What's more accurate than GPS? Answer INS. GPS is mainly used by general aviation and is only accurate when talking to a fixed base station. Most large airlines still use INS.(a more modern system built into the FMC compared to the old DC). Why do they still use INS? It is far more accurate achieving a course displacement of perhaps only 60feet at 500 kts even with a crosswind component. And, more importantly INS is completely autonomous not requiring satellites etc. Even the first INs's had an error of only 3nm after 15hours of continuous flying! (without any kind of updating). As said modern jet transports use INS and update using VOR fixes or GPS fixes.vololiberista

Wouldn't a waas enabled gps beat even that?"The WAAS specification requires it to provide a position accuracy of 7.6 metres (25 ft) or better (for both lateral and vertical measurements), at least 95% of the time.^[Actual performance measurements of the system at specific locations have shown it typically provides better than 1.0 metre (3 ft 3 in) laterally and 1.5 metres (4 ft 11 in) vertically throughout most of the contiguous US, Canada and Alaska"

Hello everyone.I see that this has become a discussion on individual's preferences. The reality is that many aircraft presently do not have GPSs and there are many issues with that type of navigation, that are likely to get worse before they get better. I've seen deviations in altitude, from GPS information as much as 700 Ft., while in level flight. I've been places where no GPS or any other signal, except ADF was available.We are still required to teach VOR navigation, for PP, and it's not likely that's going away soon.I hope that the day will never come where only one system will be available, or we will all be in deep trouble. To blindly trust only one system, is an invitation for disaster, regardless if you are IFR or VFR. Minimum VFR should be considered, and I always teach / insist on it, to be treated / considered an Instrument navigation, or you will be lost, and likely violate some airspace in busy areas, within a matter of minutes or seconds. You can be as low as 3-4000 Ft. looking down at a road and as soon as the road takes a turn you lost it. If you happen to be in the mountains, or desert, where references are sparse, you are likely to be looking for a long time to find where you are. In the mean time you may have just violated some airspace, or worse FIT. People can easily jam GPS and many things can interfere with the signal.My hope is that one day someone will design an instrument that can navigate any type of signal. We have the technology, presently, it's just not practical, from the cost / profit stand point to implement it. One of the problems I see presently, is the tendency to use up a lot of time trying to set some function up in the modern / GPS systems, and loose control of the aircraft, or maintain the proper out the window scan. TV

Total reliance on GPS for air/sea navigation is an accident waiting to happen. We put too much trust into new gizmos. Just think! when I was a boy I was taught to add and subtract etc. Now so many of us use a calculator that some can only do the simplest of sums in their head. As a trainee pilot all those years ago I was taught all forms of navigation including astral. And, how to recover from an "I'm lost" scenario. The problem with GPS especially for fast moving vehicles aka jet transports is that they are moving fast. As are the satellites. To attain real accuracy there has to be a static GPS receiver in the chain. You have to be able to see x number of satellites, assuming that they haven't been knocked out by a solar flare or by alliens!A good pilot flies by the seat of their pants (they know what's coming and how to make the a/c respond before it arrives at that point). An a/c fitted with INS also flies by the seat of its pants (mechanically!!!) As long as I can direct the a/c over a "fix" or point to a VOR/DME then I know the INS knows exactly where it is and so I know I "will" get home in time for tea!vololiberista

The point has also been made that - Total reliance is an accident waiting to happen :( But I

What's more accurate than GPS? Answer INS. GPS is mainly used by general aviation and is only accurate when talking to a fixed base station. Most large airlines still use INS.(a more modern system built into the FMC compared to the old DC). Why do they still use INS? It is far more accurate achieving a course displacement of perhaps only 60feet at 500 kts even with a crosswind component. And, more importantly INS is completely autonomous not requiring satellites etc. Even the first INs's had an error of only 3nm after 15hours of continuous flying! (without any kind of updating). As said modern jet transports use INS and update using VOR fixes or GPS fixes.vololiberista

In a way, you've got part of it correct, as the INS is ipdated with VOR or GPS. However, it's certainly not more accurate.And yes, the INS needs updates to stay in check. If there is no GPS, the INS will get updates from VOR's, DME, and the ILS. If GPS is part of the FMC, as it is in modern up to date aircraft, then GPS is the first preference to update the INS. Out of the three, INS, VOR & GPS...........GPS always comes out on top in terms of accuracy.L.Adamson

