VOR check

[treadigraph]

Noticed this chap describing a circle some 25 miles out from and around the London VOR. Just wondering what he might be checking? All the radials are working? Got a quick glimpse of his strobes as he passed here a couple of minutes back!

https://www.pprune.org/members/45458-treadigraph-albums-treadders-picture1188-vor.jpg

[Pugilistic Animus]

That looks like a (perfect) DME arc...but perhaps it's an inspection of some sort

[KelvinD]

Doesn't the call sign, VOR1, give a clue?

[treadigraph]

Yes it does thank you, I wondered what the check actually establishes.
Looks like he completed about four orbits before making a run down to St Catherine's Point and following a radial back to the VOR at 11000.

[Toadpool]

I suspect it's a flight check of a co-located DME, not the VOR.

[wiedehopf]

DME is not much to check i believe. you just need to check for good reception the technical precision is monitored on site i think.
after all DME just answers queries with some specified delay and the plane calculates distance from travel time minus specified delay.

just as an example a few days ago the FAA did a similar circle around DPK (Deer Park VOR near JFK).

now check the following NOTAMS with some DPK radials unusable.
(!ISP 04/136 (KJFK A2982/18) DPK NAV VOR 087-095 UNUSABLE 1804231222-1810311800
!ISP 04/135 (KJFK A2981/18) DPK NAV VOR 060-077 UNUSABLE 1804231221-1810311800
!ISP 04/134 (KJFK A2980/18) DPK NAV VOR 025-045 UNUSABLE 1804231220-1810311800)

so i would say they check both DME and VOR but the DME part is technically much more reliable i believe.
that's why for RNAV triple DME can get you good precision when you don't have GPS.

also the problem with the VOR isn't necessarily the radiating structure but reflections of the signals on certain radials resulting in errors.

[TelsBoy]

All navaids get flight-checked at regular intervals/at installation/after major corrective work (usually aerial work).

Regarding the above post and the NOTAMs it sounds like innaccuracies outwith acceptable tolerances were found on the noted radials, hence the NOTAM.

[treadigraph]

Thanks guys. Never noticed that activity before but then again normally at 1am I'm tucked up in bed! It's sometimes quite interesting to see what's noodling about on ADS-B in the wee hours if you can't sleep or got back from the pub late..,

[Carbon Bootprint]

Thanks guys. Never noticed that activity before but then again normally at 1am I'm tucked up in bed! It's sometimes quite interesting to see what's noodling about on ADS-B in the wee hours if you can't sleep or got back from the pub late..,
Where’s that “like” button again? :ok:

[Pugilistic Animus]

You know that could also be a 'radius to fix turn.
I think it would be a very interesting experience to ride on a flight check flight