer trips much more relaxed, allows more time to scan the air by reducing the time staring at the ground.

Used hand in hand with D/R, Nav aids, etc., I wonder why some people are still so anti GPS.

Every now and again I take a trip with the GPS turned off to make sure that I am still happy with D/R. It works, as we know, but what is wrong with using all the tools available to make the flight more enjoyable, relaxed and (IMO) safer??

LF

[englishal]

I suspect there are plenty of peeps who do just that but it ain't legal.
I'm sure a lawyer would have a field day if you busted CAS and you were navigating by DR and NOT using the onboard GPS to confirm your position :D

GPS is great, I'd rather use a GPS over an NDB any day. In fact I do, if navigating by Navaids and I've got a decent GPS onboard, I'll enter the navaid into the GPS to confirm its position. I've had VORs go tits up on me, and if an NDB goes TU how do you know unless you're id'ing it all the time [which no one does]. So GPS in my book is a very useful, reliable, tool and combined with a chart, you can pin point your position accurately in just a few seconds. In my opinion all student pilots should be given a GPS to carry with them and taught how to use it, then maybe it'd stop many of them getting lost. Ok, you can request a QDM or put a call out on 121.5, but why when there is no need...?

Just my view,
Rgds
EA:D

[A and C]

GPS is always my primary navigation sorce my aircraft has an IFR ( B-RNAV ) GPS fitted , this is mandatory equipment if you fly above FL100 and so I cant see how the head in the sand types at the CAA can claim that GPS is not a primary navigation sorce.

However I do always back the system up with other navigation sorces.

Most Airliners are now navigating with GPS as the first stop sorce of navigation data the FMC then backs this up with DME/DME , DME/VOR or IRS.

It would seem to me that properly fitted and TSO,d GPS unit is just as good as any other type of nav system, However I would not include hand held units as these are subject to all sorts of problems and are no more than usefull toys.

[Keef]

QUOTE

Most Airliners are now navigating with GPS as the first stop sorce of navigation data the FMC then backs this up with DME/DME , DME/VOR or IRS.

UNQUOTE

Those darn tax inspectors at the IRS get in everywhere, don't they! It's a brilliant new concept in infallible navigation, though.


My TSO'd, IFR-approved GPS is only legally useable for primary navigation in Europe above FL095 (or so the paperwork that came with it says). That's not to say I don't rely on it for sanity checking of my route and location: it's quick, accurate, and above all allows me to keep my eyes outside the cockpit.

[FlyingForFun]

Two points:

First of all, when I plan a VFR flight (which I assume is what we're talking about?) my primary method of navigation is looking out of the window. Always. Full stop. You can use anything and everything to back that up, including VORs, NDBs, GPS. In that respect, GPS is almost certainly the most superior navigation aid, if you can be bothered to work out how to use it properly. But none of them is ever a primary means of navigation when VFR.

Second point is that GPS databases can be wrong. There is another thread somewhere (started by me, called something like "French charts, what am I missing", if you want to look for it - the GPS issue was a bit of a side-track) where someone pointed out that there is one particular airway which is missing completely from his, and many other GPS databases. The Wycombe ATZ is the wrong size on my GPS database. And when was your database last updated? If you are using this as your primary means of navigation, you could well blunder into airspace without even knowing it's there, because the database is wrong. Can't see anything wrong with plotting the route out on a chart, confirming that it doesn't bust any airspace on the chart, and then using the GPS in flight, as long as the chart is the primary means of checking the airspace your route takes you through.

FFF
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[bluskis]

I agree with you all.

The airspace boundaries on the Garmin/Jepp data base are confusing, and not accurate enough to rely on.

Plotting on a map, identifying safety altitudes, altitudes to fly at, all the comms info from aeread, airfield plates from Jepp or another.

Enter the route into the GPS, set it to map page, make sure you dont have any entry errors.

Refer to it in flight, as an easy crosscheck on your radio nav. and your piloting skills.

In some areas, and at some levels it helps you get from beacon to beacon which are otherwise out of range or out of sight.

It is a backup when your search of notams failed to notice a VOR u/s.

The only disagreement I have . I don't agree handhelds are only toys, and by inference useless.

[Julian]

Have to agree with EA on this one, I think we are a bit head up our @rses on this one if we are going to look out of the window all day and not use whats there. Why create work for yourself? If your GPS says you should be somewhere a quick glance out of the window to check the 'feature' is where it should be leaves you more time for looking out for traffic and flying the aircraft.

I use GPS quite a but when flying in the US where the are legal. You fly full approaches on GPS. Also try flying over Arizona by map - lots of nothing!!! So GPS is a god send.

GPS data are wrong sometimes but pretty rare. I guess I am the lucky one as not found an error yet. I tend to do my flight planning on a chart and then plug it in afterwards so would notice if something was missing - or I hope I would anyway.

As for currency of the database I have one thing to say to that. If when the GPS fires up and tell you that your databse is out of date you press the 'OK' button and carry on using it knowing you are going to fly IFR or shoot approaches, etc then the best thing you can do is park up and sling the keys in the river as you should not be flying!!!!

