Post by volkerboehme on Aug 10, 2008 9:22:32 GMT -5
Concerning en route navigation in Europe (or anywhere else outside the United States).
If I remember correctly, earlier in the year, I posted at length concerning post war long range en route navigation outside the CONUS with references to the demise of the BSAA Lancastrian 'Star Dust' in the Andes. Outside the CONUS airliners with large crews could not rely on sextants, radio ranges or ADF for en route navigation, before or after WW2. Whether aeroplanes or airships.
They used a form of GPS, typically high frequency direction finding ("Huff Duff"). The British installed GPS across their Empire from 1909 onwards. The RMS Titanic was using GPS for navigation in 1912. GPS did not disclose the location of icebergs and decoding of the pre war GPS signals was slow and manual.
Description of Huff Duff: en.wikipedia.org/wiki/Huff-Duff
Decca Navigator was a later more refined and highly automated RPS. Regional not Global. It was deployed in the early fifties. It covered only the UK, the Reforger convoy approaches to the UK, Northern France, Benelux, parts of Scandinavia, Germany and most of Eastern Canada, or in other words the bits of NATO that Britain really cared about or might have wished the RAF and RCAF to fight over. Canada was a British Dominion.
Description of Decca Navigator, and other similar systems: www.vectorsite.net/ttwiz_10.html
Germany installed Radio Ranges along Lufthansa routes in and outside Germany from about 1936 onwards, but only if the nation concerned was naive enough to allow blind bombing aids to be installed on their soil by Germany. Britain wasn't naive enough and obviously Germany did not make the frequencies public so only Lufthansa and the Luftwaffe could use them.
The system used to blind bomb Warsaw in 1939 or Rotterdam in 1940 or the UK in all weathers by night over the winter of 1940-41 was almost identical to the airways system of the United States. Luftwaffe pathfinders just had an additional timing clock to automate bomb release over the Radio Range intersection which was shifted from city to city, night by night. The Ranges were in occupied Europe. By the winter of 1940 the intersections they created were over the UK.
Other European nations installed Radio Ranges only when they ratified the Treaty of Chicago in the late forties or early fifties, following the formation of ICAO. That was when they adopted the classic era means of short range navigation that had been in use over the CONUS from 1932 onwards. They were replaced by VORs from about 1956 onwards. My earlier and lengthy post concerning BSAA 'Star Dust' explained why that progression was appropriate and necessary.
A general description by Adrian: www.calclassic.com/cgi-bin/yabb/YaBB.cgi?board=General;action=display;num=1167429561;start=5#5
The FSAviator Vintage Mini-Tutorial: www.calclassic.com/cgi-bin/yabb/YaBB.cgi?board=General;action=display;num=1162429429;start=17#17
Scroll up to read the entire tutorial. This is also available as a zip file on my Tutorials page.
However the use of L/F band Radio Ranges outside the United States was quite brief and of little real importance other than for blind bombing. Australia and some other British allied nations in that geo-political region had four course Audio VHF band Ranges (VARs) that lasted for much longer.
However the primary means of long range en route aerial navigation everywhere outside the U.S. from the twenties to the late fifties, (and much later over the third world), was GPS in the H/F band. How to simulate that in FS9 seems rather obvious. The only trick is that it was slow to update so the appropriate procedure in FS9 is (quoting from the unfinished, unpublished and only partially updated propliner tutorial);
The rules for conducting a GPS navigated flight outside the United States using Marconi + Adcock H/F band avionics technology only require self disciplined use of the default FS9 GPS.
1) The aircraft, (whether civil, military or naval), must have at least a wireless operator and a navigator. Naval aircrew classified as observers were often, but not always, navigators.
2) The FS9 GPS should be consulted by popping up the window only at substantial intervals during cruise; perhaps every 10th minute for a short haul flight or every 30th for a trans-oceanic or trans-continental flight.
3) Once every position update interval a course correction, not exceeding five degrees, and always rounded to five degrees, is made after determining from the GPS picture whether the flight is currently left or right of flight plan track due to wind drift and any other cumulative navigation errors.
What is being simulated here using intermittent course changes and headings, which will be wrong by up to four degrees 80% of the time, is the error that arose from the manual plotting delay and the bearing errors inherent in using Huff Duff as the contemporary GPS system at extended range.
CREW RESOURCE IS THE KEY
Multi crew aircraft outside the CONUS knew roughly where they were all of the time, in any weather, using Huff Duff as a slow to update and slightly inaccurate GPS. Aircraft like the Ford 4-AT-E with inadequate crew resource could still only fly the pioneer way by visual reference to the scenery.
So everywhere except over the CONUS a flight in an aircraft with adequate crew resource for GPS navigation begins with a visual departure flown by visual reference to the surface until clear of all potential obstructions. This is followed by a climb to design cruising level, or operational ceiling, whether in or above cloud, directly on track to destination. Then every ten to thirty minutes intermittent use of a GPS update is used to adjust heading left or right five degrees in units of five degrees until the flight reaches a position where it is deemed to be safe to descend and begin the arrival through (potentially several layers of) cloud.
The arrival may be visual or an NDB approach as described in Part 3 of the published Propliner Tutorial (2004).
LIMITATION OF UTILITY OF HUFF DUFF
The slowly updating and somewhat inaccurate GPS used by the navigator of the Titanic in 1912 was not adequate to enter a harbour blindly in fog without reference to the local scenery. Nor was it good enough to allow an aircraft navigator to find a particular runway without visual reference to the local scenery. However the GPS of 1912 was good enough to navigate from somewhere near Ireland to somewhere near New York, in fog, whether by a ship, or by aircraft. With sufficient training and skill undersea motionless rocks or continental mountains could be avoided. Moving icebergs could not.
Just because the GPS systems used from 1909 to the 1990s were too poor to be used as approach aids, or could not be used to avoid collision with other moving objects, does not mean that they could not be used, or were not used, for long range en route navigation. GPS was the primary means of long range en route navigation in any vessel with a qualified crew complement and, save for the CONUS, continental land masses were just treated as another kind of ocean with bigger rocks and reefs projecting above their surface.
Over 99% of the aircraft navigators ever trained were military or naval navigators. The fact that military aircrew were trained to maintain radio silence and not to use Huff Duff within combat zones in time of war has no relevance to most scheduled airline operations. Airlines had no reason to maintain radio silence. They needed to maintain schedules below cloud, in cloud, and in restricted visibility. This could not be achieved using sextants or other post medieval means of navigation.
Military aircraft operators who relied on post medieval means of navigation in order to maintain radio silence were forced to postpone sorties for days at a time. Airlines did not. They flew schedules, below cloud, in cloud and in poor visibility, before, during, and after WW2. Some pre war scheduled routes were up to 14 days long, flying ten hours per day, every day, regardless of high level cloud and low visibility that obscured the sky for days on end. Mostly in airliners with no astrodome or anywhere else to use a sextant. They used wireless telegraphy to deliver a slowly updating, manually decoded GPS plot, regardless of the weather. The older the large crew airliner, and the lower its performance, the more likely it was to be trapped in or below cloud, and the more it needed Huff Duff GPS to maintain schedules.
Most FS9 users attempting to simulate long haul airline scheduled operation in airliners with large flight deck crews never quite grasp this, yet the means to simulate it within FS9 are readily available.
If I remember correctly, earlier in the year, I posted at length concerning post war long range en route navigation outside the CONUS with references to the demise of the BSAA Lancastrian 'Star Dust' in the Andes. Outside the CONUS airliners with large crews could not rely on sextants, radio ranges or ADF for en route navigation, before or after WW2. Whether aeroplanes or airships.
They used a form of GPS, typically high frequency direction finding ("Huff Duff"). The British installed GPS across their Empire from 1909 onwards. The RMS Titanic was using GPS for navigation in 1912. GPS did not disclose the location of icebergs and decoding of the pre war GPS signals was slow and manual.
Description of Huff Duff: en.wikipedia.org/wiki/Huff-Duff
Decca Navigator was a later more refined and highly automated RPS. Regional not Global. It was deployed in the early fifties. It covered only the UK, the Reforger convoy approaches to the UK, Northern France, Benelux, parts of Scandinavia, Germany and most of Eastern Canada, or in other words the bits of NATO that Britain really cared about or might have wished the RAF and RCAF to fight over. Canada was a British Dominion.
Description of Decca Navigator, and other similar systems: www.vectorsite.net/ttwiz_10.html
Germany installed Radio Ranges along Lufthansa routes in and outside Germany from about 1936 onwards, but only if the nation concerned was naive enough to allow blind bombing aids to be installed on their soil by Germany. Britain wasn't naive enough and obviously Germany did not make the frequencies public so only Lufthansa and the Luftwaffe could use them.
The system used to blind bomb Warsaw in 1939 or Rotterdam in 1940 or the UK in all weathers by night over the winter of 1940-41 was almost identical to the airways system of the United States. Luftwaffe pathfinders just had an additional timing clock to automate bomb release over the Radio Range intersection which was shifted from city to city, night by night. The Ranges were in occupied Europe. By the winter of 1940 the intersections they created were over the UK.
Other European nations installed Radio Ranges only when they ratified the Treaty of Chicago in the late forties or early fifties, following the formation of ICAO. That was when they adopted the classic era means of short range navigation that had been in use over the CONUS from 1932 onwards. They were replaced by VORs from about 1956 onwards. My earlier and lengthy post concerning BSAA 'Star Dust' explained why that progression was appropriate and necessary.
