All,Ok - navigating with GPS in a new 737 is easy... How did airliners navigate prior to that ??? For example on flights from San Diego to Hawaii. VOR's can't reach across the ocean - right ??? Thanks,Scott

Dead reckoning. Pencil and paper, a good chart or two, a slide rule, a well-calibrated compass, and the odd star if you were lucky enough to have a clear night. Of course if you were flying VFR and low you could always follow the coconuts.Mark "Dark Moment" Beaumonthttp://www.swiremariners.com/newlogo.jpg

For flights between the west coast and hawaii there also used to be a shipboard nav station called Ocean November. Theres scenery for it somewhere. I think is was just an ADF, no DME that I remember.Eric

Really ??? I am talking about 707's and 727's NOT DC-3's LOL... So you really just pick a bearing and head out over the ocean ??? No traffic control or anything ? I guess I should tune my VOR to Hawaii before I leave - at least I can pick up the signal when I am close... OH - Also - how would I pick the bearing in FS9 ???Thanks,Scott

Hey, Scott, big subject, and there a million good tutorials on the web concerning navigation; and anyway, how far back are you going. Most of the 70s/80s aircraft had Inertial Navigation Systems if they predated GPS (L-1011s, DC-10s, etc.) but I thought you were talking REAL navigation, LOL. <<>With the flight you pick as an example - San Diego to Hawaii - MS will not let you plan a route using VORs, you'll find (we're ignoring the GPS option, of course!) but it will let you plan using airways, and give you waypoints. Pull up your nav log and there are all the bearings for your flightplan.Now all you have to work out is the effect of true/magnetic variation, wind effect, slide, drift, whatever ... and you're there!Let us know when you pick up the Honolulu VOR ... if you haven't run out of fuel first. Good luck (you gotta try it now, right?)Mark "Dark Moment" BeaumontP.S. FS Nav, if you don't have it, will make all this a lot easier to plan, too.P.P.S. Only listen to half of what I say. I'm no pilot, but I don't think I'm that far out on this advice.http://www.swiremariners.com/newlogo.jpg

Back in the 50s and before- even a sextant was used on occasions.Someone mentioned Ocean Stations.There were several in the Atlantic- if I remember correctly around three on station at any one time.They used callsigns "Ocean Station C" etc(different letters) and were ,I believe provided jointly by the UK.US and Canada with vessels rotating on and off station for several weeks at a time.The OS vessels were to be heard on the Shanwick/Gandar/New York HF Oceanic Control frequencies- often heard them - I used to listen to HF aircraft freqs worldwide back then.The O S were equipped with Selcal and often relayed messages between the ground stns and aircraft when conditions were poor.Dave

<<<>>You asked this too, Scott, and Dave mentions relaying of messages if you were lucky from the OS ... but for the most part, you'd be out of any jurisdiction or even contact of any kind for the best part of your trip. Still are, on certain routes today where there is no coverage.You begin to understand why early aircraft had a dedicated navigator! What never ceases to amaze me is how the WWII bomber and fighter squadrons did their stuff over thousands of miles, again and again. ATC? They weren't allowed to be in contact anyway except in code for fear of giving away movements and positions; the enemy weren't exactly making a point of having their VORs and NDBs working as would be expected in times of peace; you were very likely to be shot at a lot; you were usually flying at night, without heat, in lots of noise, without lights, and in formation with hundreds of other aircraft, none of whom you were supposed to chat to en route unless you really had to. As well as all this, you were supposed to hit targets. Mindboggling to me. Not exactly a Cessna 172 out of Palm Beach, that. I've tried flying mission routes in FS as they were really flown using Liberators and Lancasters and even with no risk of being shot down at all, and with a cup of coffee whenever I want one, it's a daunting task to get there and back accurately.Mark "Dark Moment" Beaumonthttp://www.swiremariners.com/newlogo.jpg

Commercial airliners didn't use dead reckoning for those over water flights - way too risky! Early on (WWII era), they used LORAN C (Stands for LOng RAnge Navigation; the C was just the 3rd redition of it - i.e. A,B,C). Basically the LORAN units were ground based master stations combined with "chains". Sort of a like GPS is now, where the Satilites determine your location, LORAN used ground based stations to determine your position. Some older aircraft still have LORAN units installed in them. I know for a fact it is still up and running at this time (boats still use it).Ground speed, distances, etc. were avilable to pilots and waypoints/airports could be entered (again a primitive GPS). The usual range was approximately 1000 miles.Next came the Inertial Navigation Systems installed on the 707, DC-8s/10's, and the L-1011 and 747-200 (early '60's). These systems used accelermeters that could detect changes in aircraft acceleration and could then calculate the known position of the aircraft if the pilots inputted a starting Lat/Long. I happen to have a chart in front of me showing the accuracy of it - basically it will show you off course by 0.8nm/hour. Not too shabby, eh? On a flight from JFK to HNL the error was a little under 7 miles. It could be used for IFR enroute only, no terminal procedures (approaches).The next development was the Inertial Reference System, developed in the early 80's. Instead of using accelermeters for position guidance, it uses ringed-laser gyros to detect aircraft acceleration. It is highly accurate, but nothing more than a refined INS. It's accuracy was 0.7nm/hour. The benefits of IRS included a reduction in weight, maintance, cost, and better reliability and service life over the INS units. In addition, updated positions are aviliable to the IRS computers by cross referencing VOR radials and distances. This allows it to be continually updated with almost zero error.And after the IRS, GPS came of age. Most aircraft now have IRS's installed with GPS updating (using the VOR updating as a backup function).~SkyyP.S. Any other questions just fire away...thanks for the nice review, dusting off some old textbooks :).