[Evo]

someone pointed out that there is one particular airway which is missing completely from his, and many other GPS databases


N866 is a classic. Take a look south-west of NEDUL on the half-mil, and then take a look at the GPS. Many miss it or get the base wrong (it steps down from FL55 to FL35 outside the Solent CTA)

[FlyingForFun]

Julian,If your GPS says you should be somewhere a quick glance out of the window to check the 'feature' is where it should be...Or, alternatively, if looking out the window tells you that you should be somewhere, a quick glance at the GPS to confirm it..... Personally, I'd always go for a quick glance inside the aircraft, rather than a quick glance outside - I prefer to do more than have a "quick glance" when it comes to the outside.

I'm also confused about your suggestion totry flying over Arizona by mapI have. Over most of the state, anyway. All the way from the Grand Canyon down to Tucson, and out into California. Never found anywhere that I couldn't navigate to using a map. The aircraft I spent most of my time flying (Super Cubs) were very basic to say the least. The Piper Arrow I used for longer trips had the standard multiple-VOR setup, but no GPS, and I used the VORs to back up my visual navigation, but still had no problem using the map. (Would have used the GPS for these trips, especially over the desert to the west, if there had been one, but it wasn't necessary.) There are areas where you can't navigate using a map - over featureless desert, or oceans, for example, but Arizona isn't one of them!

FFF
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[iainpoll]

Some really good points, and well put.

I don't own a GPS and have never used one, not because my head is up my a**e, but because I would rather spend the money on hours at the moment. I am also confident in my DR backed up with VOR/DME.

In defence of GPS, I would say the 'head inside the cockpit' issue is a hollow one - next time you fly, plan a DR diversion in flight, I'm sure the amount of 'head inside cockpit' time would scare you to death - it does me!

[LowNSlow]

I plan my routes using NavPro and print out a plog and upload it to my Garmin Pilot III. To compensate for any errors inherent in NavPro or the GPS database, I plot the headings the plog gives me onto my chart to ensure that there are no unforseen airspace incursions etc due to inaccurate databases etc.

This results in a nice neat plog, and an accurate line on my chart which directly correlates with the track in my GPS.

Trundling along VFR with the trusty GPS atop the coaming I can cross check my nav easily between view out of the window, line on the chart and position against GPS track. Easy peasy. :ok: :ok:

I regard the airspace boundaries on my GPS as indicative rather than prescriptive. It's the one's on the chart that count!!

[englishal]

I think there is some confusion with proper "IFR" certified GPS's and moving map funky graphic display GPS's. I'm know you do get FGD IFR certified GPS's as well but.....

An IFR certified GPS has a database of Navaids, airports, intersections, waypoints, and GPS approaches. This is slaved to the CDI thingy, so in fact you can fly a 'virtual' radial from a waypoint. Now MOST of these things DONT move over time, for example it is very unlikely SAM will move in the near future. So even if you dB is a little old, chances are that it will still be good enough for VFR flight. For IFR flight it would need to be updated.

Now looking at my en-route chart I see that N866 is the SAM 207° R, if I want to fly this by reference to the GPS I use a virtual radial from the SAM GPS waypoint [ie where SAM is]. As this is slaved to the CDI it is EXACTLY like flying a VOR radial. I am guaranteed to have DME, ETE, ETA etc all from the GPS unit, and if SAM dies, I can still keep my track. Assuming I'm heading to ORTAC then I create a route along this 207R to ORTAC [ie N866], or even fly a virtual radial off ORTAC. Very handy especially when London info request my estimate at ORTAC. I can just read it off the GPS display. GPS approaches are made up of virtual waypoints, or fixes. You can also fly GPS overlay approaches which are in essence a non-procision approach flown by reference to the GPS rather than the NDB or VOR. I would always back up a traditional NPA with a GPS, if for nothing else to identify gross errors, ie. wrong VOR freq. If flying a ILS I will plug the OM or FAF into the GPS IN CASE something happens to the traditional equipment. If I am flying using VRPs I'll enter their co-ords into the GPS, it seems like common sense to me, especially if I'm unfamiliar.

Anyone who reckons that using a GPS is causing you head 'to be inside' too much, obviously doesn't know HOW to use a GPS properly. Takes no longer to check a position than checking the T's and P's, or using an NDB or VOR, and you should check your T's and P's at least every 15 mins as you all should know [it could be considered bad airmanship NOT to glance inside once in a while].

Moving map GPS's are nice for situational awareness, but as stated you should not rely on them to avoid CAS and the like, the dB is very possibly in error, however the positions of airfields, navaids, waypoints, fixes etc., is very possibly correct. Irv Lee did a great article on MM GPS's and CAS a while back in flyer, circumnavigating Bournemouth Class D and recording the results....

Rgds
EA:D

PS: For handheld GPS's you can download the waypoints for VORs, NDBs, Fixes, Waypoints etc etc., from the FAA's database [this includes europe]. This database is used to create IFR certified dB's so it is accurate. Like most things in America it is probably free to download, though I access it through Aeroplanner.com and download Datachunks. My handleld cheapo eTrek now contains 500 waypoints of all airfields, navaids and intersections etc., within a 300nm radius of EGHH, useful as a backup.

[FlyingForFun]

Now looking at my en-route chart I see that N866 is the SAM 207° R, if I want to fly this by reference to the GPS I use a virtual radial from the SAM GPS waypointAbsolutely. Sounds like a very sensible thing to do for an airways flight. Using the GPS as a backup for IFR flight, as you describe, is sensible even in cases where it's not legal to use it as the primary means of navigation.

However, consider the VFR pilot, who hops in his aircraft, and decides to fly along the south coast to take granny sight-seeing. He doesn't need his chart, because his trusty GPS will keep him clear of airspace. Next thing, he's blundering through N866, because it isn't shown, or has an incorrect base, on his GPS.

Completely different situation to yours, englishal, with completely different consequences.

FFF
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PS - As you may have gathered from my postings on the subject, I'm not an expert GPS user. However, I believe that the scale on my CDI, when slaved to the GPS, shows nautical miles off track. This is different to when it is slaved to the VOR, when it shows degrees off track. It may be possible to show degrees off track if your waypoint is a VOR, I don't know, I've never tried it. This isn't a particularly major issue, but I only raise it because englishal is implying that the two methods are directly comparible, whereas it may be that they're not.

[englishal]

Yea it is XT error [nm], not degrees. But sensitivity changes with distance so it ccould be considered an angle of sorts. Ok, rephrase to "Similar" :D

In my example, I am assuming a VFR pilot crossing the channel at 3000', ie. under the airway. But likewise you can create a virtual airway along the S coast, with reference to your chart of course, designed to keep you clear of CAS. Flying WITHOUT a chart is probably a criminal offence.

I guess my main point [but I got carried away, a danger of ppruning too much :D] is that GPS is a very valuable aid to nav, if you have one, know how to use it, always carry a chart and backup all forms of nav with an alternate [visual, traditional navaids].

Cyer
EA:D

[Mike Cross]

It depends on how you define "Primary", and there's a difference between "Primary" and "Sole".

I agree with FFF. If you are VMC you should be looking outside and glancing in. Your primary means of navigation is your eyes and the map. You may have one or more secondary means of navigation, be they VOR/DME, ADF or GPS which you use to cross-check.

How do we keep in a straight line in VMC? I suspect most of us do it by picking something in the distance that is on our track and heading towards it. We may be following a compass course or a radial or a GPS track but our primary means of navigation is visual, cross-checking with our nav-aids. We are not concentrating on the nav-aid with the occaisonal glance outside.

My aircraft has no radio nav-aids so I mark my track on the chart, work out a PLOG and navigate visually. I use my hand-held GPS in a bracket as a cross-check. I put the route into my GPS and am therefore able to quickly and easily check whether the wind is as forecast or if I am being drifted to one side. This enables me to fly far more accurately. If it packs up I can happily continue without it.

The "GPS as Primary" premise is a bit of a red herring really. If you plan to fly using traditional radio nav-aids you can screw it up just as much by not plotting the route on the chart and not keeping up to date with your current position.

Mike

[Potter1]

Just an observation, going back through Monocock’s threads I'm slowly coming to the conclusion that HE/SHE is a CAA Safety Inspector…….:ooh:

It’s lucky this is (mostly) an anonymous forum.



P…

How far can I get on 50ltrs:ok:

[Mike Cross]

Avgas or Stella?

Mike

[Potter1]

Doesn't matter, at my local field there about the same price.

:{

P...

[Julian]

Yep, you should always have a chart - as you should check its a IN DATE chart. Much like checking the date on your GPS Db.


FFF, I can see what you are saying and whichever way you work in/out or out/in you are still utilising your GPS. You of course have your chart there if things go t1ts up. I loved flying in AZ did LGB to Scottsdale but we did it at night - absolutely no features at all so GPS came in very handy. Turned into a $1000 steak :}

I havent seen EAs FAA Db but if anyone finds it freeware then would be very interested to know the details.

[IO540]

Monocock

Almost everybody who flies modern planes uses a GPS as primary. In VMC you might map-read as a check. In both VMC and IMC you can use VOR/DME and that is probably more sensible than visual navigation anyway because so many wrong surface features look like you expect them to.

There are few if any failure modes in a decent GPS (e.g. a GNS430/530 or a KLN94B, etc) which would allow you to fly a completely wrong track without it being obvious. But these things are easily done with the other nav methods.

With all respect to WW2 bomber pilots and dead reckoning, most of their bombs ended up many miles from the target, until the pathfinder squadrons came in later. Dead reckoning etc is OK if there are fairly regular features to check your track against.

Flyin'Dutch' & FlyingForFun

Yes, the GPS database can have wrong airspace boundaries and some airways are missing or shown as just a line. But that does not matter because one plans the flight on the printed chart and then loads the flight plan into the GPS, and checks that the GPS displays what you drew on the chart. One then tracks the GPS track, by adjusting the heading so the displayed track line lines up with the desired track. The heading can be maintained manually by reference to the GPS or by reference to an HSI driven from the GPS, or with an autopilot which tracks the GPS track. You get precision navigation, with very low workload (enabling you to spend more time monitoring everything, looking out, etc) and with very little possibility of making a gross error.

You also get something else: more enjoyment of the journey.

In this respect a good handheld unit is just as good.

If the airspace boundaries on the GPS database are wrong that might matter only if you are messing about up there, doing general maneuvres and relying on the displayed boundary. Normally that's OK but it is wise to tune in a DME or such to double check.


