Use of VOR

[griff10]

Hi guys, this is my first post on PPRuNe, site looks great.

I am curious to know the role that VOR currently plays in commercial jet aviation. As GPS is utilized as primary navigation with ILS for landing has VOR taken a more secondary role as a redundancy system or does it still see some use during flight i.e on approach?

Also if there are additional forms of naviagation still being used in this area such as ADF, DME or IRS could you explain in what role these are used.

Thanks for the help!

[NG_Kaptain]

Welcome Griff,
I fly Airbus twin-isle aircraft, all are fitted with GPS. The VOR is secondary to our operation, I cannot think of the last time I used a VOR as a primary nav source, probably on the MD80 in the 80's. Remember using it on the DC9 doing some fairly long sectors over water and using it taking cross radials using the one in sixty rule to correct our track.


Cheers.

[bucket_and_spade]

Believe it or not, up until only a year or two ago, we used to occasionally fly raw data VOR approaches on our Boeing 757s...despite them being perfectly capable of flying the approach much more accurately by flying the approach with reference to the FMC position (primarily based on GPS if fitted) since they left the factory back in the 80s!

It was a certification issue which meant we weren't technically allowed to use the onboard technology to it's full extent.

Now we are fully approved for 'managed' approaches (i.e. approaches flown from an approach loaded in the FMC) - either purely GPS-based or an overlay of an existing VOR/NDB approach. The raw data from the navaid is still dislayed during the approach as a cross-check.

Some of our 757s still don't have GPS installed and sometimes suffer significant map shift so we occasionally revert to flying the raw data VOR/NDB approach.

Large UK charter airline.

B&S :ok:

[Pub User]

A lot of the Greek islands only have VOR approaches, so if flying into one of them with a machine that doesn't have GPS (there are still plenty around), you need to do a VOR approach.

It's also quite common in these same locations for the FMC to be unable to maintain required performance at lower levels, as there are not enough DMEs in range, so you may actually have to track the beacon rather than use FMC nav.

[ZOOKER]

Call me a nostalgic Luddite if you will, BUT:- It's like the ravens leaving The Tower Of London.
The day they turn Pole Hill off, the U.K ATC system will fall.

[griff10]

Thanks very much for the help guys, cleared it up for me!

[STBYRUD]

Outside of the 'aviation first world' where each runway has an ILS, for example in the Middle East, it is still very possible that you will have to fly an actual NDB or VOR approach - whether you will actually fly the needle or let LNAV do the work and monitor the approach conventionally depends on the operator and certification though. I flew to two airports recently that didnt have any kind of straight-in instrument approach but merely VOR or NDB based letdown procedures - always good fun (in nice weather ;) )

[Blinkz]

In the Airbus it uses a mixture of IRS and GPS positions to compute the aircrafts position. The IRS is updated using DME/DME and VOR/DME position fixing. As has been mention it is still common to use VOR approaches as well, either if the ILS is off the air or simply for small airports.

NDBs on the other hand seem to be quickly becoming obsolete!