NOTAM FORMATS AND MEANINGS

[Edgefly]

Ran into a couple of new(to me,at least) situations in Notams and solicit any specific guidance from those who may know. The first has to do with a current NOTAM which says ELZ Tacan ots (out of service) for DME and Azimuth ....Until some date. Since this navaid also provides VOR services lcl to my home base, I was curious if that meant that the VOR was also inop. Pursued this with the CFI at a local school and he wasn't sure either. Later I asked the weather briefer if he knew (he didn't) and couldn't say who I could ask. I've since done a little research and haven't been able to find anything in AIM, PHAK etc. Second situation arises in the form of GPS notams which indicate at least in areas close by that GPS services are limited by pseudo random noise with some additional coded info which is probably effected areas and dates and perhaps degree of impairment.

So, my question is where is the source of format information for NOTAM formats ? If it is necessary to contact the FAA directly, which office/section/group or whatever ? Incidentally, the VOR service is in service at ELZ even if the Tacan service is apparently not. This is presented as only a single case not as a general principle.

 

[poadeleted20]

Navaids like that can be any one of the following:

VOR -- VOR azimuth only
VOR-DME -- VOR azimuth plus DME
TACAN -- TACAN azimuth plus DME
VORTAC -- both VOR and TACAN azimuth plus DME

This is explained in the Instrument Flying Handbook, Chapter 9, as well as the AIM Section 1-1.

As shown on the L-chart and noted in the A/FD, ELZ is a VORTAC, and so has all three signals. If ELZ's TACAN azimuth and DME are OTS, that leaves the VOR azimuth (the one you need for the VOR-A approach to KELZ) operational unless that portion is otherwise NOTAM'd OTS. However, the loss of the DME signal means the LOC/DME RWY 28 approach is NA unless you have GPS to identify the HALOS DME fix which is the IAF/FAF.

You can google pseudo random noise (PRN) and GPS if you really want, but the GPS pseudo random noise NOTAMs on a couple of satellites don't effect much of anything unless you don't have five other fully operational satellites in view, and there's not much you can do about it anyway. Your GPS takes care of this without your help.

 

[BillTIZ]

I would suggest that if it said the TACAN was OTS for AZ and Distance that the UHF freq had the problem and not the VHF VOR AZ information, but I would not expect DME information.

If it said the VORTAC was OTS for AZ and distance then any communications over the VHF freq HIWAS etc was still usable.

 

[denverpilot]

Caveat to Ron's well written reply...

I've had a TACAN NOTAM on a VORTAC turn into a full blown VORTAC outage on me before.

If the NOTAM is the standard NOTAMs they're issuing for reception problems in a certain range of bearings off the facility these days, that's one thing.

When they issue a maintenance NOTAM, that usually shows up as a complete outage, so remember when you see one, that some fool is down there messing around in the equipment rack with a screwdriver.

Other stuff may fail. Always. Tune and identify. And if the flag acts goofy, ID it again.

 

[Edgefly]

Thanks for rational replies gents. I guess it's up to me to sort out the importance of the gps notams. I'll try that.