Radar Identified, Ident and say Passing Alt

[Gannet167]

I depart an airfield that regularly and after contacting terminal in the climb out they say " (callsign) you're radar identified, ... squak ident and say passing alitude." Now, I'm generally the only aircraft moving within 100 miles and certainly the only one taking off - so why are they asking me to ident and why are they asking me to say passing altitude? They have me on primary and secondary and my ADS-B transponder sends off all the info you'd ever want and some I'd rather not share with ATC.

If I'm radar identified, am I not ... identified? If they're confused as to which aircraft I am (hence the ident) how could that possibly be?

[photofly]

and why are they asking me to say passing altitude?

To verify that your altitude encoder is sending them the same information as your altimeter is telling you (i.e. is calibrated correctly).

[W0XOF]

If you are already radar identified, there is no reason to have you squawk ident. However, say passing altitude is to "verify" your altitude for the reason Photofly mentioned.

[System Message]

They ask your altitude to confirm the mode c altitude, but why don't they then say what their display reads so that confirmation goes both ways?

[DeuceEng]

Squawking ident is one of the ways that ATC radar identify an aircraft. PSR and SSR are accurate but they still have flaws. ATC needs to confirm that it is you, that you are on the correct discrete code and that the altitude readout on their screen is accurate.

Not knowing the unit and their procedures, I cannot say why they are not employing other radar ident techniques, but they need to have some sort of confirmation it is you getting airborne. As for the altitude, the only way to verify that is by you saying your altitude. You can save air time by saying your altitude on your initial contact and you should only get a request to squawk ident back.

[Gannet167]

Thanks for the replies. I generally check in with terminal by saying "(callsign) climbing through xxx for xxx feet" so they know my altitude. I think this is what ATC normally likes to hear? Plus, this is generally when I'm the only airplane around for 100 miles. They reply with "radar identified, say passing alititude and ident" and it just frustrates me. If you've identified me, then in my mind it stops there unless my transponder has suddenly gone off line. End of story. But even though I'm identified, they need the ident to ensure that I am still the one and only airplane in 100 miles. And passing altitude. In the middle of doing checklists and putting up flaps and gear and all that good stuff, this ATC unit really makes life more complicated than it needs to be. Having flown all over, I've never seen this before - only at this one airport.

[photofly]

The alt/encoder check and "radar identified" are different things. There's a list of ways ATC has to use to radar-identify you; from memory these include:

1. a turn or turns on instruction, verified on the radar scope
2. squawk ident requested and observed
3. new squawk issued and observerd
4. if you're on an IFR departure (only) from an airport and you appear on the radar scope in a position and direction consistent with the IFR departure clearance

and probably some others. As far as I know, you could be the only aircraft on the entire planet and ATC still has to use one of these methods before you are formally "radar identified". There has to be some kind of interaction; merely having a blip in the the right place with the right sqawk isn't enough. Anyone from ATC want to confirm/deny?

Also I believe that if ATC tells you you're observed at a particular altitude you're supposed to tell them if you're at a different altitude so they can tell you stop altitude squawk if necessary. Good to hear from ATC on that one too.

As for why this one place does things a bit strangely... maybe he or she is just doing it wrong? Why not call them to ask?

why don't they then say what their display reads so that confirmation goes both ways?

It's not part of the protocol for you to know (or need to know) if your mode c is accurate; if it's it not they'll ask you turn it off. (Which is not to say you can't ask, it's just that you don't need to care.)

[Braun]

They shouldn't say radar identified and squawk ident. It's one or the other. Sometimes it's just a force of habit of saying one or the other. No one's perfect hehe. But if you are radar identified you shouldn't have to squawk ident.

[kevenv]

They shouldn't say radar identified and squawk ident. It's one or the other. Sometimes it's just a force of habit of saying one or the other. No one's perfect hehe. But if you are radar identified you shouldn't have to squawk ident.

+1

[HeadingAltitudeSpeed]

They shouldn't say radar identified and squawk ident. It's one or the other. Sometimes it's just a force of habit of saying one or the other. No one's perfect hehe. But if you are radar identified you shouldn't have to squawk ident.

Exactly. But I will take a guess that you are departing off a small airport within a much busier terminal environment. The controller probably radar identifies aircraft of the main airport routinely by the method of target position within 1 mile of departure end consistent with departure time and instructions ( there are 10 other ways btw). when you call of the other field it is instinct to say radar identified, and as the words exit his mouth he is already correcting the error with a squawk ident instruction. Is it perfect? Nope. But when 1 out of 300 aircraft calls like that it happens.

Usually the problem is that the ability to use the above method is only hindered by a technicality. So for all intents and purposes you are identifies (like you would be off the other airport) but because it actually is missing one of the other requirements another method must be employed.

Another option is that a local practice may have been developed to use squawk ident anytime say altitude is used. It could stem from a problem with local operators or someone in the unit getting burned somehow in the past. There are regional differences that occur, and often for a very valid reason.

It will usually be beneficial to post the location of these questions to assist in tracking down an answer for you. If it's not my site I usually know someone working at the one in question and can get it from the horses mouth.

[Nordo]

They reply with "radar identified, say passing alititude and ident" and it just frustrates me.

If it is frustrating for you to push a button (that is commonly found on the yoke) and say your altitude over the radio so that somebody can positively identify you and provide you with separation and clearance for the safety of not only your aircraft, but others that you may be passing along your journey...perhaps you may be in the wrong field.

I can see how you may wonder why they ask such things, so you can better understand how they provide their service to you and your passengers, but to say that it is frustrating; you must be kidding. Right??

[justwall]

Verifying your altitude is used to provide altitude seperation with other aircraft in the area. Without a verified altitude it makes it pretty hard to know if the mode c portion of your transponder is giving us the right readout. I have seen a couple times recently when a helicopter departs and his mode c is off by 500ft or more for the first couple minutes due to warming up in the colder weather and then it will level out. If a controller were to use altitude to seperate two aircraft the altitudes must be verified for both.

[HeadingAltitudeSpeed]

They reply with "radar identified, say passing alititude and ident" and it just frustrates me.

I notice this is the second time you are frustrated and unhappy with the way a service is being provided. When an attempt to track down the location and provide a comprehensive answer you suddenly go silent. Why? Is there more to these stories than you have provided?