But this debate will go on for ever. Bringing GPS into GA as a basic skill would mean changing the ICAO PPL syllabus and make GPS installation mandatory in training planes. The flight training business will always lobby against anything which makes PPL training look more costly. There are far too many people in positions of influence who haven't flown for years and if they have, e.g. instructors, it is in something very old, and with most of the GA scene operating very old planes anyway, and having no money to change even if they wanted to, there is little that can be done. I don't predict anything will change in the next 20 years as far as legality at the basic level is concerned, though by then the average C152 will be 40-50 years old!!

[FlyingForFun]

Julian - fair point, I was assuming day-time. At night, things are slightly different. I didn't fly north of Phoenix at night when I was in Arizona - the club I was renting from wouldn't actually allow this unless you have an IR, which seems sensible.

IO540 - a couple of points on your post. Your method of plotting your route on a chart first, then programming it into the GPS, sounds fine. How do you deal with the "taking granny sight-seeing" type of flight that I described earlier? Or an in-flight diversion?

Also, I'd contest your statement that "You also get something else: more enjoyment of the journey." We're all different, we all want different things out of our flying. You obviously get more enjoyment out of this type of flying, and that's fine. Personally, I don't. I prefer having to identify ground features - it keeps me busy, makes me more aware of my surroundings, and generally makes things more interesting. Both of those are fine, so long as neither of us tries to generalise and say that everyone will find our method more enjoyable than the other.

FFF
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[bluskis]

IO540

Could you clarify a couple of points.

Why would/should GPS be added to the PPL syllabus? Autopilot operation is not.

You appear to think 20 year old GA pilots are streets better than 40 year old GA pilots, I don't thing there is much evidence for that either way. How are you basing this opinion?

The UK air fleet and the US airfleet is and has always been of a certain age. Look at production figures cf fleet numbers.

This has never stopped airplanes having updated avionics.

What is stopping updating by many people at the moment are the following,

Constantly shifting specifications of what is required, re S mode, FM immunity, GPS validity, frequency splits , the high price of approved GPS units, the bad operational history of these units, units that have been offered to GA as approved, only to turn out they are not, at least in Europe,and possibly not least, the bureauratic difficulty of actually getting and maintaining a full JAA IR.

The blame you appear to lay at the door of old and impoverished pilots would be better laid at the door of the authorities who appear to have undisclosed reasons why they cannot go down the path the FAA have trodden.

[IO540]

FlyingForFun

Fair point. I too fly "for fun" a lot of the time, just doing a "local". None of this is incompatible with using a GPS. A diversion isn't a problem; if you want to go off a bit to have a look at something, you just go and then return to the original route (displayed on the GPS moving map). I do that all the time, either to look at something, or to divert around some airspace to save yourself descending for a bit, only to climb again later. However if you do general flying around then you do end up relying a lot more on the airspace boundaries shown on the GPS map; one tends to then check them against the same shapes on the chart but a subtle error in the database (e.g. a TMA line shown 2nm off) might not be picked up if the general shape looks right. But I've never come across this.

Obviously if you have only the very basic GPS, no moving map, then this sort of thing is difficult and I personally would not touch one of those with a bargepole. A decent GPS costs about 5 hours' airborne time.

I think one gets more enjoyment if the basic navigation is taken care of, so you don't have to time each leg and carefully identify the appropriate ground feature at each waypoint - remember that if you get to a WP and cannot find the expected feature (which could simply be because it isn't easy to see) then you've got a serious problem to deal with, and it's no good just pretending it is probably down there somewhere... Not the sort of thing you want to do with passengers especially.

bluskis

"Why would/should GPS be added to the PPL syllabus? Autopilot operation is not" And neither is how to fly over mountains, or land on lakes. We are talking about GPS usage here, i.e. navigation. There is a good case for bringing in GPS at PPL level, in my view, though I accept there is no way it will be officially approved in the foreseeable future.

I think that unless GPS is fully brought in, one will always have most of the instructors going around spreading tales of how easy it is to get lost with it, etc. and if you buy one, post-PPL, you keep it in your bag whenever one of your old instructors is about :O

I have re-read my post and can't see a comment about pilot age; I don't think this comes into it at all anyway. I am over 40 myself.

I do disagree with most of your reasons for the general lack of upgrading. I have met too many pilots and owners to believe that, and I own my own plane too, not a cheap one. Yes you could fit modern avionics into a 30 year old plane but the stuff would cost more, perhaps double, than the whole plane is worth. Like gold-plating the bathroom taps in a council house, you lose most of the investment when you sell. Schools don't upgrade (no perceived need to, and usually no money), syndicates don't upgrade much (usually most members fly VFR only and won't agree to pay; I've met a number of people trying to offload their shares because of this), most owners are too cash strapped and understandably don't want to waste money for the reason given. Decent avionics are very expensive, a rip-off for what you actually get. But a good non-BRNAV GPS doesn't cost much; eg a KMD150 which is a pretty good big colour panel-mount unit is about £2.5k. Money itself isn't the problem (which is why the American GA fleet is just as decrepit as the UK one); it is the fact that spending it on an old plane is mostly a waste.

Also most avionics is very poorly constructed. If, like most people, you park outside, after a UK winter you are likely to get some items not working, and if these things cost £2000 to fix you won't spend the money again. I have flown in a number of planes which were at some point (usually when in the original private ownership) in the past fitted with very good stuff but the stuff was not repaired once it failed. If you want good avionics you really ought to have hangar space.