A general description by Adrian: www.calclassic.com/cgi-bin/yabb/YaBB.cgi?board=General;action=display;num=1167429561;start=5#5
The FSAviator Vintage Mini-Tutorial: www.calclassic.com/cgi-bin/yabb/YaBB.cgi?board=General;action=display;num=1162429429;start=17#17
Scroll up to read the entire tutorial. This is also available as a zip file on my Tutorials page.
However the use of L/F band Radio Ranges outside the United States was quite brief and of little real importance other than for blind bombing. Australia and some other British allied nations in that geo-political region had four course Audio VHF band Ranges (VARs) that lasted for much longer.
However the primary means of long range en route aerial navigation everywhere outside the U.S. from the twenties to the late fifties, (and much later over the third world), was GPS in the H/F band. How to simulate that in FS9 seems rather obvious. The only trick is that it was slow to update so the appropriate procedure in FS9 is (quoting from the unfinished, unpublished and only partially updated propliner tutorial);
The rules for conducting a GPS navigated flight outside the United States using Marconi + Adcock H/F band avionics technology only require self disciplined use of the default FS9 GPS.
1) The aircraft, (whether civil, military or naval), must have at least a wireless operator and a navigator. Naval aircrew classified as observers were often, but not always, navigators.
2) The FS9 GPS should be consulted by popping up the window only at substantial intervals during cruise; perhaps every 10th minute for a short haul flight or every 30th for a trans-oceanic or trans-continental flight.
3) Once every position update interval a course correction, not exceeding five degrees, and always rounded to five degrees, is made after determining from the GPS picture whether the flight is currently left or right of flight plan track due to wind drift and any other cumulative navigation errors.
What is being simulated here using intermittent course changes and headings, which will be wrong by up to four degrees 80% of the time, is the error that arose from the manual plotting delay and the bearing errors inherent in using Huff Duff as the contemporary GPS system at extended range.
CREW RESOURCE IS THE KEY
Multi crew aircraft outside the CONUS knew roughly where they were all of the time, in any weather, using Huff Duff as a slow to update and slightly inaccurate GPS. Aircraft like the Ford 4-AT-E with inadequate crew resource could still only fly the pioneer way by visual reference to the scenery.
So everywhere except over the CONUS a flight in an aircraft with adequate crew resource for GPS navigation begins with a visual departure flown by visual reference to the surface until clear of all potential obstructions. This is followed by a climb to design cruising level, or operational ceiling, whether in or above cloud, directly on track to destination. Then every ten to thirty minutes intermittent use of a GPS update is used to adjust heading left or right five degrees in units of five degrees until the flight reaches a position where it is deemed to be safe to descend and begin the arrival through (potentially several layers of) cloud.
The arrival may be visual or an NDB approach as described in Part 3 of the published Propliner Tutorial (2004).
LIMITATION OF UTILITY OF HUFF DUFF
The slowly updating and somewhat inaccurate GPS used by the navigator of the Titanic in 1912 was not adequate to enter a harbour blindly in fog without reference to the local scenery. Nor was it good enough to allow an aircraft navigator to find a particular runway without visual reference to the local scenery. However the GPS of 1912 was good enough to navigate from somewhere near Ireland to somewhere near New York, in fog, whether by a ship, or by aircraft. With sufficient training and skill undersea motionless rocks or continental mountains could be avoided. Moving icebergs could not.
Just because the GPS systems used from 1909 to the 1990s were too poor to be used as approach aids, or could not be used to avoid collision with other moving objects, does not mean that they could not be used, or were not used, for long range en route navigation. GPS was the primary means of long range en route navigation in any vessel with a qualified crew complement and, save for the CONUS, continental land masses were just treated as another kind of ocean with bigger rocks and reefs projecting above their surface.
Over 99% of the aircraft navigators ever trained were military or naval navigators. The fact that military aircrew were trained to maintain radio silence and not to use Huff Duff within combat zones in time of war has no relevance to most scheduled airline operations. Airlines had no reason to maintain radio silence. They needed to maintain schedules below cloud, in cloud, and in restricted visibility. This could not be achieved using sextants or other post medieval means of navigation.
Military aircraft operators who relied on post medieval means of navigation in order to maintain radio silence were forced to postpone sorties for days at a time. Airlines did not. They flew schedules, below cloud, in cloud and in poor visibility, before, during, and after WW2. Some pre war scheduled routes were up to 14 days long, flying ten hours per day, every day, regardless of high level cloud and low visibility that obscured the sky for days on end. Mostly in airliners with no astrodome or anywhere else to use a sextant. They used wireless telegraphy to deliver a slowly updating, manually decoded GPS plot, regardless of the weather. The older the large crew airliner, and the lower its performance, the more likely it was to be trapped in or below cloud, and the more it needed Huff Duff GPS to maintain schedules.
Most FS9 users attempting to simulate long haul airline scheduled operation in airliners with large flight deck crews never quite grasp this, yet the means to simulate it within FS9 are readily available.