Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
User avatar
passengerpigeon
Topic Author
Posts: 35
Joined: Tue Jul 26, 2016 7:51 pm

Airliner navigation immediately before GPS

Mon Dec 02, 2019 12:08 am

How did airliners navigate in the days immediately prior to the advent of GPS for commercial aircraft in the mid-1990s? I am familiar with navigation methods used by fully non-computerised aircraft (NBDs, LF ranges, VORs and wind drift scoping overland, and astral navigation and dead reckoning to cross water), but the introduction date of airliner GPS systems means that some aircraft types that we don't think of as obsolete today (e.g. A320, 767, 757) must have started life without GPS. How did these computerised planes navigate compared to the earlier analog ones? Did they start life with modern keypad FMCs capable of flying fixes, and if so, how did those computers calculate where they were before receiving GPS capability? With regards to overwater navigation, how was this done in particular? If I was flying a 767 or 747-400 across the Atlantic shortly after either of those planes were introduced, how would I avoid getting lost at sea?

On another note, when was the last time you can remember a scheduled commercial flight flying without GPS? It seems like every time I see a modern cockpit photo or video of a vintage plane (e.g. DC-3, DC-9 or C-46) that is still in commercial service, there's a TomTom clamped to the dashboard.
 
User avatar
Starlionblue
Posts: 19937
Joined: Fri Feb 27, 2004 9:54 pm

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 12:23 am

Inertial navigation came into widespread use in airliners in the 1970s, I believe. The principles and early research came from WWII rocketry. INS combined with star sighting and radar ranging were used to navigate Apollo spacecraft to and from the Moon.

So to answer your question, inertial navigation (INS) and radio triangulation were used, and still are. Modern navigation systems use a combination of inertial navigation, GPS and radio triangulation to compute position.

If a 747 was flying over the Atlantic, say, INS would drift over time. So the aircraft would probably be off the nominal track by a number of miles once it reached the other side. As soon as it entered range of VOR/DME stations on ground, the position would be automatically corrected and it would return to the proper track.

An inertial navigation unit consists of a set of gyros and accelerometers. The accelerometers, one for each axis, detect acceleration, which together with time gives speed in each axis. The gyros, also one for each axis, detect angular acceleration (turning). So from a known starting point*, the position and attitude of the aircraft can be determined. Drift is normally less than a nautical mile per hour. Back in the day, gyros used to actually spin, but nowadays solid-state ring laser gyros are used.

GPS fixes did not exist, since no GPS. AFAIK, the Tristar used an early computerised navigational system where the next three fixes would be typed in, lat and long. The precursor to modern lateral navigation from an FMS.

*The reason parking bays have latitude and longitude displayed in front of the cockpit is so that navigation systems can be checked. Inertial navigation only works if the starting point is known.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
User avatar
passengerpigeon
Topic Author
Posts: 35
Joined: Tue Jul 26, 2016 7:51 pm

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 12:45 am

Starlionblue wrote:
So to answer your question, inertial navigation (INS) and radio triangulation were used, and still are. Modern navigation systems use a combination of inertial navigation, GPS and radio triangulation to compute position.


So did pilots of early non-GPS A320s, 757s and 767s have to tune into each radio beacon by hand like in previous-generation aircraft, or could you plug the frequencies/identifiers into a computer system and have it retune the radios as the plane went along?

Starlionblue wrote:
GPS fixes did not exist, since no GPS. AFAIK, the Tristar used an early computerised navigational system where the next three fixes would be typed in, lat and long. The precursor to modern lateral navigation from an FMS.


In that case, what was in the place of the current FMC panel in the aforementioned aircraft?
 
User avatar
fr8mech
Posts: 8023
Joined: Mon Sep 26, 2005 9:00 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 12:58 am

passengerpigeon wrote:

So did pilots of early non-GPS A320s, 757s and 767s have to tune into each radio beacon by hand like in previous-generation aircraft, or could you plug the frequencies/identifiers into a computer system and have it retune the radios as the plane went along?


Both. The FMC could auto-tune the VOR frequency, or the crew could do it on their own.
When seconds count, the police are minutes away.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
User avatar
zeke
Posts: 14987
Joined: Thu Dec 14, 2006 1:42 pm

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 1:31 am

passengerpigeon wrote:
If I was flying a 767 or 747-400 across the Atlantic shortly after either of those planes were introduced, how would I avoid getting lost at sea?


It would be based off inertial navigation with automatic ground updates. After a long flight without navaid update sometimes you would see a 5 mm map shift once back within navaid range.

Airbus used DME DME update, the distance from two or more navaids for terminal area updates, it is just as accurate as GPS. GPS is essentially the same thing, DME DME update from a satellite.

In many charts today you can still see a requirement of either GNSS or DME-DME required aircraft capability.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
User avatar
Starlionblue
Posts: 19937
Joined: Fri Feb 27, 2004 9:54 pm

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 3:28 am

passengerpigeon wrote:
Starlionblue wrote:
So to answer your question, inertial navigation (INS) and radio triangulation were used, and still are. Modern navigation systems use a combination of inertial navigation, GPS and radio triangulation to compute position.


So did pilots of early non-GPS A320s, 757s and 767s have to tune into each radio beacon by hand like in previous-generation aircraft, or could you plug the frequencies/identifiers into a computer system and have it retune the radios as the plane went along?


