TAF help what is VDN

[blue monday]

Was oing a flight plan into Annecy LFLP yesterday and the TAF had 9000VDN, neither i knew what VDN stood for, niether did my ops manager or the Pilot??:eek::confused: anyone know what it ment

[Bullethead]

G'day Blue,

Are you sure it wasn't a typo?

NDV is an abbreviation for No Directional Variation, so 9000NDV would mean 9000 metres vis in all directions.

Regards,
BH.

[Spitoon]

I think I've come across this abbreviation in French (perhaps only French MIL) stuff. Although why it might be used in a TAF in this way I don't know - but if it helps....

VDN = vol de nuit = night flight

Bullethead's response seems to make more sense but I would have expected a typo to get picked up by the filtering/validation that is common on such messages. The only other thing that comes to mind is that although it's a while since I did met stuff, if there was no directional variation in the vis just one value was given - if it did vary a second value and a qualifier was included.

[blue monday]

Could be a Typo i suppose but i should have thought any TAF or METAR would be double checked before being submitted.

[oz in dxb]

These letters are used to determine the RVR (Runway visual range) for a specific R/W.

They are used in METAR, SPECI and TAFs

R=R/W
N= No change in the RVR
U= Up/improved RVR
D= Downward/deteriorating RVR
The letter V is used when a minimum and maximum RVR is specified
P= more than
M= less than

Oz

[usedtofly]

Hi Blue,

To be precise, NDV is No Directional Variation on AUTO METARs only

Cheers

UTF

[blue monday]

Hi Blue,

To be precise, NDV is No Directional Variation on AUTO METARs only

Cheers

UTF

Thanks UTF, will let the others know too.:ok: