How do Airliners navigate without GPS?

[Just a civilian pilot]

The two engines over ocean flights are laughably referred to as ETOPS flying.

Engines Turning or Passengers Swimming

Twin engine airliners have an amazing safety record and save airlines lots of money.

Unaware of any accidents that caused passengers to swim because of only two engines. Even the two engine Airbus 319 that lost power on both engines ( Sully ) and ditched ( still did not have to swim due to experienced pilots ) after sucking in lots of soccer ball sized Canada Geese , might not have been able to keep flying given how many birds were in front of it.

Airlines save money ( fuel, less engine maintenance ) and pilots get better performance given they are generally “ over powered” compared 4 engine aircraft ( if they have a big enough wing and can go high with the extra thrust ….B777 my airline flies cannot get up high when heavy high despite lots of power versus the A330 ).

The 4 engine A340 was ( except 500 series we flew ) a dog, performance wise versus the two engine A330 that we now use.

Fatal crash below involved a 4 engine jet due to birds.

1995 Alaska Boeing E-3 Sentry accident - Wikipedia

en.wikipedia.org

 

[billt460]

Speaking of trans ocean flying, there is something about watching this that is mesmerizing. If you stare at the bottom edge of the windshield, you really get an idea of the speed as the contrails zip by. And that is with at least a 1,000 ft. separation.

 

[SC Maintenance]

Sort of unusual, but I flew from Miami to Charleston recently, and we seemed to more or less follow I-95. I know the entire coast pretty well in general, and it was easy to know where we were. I was surprised, I figured they would be more likely to stay off shore a bit?

 

[Popsickle]

I flew the twin otter in the arctic for a bit in the mid 2000s. We had a very early and basic GPS that would regularly loose signal. It wasn’t a big deal as we technically were mostly VFR going in/out of unprepared surfaces with no navaids. One of the companies I worked for still had a celestial compass in each aircraft. I did a few trips in the winter (24h no sun) from Resolute to Griese Fiord, all I remember is it was VOR/DME visual with a big hill with a bunch of red lights on it right by the runway.

 

[Just a civilian pilot]

I flew the twin otter in the arctic for a bit in the mid 2000s. We had a very early and basic GPS that would regularly loose signal. It wasn’t a big deal as we technically were mostly VFR going in/out of unprepared surfaces with no navaids. One of the companies I worked for still had a celestial compass in each aircraft. I did a few trips in the winter (24h no sun) from Resolute to Griese Fiord, all I remember is it was VOR/DME visual with a big hill with a bunch of red lights on it right by the runway.

Which airline were you flying for if you don’t mind me asking?

 

[Exhaustgases]

Put it this way Lindbergh made is across the ocean with no GPS or any other fancy system.

 

[Cujet]

Although difficult to see here, there is a "Estimated Position Uncertainty" number displayed at all times (bottom right of the primary flight display) . It gives a number in Nautical Miles, and is basically a circle of error with regard to GPS.

As explained above, the triple "IRU's" need no input, and know exactly where the aircraft is. This is compared to the GPS position.

In recent years, I've never seen the number be anything other than perfect. However in the distant past, I did experience a brief GPS testing event, where GPS was way off.

 

[Popsickle]

Which airline were you flying for if you don’t mind me

Kenn Borek

 

[Popsickle]

I flew the twin otter in the arctic for a bit in the mid 2000s. We had a very early and basic GPS that would regularly loose signal. It wasn’t a big deal as we technically were mostly VFR going in/out of unprepared surfaces with no navaids. One of the companies I worked for still had a celestial compass in each aircraft. I did a few trips in the winter (24h no sun) from Resolute to Griese Fiord, all I remember is it was VOR/DME visual with a big hill with a bunch of red lights on it right by the runway.

My mistake, it’s been a while, Griese fiord like most other communities in the Arctic had only NDB/DME.

 

[billt460]

Has anyone ever tracked down the guy whose voice is the one in the cockpit that says, "Terrain Pull Up"!... Or "500"... "400"... "Minimums".