The FM would auto-tune beacons. Just like it does today.

As fr8mech notes, you could also "hard tune", using frequency or ident. Again, just like we can today.

passengerpigeon wrote:
Starlionblue wrote:
GPS fixes did not exist, since no GPS. AFAIK, the Tristar used an early computerised navigational system where the next three fixes would be typed in, lat and long. The precursor to modern lateral navigation from an FMS.


In that case, what was in the place of the current FMC panel in the aforementioned aircraft?


In many cases there was nothing. However, various contraptions have been tried from time to time, including moving paper maps on spools.

Here's a Trident with a moving paper map. Image

(EDIT) Here's a Tristar with one navigation panels on the FO side, and some screen in the middle. Image

Here's a 727 with no nav panels. Image

Here's a Tristar with the nav panels. Image

Here's a 727 which I'm guessing has been retrofitted with some sort of FMS. Image
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Woodreau
Posts: 1899
Joined: Mon Sep 24, 2001 6:44 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 3:54 am

The last commercial flights that operated without GPS in the United States were probably flown by Beechcraft 1900D aircraft. I believe the last commercial airline flight using Beech 1900 aircraft ended in March 2018, when the airline that operated them, Great Lakes Airlines, ceased operating.

Airlines that operated the Beech 1900 did not spend any extra money to install GPS or any FMS, which were optional equipment. Beech 1900s did have a GPS receiver installed as part of the TAWS system, but TAWS did not interface with the aircraft navigation system.

Navigation on these flights was usually filed via airways and flown from VOR to VOR, but in actual practice, flights rarely flew on airways, it was usually radar vectors direct when able.
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
 
mmo
Posts: 2054
Joined: Thu Apr 18, 2013 3:04 pm

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 7:38 am

Just a little bit more info about nav systems. The first "high tech" nav system installed was the INS. It had mechanical gyros which sensed acceleration in three axes and updated the position like that. The initial position had to be entered for the INS to know where it was. Nav accuracy was directly related to the length of the flight. The limit was 3+3T where T is the length of time the INS was in NAV. I am only familiar with the Delco Carousel units but they could hold 9-way points then you had to enter more as the flight went along.

Then as IRS/FMC began to enter the market there was an interface added to the INS which provided the ability to load pretty much the entire flight plan and IIRC, provided for updating the computed position by DME/DME. The INS position computed could not be updated by the DME/DME just like the IRS functions today with GPS.

Finally, the 757 came along pre GPS and there was a hierarchy of updating the FMC position. If you left the VOR in auto you could watch it update along the route. DME/DME was primary with ILS DME being favored, then you had varying priority such as vor/vor vor/dme the slash being indicative of the Land R nav function being used to update the FMC position.

Finally, you had GPS functioning and that was pretty much automatic with no pilot inputs, except in China where you had to inhibit GPS updating since the WGS-84 database was not used in China. Again, the IRS position itself was never updated but the FMC position was updated by the GPS input.

Just wanted to fill in some of the blanks.
If we weren't all crazy we'd all go insane!
 
N1120A
Posts: 26562
Joined: Sun Dec 14, 2003 5:40 pm

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 5:32 pm

Woodreau wrote:
The last commercial flights that operated without GPS in the United States were probably flown by Beechcraft 1900D aircraft. I believe the last commercial airline flight using Beech 1900 aircraft ended in March 2018, when the airline that operated them, Great Lakes Airlines, ceased operating.

Airlines that operated the Beech 1900 did not spend any extra money to install GPS or any FMS, which were optional equipment. Beech 1900s did have a GPS receiver installed as part of the TAWS system, but TAWS did not interface with the aircraft navigation system.

Navigation on these flights was usually filed via airways and flown from VOR to VOR, but in actual practice, flights rarely flew on airways, it was usually radar vectors direct when able.


There are still 767s flying out there without GPS.

Also, as far as I know, most 1900 operators put in at least a Garmin GNS unit before their retirements.
Mangeons les French fries, mais surtout pratiquons avec fierte le French kiss
 
Chemist
Posts: 734
Joined: Tue Oct 20, 2015 4:46 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 6:01 pm

My uncle was an avionics mechanic for Western Airlines. I remember talking with him in the 1980s about navigation.
He said that Western's 720B aircraft had used VORs, and dead reckoning while say LAX-HNL. they would get close enough to HNL and pick up the local VORs.
He told me that once other airlines started flying the 747 which had the then-new INS, the INS was so accurate that if a Western 720B took off LAX to HNL behind an HNL-bound 747, they could follow the contrails to the islands. He said the INS on the 747s would get the plane to within 3 miles of HNL. At the time I was amazed that there was navigation so accurate that they would only be off by 3 miles after >2000 mile trip!

How times have changed...
 
GalaxyFlyer
Posts: 5635
Joined: Fri Jan 01, 2016 4:44 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 6:05 pm

That’d be a long DR, about 1,600 nautical with lots of wind changes. Certainly, there’s no OpsSpec allowing it. Probably had a navigator with LORAN, celestial and Doppler.
 