You are absolutely right about the IR stuff. Something ought to be done to make a PPL/IR a lot easier to do. But at least we have the IMC Rating which is a lot better than nothing. But then not many frequent instrument pilots fly self fly hire aircraft... so back full circle.

[Timothy]

If you use GPS as a backup (whether en route or in an approach) and the two readings diverge, which do you believe?

In my real experience, every time this has happened, bar one, the GPS has been right and the radio aid wrong.

The one exception was when I had managed (in an old clunky first generation hand-held, long since discarded) to press the keys in the wrong order and enter a Longitude of 000.00 instead of Fairoaks (about half a degree W) and the GPS told me to fly into LHR zone (which of course I didn't because I used OCK and WOD as well.)

But every other occasion (including when Alan Mann wired my HSI to give reversed sense readings, on both VOR and ILS, when night and coastal effects have bent Shoreham's 03 inbound by 30deg, when the ADF has failed, when the OBS was out by 5 deg, when the DME has failed etc) the good old panel mount IFR approved BRNAV Garmin 155 XL has just plodded along and told me exactly where I am and where I should go next.

As the first error is very unlikely to happen in a modern GPS (in those early days there was no database and you just had to put everything in by Lat/Long, which was a disaster waiting to happen) I can think of no reason on earth not to use GPS as the primary source, properly backed up by visual or radio navigation.

There is this spectre held over us that the military can distort or switch off the signal at will, but that happens far less often than convential aids failing.

No, it seems to me that the CAA's refusal to acknowledge GPS as a primary source (properly backed up by other sources) shows an inate and deep conservatism that has been responsible for this country falling behind in so many different fields (not least the jet engine.)

W

[alphaalpha]

To answer Monocock's original question, I do use GPS as the 'first' navigation tool after having preplanned the route and drawn it on the paper chart. VFR navigation is confirmed by looking out at ground features, IFR is monitored by conventional navaids, VOR, DME, NDB, which is the wrong way around, but works very well indeed (but see below).

To add a few new points:

Yes you need to keep your GPS database up to date and be aware of its limitations, eg reviewing the Jepp website for notams. But how many pilots review the CAA website for changes to their half-million charts since publication? There are an awful lot of controlled airspace changes in the Liverpool and Newcastle areas which were not shown the the Northern chart until it was reprinted recently.

I am very much of the view that there is a need for training in the use of GPS for both VFR and IFR pilots. This should cover both the 'how to do it' aspects and the gotchas. It should be post ppl, as this is the stage that it will be most usefully applied, as the new ppl starts venturing off on his/her own cross countrys.

Another Gotcha: I flew right seat IFR into Annecy last year. Annecy has an ILS and an NDB a few miles from the airfield and on the ILS approach. Annecy is in a mountainous area. Both navaids have the same ident 'AT.'

You have proably guessed what happened. The local approach controller gave us an unexpected routing, increasing workload. We punched in 'go to AT.' Saw the choice of two, selected the first one which had the on screen legend 'Annecy France.' And headed off for the ILS AT (which was on airfield) instead of the NDB AT. We were descending in cloud. However the P1, saw the ADF needle was pointing 30 degrees to the right, realised something was wrong, and we were soon sorted out. Believe me, a very easy mistake to make in a single pilot IFR, high workload situation, and a mistake that would not be made using the conventional radio navaids.

Finally, in my opinion, one of the biggest advantages of an aviation GPS, especially with moving map, is the excellent situational awareness it fosters. A big help in IMC, when a glance at the screen saves a lot of brainpower just when you need it most.

One poster said 'a good servant, but a bad master.' I agree, hence my plea for training.

AA.

[englishal]

Once flew an approach in the states, ILS with freq something like 112.4 Instead we dialed in 114.2, which just happened to co-incide with a nearby VOR [on a hill]. Everything happend very quickly, vectored onto the "localiser", forgot to ident it due to work load and inexperience, and then wondered why the GS wasn't coming in. Luckily had the GPS set to the airport, realised we were heading off at a tangent, corrected and survived :D

You live and learn!

EA

[Timothy]

EA

This is exactly my point. There are just as many "gotchas" in the world of traditional Navaids, it's just that the old codgers at the Belgrano know about them and have written many publications and training manuals about how to avoid them. On the other hand GPS is just too new for them.

It is just as easy to misdial an ILS freq as it is to enter the wrong waypoint, and not identing is about as serious and reprehensible as not checking the range and bearing the GPS produces. It's the same pilots making the same errors and ommissions. The technology is secondary.

W

[IO540]

WCollins

Very well put. Worth mentioning that if you flew the 21 EGKA approach instead of the 03 one, down to IR minima, and the ADF was about 20deg out, you would be about 150ft below nearby terrain, and would not be writing about it :O I am not sure one would spot that the discrepancy between the ADF and one's actual heading was rather more than would be accounted for by the wind.

As to the question which one to trust, I once put this to an old ATPL instructor. I asked him, if an ADF told him he was in the right place, and a GPS told him he was about to die, which would he trust. He said he would trust the ADF because it's the proper instrument to use for the approach.

