ADF v. GPS
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Above The Clouds
Your reply/question is awfully mixed up, mixing "company manual" (AOC type) rules with old aviation chinese whispers.
So let me ask you for a reference for
Who actually said so?
mm_flynn has got it right (as usual).
Moving onto practicalities and safety (rather than legalities) there is a load of things one should or should not be doing e.g.
- using waypoints with hand entered coordinates (unless somehow verified beforehand) is not a good idea, especially in a shared aircraft
- one should still fly the published lateral track because the obstacle clearance is based on that
- be careful with GPS "overlays" for non-RNAV approaches, pulled out of the database, as these are sometimes partial-only, with segments missing (which is why I always fly literally what is on the approach plate, using the OBS mode of the GPS, and sometimes use VOR/DME in SIDs because it is simply easier)
Your reply/question is awfully mixed up, mixing "company manual" (AOC type) rules with old aviation chinese whispers.
So let me ask you for a reference for
and we can't do the above legally
mm_flynn has got it right (as usual).
Moving onto practicalities and safety (rather than legalities) there is a load of things one should or should not be doing e.g.
- using waypoints with hand entered coordinates (unless somehow verified beforehand) is not a good idea, especially in a shared aircraft
- one should still fly the published lateral track because the obstacle clearance is based on that
- be careful with GPS "overlays" for non-RNAV approaches, pulled out of the database, as these are sometimes partial-only, with segments missing (which is why I always fly literally what is on the approach plate, using the OBS mode of the GPS, and sometimes use VOR/DME in SIDs because it is simply easier)
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The leaflet you reference is entitled
Flying RNAV (GNSS) Non-Precision
Approaches in Private and General
Aviation Aircraft
which is a different topic to what has been discussed. It does briefly refer to flying other types of approaches using a GPS but as with all this advisory material it is no more than the personal opinion of a person in the CAA. That is not to say it is bad or wrong, but it is not the law.
Flying RNAV (GNSS) Non-Precision
Approaches in Private and General
Aviation Aircraft
which is a different topic to what has been discussed. It does briefly refer to flying other types of approaches using a GPS but as with all this advisory material it is no more than the personal opinion of a person in the CAA. That is not to say it is bad or wrong, but it is not the law.
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Two things -
1) GPS was initially not allowed to be as accurate as it is now. The US military employed Selective Availability (SA) which is an artificially inserted "wobble" in the satellite signal. This meant that the military chaps could clean the signal and have good Nav, while the civvies and the enemy had reasonable but not super accurate Nav.
SA was turned off in May 2000. There remains the possibility that this could be turned back on again. As a result, GPS procedures remained somewhat risky, since they _could_ turn on SA and mess up all the global approaches just like that. However, differential GPS techniques had already started to overcome this problem.
Several things have happened since 2000. For the first 5 years or so, use of GPS tended to be limited to specialist, niche arenas such as maritime and aviation. In the last 7 years, global use of GPS technology has exploded particularly with in-car navigation, but also with multiple uses ranging from stock management to improved emergency services deployment, and these days most people in the western world have some sort of smart phone with a GPS device.
This embedding in day to day life makes it much harder for the US government to make the SA call, since the knock on effect could be a bit of an own goal, not that the US have a reputation for that.
In addition to this, there are now additional satellite constellations coming online which mean that the reliance on US systems is less of a concern, plus DGPS is well developed and reduces most of the SA error.
Both of these factors mean that considering GPS procedures is _now_ a much more realistic proposition.
Actually, imo, the biggest threat to GPS navigation right now is not the US government, but the sun. The current solar sun spot activity maximum and increase in number and intensity of Coronal Mass Ejections - Solar Flares means a greater likelihood of satellites in one part of the sky being knocked out (electronically) for a period of time. If you're unlucky, you could be caught out with reduced accuracy (read up on GDOP for the theory) due to relying on signal from one other part of the sky.