Total reliance on GPS for air/sea navigation is an accident waiting to happen. We put too much trust into new gizmos. Just think! when I was a boy I was taught to add and subtract etc. Now so many of us use a calculator that some can only do the simplest of sums in their head. As a trainee pilot all those years ago I was taught all forms of navigation including astral. And, how to recover from an "I'm lost" scenario. The problem with GPS especially for fast moving vehicles aka jet transports is that they are moving fast. As are the satellites. To attain real accuracy there has to be a static GPS receiver in the chain. You have to be able to see x number of satellites, assuming that they haven't been knocked out by a solar flare or by alliens!A good pilot flies by the seat of their pants (they know what's coming and how to make the a/c respond before it arrives at that point). An a/c fitted with INS also flies by the seat of its pants (mechanically!!!) As long as I can direct the a/c over a "fix" or point to a VOR/DME then I know the INS knows exactly where it is and so I know I "will" get home in time for tea!vololiberista

Your incorrect about the INS being the most accurate (it only is when updated with the GPS), and you're wrong on your assumption how GPS works. There are 24 satellites in addition to a WAAS satellite (which was two until last month). A decent GPS reciever will normally pick up at least eight satellites if not more. It needs four for a good fix, and will throw out any timing signals that don't agree with the others. GPS is not a new gizmo. I've been using them for 17 years. Sure, it's newer than than ancient, has been, relic of the past, and primitive VOR system, but still not new. Either system rely's on electronics regardless. Of course, if your head/mind is capable of looking up any phrase, such as Google can within seconds out of the world wide internet, than it should do well for the timing signals from GPS satellites. Otherwise, just use a GPS.The static part of GPS is WAAS. It's a ground based unit that's surveyed for exact longitude, latitude, and altitude. It corrects GPS signals for even greater accuracy, and relays this to the WAAS satellite.L.Adamson

Then have at it. And make sure you snag some branches in your wheel spats. Otherwise, it ain't worth it.I just hope you do understand risk management when it comes to flying. When it seems like you come on the board arguing that flying around with nothing more than a hand held gps or two going direct here there and everywhere each time you fly is just as safe if not better than using whatever backed up with whatever else with carefully considered routes, then you do represent to others a very risky attitude.

Kevin. Naturally I had to run your "airliner pilot" thoughts past a few individuals today. Can't repeat what they said either. Afterall, do you have any clue to how many camping airfields there are in the state of Idaho? There are many, and they're there for the explicate reason of allowing pilots and their families to come up and stay a few days. Some even have all the facilities. It's over mountain country, and no VORs. Utah has it's own excellent airstrips that are nestled in canyons, along river, etc, and are not serviced by VORs. Backcountry flying is a big thing out here. Many clubs are devoted to it. So really, let's don't go overboard with this risk management & risky attitude scenarios. It's like me going to Zion Canyon and telling people who climb 1500' vertical cliffs, not to do it, and that they are fools. They even have to spend a night on a small platform that's anchored with their ropes to a straight rock wall. That type of activity is past my own risk tolerance, but I have no business telling them otherwise.As I said previously, airliner pilots certainly do take on a different attitude because of years of redundancy. It's like my daughter, who was very adventurous in her youth, and thought nothing of aerobatic training in a Pitts. She loved that kind of stuff. Then she had kids, became a mother, and developed a completely different survival attitude. She just won't do those type of activities anymore. Does that make aerobatics wrong and foolish? Of course not, but it does carry an added element of risk. It's the same for me, as my type of flight carries an element of risk, but it's certainly worth it. And no, I won't be somersaulting motorcycles, or skateboards anytime soon.L.Adamson

Then have at it. And make sure you snag some branches in your wheel spats. Otherwise, it ain't worth it.I just hope you do understand risk management when it comes to flying. When it seems like you come on the board arguing that flying around with nothing more than a hand held gps or two going direct here there and everywhere each time you fly is just as safe if not better than using whatever backed up with whatever else with carefully considered routes, then you do represent to others a very risky attitude.

