Radar contact lost

NASTPO Newcomer Florida

I have a questions regarding the 3 sweeps and 15 seconds rule i have been looking for a straight week for the guidelines of calling radar contact lost and I cannot find it anywhere! So here are my 2 questions
1. Your doing an ASR approach (using STARS scope) And your primary target drops, however you still have the secondary how long until you have to call RADAR contact lost?
2. if anyone knows where can I find that answer? word of mouth is a dangerous thing and the whole point is to find out where it is. If anyone can even point me in the right direction I would be very grateful I have searched every pub I have access to ie: 7110.65s, 80t-116 , AIM, AOM, STARS manual, human factor reports, shoot i even looked in the RWOP and FWOP.

xxDYxx Rookie Florida (KPAM)

I have also been pretty angry that there is no definition of Radar Contact Lost, at least per the 7110.65. The only thing I can tell you is what the AFI 13-203 says (Air Force ATC Reg). It defines a usable target as one that is not missed for more than 2 radar sweeps. So if you target disappears for three sweeps, he's Radar ID Lost. For ASR you need a return every sweep past the FAF up until the MAP. Sorry I know your prob not in the Air Force but this is the best answer I've ever found to the question.

RadarContact Scope Dope High Desert TRACON

Yeah I use what he said above, plus the fact that the ASR rotates at once per 4.xx seconds or something and since STARS doesnt really display a sweep I use about 12 seconds. Not really science, but it keeps my 3 levels from yelling radar contact lost every time they see a tag go into CST.

Centerpuke Junior Member ZTL

pretty easy at the center, haha. When the target goes into coast #, radar contact is lost.

NASTPO Newcomer Florida

No I am in the Navy but ATC is ATC lol the point is that we all do it the same right? 8-) Anyway thanks for the replies, I guess it's a judgement call on my part. The problem at my facilty is that my target on the ASR seems to drop out around 4 miles which is near a tower so i am thinking the tower is temporarily interfering. the target usually comes back within 10 seconds. So again thanks for ya'lls replies and If anyone does find it published somewhere then share the wealth please.

DASAUTO Banned

If that is the case (tower impeding the return), I would consider that a safety risk for an ASR approach. Course guidance should be issued every 15 seconds. So, depending on when you last issued guidance, there is a possibility of not being able to issue course guidance as prescribed in the 7110.65.

This approach procedure should not be used until a solution/fix can be implemented.

If this is a common occurrence (i.e. you lose radar on most a/c in the same area for approx. 10 seconds), then this needs to be brought to the facility manager's attention.

My 2 cents.

DairyCreamer Senior Member Elsewhere

I don't think that's true.

What if a transponder code changes accidentally (maybe a digit gets bumped, or the device malfunctions)? What if they lose their transponder entirely and go primary only? Would you really tell these aircraft RC Lost?

If their target goes away entirely, sure, that's one thing, but coast can't automatically mean RC lost. My primary (not primary radar ) reference is .65 5-2-14

~Nate

DairyCreamer Senior Member Elsewhere

I was looking through some data, and I can't find the specific ASR you guys use at HMN. I assume 9 or 11, but tell me if that's wrong.

Either way, ASR9/11 rotates at 12.5 RPM, or once every 4.8 secs

/nerd... wait, no, that never ends... nooooooooooooooo!

Source: http://www.cv.nrao.edu/~rfisher/Radar/WW-10147.pdf

~Nate

RadarContact Scope Dope High Desert TRACON

Haha nice find... yeah we're an ASR9. Funny thing about our radar, is that it SUCKS! Recently we've been having problems with the secondary radar within 20NM. If we switch to the Deming radar feed, some 100mi away, it picks up our planes without any problem. Pretty sad huh? Especially when it's gotta go over the Organ mountains too.

Centerpuke Junior Member ZTL

The track will not automatically go into coast if the transponder is altered or malfunctions. First the data block will go into FREE track. This is the point where the code or target will be analyzed. Obviously there will be a similar code in the vicinity of the track. Very rarely should a target make it all the way to coast without you having some idea of what is happening. Also, enroute aircraft that have their code changed by an ajoining center will never be told radar contact lost.