15
$\begingroup$

In the olden days there used to be a navigation officer in commercial airlines who had the tasks of navigation and radio communication. But, in modern commercial airliners there is no navigation officer.

Do the pilot(s) take the additional responsibility of radio communication and navigation? Or is the navigation part now done by onboard computers and systems?

If the electronic navigation system fails, are there any backup plans? Are physical maps and a compass then used to determine the direction and position?

$\endgroup$
21
$\begingroup$

Navigation has gotten much simpler over the years. Initially, navigation would be done by a combination of dead reckoning, looking out the window for landmarks, and for night or long-distance flights, by celestial navigation (many old airplanes have a window at the navigator's station specifically to let the navigator see the stars). This took quite a bit of time and effort, so the pilot couldn't do it and also fly the airplane.

In the 1920s, radio navigation was added to the navigator's toolkit, but finding bearings to beacons and calculating a location was still an entirely manual process. Additionally, radio beacons didn't cover the entire world, so older navigation techniques were still needed for most flights.

In the 1950s, fully-automatic radio direction finding systems became common and navigation beacons were available across most of Europe and North America. At this point, the workload involved in navigation dropped to the point that the pilot could also navigate: plot out the sequence of NDBs to follow ahead of time, then tune the radio and follow the navigation display.

Very recently, navigation has been integrated with the autopilot to the point that the pilot can punch in a sequence of waypoints and have the airplane fly the route entirely on its own.

And yes, even today if the electronic navigation system fails, the fallback is map, compass, and slide rule.

| improve this answer | |
$\endgroup$
  • $\begingroup$ But the sextant has been removed from the fallback, I guess. $\endgroup$ – cpast Mar 23 '15 at 17:30
  • 5
    $\begingroup$ I would note also that "the electronic navigation systems" consist of a bunch of different independent systems (NDBs, VOR/DMEs, GPS, INS) and the chance of all of them failing is negligible barring, say, an EMP. Of course, in the EMP case, your first concern will probably be that your engines just stopped working, thanks to very unhappy FADECs. To further complicate matters, the pax will be complaining of dead IFE systems and PEDs. :) $\endgroup$ – reirab Mar 23 '15 at 20:59
  • $\begingroup$ ...and no lights, no AC, sudden quietness in the cabin as the engines have stopped.... $\endgroup$ – Burhan Khalid Jan 7 '18 at 7:05
  • $\begingroup$ @BurhanKhalid ...followed by screaming. $\endgroup$ – T.J.L. Jan 8 '18 at 19:39
3
$\begingroup$

The other answer to this is just how I would have said it however I will respond to your second point of electronic failure and what you can do.

First off I am sure you know that airplanes carry a great amount of redundancy to avoid this and the changes of everything failing is almost 0 but lets say it does happen. I will go through what you can do and what backups you have. First lets talk GA VFR situations.

I am only VFR rated and fly only single engine planes. When it comes to navigation I have 2 options, paper maps, and no the electronic flight bag which I have just moved to. When I fly i carry my iPad (with external GPS receiver) and my iPhone. Both have the east half of the country worth of maps and procedures/info downloaded to them and independent GPS receivers. My pre-flight starts the night before making sure I have everything charged up. Now I'm in the plane my iPad overheats or crashes, I move to my phone, buys me another 30 min then it crashes, I move to my paper maps, compass and stop watch. As for stop watches I usually have 3, a chronograph on my watch, a hand held mechanical, and the one mounted in the plane (some times there are 2 mounted depends on what I am renting that day). This allows me to fly dead reckoning to my destination using my map, plotter and flight computer. Again doing some guesstimating in my head and some quick calculations. Now lets say for some reason none of my stop watches are working, my maps flew out the window, and I dont know any of the VOR frequencies in the area.

Look out the window until you see a landing strip, then buy some new maps...

Now lets move to some bigger planes. Large planes carry numerous electronic navigation aids. Along with using GPS, they have inertial navigation systems which are capable of working on their own. Although inaccurate (by today's standards) they will tell you how far/fast you have traveled from which you can extrapolate location. Since commercial planes fly under IFR most of the time, assuming one of the radios on the plane is functional ATC can guide them down assuming all of their equipment is no longer working. Again in the end of the day physical maps will get you where you need to be although I dont know if large planes carry VFR maps along with their IFR route charts.

Again the key here is redundancy and the fact that its highly unlikely that all systems on a plane will fail simultaneously. That being said even if it does happen the pilot should have a fair idea of where they are/where they are going and should know a general compass heading to divert to another airport.

Historically navigation equipment was also more cumbersome than the iPad I have on my knee board and knowledge aside, a navigator simply provided another set of hands and eyes to operate the devices which were often mounted behind the pilot. There is only so much display area on an aircraft dash for gauges and devices.

For what its worth its also worth noting that flight engineers are on their way out now. The 747 which once required an engineer eliminated the need with the 747-400 variant by including glass cockpits making everything available to the pilots. If you read up on the early days of aviation you will also find that pilots were often their own mechanics, fixing the planes at stops and what not. In a way its not that we don't need the position it's that the task has been offloaded elsewhere.

| improve this answer | |
$\endgroup$
  • 1
    $\begingroup$ Surely you mean GPS reciever and not transceiver? $\endgroup$ – user Mar 24 '15 at 12:37
  • 1
    $\begingroup$ My mistake you are correct, there is no transmission involved. $\endgroup$ – Dave Mar 24 '15 at 13:26
0
$\begingroup$

The basic job of a navigation pilot is to mark all the landmarks on his map and to verify whether the plane is going in the right direction.There is a high probability that the plane might miss a landmark and create a confusion among the pilot and the navigator. Now we have GPS,which is more accurate and easier for the pilot.You get every piece of information there is.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.