Personally, I would divert to some place with an ILS. I've seen an ADF point about 100 degrees out, due to a storm which I knew was some 20 miles away. Exactly the time you might be doing an IAP down to minima...

[Zlin526]

GPS? Never used one. I find a chart & compass works well, and doesnt need endless supplies of batteries.

[rustle]

IFR reality - (IFR approved) GPS plus other conventional aids;
IR renewals - conventional aids only :rolleyes: ;

VFR: chart and GPS -- or GPS and chart - depends who you ask...

[Timothy]

Rustle

My IRE lets me use GPS (and indeed autopilot). He takes the view that a competent IR pilot will use all the equipment at his or her disposal, and that he would rather check that I use it safely than check that I can use one set of kit on test, then know that I am going to fly using different technologies.

He certainly expects me to back up the ADF with GPS. I think that his expectation would be that if they differed by more than 5deg I should perform a missed approach and decide, at a safe altitude, where the problems lies, and then shoot a safe approach, if necessary somewhere else.

But this guy is a solid sensible safe IRE!

W

[bookworm]

Worth mentioning that if you flew the 21 EGKA approach instead of the 03 one, down to IR minima, and the ADF was about 20deg out, you would be about 150ft below nearby terrain, and would not be writing about it I am not sure one would spot that the discrepancy between the ADF and one's actual heading was rather more than would be accounted for by the wind.

I don't think it's quite that bad. Inside the 1200 ft stepdown fix at 3d, there's no terrain above 800 ft, and inside the 800 ft stepdown fix at 2d there's no terrain above the MDA of 700 ft.

You'd need to have both the ADF and the DME lying to come to grief. Of course, it makes good sense to have a close eye on the GPS throughout!

[Julian]

Wcollins,

Interesting point. When I took my IR Flight Test my instructor told us that the examiner would expect you to use the aircraft to its full capacity whilst reducing your workload - therefore if you had GPS and A/P fitted you would be tested on them - HOWEVER - You better be 110% clued up on them because if you made one screw up he would fail you.

Hence why he always used to pull the fuse and stick an INOP lable on the kit for the flight test.

[englishal]

therefore if you had GPS and A/P fitted you would be tested on them
Quote from the examiner on my IR test after he noted the INOP sticker on the AP and GPS:

"Why is this GPS and AP inop now? It was ok this morning when I was flying the aircraft"

:D

[Genghis the Engineer]

A passing thought or two...

- It does appear that there are two issues here?

(1) Should the GPS be used for primary navigation? probably. Should it be used for sole navigation? certainly not.

(2) Should the GPS be used for primary flight planning? never!. Should the GPS be used to check chart based flight planning, why not - probably a good idea.

All for excellent reasons given by my esteemed colleagues above.

G

[Circuit Basher]

Genghis - I reckon I could be sold on those statements! Neatly summarises the 'P1$$ poor planning produces p1$$ poor performance' approach (ie) Use most accurate information available for planning and factor in all valid information available in flight, cross-checking continuously and disregarding spurious information.

[vfr-uk]

great post monocock.

I had also added my own rant about GPS and related things here, and was pleased to see I'm not the only one who is ready to move on with technology.....

http://www.pprune.org/forums/showthread.php?s=&threadid=95225

[mad_jock]

I have always suffered from the can't be arsed factor learning how all the knobs need pushing. Seem to manage fine getting from A to B using mark one eye ball and VOR/DME's, ADF's

I can just work out how one of the garmins work and dial in a COMMS/VOR freq but thats about it. If a map comes up fair do's but because i am not used to using one its not in my instrument scan so after 5mins I forget its there.

Can't afford to buy one myself so won't put the effort into learning the kit for one ferry flight.

MJ

[flower]

Hands up i'm not a pilot so maybe my opinion doesn't really count here

Mark 1 Eyeball ,Chart and compass best tools a PPL can have , absolutely agree.

So you brief correctly , check all the weather charts everything seems fine for a lovely days flying. For those of us living in the UK we are all aware however how quickly the weather changes. You suddenly find yourself dodging showers, and in doing so maybe you lose your "fix" on the ground, you are trying to steer clear of cloud as your licence says you must, uumm where am I??

Maybe ATC have requested you take an alternative track , maybe just 10% off what you had planned, then say" to resume own navigation" without advising you of your exact position, uumm where am I ??

This is where GPS should be used to check your position.

Having GPS as a back up tool is a safe option, it should not when flying VFR be used as a primary tool of navigation but as a backup and inparticularly as a piece of safety equipment. I think it is an excellent tool to have onboard your aircraft.

Technology is for our benefit, im sure I could encounter a few elderly retired ATCOs who think controlling was better when we didn't have Radar or Secondary Surveillance Radar.!!!

Chart , Compass and Mark 1 Eyeball, GPS as a backup tool

[Timothy]

Maybe ATC have requested you take an alternative track , maybe just 10% off what you had planned, then say" to resume own navigation" without advising you of your exact position, uumm where am I ?? Flower

ATC will always tell you your position under these circumstances as part of the "resume own navigation" instruction and if they forget you can ask.

When I was a very young and inexperienced pilot (oh! happy days) under these circumstances I would even ask to be put back on my track, and ATC obliged.

