The VOR indicator

[babyboeing400]

On the top left corner of the VOR display,there's NAV and VLOC...i know VLOC stands for VOR localiser..but what does NAV mean? What does it mean when NAV illuminates instead of VLOC? thanks lots...:O

[despegue]

Which aircraft are you refering to?

I PRESUME that your NAV function handles LNAV (Lateral Navigation) through the FMC, so your needle points to your next waypoint. This is how it works on non-EFIS B737's at least (more or less)

[babyboeing400]

nah....i'm flying the Diamond DA40 actually..a single-engine prop plane..i'm still under training...:-p

[BEagle]

On some displays, it is possible to select a GPS waypoint to waypoint cross-track error signal to a VOR-type display. Perhaps your 'NAV' display illuminates when this the source for the CDI indication?

Oh - and never 'plane'! That's something used by a carpenter. We talk of 'aeroplanes' or generically of 'aircraft'. Those who don't use the Queen's English talk of 'airplanes' though.

[Brooklands]

BB400,

Perhaps the two lights are there to indicate the type of the nav aid you're tracking, as the localizer is 4x more sensitive (2.5 degrees at max deflection) than a VOR (10 degrees at max deflection)

Brooklands

[strafer]

Remember the five 'P's BEagle...

Proper personality's prevent pointless pedantry;)

[Wunper]

Strafer

I'm with Beags on this one

"planes" are what non aviators catch to go on holiday in.

:}

W

ps While I'm at it the other one that makes me wince are people calling Ships "boats" We all know that a boat is either a vessel that submariners go to sea in or a craft that one rows across the serpentine ;)

[threegreenlights]

OK OK I know it's a tad off thread BUT....

Isn't a BOAT something that can be lifted out of water and a SHIP something that you have to remove the water from - i.e drydock.

Perhaps that's why I fly and not sail?
Can any seadogs confirm please?

[TheOddOne]

I believe submariners refer to their craft as 'boats'.

They also have a lovely saying:

'There's 2 sorts of craft in the ocean. Submarines and targets.

Coat, hat, in hand, door handle in other....


The Odd One

[Spitoon]

I think you'll find it's to do with the 'sensitivity' of the receiver. When you're tracking a localizer you want to know quickly if you're drifting off track whilst in NAV mode slight drifting is less imoportant so for a particilar deviation from the nominal track the needle will show a greater swing in VLOC mode than in NAV mode. It's a long time since I used thought about such things but I seem to recall that one box I've used was five times as sensitive in VLOC, i.e. a one degree deviation in VLOC would give one a dot deflection whereas in NAV you got the same one dot when you were five degrees off track (or something like that).


Edit - Sorry, I thought they were buttons but on re-reading the original post I see they are indicators.

[Cabin doors 2 manual]

Nav Warning means the signal is too weak for the vertical needle to correctly register and should be ignored.

and

VLOC (usually GS) Warning means the signal is too weak for the horizontal needle to correctly register and should be ignored.

[jau]

In the 18-19th centuries a ship was defined as a first rank sailing vessel having a bowsprit and three or more square-rigged masts (ship-rigged), each composed of a lowermast, a topmast, and often a topgallant mast.

My maritime law books define a ship as having 'a continuous upper deck.'

:hmm:

[DFC]

I will have to look up the book. However, I think that the answer to the original question is;

VLOC - VOR or Localiser information (depending on frequency in Nav box) - the dots represent angular deviations from a point source (the VOR or the LOC).

NAV - GPS derived information is displayed and the dots represent a certain fixed distance parallel to the chosen track.

Basically, keep it one dot right in VLOC and you will get there (just not on the chosen track) but do the same in NAV and you will never get there - you will simply parallel the desired track and pass 1nm or whatever the scale to one side of the waypoint.

The book should give the exact info.

Regards,

DFC

[NoTurningBack]

bb400,

I fly a Diamond Star DA40D which uses a garmin GNS430.
This is a link to the manual for the CDI unit in the aircraft that I fly.
Verify that yours is the same and you should find all you need to know.

http://www.midcontinentinstruments.com/master1.html?manuals.html&1

For some reason my first link would not work, if you go to the above page you need to look at the MD200 series CDI's.


Good Luck


NTB

[Piltdown Man]

It's a fair question. I was going to answer that a read of the appropriate manual should answer the question. But if the manual as suggested by No Turning Back is correct, it is of no real use. IMHO the flags VOR, VLOC and GPS are source indicators. I reckon that there will also a source selector panel somewhere else and it will say something like NAV1 and GPS.

As an aside, I never understood any of the electric gismos in any powered aircraft untill I did my IMC rating. I also felt that I had no need and with hindsight I think I was right. TLAR is still the best nav system known to man.

[NoTurningBack]

PM,

They are source indicators, on our aircraft the selection of GPS/VLoc is made through the GNS430.
Press the CDI Button to select GPS or VLOC.

The Nav/VLoc selection is made through the frequency used in the Nav receiver.

(We have VLOC,NAV & GPS indicators on ours).

TLAR :confused:

NTB

PS I agree, not a great manual the clues are implied

[Piltdown Man]

TLAR = That Looks About Right

[ShyTorque]

Does this indication not merely indicate, as appropriate, a VOR or an ILS frequency, tuned on the appropriate NAV box?

Next time you fly try selecting your local VOR, followed by the nearest ILS frequency and observer if the indicator acknowledges the fact and changes over.

Our displays default to "NAV" / "ILS" on start (depending on the selected "NAV" box selection). We normally change the display over to "FMS" on the control panel so we can observe the flight director following the programmed route.

[Piltdown Man]

Yes but... Say you tune in a valid localiser frequency and select it for navigation. The VLOC annunciator (light or flag) should show that this is the selected source BUT only if the signal is valid will the CDI and Glideslope flags disappear.

[ShyTorque]

Piltdown Man,

Yes, of course, you would obviously need to carry out that check in the vicinity of a suitable ILS signal. However I think I don't understand your point. :confused:

P.S. On our aircraft, the ILS localiser and the glideslope displays only appear when valid, as it's an EFIS display.