User avatar
zeke
Posts: 14987
Joined: Thu Dec 14, 2006 1:42 pm

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 6:21 pm

Woodreau wrote:
The last commercial flights that operated without GPS in the United States were probably flown by Beechcraft 1900D aircraft. I believe the last commercial airline flight using Beech 1900 aircraft ended in March 2018, when the airline that operated them, Great Lakes Airlines, ceased operating.


Looking at this Great Lakes 1900 up for sale, they did have GPS installed. I looked at the panel for that aircraft and didn’t see a GPS on it. Some of the King Airs and 1900s had their GPS units on the centre pedestal.

https://www.controller.com/listings/air ... raft-1900d
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
kalvado
Posts: 2733
Joined: Wed Mar 01, 2006 4:29 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 7:18 pm

Starlionblue wrote:
Inertial navigation came into widespread use in airliners in the 1970s, I believe. The principles and early research came from WWII rocketry. INS combined with star sighting and radar ranging were used to navigate Apollo spacecraft to and from the Moon.

So to answer your question, inertial navigation (INS) and radio triangulation were used, and still are. Modern navigation systems use a combination of inertial navigation, GPS and radio triangulation to compute position.

If a 747 was flying over the Atlantic, say, INS would drift over time. So the aircraft would probably be off the nominal track by a number of miles once it reached the other side. As soon as it entered range of VOR/DME stations on ground, the position would be automatically corrected and it would return to the proper track.

An inertial navigation unit consists of a set of gyros and accelerometers. The accelerometers, one for each axis, detect acceleration, which together with time gives speed in each axis. The gyros, also one for each axis, detect angular acceleration (turning). So from a known starting point*, the position and attitude of the aircraft can be determined. Drift is normally less than a nautical mile per hour. Back in the day, gyros used to actually spin, but nowadays solid-state ring laser gyros are used.

GPS fixes did not exist, since no GPS. AFAIK, the Tristar used an early computerised navigational system where the next three fixes would be typed in, lat and long. The precursor to modern lateral navigation from an FMS.

*The reason parking bays have latitude and longitude displayed in front of the cockpit is so that navigation systems can be checked. Inertial navigation only works if the starting point is known.

Inertial navigation wasn't a big thing during WWII, it was developed for later ballistic missiles, and culminated with "beryllium baby" - AIRS - developed for MX missiles. There is a book " Inventing Accuracy. A Historical Sociology of Nuclear Missile Guidance" by By Donald MacKenzie.
Unfortunately, those are very expensive ($1M per unit in 1980, if I got it right) and tend to drift in time; what is good for 30 min of ICBM flight can be problematic for the multi-hour ocean crossing.
Laser gyros - with no fast-moving parts, where laser beam is spinning in a loop - were a better choice. I don't remember the numbers, those conversations were a while ago; I believe 10 km (6 miles) drift off-track on Atlantic crossing was the requrement where optics kicked in.
 
Chemist
Posts: 734
Joined: Tue Oct 20, 2015 4:46 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 7:55 pm

GalaxyFlyer wrote:
That’d be a long DR, about 1,600 nautical with lots of wind changes. Certainly, there’s no OpsSpec allowing it. Probably had a navigator with LORAN, celestial and Doppler.


Yes, he said that they used celestial as well. I got to visit a 720B cockpit and the glass dome was there above the FE panel.
 
Tristarsteve
Posts: 3663
Joined: Tue Nov 22, 2005 11:04 pm

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 8:29 pm

Here's a Trident with a moving paper map. Image


My first civil aircraft was the Trident. That map is driven by the Decca Navigator system using Decca's navigation beacons in Europe.
The three dials above the map were part of Cat3B autoland. The centre dial shows distance to go to the end of the runway. The crew dialed up the distance from the touchdown point before landing.

I remember flying between ARN and LHR on BA B737-200 many times in the 1990's. They flew the route up till 1999. They had no INS and no GPS.
There was a waypoint in the middle of the North Sea called Dunker. There was no beacon there, just a dot on the map. Anyway it was out of VOR range and the crew had to make this quite sharp turn on DR.
 
GalaxyFlyer
Posts: 5635
Joined: Fri Jan 01, 2016 4:44 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 9:04 pm

Inertial navigation wasn't a big thing during WWII


Well, considering Draper Labs started work on inertial nav in 1952, it wasn’t anything, big or small, in WW II.

GF
 
kalvado
Posts: 2733
Joined: Wed Mar 01, 2006 4:29 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 9:45 pm

GalaxyFlyer wrote:
Inertial navigation wasn't a big thing during WWII


Well, considering Draper Labs started work on inertial nav in 1952, it wasn’t anything, big or small, in WW II.

GF

World is a little bit bigger than US. Germany had some very advanced weapons - not that those were that efficient, but some things were ahead of the curve. So did some things on all sides, dire need makes people more inventive i suppose...
Anyway, Allies had nothing similar to german V-2 rocket - and V-2 utilized the inertial navigation system. (google "LEV-3 V-2 rocket"). It was pretty crude by today's standards; and V-2 itself had limited success - but it did exist.
 
GalaxyFlyer
Posts: 5635
Joined: Fri Jan 01, 2016 4:44 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 10:17 pm

I was thinking of the V2, but that’s not guidance so much as stabilization. It didn’t use controls to guide the missile to a pre-determined target, it just stabilized the initial trajectory and timed motor cut-off. The Draper INS could guide a missile to its target continuously.