W

[flower]

WCollins

For your Info I am an ATCO of 14 years experience I am well aware that we tell you your position , but I am unable to give you an exact position try as I might unless you are over a reporting point. I am only able to give you a best guess . My radar screen has limited information on it so as not to clag the screen up.

So I will say approximately 13 miles SW of etc.

If pilots were happy with Lat and Long I can give them there exact co-ordinates but I find most do not want that info.

As an addition to my previous comments I have experienced Pilots getting lost very quickly, so to have a quick check on GPS may have even averted one tragedy that is close to me. :sad:

[Genghis the Engineer]

Thing is Flower, the modern GPS is astoundingly user friendly. You can program a route in and contentedly follow it from A to B, via C, D, E, F...Z if you wish. This is of-course whilst it's working properly - they can occasionally drop out altogether (I find this is a particular problem myself when just under an overcast, or in particular aircraft types using a handheld).

So you can fully understand anybody wanting to use it for primary nav. Compared to using other radio navaids, or even careful Ded-reckoning it's very low effort freeing up effort for lookout, enjoying the scenery, etc.

I think that the main problem, as I suggested earlier, is pilots who use it for sole navigation not checking it regularly against other navigational tools, whatever they may be.

The secondary problem is when it is used for primary flight planning - GPS airspace databases are notoriously inaccurate, may often not contain very helpful height information where airspace is concerned (oh yes and airspace heights are always based upon pressure altitude, not GPS altitude which is geometric - so even if a GPS does give that information it can lead you astray). However, it's a very good route calculator so useful for double-checking times / headings / distances on a route that has already been manually plotted and confirmed to go the right way and not anywhere you shouldn't be. It can also do a good job of direct diversion planning in the air (with the obvious proviso of checking the airspace manually).

G

[flower]

Genghis

Fully understand your comments, I am a great believer in Technology and using what is available, im no luddite far from it.

Just have reservations, great reservations about it as Primary navigation tool.
Maps, Charts ,Eyeballs very seldom let you down, and if you get to reliant on such an aide what happens if /when it fails.

[Andrew Sinclair]

For me the actual flying day is only half the aviation hobby. The flight planning, airfield research, plotting the track, calculating the heading from the winds aloft with the slide rule, checking and plotting the NOTAM on my map is the other half and I spend hours, sometimes over days doing that part.

I have two GPS systems, one panel mounted and the other of the moving map variety which has a track recorder in it. The best use I have found for it is to replay the flight afterwards to see how close to the pre-planned track I was during the flight.

Excellent technology, no doubt in my mind about that, but it would take away some of the fun and challenge for me.

Just a thought, but each to their own......

[slim_slag]

Ghengis,

If I'm flying a VFR cross country in the US which goes further than a couple of VORs I'm going to be flying the airways. When I'm doing that the only flight planning thing I really care about is whether I can reach my destination with the fuel I start off with.

I don't care about airspace because I am allowed in anything below 17,999 if its on an airway, and in most places I can climb above the rocks. Sure, if I am in the Rockies I might have a problem, but a quick scan of the VFR sectional will tell me which VORs to plug into the GPS.

Program the airway route into your GPS and you know roughly when you run out of fuel. Apply your personal "feel good" factor to that, and you have a route with places to start looking for fuel stops.

It's basically IFR without a clearance. I could easily fly it using an IFR en route chart, the lines are drawn for me. If I was VFR over the top I may as well use the IFR en route chart. So would flying x countries on airways be an exception to your "never" use a GPS for primary route planning?

(Sure, I know you cannot fly airways so easily in other parts of the world, but this site crosses frontiers)

[Genghis the Engineer]

Slimslag - my argument is not that you shouldn't program your route into your GPS, but that you should be using some other means ALSO. The obvious means if you are programming a VOR for an airways routing into your GPS, is to program it into a VOR receiver as well! Also you may be less worried about flight into class A, B or D airspace than we are here - but I'm willing to bet that if flying IMC you do want to know your height relative to the nearest cumulo-granite, and a chart will do that better than your GPS.

Flower - charts and eyeballs do let you down - it is very easy at a few thousand feet for one town to look like another, two roads on similar headings to be confused or the shape of a lake to not be quite as it seems on a chart. I emphasise that I'm totally against GPS for sole navigation, but equally pilots (sometimes very experienced ones) occasionally get things wrong when flying by visual navigation alone - the more data inputs we take and compare the better a job we're likely to make of it. By primary all I mean is programming the route into the GPS, following the needle on the display, but confirming satellite signal and cross-checking to VOR/visual/NDB/whatever's available every 5 minutes or so and then reverting to those if the GPS is leading you astray.

(Just as an aside, how many times have you and other air-trafficers asked "have you XXX in sight" when a pilot is, over, 10km away and the TAF shows viz of under 10km?" - have you ever tried navigating accurately and visually in minimum VMC, we do it, but you need all the help you can get.)

G

[slim_slag]

Genghis,

Slimslag - my argument is not that you shouldn't program your route into your GPS, but that you should be using some other means ALSO.

You made two comments.

"(1) Should the GPS be used for primary navigation? probably. Should it be used for sole navigation? certainly not."

I agree when flying VFR, which is what we are talking about. When flying airways VFR, I would use my eyes (when I had visual references of the ground), the VOR (if I have one), and a GPS. I would not fly VFR over the top without a VOR/DME, and more recently a GPS. I just don't trust paper and pencil when I cannot see the ground and I am up there with a finite amount of fuel.

