I could be wrong but I believe you only need to do this once per facility.
Maybe it is a regional thing, because here they will ask you for it even intra-facility if you don’t proffer it on callup. TRACON-wise, we have the two “consolidated” “approach controls” now - SOCAL from Santa Barbara all the way through San Diego, and “Sierra” (brand new) for the Bay area. Even though you are being handed from one “SOCAL approach” to another, they may be in different physical facilities, and you have no way of knowing this.
It is also important to note that ATC is required to provide for separation between all IFR aircraft and participating VFR aircraft. In both of those cases, they will have a “Verified” mode C altitude or a reported altitude by the aircraft.
Marty,
I’ll go out on a limb here and suggest that ATC is only responsible for separation of all IFR aircraft and special VFR aircraft. Of course when I’m flying VFR, I’m special so they have to provide separation. [;)]
ATC’s primary job is to provide both vertical and horizontal separation with IFR to IFR aircraft. Yes, there are cases where they are “obligated” to separate participating VFR aircraft. This “separation” is not the same separation as would be from IFR to IFR. Basically, if there’s green space between the targets on the controller’s scope, there’s separation. If not, then the controller is obligated to provide at least 500 ft separation. The “guarantee” for separation is only IFR to IFR. And this separation is more significant.
For those that fly VFR, ATC really can’t ask you to do much in the way of vectoring you around traffic. They can (and do) suggest alternatives. But when you are within about two miles of the conflicting traffic (assuming this traffic is not talking to ATC), ATC can’t even give you a real good suggestion either. You are just way too close for them to know what to suggest to have a positive outcome. With 6 or 12 second refresh rates, two aircraft headed towards each other is a very small window. So, you need to make these decisions early when ATC first makes it known to you.
I also try to ask for a Mode C check at least once a flight to ensure that I am transmitting accurate info.
I don’t know how to NOT do that - as mentioned, I need to when checking in with each new controller/facility anyway. And I know what altitude my transponder is reporting, because it tells me on its display. It would take a very strange and twisted fault for it to actually be transmitting something different!
Two more cases: VFR aircraft while in Class B or active Class C airspace.
Same issue. ATC does not have a responsibility to separate (using IFR separation standards) VFR from IFR and VFR from VFR independent of the class of airspace. So, there’s no guaranteed separation implied. So two participating VFR aircraft could pass within 500 feet laterally and there’s not an eyebrow raised. However, if this happens with IFR to IFR aircraft, someone’s in trouble (unless the pilot is assuming visual separation).
Scott,
Actually there will be several eyebrows raised. Namely those of the pilots (assuming they see each other). However I agree that IFR separation standards apply only to IFR/IFR regardless of airspace.
Separation standards do apply if you are VFR with a clearance into a Class B. Reference: Air Traffic Publications ATA-10
3-2-3. CLASS B AIRSPACE
e. ATC Clearances and Separation: An ATC clearance is required to enter and operate within Class B airspace. VFR pilots are provided sequencing and separation from other aircraft while operating within Class B airspace. REFERENCE- AIM, TERMINAL RADAR SERVICES FOR VFR AIRCRAFT, PARAGRAPH 4-1-17.
1. VFR aircraft are separated from all VFR/IFR aircraft which weigh 19,000 pounds or less by a minimum of:
(a) Target resolution, or
(b) 500 feet vertical separation, or
(c) Visual separation
2. VFR aircraft are separated from all VFR/IFR aircraft which weigh more than 19,000 and turbojets by no less than:
(a) 1 1/2 miles lateral separation, or
(b) 500 feet vertical separation, or
(c) Visual separation.
This is true, but it is does not even come close to IFR to IFR separation requirements. You are comparing apples and oranges. Basically what you pointed out says if there is what controllers call “green in between” then there is separation (target resolution).
When the workload goes up, the VFR to VFR “separation” and advisories usually takes a back seat to their main focus, namely, IFR separation. This is why I say there is no guaranteed separation.
This is why I say there is no guaranteed separation.
You are correct in stating it is not IFR separation. It is not correct to state that there is no guaranteed separation. There are separation requirements ATC must follow, as cited. It is just as “guaranteed” in the sense that it is an ATC requirement to adhere to it as IFR separation. The degree of separation may be different, but, as you can see in the separation standards, you must be separated. It makes sense for smaller, slower guys to be separated by less than IFR criteria. As long as paint isn’t removed, you have separation.