GF
 
kalvado
Posts: 2733
Joined: Wed Mar 01, 2006 4:29 am

Re: Airliner navigation immediately before GPS

Mon Dec 02, 2019 11:08 pm

GalaxyFlyer wrote:
I was thinking of the V2, but that’s not guidance so much as stabilization. It didn’t use controls to guide the missile to a pre-determined target, it just stabilized the initial trajectory and timed motor cut-off. The Draper INS could guide a missile to its target continuously.

GF

One is pretty close to the other, to the point they are almost impossible to distingush. Most rocket flights have pretty limited, if any, lateral change as that consumes precious fuel. So would you call flight in a straight plane - e.g. Space Shuttle - controlled or stabilized? Initial rotation on the ground vs initial rotation after takeoff makes some difference, of course. But flight along pre-computed trajectory in a single plane is a common task. Its a gig of solid state rockets with limited control of thrust and burn duration what makes things more convoluted than they should be.
Besides, most importantly for this discussion, V-2 is said to have a gyrointegrator for speed integration and controlled engine cutoff. It is a single-axis integrator only, but that is arguably the keymost component of inertial navigation..
 
phllax
Posts: 588
Joined: Wed Jan 11, 2006 6:53 am

Re: Airliner navigation immediately before GPS

Tue Dec 03, 2019 4:51 am

What was an Omega?
 
RetiredWeasel
Posts: 789
Joined: Sat Jul 05, 2014 8:16 pm

Re: Airliner navigation immediately before GPS

Tue Dec 03, 2019 5:01 am

phllax wrote:
What was an Omega?


This will explain it better than I could.
https://en.wikipedia.org/wiki/Omega_(navigation_system)

We used Omega (dual units) on B-727s flying out of Guam to Japan, Korea, Taiwan etc for nav in the western pacific. Not quite as accurate as INS (which we didn't have in the 727s) but would usually be within 4 miles or so once in VOR range.
 
B2147
Posts: 10
Joined: Tue Apr 26, 2005 3:29 pm

Re: Airliner navigation immediately before GPS

Tue Dec 03, 2019 8:14 am

Tristarsteve wrote:
Here's a Trident with a moving paper map. Image


My first civil aircraft was the Trident. That map is driven by the Decca Navigator system using Decca's navigation beacons in Europe.
The three dials above the map were part of Cat3B autoland. The centre dial shows distance to go to the end of the runway. The crew dialed up the distance from the touchdown point before landing.

I remember flying between ARN and LHR on BA B737-200 many times in the 1990's. They flew the route up till 1999. They had no INS and no GPS.
There was a waypoint in the middle of the North Sea called Dunker. There was no beacon there, just a dot on the map. Anyway it was out of VOR range and the crew had to make this quite sharp turn on DR.


Hello,

Yes, those were the days…

Wasn't the name of that fix in the North Sea in fact "Dandi"? Brings indeed back nice memories, like the standard good old soutbound routing from ARN via the VOR's "Dunker", "Shilling" and "Hilda".
 
aeropix
Posts: 268
Joined: Mon Jun 06, 2005 2:08 pm

Re: Airliner navigation immediately before GPS

Tue Dec 03, 2019 2:45 pm

Woodreau wrote:
The last commercial flights that operated without GPS in the United States were probably flown by Beechcraft 1900D aircraft.... but in actual practice, flights rarely flew on airways, it was usually radar vectors direct when able.


Yes I remember those days, everyone was using handheld GPS and saying something like "If you could give me a Radar Heading of 267 degrees for 183 NM, that might send me direct to XXX fix (Wink Wink)", thus alerting the controller that you had the (non-approved, non-installed) navigation ability and often they would grand those long directs on that wink-wink nudge-nudge basis.

I remember everyone was using Magellan or Lowrance branded units, and that Garmin was mostly for cars or boats at the time! Now the former two companies have pretty much disappeared and Garmin is so market-saturated that they are even creeping into the biz jet and commercial markets. How times have changed!
 
Woodreau
Posts: 1899
Joined: Mon Sep 24, 2001 6:44 am

Re: Airliner navigation immediately before GPS

Tue Dec 03, 2019 3:35 pm

Lol mine was an $80 eTrex hiking GPS. I had all the airports we flew to saved as custom waypoints After takeoff, punch in direct to hiking waypoint.

I just asked ATC for a radar vector of “whatever the hiking gps told me.”

Tuned the on field DME in the VOR and everyone was happy.


I know none of the 1900s I flew at my airline had GPS, but when I happened to see the 1900s after they were sold, the new owners usually did install GPS, autopilot and flight directors, heated brake pads, etc. .none of the luxuries us lowly airline pilots were allowed to have operating under 121 carrying paying passengers.
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
 
User avatar
747classic
Posts: 3109
Joined: Sat Aug 15, 2009 9:13 am

Re: Airliner navigation immediately before GPS

Tue Dec 03, 2019 4:14 pm

mmo wrote:
Just a little bit more info about nav systems. The first "high tech" nav system installed was the INS. It had mechanical gyros which sensed acceleration in three axes and updated the position like that. The initial position had to be entered for the INS to know where it was. Nav accuracy was directly related to the length of the flight. The limit was 3+3T where T is the length of time the INS was in NAV. I am only familiar with the Delco Carousel units but they could hold 9-way points then you had to enter more as the flight went along.


