If I hopped on a 747 in 1980 and flew from San Francisco to Sydney Australia, how would the crew navigate the flight?

Pretty sure it was Inertial Navigation.

INS

Early 747s though had a port in the top to navigate by the stars.

Celestial Navigation

Loran or Inertial Navigation Systems would be my guess.

Recall that Charles Lindbergh had none of that. Pretty amazing.

Giant Arrows on the top of mountains ??


Washington County, Utah

I thought it was IFR.

I Follow Rivers and I Follow Roads

quote:

Originally posted by TomV:
Giant Arrows on the top of mountains ??

quote:

Originally posted by Yanert98:
I Follow Rivers and I Follow Roads

Good luck finding rivers, roads, or mountains in the middle of the Pacific Ocean between California and Australia.

Interesting. VORs were in use in the 1950s, but their range is only about 200 miles.

Just hunting around I found the VAR systems before VOR has a range of about 100 miles.

The Inertial Nav Systems require a bit more thought.



https://youtu.be/ekzwbt3hu2k

+

kz1000,

they just shot an azimuth and went for it?

quote:

Originally posted by kz1000:
[map image]

"Okay, Steve. So according to the Pacific Ocean map, you're going to hang a left at this big wave, then a gradual right at that other big wave, then straight on until you pass the tiny speck of an island that you'll miss if you blink, then..."

I can’t speak for a 1980’s commercial airliner but in the circa 1970’s A-4 Skyhawks I flew as a flight instructor we used TACAN.

“A tactical air navigation system, commonly referred to by the acronym TACAN, is a navigation system used by military aircraft. It provides the user with bearing and distance (slant-range or hypotenuse) to a ground or ship-borne station. It is a more accurate version of the VOR/DME system that provides bearing and range information for civil aviation.”

The Harrier version I flew had INS and TACAN for navigating.

For large over water navigation away from navigation stations they may have used time/distance/heading and/or celestial navigation but I’m not sure. For my one TransPac we just followed the KC-10 like ducklings after their mother.

You think it was tough for a 747 to fly as you described in the original post?


You need to read this story, Pan Am Clipper had to fly the wrong way around the world to get home to New York Harbor in the days after Pearl Harbor. They didn't even have proper maps!!!!! And as it's a seaplane, they can't land on land. Fuel was a problem.

The plane was deemed to be a strategic asset to America and we needed it back, not lost to the Japanese.

I bought the book after I read this web story, it's multi pages so be sure to look for the link to the next page at the bottom of each.

I love this story and I don't know why it hasn't been made into a movie or video documentary.

It's astounding that they were able to do this seemingly impossible task, but they did.

I hope you enjoy this story, and think of how it happened.

Pan Am Clipper, Boeing 314
.
.

That doesn't work over the vast expanse of the Pacific. Maybe you'll see an Island every couple of hours.

quote:

Originally posted by Yanert98:
I thought it was IFR.

I Follow Rivers and I Follow Roads

1980 in the 747 would have been the older style Carousel INS units and of course, all-analog instrumentation.

The 747 did feature a sextant port near the cockpit door, and paper plotting charts. Paper plotting charts are still in use today for oceanic legs.

I flew one of the las 747-100's in service, and in fact parked it on its final flight. By then, it had triple IRS navigation, with triple GPS, DME/DME, etc.

The older Carousel units only held a few waypoints, meaning that the trip couldn't be put in the box; only a few waypoints ahead, and the unit continuously had to have fixes added as the flight progressed, with paper calculation of fuel and time, and all-manual HF position reports, per typical oceanic flying.

INS, or inertial navigation system (IRS: inertial reference system) uses a system or gyroscopes and accelerometers to detect movement. The system is initialized at the departure location with an accurate position, and over the course of the next hours, gradually degrades in accuracy. The INS system doesn't require external input: it doesn't require ground based radio stations, or satellite based navigation. It's self-contained. It does, however, continuously have position error increases as the flight progresses. INS gyros became laser ring gyros with IRS units, and eventually progressed to solid state accelerometers that experience less deterioration in accuracy. With GPS input, the units are continuously updated, so that accuracy remains quite precise over long distances.

The INS units also provide input for braking systems, instrumentation, and other systems operational aspects of the airplane.

quote:

Originally posted by TomV:
Giant Arrows on the top of mountains ??

It worked for the Post Office.

^^^what sns3guppy said^^^
When over water, INS used to be the primary means of Navigation (prior to gps), when once past useful range of line-of-sight land nav. transmitters (VORs). GPS is much more accurate than Loran, or INS ever was. VORs too, for that matter.

When did commercial airlines stop using navigators as part of the crew?

I took a class in advanced radio navigation back in pilot school (UAA) from one of the original flying tigers freighter pilots (retired FedEX). He taught us how to work that RMI needle, and the principals and application of dead reckoning. I've flown military transport over the water long distance several times...using the mars radio (HF) to relay position reports. We may have more modern methods these days, but the transoceanic system still uses a lot of dead reckoning principles. Even with an inertial navigation system the principles of GIGO still apply. Flying to the Azores once a nav tried showing me how to use the sextant, but I was lost. I wish I had cared more at 19...and soaked up that knowledge. I flew with some really awesome crews over the years, and now that I'm a pilot I wish I had absorbed more and asked more questions from the old guys.

quote:

Originally posted by mojojojo:
For my one TransPac we just followed the KC-10 like ducklings after their mother.

I sure hope so

I'd stay REAL close too.