<<>>But I don't think LORAN was ever global coverage, was it, Skyy? As you say, they were all ground based stations. Not sure on that one myself, although you're right that it was - and to some extent, still is - a mainstay of the shipping world.To my horror, it is now no longer a requirement for Merchant Navy cadets to learn to use a sextant. Which is fine, oh yes, until someone pulls the plug out of the GPS one day.Mark "Dark Moment" Beaumonthttp://www.swiremariners.com/newlogo.jpg

Thanks everyone for the great responses... I guess it is not too unrealistic to use the GPS unit then... I always felt like I was cheating or something when using it on the older airliners... The only difference is probably the amount of error they saw and the format of the data prior to GPS... That dead reckoning had me scared for a while - one little miscalculation and your swimming with the sharks...I should have thought more myself... I spent six years on Submarines... We had a commercial off the shelf Loran unit but it was only good when fairly close to the coast... The military had a low frequency stations scattered around the globe called Omega... This we could get anywhere, but the accuracy of the fix wasn't very good... I do not know if there was a civilain equivlent... Thanks,Scott

Yes, you're correct. There was no way of navigating using it over the ocean in the Pacific. However, the dawn of the jet age and resulting increase in aircraft range necessitated a navigational device capable of crossing the oceans, which conveniently was when the INS units were developed. I've got a map showing the LORAN coverage, it looks like a sizable gap from the west coast of the US to the Hawaii LORAN unit (however there is descent coverage of the Atlantic to the UK). Were there any commerical (i.e. pax) aircraft capable of making the west coast jump to Hawaii prior to the 707? I'd be interested in knowing how they did indeed navigate.I couldn't image being in the Spirit of St. Louis crossing the Atlantic on nothing but headings. That's just crazy!~Skyy

Interesting post Dave...I still listen to SSB HF Oceanic on my RS DX-390... I regularly get the position reports until aircraft hit between 30 and 20W in the Atlantic, and in the Pacific I sometime pick them up as well. Although it can seem a dull way to spend an hour or two, what makes it interesting is picking up the collection of accents that those crossing the pond have. I pick up Gander voice very clearly, the aircraft I can hear if I listen with in ear head phones...faint but you can understand them. I'll be sorry when some day in the not too distant future aircraft move from HF to digital Sat. Comms and they are relayed by Sat. Of course, hopefully someone will build a unit that can pick up those comms as well....-JohnP.S. I even applied a mod to my 390... Listening to aircraft on HF requires one to move between a range of freqs. depending on the band you're watching. Problem with that is the 390 muted when turning the tuning dial, so you couldn't catch an active transmission unless you stopped at the right freq., at the right time. I found on the web a mod which involved cutting the wire to the muting circuit. Crazy I tried it considering cutting the wrong wire would have made my unit a $150 paperweight. But I risked it anyway, and thirteen years later the radio still catches HF and a very interesting addition to my love of all things aviation..

<<>>It does give you a lot more info than you would ever have got from Loran ... try using INS in the earlier jets for more realism. There was a third party INS released recently for FS2004 which you can incorporate into your panels. I've yet to fit it myself yet in FS2004 (too busy with other stuff) but I believe it works.<<<>>>>It's another way of saying VFR, really! VFR is a combination of seeing where you're at and checking it with where you should be.I yacht a lot; I wouldn't be without my course planned by DR as well as whatever fancy stuff I'm navigating with, just in case. Electrics get wet sometimes ...Mark "Dark Moment" Beaumonthttp://www.swiremariners.com/newlogo.jpg

Lots of ways were developed for long range navigation before GPS. As mentioned, the most recent predecessor to GPS was inertial nav which was/is pretty close to GPS in terms of effective precision navigation. Before and concurrent with inertial nav was, as mentioned, Loran; first A and then C. Usually pretty good and giving postition information but they were limited in range. Not too bad over the North Atlantic but not too great anywhere else. The US Navy developed an world-wide follow-on to Loran called Omega which used similar principles but at very low frequency; some airlines used Omega for awhile. I never found it worked all that well but when it did it was about as precise as Loran, which is to say pretty good...get ya to Hawaii okay. But before GPS and triple inertials, 707s, DC8s etc flew long distances by DR nav with positioning data based on Loran and celestial (bubble sextant) and VOR within 150 miles or so of their destination.There is ATC over Oceanic routes and has been for a long time. Not the same positive/radar control like over land but aircraft file flight plans and report their progress/position periodically so they can be tracked for aircraft separation. Although there are better ways now, for decades the voice reports have been (and still are) made with HF radios. Somebody just uploaded a recording of these Oceanic calls the other day.It wasn't as scary as it sounds without GPS.Jeff

>Were there any commerical (i.e. pax) aircraft capable of making the west coast jump to Hawaii prior to the 707?I'd be interested in knowing how they did indeed navigate.I couldn't image being in the Spirit of St. Louis crossing the Atlantic on nothing but headings.That's just crazy!