Delco Carousel IV Inertial Navigation System (INS), very expensive to maintain, high failure rate.
Note the gimbel(s) , inside are the three accelerometers . All the circuitboards are for gimbel control and for the actual deadreckoning (computing acceleration, to speed and distance a function of time).

Image

See : https://airandspace.si.edu/collection-o ... al-airline

Carousel IV Control Dispay Unit (CDU), with only 9 waypoints.
Actual wind + direction was displayed as a funcion of computed INS airspeed, HDG and measured True Air Speed (derived from the IAS measured by the airspeed probes.)

Image

See : http://polytoximania.blogspot.com/2015/ ... oxing.html
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
RetiredWeasel
Posts: 789
Joined: Sat Jul 05, 2014 8:16 pm

Re: Airliner navigation immediately before GPS

Tue Dec 03, 2019 4:49 pm

747classic wrote:

Delco Carousel IV Inertial Navigation System (INS), very expensive to maintain, high failure rate.


NW replaced all the Delco's around the mid 90's with the Litton LTN-92s which had a laser ring gyro. Added much to the reliability while enhancing and simplifying crew procedures.

Until they retired their last 747-200 in 2007, there was never a GPS installed to interface with the INS position to correct it. Interestingly, when the EGPWS was installed, it had a dedicated GPS to run the terrain map, but the crew couldn't access it to see position or anything.
 
Tristarsteve
Posts: 3663
Joined: Tue Nov 22, 2005 11:04 pm

Re: Airliner navigation immediately before GPS

Tue Dec 03, 2019 9:06 pm

Wasn't the name of that fix in the North Sea in fact "Dandi"? Brings indeed back nice memories, like the standard good old soutbound routing from ARN via the VOR's "Dunker", "Shilling" and "Hilda".


Yes you are right. There was another in the North sea balled Beano!!
 
BravoOne
Posts: 4094
Joined: Fri Apr 12, 2013 2:27 pm

Re: Airliner navigation immediately before GPS

Fri Dec 20, 2019 7:09 pm

Chemist wrote:
GalaxyFlyer wrote:
That’d be a long DR, about 1,600 nautical with lots of wind changes. Certainly, there’s no OpsSpec allowing it. Probably had a navigator with LORAN, celestial and Doppler.


Yes, he said that they used celestial as well. I got to visit a 720B cockpit and the glass dome was there above the FE panel.



Just saw this one a could not resist adding to the thread.

More specifically in the Western Airlines case all the B707-347Cs and B720-047Bs were equipped with Bendix dual doppler, Edo 600T Loran and a periscopic sextant (no glass dome), mount adapted to a Kollsman sextant. For the first six to twelve months on HNL ops the that contracted for around 15 navigators from IASCO to teach the crews the in and outs of oceanic ops. They kept two of the navigators full time until the day came when there were no further Boeing ops on the central eastern pacific and the DC10 was used exclusively. Western had several pilots on their pilot seniority list with Flight Navigator ratings but they were never used for this operation.

The Bendix dual doppler, and Edo loran, along with the Bendix Polar Path Compass system was pretty much the industry standard for all airlines prior to the Delco Carousel first seen on the 747. As another poster pointed out the Litton and Collins INS systems made their way into the fleets as well.

Certain that at no time did WAL or anyother airline DR to HNL, or follow contrails although it did give you a comfortable feel when you saw a 747 above you obviously going to HNL:)
 
GalaxyFlyer
Posts: 5635
Joined: Fri Jan 01, 2016 4:44 am

Re: Airliner navigation immediately before GPS

Fri Dec 20, 2019 8:26 pm

A friend who flew 130s liked to tell the story of the nav on his first MCC-HIK leg buying drinks and celebrating his successful navigation on the longest overwater leg. Finally the crusty old major AC looked at him and said, “listen, nice job, but with 3 or 4 contrails in view the whole way, we were going to Honolulu, with or without your help, but thanks anyway.”
 
timz
Posts: 6582
Joined: Fri Sep 17, 1999 7:43 am

Re: Airliner navigation immediately before GPS

Sat Dec 21, 2019 9:41 pm

The Western 720B flights to Hawaii were all (?) day flights -- did the navigators bother sighting the sun thru the sextant, and drawing one position line on a chart?
 
BravoOne
Posts: 4094
Joined: Fri Apr 12, 2013 2:27 pm

Re: Airliner navigation immediately before GPS

Sat Dec 21, 2019 9:57 pm

timz wrote:
The Western 720B flights to Hawaii were all (?) day flights -- did the navigators bother sighting the sun thru the sextant, and drawing one position line on a chart?



Not sure where your going with that question? Cel nav is possible both during night and day and the only exception to that rule that I know of, would be during high latitude polar twilight when neither the stars, nor sun would be adequate for a celestial fix. WAL flew both night and day ops between the islands and the mainland and the nav would typically do six cel fixes on this route, relying mostly on the Loran and doppler for navigation. Recall that their job was to instruct the crews in the use of the Doppler and Loran and not use the cel nav for the most part. As a practical solution and as everyone got comfortable with the Doppler accuracy the nav would do a coast out fix and one more approaching the ADIZ just to make sure they were in the groove before entering. The Dopple accuracy was a direct function of the Bendix Polar Path compass system albeit it was not in a polar region. Hope that was not a long winded answer to your question.
 
thepinkmachine
Posts: 413
Joined: Tue Apr 28, 2015 4:43 pm

Re: Airliner navigation immediately before GPS

Sun Dec 22, 2019 5:03 am

@BravoOne - how would the NAV take cel fixes during daytime? I know the sun is there, but it only gives one LOP and for a proper fix you need 2 (preferably 3 lop's). Were they using the running fix technique, or some other tricks?