I was asking about your point

"(2) Should the GPS be used for primary flight planning? never!"

Never???

I think your point about low visibility is a good one. Many years ago when the 3 miles limit was set, there were not things sticking hundreds of feet out of the ground and little controlled airspace. Nowadays if you are in low vis ops, congested airspace and close to the ground a GPS is pretty much essential kit. It's not about being a crap pilot because you cannot navigate using the stars and a sextant, it's about staying alive.

[Genghis the Engineer]

(1) Amplfying the point slightly, what I'm saying is that you shouldn't use a single source of information (except possibly clear sight of familiar terrain) for navigation. You seem to be agreeing with me in your statement about VOR/DME. Even when flying visually we also normally use a compass and /or HSI - a second source of information.

(2) Never, until GPS databases contain fully accurate and updated airspace and terrain information, including height data and also allow wind / drift calculations.

G

[flower]

Ghengis,

WhenI sit down in position I am fully briefed and that includes the Weather.

If a pilot is lost I can take all sorts of actions to help, but to ask them if they are visual with something further than the reported visibility I really should be reassessing my position as an ATCO, thats plainly ridiculous, if you have encountered this I suggest a phone call to the unit concerned after landing.

If you read my original post you will see I agree with you , GPS helps you find your position should you become disorientated , lost etc, However I disagree about charts letting you down , if you have an upto date chart the thing that has let you down is not the chart its simply you have become disorientated and that is where I believe GPS is an excellent tool.

I am well aware how different things look from the skies, although I do not possess a PPL myself I have a few hours under my belt and have flown many times in Light aircraft, the benefit I have here is that I have hundreds of thousands of hours controlling traffic , have seen more incidents with GA aircraft than I wish to and know full well that this afternoon too I am likely to encounter GA with various problems such as unsure of there position.

Genghis I know this is where we speak with one voice , You should never rely to heavily on one tool to navigate , all forms of navigation shoud be regularly exercised by the pilot.

Taking this post back to my ATC roots, we have every piece of equipment going to help us do our job as safely and efficiently as we can, excellent radar, DRDF etc, but the fail safe procedure that we have as ATCOs are paper Flight Progress strips, with details of all aircraft we are controlling in front of us, we move these paper strips around are active bays , we write on them stating exactly what we have done with them , headings levels , speeds ,, positions. Why do we as ATCOs not want to lose these paper Flight Progress strips, well if all else fails we have them in front of us, power failures , computers crashing , radar failures, we can still keep controlling aircraft with these simple pieces of paper and keep you all safe.

The same applies IMHO with charts ,compass and Mark 1 eyeball

[slim_slag]

(2) Never, until GPS databases contain fully accurate and updated airspace and terrain information, including height data and also allow wind / drift calculations.

Wind is easy to knock off, that's not part of your primary flight planning. Winds aloft are only known when you are aloft, that is part of the en-route flight planning which never ends until you reach your destination. Get the weather before you depart of course, and consider forecast winds aloft, but I don't care about them when deciding whether I am going somewhere.

I'm pretty sure GPS systems have airspace and terrain information. Even so, it doesn't matter. When I primary flight plan over some distance all I care about is whether my route means I can reach my destination with fuel in the tank. Apart from the Rockies, I can climb above any terrain. If I am going some distance I will want to get high anyway because it's more efficient. If my planning changes due to weather (secondary route planning) or en-route conditions (tertiary route planning) then I will look at the chart again. These are my definitions of route planning, YMMV.

You might find GSP route planning difficult in the UK. In other parts of the world, your "never" does not apply, IMO.

[englishal]

Well if every light aircraft had a $100 GPS linked to a $100 radio transmitter, transmitting the lat and long every second, and every light aircraft had a box which received these [low power] transmissions and worked out conflicting traffic information, for under $500 / aircraft you could do away with LARS, MODE S, and a whole bunch more. Now if ATC could receive these trasmissions, why is there any need for Radar?

EA:D

[slim_slag]

EA,

I think that's the basis of the free flight project. No Mode S though, I think the FAA are going straight to ADSB. Mode S is not a sensible way to proceed for us little boys :) You will still need controllers exercising control in terminal areas, but in the en-route structure the computers will do it all. I doubt radar will disappear, but controllers will be monitoring more. Or that's what I have heard.

Genghis,

Just a final word. Have you used Duats in the US? This has a nifty little flight planner, you enter your origin, destination, planned altitude and whether you want to fly via low altitude airway structure. There is also a little check box which says something like 'no wind flight plan'.

When I fly the airways further than a couple of VORs away, thats what I use. It works out my route, and tells me time and distance without wind. Thats all I care about when primary flight planning. I also get the weather but only for the 'big picture'. I'll also look at the chart, but I will not go near a pen or paper to flight plan.

If I decide to fly myself and not take Southwest Airlines which is what I normally do, before I leave for the airport I get the latest weather, NOTAMS, then print out a 'with wind' flightplan. That's what I use until en-route conditions cause my flight plan to change. You don't know what the real flight plan is until after you land.

Duats is just a black box of navigational points, it could easily have a GPS behind it. That's what I and many other people use for primary flight planning for a certain percentage of flights.