ATCers Radar Out - ???

[minitour]

Back when I got here in Sept, we had a day of pretty low IFR (don't recal the details) and the radar happened to go out...yikes.

Anywho, the weren't letting any "training" flights out unless you were /G because they were only letting GPS approaches into and out of the airports.

Just wondering why.

I know there's procedures in place for non-radar environments, but...any reason for ONLY GPS approaches?

I can't imagine this being something that would happen routinely (sp). If someone blasted off w/o GPS and then radar went down...you couldn't make him do a GPS approach.

Just curious as to what could have been the possible reasons behind it?

-mini

 

[88_MALIBU]

Well Im not sure but it may have had something to do with the pilots instantanious lat and long knowledge incase he needed to give it.

 

[minitour]

Well Im not sure but it may have had something to do with the pilots instantanious lat and long knowledge incase he needed to give it.

ah...that makes sense now

Thanks

 

[User546]

For clarification, did just the tower loses its radar feed, or was the whole "approach" area down without radar?

 

[minitour]

For clarification, did just the tower loses its radar feed, or was the whole "approach" area down without radar?

approach...

Which would have made ILSs really REALLY suck...

I couldn't imagine all those airlines having to hold and do full procedures (those are emergency procedures, arent they?)....yikes!

Still...if its all you got...

 

[U of I Tweak]

Before GPS

Well Im not sure but it may have had something to do with the pilots instantanious lat and long knowledge incase he needed to give it.

Correct me if I'm wrong....but didn't there used to be a time when no one had a GPS, and radars failed? I can understand keeping training flights to a minimum when the radar's out, just to keep revenue flights from wasting time with excessive holding and such, but I would hope they know how to handle traffic without GPS when the radar goes down.

-and malibu, this is not meant as a knock against you or anything...I'm just hoping that controllers, like many pilots I know, aren't getting too reliant on their magic boxes.

 

[Vector4fun]

I'm only guessing here, but the primary backup system for most Terminal radar facilities should the radar site go down is CENRAP. Basically, the Tracon pulls radar data from a nearby Center site via modems. This data is then processed thru the ARTS much like our normal radar data. The result, however, is sort of like Radar in slooowww motion. Since Long Range radar only updates at like 1/3 the rate of terminal radar, (slower sweep), plus the limitations of a modem for data transfer, the targets we see are like 30-40 seconds behind the actual aircraft. That's a loooonngg time for a jet. We're not allowed to use Mode C for separation under CENRAP.



Mini, was OKC providing approach control in the area, or was ZFW? I'm just guessing there wasn't good enough radar coverage at low altitudes for vectors to the final approach course, and they only wanted aircraft that could navigate directly to an IAF allowing a straight-in approach. Also that could navigate directly to specific enroute fixes.

And to answer U of I, I haven't had a non-radar refresher in years and years. Some newer folks have *never* worked non-radar except, perhaps in a lab. We have some basic procedures in the local books, but never practice them. What's scary is that if the ARTS computers crash, there is no CENRAP either. Now my facilty has dual ARTS processors, but many smaller ones do not. Even though I did nothing but non-radar approach for 5 years, the airspace here is not set up for non-radar at all, neither are the approaches and transitions. It would be very slow and messy...

 

[minitour]

Mini, was OKC providing approach control in the area, or was ZFW?

Normally its OKC...that day I don't know if it was them or Ft. Worth...didn't get up. Weather was pretty low, but a few students called for clearance and were told "unable IFR"...that's all I can go by

-mini

 

[Kawasumi_Kichou]

Following on Vector4fun's comments, what's funny is when the radar goes down, it's usually the newest guys in the facility who end up taking over the sectors, since they are the most recent out of the academy and the most current on manual or non-radar procedures. The FPLs just call for a supervisor and unplug.

I've only personally experienced it once, while flying in ZLA airspace. Was fun listening to the guy ask for everybody's estimates to their next reporting points. Everybody was scrambling. Fun in mean sort of way.

 

[wxman13]

Cenrap

The mentions above about seldom/nonexistent refresher training for non-radar work wig me out a bit. When I got a tour of Chinook Approach (KPSC area) they actually switched over to CENRAP on one scope because they were training a controller. It was interesting to see it work, but man, can't the FAA shell out for faster modems or something? Wait, I'm sure I already know the answer to that...

The whole lack of hiring thing has been getting a fair amount of press lately, but as a pilot with only a shred of knowledge of the ATC world, non-radar sounds like kind of important training. Kind of like flying partial panel under the hood. I'm guilty of not doing that in the last year, so maybe I'm just as bad...

 

[Vector4fun]

Well, I didn't mention, but could have, that if the ARTS goes down, there's still also a "10 channel beacon decoder". Basically like radar from the late '50s. We can assign all arrivals, say, code 5100, and all overflights code 5000, and leave the departures on their discrete code for Handoff to the Center. When we set that up, code 5100 will have (for example) double beacon slashes, code 5000 will have 3 beacon slashes, and normal discrete codes a single slash. There are no tags or Mode-C at all. Don't have any "shrimp boats" to drag out of the closet any more. That said, I haven't even used the decoder in 6-7 years...

Were we to loose all radar here, we'd probably give much of our airspace back to the Center and let them use their Radar down to 50 or 60 or so. They'd clear aircraft to one of the LOMs and stack them in holding, we'd just take them off the bottom of the stack one at a time, and scream like bloody mad for Techs on overtime...

 

[SkyBoy1981]

Like Vector said, its probably because they want you to be able to navigate to the most straight in IAF possible. Sometimes this requires GPS or RNAV to accomplish. GPS approaches often have the "T" design so that its easy for aircraft to establish themselves on the procedure without holding or procedure turns. All you have to do is go straight to one of the IAF's, and you're on the approach. This would be much more efficient in non radar than sending everyone to some LOM to enter a holding pattern or procedure turn for course reversal.