Also, I know it's a long shot, but...

I just got myself beautiful Kolsmann periscope sextant. It's in great condition, but unfortunately it's missing te bubble apparatus. Anyone know where I can get parts to fix it?
"Tell my wife I am trawling Atlantis - and I still have my hands on the wheel…"
 
Flow2706
Posts: 233
Joined: Sat Jan 28, 2017 7:20 pm

Re: Airliner navigation immediately before GPS

Sun Dec 22, 2019 5:24 am

There are still non-GPS airliners flying in Europe. In my company we have two A320s without GPS (build in the late 90's, so back then it was obviously still only an option when buying the aircraft from Airbus)...not a big deal, DME-DME updating and IRs are rather good an operationally there is really not much of a difference between A320 with and without GPS...the position updating etc is done automatically through the FMGC, so it's only required to do a navigation accuracy check once in some conditions (which is essentially comparing the FMGC position with a known fix, i.e. a VOR...if the FMGC position and the bearing/range from the VOR agree the FMGC position is accurate). You can also fly most RNAV procedures without GPS, but some procedures requires the aircraft to be GPS equipped. Also in some areas of the world there is some GPS jamming going on so you are navigation without GPS in these areas (for example in Cyprus).
I heard that Lufthansa also has a few A320's without GPS (they do have some really old aircraft in their fleet...), but I am not sure if that is true.
 
Swampfoot
Posts: 4
Joined: Fri Mar 18, 2016 6:07 pm

Re: Airliner navigation immediately before GPS

Sun Dec 22, 2019 5:50 am

We had Omega navigation systems in the 707-320C freighters we used with Buffalo Airways in Madrid and Stansted back in 1990. I think there were eight stations around the world, but only three were needed for a position fix.
A&P (1989), AME (Apprentice), Astrophotographer. I want to meet your cat.
 
BravoOne
Posts: 4094
Joined: Fri Apr 12, 2013 2:27 pm

Re: Airliner navigation immediately before GPS

Mon Dec 23, 2019 7:22 pm

thepinkmachine wrote:
@BravoOne - how would the NAV take cel fixes during daytime? I know the sun is there, but it only gives one LOP and for a proper fix you need 2 (preferably 3 lop's). Were they using the running fix technique, or some other tricks?

Also, I know it's a long shot, but...

I just got myself beautiful Kolsmann periscope sextant. It's in great condition, but unfortunately it's missing te bubble apparatus. Anyone know where I can get parts to fix it?


Your correct regarding the use of celestial plots during sunlight. A lot of DR was involved but it still worked out quite well. In the case of mainalnd HNL ops the ocean station November was always a good back up. As you may recall it operated with a grid that could pin point your position within 10NM....most of the time. Keep in mind that the Doppler and Loran were the primary nav tools during this time period.

Don't know a resource for Kollsman sextant parts but I think they may be still in business, making what I'm not sure. I gave away a nice Kollsman sextant a couple of years ago. I seem to recall seeing them on Ebay and it might be easier to just by another one and part it out. Is your unit from the USAF or does it have an airline code stamped on it?
 
BravoOne
Posts: 4094
Joined: Fri Apr 12, 2013 2:27 pm

Re: Airliner navigation immediately before GPS

Mon Dec 23, 2019 7:27 pm

Swampfoot wrote:
We had Omega navigation systems in the 707-320C freighters we used with Buffalo Airways in Madrid and Stansted back in 1990. I think there were eight stations around the world, but only three were needed for a position fix.


Some DC10's that we operated were delivered with dual Collins INS units. That was never a very popular INS and only a few operators used that> I guess the repair bills were quite high so the airlines removed one INS and substituted a Litton LTN211 Omega in its place. Seem to work pretty good and a lot cheaper to maintain.
 
Nicoeddf
Posts: 961
Joined: Thu Jan 10, 2008 7:13 am

Re: Airliner navigation immediately before GPS

Mon Dec 23, 2019 10:00 pm

Flow2706 wrote:
There are still non-GPS airliners flying in Europe. In my company we have two A320s without GPS (build in the late 90's, so back then it was obviously still only an option when buying the aircraft from Airbus)...not a big deal, DME-DME updating and IRs are rather good an operationally there is really not much of a difference between A320 with and without GPS...the position updating etc is done automatically through the FMGC, so it's only required to do a navigation accuracy check once in some conditions (which is essentially comparing the FMGC position with a known fix, i.e. a VOR...if the FMGC position and the bearing/range from the VOR agree the FMGC position is accurate). You can also fly most RNAV procedures without GPS, but some procedures requires the aircraft to be GPS equipped. Also in some areas of the world there is some GPS jamming going on so you are navigation without GPS in these areas (for example in Cyprus).
I heard that Lufthansa also has a few A320's without GPS (they do have some really old aircraft in their fleet...), but I am not sure if that is true.