I just read this again, my wife read this again...........and..........I'll start with the "carefully considered routes". You're making a lot of assumptions here. My wife is very aware of my carefully planned routes, and the time I take to do it. She flys with me most of the time. She's done it for several decades.As to "nothing more than a hand held gps".................I wouldn't belittle that piece of equipment. It's well known that hand helds were the first to contain far more information than any panel mount. The reason was simple, hand-helds just don't require the complexity of FAA certified panel mounts. However, my Garmin 696 hand-held is anything but a simple device. It's the best piece of equipment available for any cockpit, short of a full blown glass panel. There is a wealth of information out of this little box, that pilots of the old days could dream about. Or should I say "dead pilots"...And if you don't agree, I'll just flip out accident after accident reports, as well as as the board of inquiry results. You wouldn't believe how many times the subject of moving map GPS comes up, and how it could have changed the possible outcome. Is it any surprise that the US Navy handed out hand-helds to it's pilots after one of their C-130's crashed into terrain near Jackson Hole? It didn't surprise me at all. I just wondered why airlines couldn't do the same as a temporary measure. Of course, it's regulations and all. BTW, have you ever looked into the cockpits of all these WWII era bombers that fly around, as well as a restored Connie? They all have hand-helds stuck on the panel or near the wind screen somewhere. That doesn't surprise me one bit...L.Adamson

Hello everyone.I see that this has become a discussion on individual's preferences. The reality is that many aircraft presently do not have GPSs and there are many issues with that type of navigation, that are likely to get worse before they get better. I've seen deviations in altitude, from GPS information as much as 700 Ft., while in level flight. I've been places where no GPS or any other signal, except ADF was available.

There are NOT many issues with GPS navigation. I don't know where you come up with this stuff. If you've seen 700' deviations, then get a decent GPS and one with WAAS. I'm always comparing GPS altitudes to the altimeter, and made it a point for years to compare the GPS altitude in my vehicles to every mountain pass that contained an altitude sign. Usually, the GPS was within 10' if not much less. 20' was unheard of. And who knows, the altitude survey could have been off.More than not, if I get a very current altimeter setting for the aircraft, the Garmin GPS "panel page" altimeter will exactly follow the aircraft's. On a long cross country I can see variances of 10 to slightly more than 100'. But a lot of that comparison has much to do with pressure & exact altimeter settings. It's the altimeter than can easily & legally be off. Other than that, limitations of GPS availability...... just doesn't happen much in the USA. That's also a solid and verifiable fact.L.Adamson

Kevin. Naturally I had to run your "airliner pilot" thoughts past a few individuals today. Can't repeat what they said either. Afterall, do you have any clue to how many camping airfields there are in the state of Idaho? There are many, and they're there for the explicate reason of allowing pilots and their families to come up and stay a few days. Some even have all the facilities. It's over mountain country, and no VORs. Utah has it's own excellent airstrips that are nestled in canyons, along river, etc, and are not serviced by VORs. Backcountry flying is a big thing out here. Many clubs are devoted to it. So really, let's don't go overboard with this risk management & risky attitude scenarios. It's like me going to Zion Canyon and telling people who climb 1500' vertical cliffs, not to do it, and that they are fools. They even have to spend a night on a small platform that's anchored with their ropes to a straight rock wall. That type of activity is past my own risk tolerance, but I have no business telling them otherwise.As I said previously, airliner pilots certainly do take on a different attitude because of years of redundancy. It's like my daughter, who was very adventurous in her youth, and thought nothing of aerobatic training in a Pitts. She loved that kind of stuff. Then she had kids, became a mother, and developed a completely different survival attitude. She just won't do those type of activities anymore. Does that make aerobatics wrong and foolish? Of course not, but it does carry an added element of risk. It's the same for me, as my type of flight carries an element of risk, but it's certainly worth it. And no, I won't be somersaulting motorcycles, or skateboards anytime soon.L.Adamson

If your purpose is to go visit the back country camps, then whatever risks that back country flying entails is normal and acceptable. If the purpose is not to visit the back country, then the inclusion of back country flying risks in the flight is foolish.If your purpose is to fly over water to spot fish, then whatever risks that over water flying entails is normal and acceptable. If the purpose is not to spot fish, then the inclusion of low altitude, over water flight risks in the the flight is foolish.If your purpose is to attack a heavily defended target, then whatever risks that flying into a SAM envelope entails is normal and acceptable. If the purpose is not to bomb a defended target, then the inclusion of risks associated with flying through SAM zones would be foolish."It's the same for me, as my type of flight carries an element of risk, but it's certainly worth it." - And that's all I'm really trying to make you and other people see, about your approach to flying. Your approach carries an added element of risk. Not saying whether it is wrong or not. Since if it is acceptable to you and your passengers, then it is perfectly fine. All I'm trying to make you see is that your methods carry more risk than the positions that some of the other people here hold. You can espouse the techniques you use in flight planning and plotting direct here and there all day, as long as you be honest and acknowledge the added elements of risk that what you do will entail into the flight.