This is a small risk, but nevertheless it exists.
2) Talking about using handheld GPS for navigation, at least one police force I know was using a PDA with Memory Map as a navigational aid in their heli back in 2004. This was in addition to all the usual kit, but velcro'd to the kneeboard the handheld was definitely in use.
I'd rather have everything available to me - GPS, RNAV, and Mk 1 eyeball. 2 out of 3 would be my minimum, and I wouldn't like to lose any of them as a long term option. Just imo.
1) GPS was initially not allowed to be as accurate as it is now. The US military employed Selective Availability (SA) which is an artificially inserted "wobble" in the satellite signal. This meant that the military chaps could clean the signal and have good Nav, while the civvies and the enemy had reasonable but not super accurate Nav.
SA was turned off in May 2000. There remains the possibility that this could be turned back on again. As a result, GPS procedures remained somewhat risky, since they _could_ turn on SA and mess up all the global approaches just like that. However, differential GPS techniques had already started to overcome this problem.
Several things have happened since 2000. For the first 5 years or so, use of GPS tended to be limited to specialist, niche arenas such as maritime and aviation. In the last 7 years, global use of GPS technology has exploded particularly with in-car navigation, but also with multiple uses ranging from stock management to improved emergency services deployment, and these days most people in the western world have some sort of smart phone with a GPS device.
This embedding in day to day life makes it much harder for the US government to make the SA call, since the knock on effect could be a bit of an own goal, not that the US have a reputation for that.
In addition to this, there are now additional satellite constellations coming online which mean that the reliance on US systems is less of a concern, plus DGPS is well developed and reduces most of the SA error.
Both of these factors mean that considering GPS procedures is _now_ a much more realistic proposition.
Actually, imo, the biggest threat to GPS navigation right now is not the US government, but the sun. The current solar sun spot activity maximum and increase in number and intensity of Coronal Mass Ejections - Solar Flares means a greater likelihood of satellites in one part of the sky being knocked out (electronically) for a period of time. If you're unlucky, you could be caught out with reduced accuracy (read up on GDOP for the theory) due to relying on signal from one other part of the sky.
This is a small risk, but nevertheless it exists.
2) Talking about using handheld GPS for navigation, at least one police force I know was using a PDA with Memory Map as a navigational aid in their heli back in 2004. This was in addition to all the usual kit, but velcro'd to the kneeboard the handheld was definitely in use.
I'd rather have everything available to me - GPS, RNAV, and Mk 1 eyeball. 2 out of 3 would be my minimum, and I wouldn't like to lose any of them as a long term option. Just imo.
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I too think the USA is hugely unlikely to reintroduce SA (or some other form of it) because it would be a huge economic own goal.
However GPS with SA (as SA was when we had it) still delivered a navigation accuracy about 10x better than NDB tracking.
Regarding Galileo, I am certain that there is a secret agreement between the EU and the USA whereby EU would shut their system down if the USA shut theirs down (or shut down the civilian signal) as a result of coming under a missile attack (or similar). So the extra protection provided by Galileo, in the already incredibly unlikely event of a US shutdown, is illusory. As in WW2, GA and much other aviation would be banned immediately anyway.
Those who think that conventional navaids provide some magical protection against subtle failures can read this. And this shows the kind of dangerous conventional IAP which might get flown as a result of such a failure. In comparison, with GPS the equipment failure is normally really obvious (with any remotely modern equipment).
However GPS with SA (as SA was when we had it) still delivered a navigation accuracy about 10x better than NDB tracking.
Regarding Galileo, I am certain that there is a secret agreement between the EU and the USA whereby EU would shut their system down if the USA shut theirs down (or shut down the civilian signal) as a result of coming under a missile attack (or similar). So the extra protection provided by Galileo, in the already incredibly unlikely event of a US shutdown, is illusory. As in WW2, GA and much other aviation would be banned immediately anyway.