You are right. LH is flying a couple 1st gen a320 without GPS.
Enslave yourself to the divine disguised as salvation
that your bought with your sacrifice
Deception justified for your holy design
High on our platform spewing out your crimes
from the altar of god
 
LH707330
Posts: 2317
Joined: Fri Jun 15, 2012 11:27 pm

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 2:45 am

Nicoeddf wrote:
Flow2706 wrote:
There are still non-GPS airliners flying in Europe. In my company we have two A320s without GPS (build in the late 90's, so back then it was obviously still only an option when buying the aircraft from Airbus)...not a big deal, DME-DME updating and IRs are rather good an operationally there is really not much of a difference between A320 with and without GPS...the position updating etc is done automatically through the FMGC, so it's only required to do a navigation accuracy check once in some conditions (which is essentially comparing the FMGC position with a known fix, i.e. a VOR...if the FMGC position and the bearing/range from the VOR agree the FMGC position is accurate). You can also fly most RNAV procedures without GPS, but some procedures requires the aircraft to be GPS equipped. Also in some areas of the world there is some GPS jamming going on so you are navigation without GPS in these areas (for example in Cyprus).
I heard that Lufthansa also has a few A320's without GPS (they do have some really old aircraft in their fleet...), but I am not sure if that is true.


You are right. LH is flying a couple 1st gen a320 without GPS.

...but I thought all innovation stopped after the A320 first flew ;)
 
Nicoeddf
Posts: 961
Joined: Thu Jan 10, 2008 7:13 am

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 9:02 am

LH707330 wrote:
Nicoeddf wrote:
Flow2706 wrote:
There are still non-GPS airliners flying in Europe. In my company we have two A320s without GPS (build in the late 90's, so back then it was obviously still only an option when buying the aircraft from Airbus)...not a big deal, DME-DME updating and IRs are rather good an operationally there is really not much of a difference between A320 with and without GPS...the position updating etc is done automatically through the FMGC, so it's only required to do a navigation accuracy check once in some conditions (which is essentially comparing the FMGC position with a known fix, i.e. a VOR...if the FMGC position and the bearing/range from the VOR agree the FMGC position is accurate). You can also fly most RNAV procedures without GPS, but some procedures requires the aircraft to be GPS equipped. Also in some areas of the world there is some GPS jamming going on so you are navigation without GPS in these areas (for example in Cyprus).
I heard that Lufthansa also has a few A320's without GPS (they do have some really old aircraft in their fleet...), but I am not sure if that is true.


You are right. LH is flying a couple 1st gen a320 without GPS.

...but I thought all innovation stopped after the A320 first flew ;)


Shhhhhhhhh! ;-)
Enslave yourself to the divine disguised as salvation
that your bought with your sacrifice
Deception justified for your holy design
High on our platform spewing out your crimes
from the altar of god
 
strfyr51
Posts: 4900
Joined: Tue Apr 10, 2012 5:04 pm

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 7:03 pm

Many years ago before GPS on the way to Hawaii there was an ocean station November which was some sort of floating Beacon or a ship there. We flew with the early inertials on the P3's with GACs and Flux Gates and a Huge Platform in an aft cabin closet. They required constant updating but we navigated around the world on UHF/DF cuts that pinpointed our location within 15FT. The first modern INS we saw was the early Litton 72, though I learned celestial Navigation as we had a plotter / azimuth scope on board though most of the time we used the port to vacuum the airplane after a Patrol. The Carousel and the later INS units I saw after leaving the Navy in 1977.
 
GalaxyFlyer
Posts: 5635
Joined: Fri Jan 01, 2016 4:44 am

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 7:39 pm

There were ocean stations (ships manned and run by the USCG and others) in the Atlantic and Pacific, primarily as weather stations but aided aviation
 
thepinkmachine
Posts: 413
Joined: Tue Apr 28, 2015 4:43 pm

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 7:48 pm

@BravoOne and @Styrfr51 and @Galaxyflyer, thanks for insight.

What kind of beacon was this station November? NDB, or or something more sophisticated?

As for my sextant, I think it’s a USAF one, but I bought it on some junkyard sale and have no details of its origin. It’s in pristine condition, has very good optics, fully serviceable mechanical averager, just missing the bubble apparatus...

Took it with me onto my 787 for an Atlantic crossing the other day. You should have seen the look of the faces of my F/O’s ;)
"Tell my wife I am trawling Atlantis - and I still have my hands on the wheel…"
 
BravoOne
Posts: 4094
Joined: Fri Apr 12, 2013 2:27 pm

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 8:23 pm

I use to have one on my desk at Boeing and told everyone it was the new advanced standby nav system for the 787. Got a few laughs from those that even recogonized what it was.

As GF mentioned the Oceans stations were run by the USCG as well as the Canadian Coast Guard. They worked in a Grid, each grid space being 10NM and labeled alphabetically. They would broad cast their position as a alpha value and you could plot your position as a reference to their known NDB position. They would give a relative bearing and distance from their grid.....Or at least that is how I recall they did it. By the eighties they had been disbanded as a cost saving measure. Probably only had a visual sighting on the ship once or twice in hundreds of crossings. I think they were "on station" for 60 days at a time?? The Ocean Station USCG Pontchatrain that handled the Pan Am Stratocruiser didtching in the 55/56 time frame was right up til the end in the 70's. Use to get the Stews up front to give them "well wishes" or special messages from time to time.

https://en.wikipedia.org/wiki/USCGC_Pon ... n_(WHEC-70)
https://en.wikipedia.org/wiki/Weather_ship
Last edited by BravoOne on Wed Dec 25, 2019 8:39 pm, edited 2 times in total.
 