I just read this again, my wife read this again...........and..........I'll start with the "carefully considered routes". You're making a lot of assumptions here. My wife is very aware of my carefully planned routes, and the time I take to do it. She flys with me most of the time. She's done it for several decades.As to "nothing more than a hand held gps".................I wouldn't belittle that piece of equipment. It's well known that hand helds were the first to contain far more information than any panel mount. The reason was simple, hand-helds just don't require the complexity of FAA certified panel mounts. However, my Garmin 696 hand-held is anything but a simple device. It's the best piece of equipment available for any cockpit, short of a full blown glass panel. There is a wealth of information out of this little box, that pilots of the old days could dream about. Or should I say "dead pilots"...And if you don't agree, I'll just flip out accident after accident reports, as well as as the board of inquiry results. You wouldn't believe how many times the subject of moving map GPS comes up, and how it could have changed the possible outcome. Is it any surprise that the US Navy handed out hand-helds to it's pilots after one of their C-130's crashed into terrain near Jackson Hole? It didn't surprise me at all. I just wondered why airlines couldn't do the same as a temporary measure. Of course, it's regulations and all. BTW, have you ever looked into the cockpits of all these WWII era bombers that fly around, as well as a restored Connie? They all have hand-helds stuck on the panel or near the wind screen somewhere. That doesn't surprise me one bit...L.Adamson

The way you deify and put absolute trust into one gadget scares me.

The way you deify and put absolute trust into one gadget scares me.

deify :( How about flying IFR without GPS equipment

The way you deify and put absolute trust into one gadget scares me.

Kevin, There are many other commercial airline pilots who give GPS the top notch for navigation. These are people who regularly fly FMC systems that include all three nav systems. I don't know what your GPS experience is, but I've heard from plenty of others. I know because I ask a lot. And yes, I do put much more trust into it, than previous radio nav systems. On the other hand, it's VFR, so it doesn't really matter. However, it hasn't failed since the early ninties (was less than a minute), and it hasn't yet screwed a coordinate. That's a pretty decent statistic if you ask me.If the GPS system goes down, I doubt we'll see much GA flight as well as commercial. It would be like 911. In the meantime, I have the two GPS's that act as a backup. It's VFR, it's day time, but best of all is the XM weather. It allows me to make intelligent decisions, that's always been somewhat of a guessing game in the past. And I'm far from being alone, when it comes to this weather advantage. Pilots who frequently use it, don't leave home without it.......as the saying goes. L.Adamson

Hi Larry.I typically would not respond to this type of message but since I know you are a Pilot, in real world, I will try to see if I can help you not get into a situation that you are not prepared for. I would recommend that you go here: http://www.raimprediction.net/, FAA site, or here: http://www.navcen.uscg.gov/gps/almanacs.htm, before you decide to take a flight and rely on the GPS only.As to my experience when I've seen the deviation, both were in the area of Dana Point, with IFR certified GPS units. We were VFR, practicing VOR (SLI 115.70) tracking on V23 at 2500. for about 20-30 seconds we got an indication of 3300. I happen to follow closely the GPS development and I get the "InsideGNSS" Magazine. Go to www.insidegnss.com, if you want more details. This is somewhat technical in nature but it does have some information that you may understand.I would strongly suggest that you back your GPS device with something else, especially if and when you fly in unpopulated / mountainous area. TV

Well I am still baffled by this thread.Dead reckoning, dots and dashes airways, adf, vor, gps, and now glass panels.Are not all these technologies a continued uphill movement in safety?I did this video a year ago-kinda cool showing my kln94 that was state of the art not that long ago with my portable tablet which goes way beyond....

The kln94 is still my legal-but even it is looking downright primitive today..To be honest-what is this thread about? A rejection of new technologies that add to safety?-I'll bet no one is against that? A statement of yes it is great but I can use the old technology with my hands tied behind my back-bet most of us can and congratulations....but if we had a choice would we not want to use the one that gives us the most information in the best way?A statement of nothing is reliable so you should have a backup-doubt anyone disagrees with that? Me-I don't know why the faa did away with loran which is what I was using very nicely before gps took over..A statement that flying is risky and we all make choices which for our situation we feel is prudent.So far all of the people taking these risks have been around this board for an awfully long time so perhaps judgements are not so bad for the mission being taken? :( ...and yes an early portable apollo gps saved my bacon when my real altimeter went out in imc over hostile mountains. Yes I knew the altitude readout was unrealiable-but it was reliable enough to save my bacon. If I hadn't had it I don't know what would have happened.Talk about backups...