Those who think that conventional navaids provide some magical protection against subtle failures can read this. And this shows the kind of dangerous conventional IAP which might get flown as a result of such a failure. In comparison, with GPS the equipment failure is normally really obvious (with any remotely modern equipment).
Those who think that conventional navaids provide some magical protection against subtle failures
WAAS and EGNOS require training in the sim.
Lets see how far you get completing a WAAS approach that states RNAV (RNP) or SAAAR on the chart then
So there is no rule against flying an approach marked NDB while looking at your hand held GPS (although you must have a working NDB on board and the navaid must be working). Clearly you still need to follow the flight profile and if you fail to achieve that, you could reasonably by done for Careless and Reckless if you were using something clearly not up to the job.
Better avoid enforcement action by turning off the GPS and providing a nice wandering approach track that ends in the general area of the runway.
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This is a real danger. When the authorities see that you have exactly followed the inbound track with no significant deviations they will know that you have been following your $ 500 hand held GPS track guidance instead of the $ 5000 installed ADF
Better avoid enforcement action by turning off the GPS and providing a nice wandering approach track that ends in the general area of the runway.
Better avoid enforcement action by turning off the GPS and providing a nice wandering approach track that ends in the general area of the runway.
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The simple solution to that would be to create a few user waypoints a couple of miles either side of the inbound track
For extra authenticity you would create a big dogleg at about 2D - 3D, for any coastal airport
But all this work would be wasted unless the airport has radar, or you crash in which case the AAIB will retrieve the radar tapes from the nearest radar unit
For extra authenticity you would create a big dogleg at about 2D - 3D, for any coastal airport
But all this work would be wasted unless the airport has radar, or you crash in which case the AAIB will retrieve the radar tapes from the nearest radar unit
Originally Posted by Final 3 Greens
Say what you will about ADF, it is a great way of finding your local CB cloud.
Originally Posted by Big Pistons Forever
This is a real danger. When the authorities see that you have exactly followed the inbound track with no significant deviations they will know that you have been following your $ 500 hand held GPS track guidance instead of the $ 5000 installed ADF.
Better avoid enforcement action by turning off the GPS and providing a nice wandering approach track that ends in the general area of the runway.
Better avoid enforcement action by turning off the GPS and providing a nice wandering approach track that ends in the general area of the runway.
Actually, the ATC (radar-equipped) expects you to fly exactly on the extended centerline even when flying a non-precision approach. I got vectored back to the actual centerline when for example the both CDIs were centered for VOR/DME approach, since ATC thought I was overshooting the final track - I assumed it's because everybody is always flying non-precision approaches with GPS guidance and using the actual navaid just for backup/monitoring.Although I seriously await the day when one would be punished/warned by the CAA for flying the non-precision approach too accurately (e.g. with GPS) instead of following the needles. I consider the approach flown with GPS guidance to be almost a precision one, since it gets you directly to the runway threshold, mostly lined up with centerline. On the other hand, traditional non-precision approaches get you somewhere in the vicinity of the airport IF the weather is good, IF it isn't dusk/dawn, IF there isn't some electric activity around, IF the airport isn't too close to sea, IF you keep wings level throughout the approach and IF you're VERY lucky, it gets you within +-10° of runway heading.
I really don't understand people who fly approaches with GPS if you can fly much more accurately using the traditional navaids
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IIRC they have done away with the requirement to carry an ADF for all IFR in CAS i.e. enroute. That requirement has been bizzare for a very long time.
But there is no US-style dispensation allowing a GPS to substitute for an ADF.
You thus still need to carry an ADF if you overtly fly an approach involving an NDB - though I must say I have never seen this written, and there has been much debate about it over the years.
But there is no US-style dispensation allowing a GPS to substitute for an ADF.
You thus still need to carry an ADF if you overtly fly an approach involving an NDB - though I must say I have never seen this written, and there has been much debate about it over the years.