BravoOne
Posts: 4094
Joined: Fri Apr 12, 2013 2:27 pm

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 8:31 pm

strfyr51 wrote:
Many years ago before GPS on the way to Hawaii there was an ocean station November which was some sort of floating Beacon or a ship there. We flew with the early inertials on the P3's with GACs and Flux Gates and a Huge Platform in an aft cabin closet. They required constant updating but we navigated around the world on UHF/DF cuts that pinpointed our location within 15FT. The first modern INS we saw was the early Litton 72, though I learned celestial Navigation as we had a plotter / azimuth scope on board though most of the time we used the port to vacuum the airplane after a Patrol. The Carousel and the later INS units I saw after leaving the Navy in 1977.



Had a freind who was flying the P3 in the late 60's and doing Pac flight with a technical stop on Midway. When they to took of the first thing he did was turn to a easterly heading as after all they were heading to the far east. Tells that joke on himself frequently. Wound up at Braniff after the USN and then a corporate operation after than. Funny guy!
 
GalaxyFlyer
Posts: 5635
Joined: Fri Jan 01, 2016 4:44 am

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 8:50 pm

I shoot with a guy that was assigned to the USCG Ocean Stations “back in the day”. They had radar that could send a radar fix to a plane in addition to the NDB. He said it was miserable duty in the winter North Atlantic, everybody would be sick, banging ice off the superstructure, dark and stormy. Yes, the USCG did 60 days on, 30 days in port. ICAO set up the program after WW II.

There was a Flying magazine article years ago about a DC-8 crossing and the airliner transmitted its INS position down to the ocean station to help them establish their position in a storm.
 
BravoOne
Posts: 4094
Joined: Fri Apr 12, 2013 2:27 pm

Re: Airliner navigation immediately before GPS

Wed Dec 25, 2019 9:17 pm

GalaxyFlyer wrote:
I shoot with a guy that was assigned to the USCG Ocean Stations “back in the day”. They had radar that could send a radar fix to a plane in addition to the NDB. He said it was miserable duty in the winter North Atlantic, everybody would be sick, banging ice off the superstructure, dark and stormy. Yes, the USCG did 60 days on, 30 days in port. ICAO set up the program after WW II.

There was a Flying magazine article years ago about a DC-8 crossing and the airliner transmitted its INS position down to the ocean station to help them establish their position in a storm.


Yea, I seem to recall them asking for assistance with their position but don't recall the details. I do recall one of the ships getting stuck on station for an additional 30+ days when the relief ship had a mechanical coming out of Pearl Harbor. To make matters worse it was over the Christmas holidays. N. Atlantic duty was probably a lot worse than the CEP. The guys on November would talk of swimming while someone watched for sharks. Argh!
 
cpd
Posts: 6376
Joined: Sat Jun 28, 2008 4:46 am

Re: Airliner navigation immediately before GPS

Thu Dec 26, 2019 6:53 pm

747classic wrote:
mmo wrote:
Just a little bit more info about nav systems. The first "high tech" nav system installed was the INS. It had mechanical gyros which sensed acceleration in three axes and updated the position like that. The initial position had to be entered for the INS to know where it was. Nav accuracy was directly related to the length of the flight. The limit was 3+3T where T is the length of time the INS was in NAV. I am only familiar with the Delco Carousel units but they could hold 9-way points then you had to enter more as the flight went along.


Delco Carousel IV Inertial Navigation System (INS), very expensive to maintain, high failure rate.
Note the gimbel(s) , inside are the three accelerometers . All the circuitboards are for gimbel control and for the actual deadreckoning (computing acceleration, to speed and distance a function of time).

Image

See : https://airandspace.si.edu/collection-o ... al-airline

Carousel IV Control Dispay Unit (CDU), with only 9 waypoints.
Actual wind + direction was displayed as a funcion of computed INS airspeed, HDG and measured True Air Speed (derived from the IAS measured by the airspeed probes.)

Image

See : http://polytoximania.blogspot.com/2015/ ... oxing.html


Those are a blast from the past! I remember what you had to do with long flight plans, not ideal compared with the convenience of today’s modern FMC units. Yes, some of these old INS units were updated with the ability to recall a portion of the route from memory, but still very rudimentary.

And don’t forget the card reader...
 
BravoOne
Posts: 4094
Joined: Fri Apr 12, 2013 2:27 pm

Re: Airliner navigation immediately before GPS

Thu Dec 26, 2019 8:30 pm

I believe the Litton LTN92 had a NDB from which to draw from and the L1011-1's that DAL operated had a Hamilton Standards NDB that lnterfaced with a poor mans FMS which enabled you to work around the Carousel IV, 9 wpt limitation, Unfortunately the Carousel itself had a MTBF of something around 1000 hours. Not good....

Who is online

Users browsing this forum: Baidu [Spider] and 28 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos