If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
class C and B comms on sectionals?
In the legend on sectional charts there are a number of frequencies
listed for the various class B and C airspaces and airports. For example, the northern florida chart has jacksonville listed as "120.75 (091-180)". Now, during my commercial checkride a month ago my examiner asked me what the numbers in parenthesis were and I said they were courses from that C-airspace primary airport. So if you would draw lines from Jacksonville international and out on a magnetic course of 091 and 180 degrees, you would have as a result a pie-shaped sector on the chart. If you're approaching the C-airspace and your location is withing that pie-sector you should use 120.75 Mhz to get your clearance to enter the airspace. There is also a small COMMs box on the chart itself located southeast of the airspace so that makes sense to me. However, my examiner said that 091-180 in the legend are in fact RADIALS. The airspace in question on my checkride was the B airspace around orlando, and she said these numbers are radials from (in that case) ORL VOR and not courses from the airport. 1. Why would they use VOR radials for this on a VFR chart, when a VOR isn't even required for VFR flight? 2. The C airspace set up for Jacksonville international doesn't even have a VOR. Is there a source where I can get more information on the legend that the sectionals have? |
#2
|
|||
|
|||
The Aeronautical Chart User's Guide? I couldn't find anything in it that
helps, though. Bob Gardner "Magnus" wrote in message ... In the legend on sectional charts there are a number of frequencies listed for the various class B and C airspaces and airports. For example, the northern florida chart has jacksonville listed as "120.75 (091-180)". Now, during my commercial checkride a month ago my examiner asked me what the numbers in parenthesis were and I said they were courses from that C-airspace primary airport. So if you would draw lines from Jacksonville international and out on a magnetic course of 091 and 180 degrees, you would have as a result a pie-shaped sector on the chart. If you're approaching the C-airspace and your location is withing that pie-sector you should use 120.75 Mhz to get your clearance to enter the airspace. There is also a small COMMs box on the chart itself located southeast of the airspace so that makes sense to me. However, my examiner said that 091-180 in the legend are in fact RADIALS. The airspace in question on my checkride was the B airspace around orlando, and she said these numbers are radials from (in that case) ORL VOR and not courses from the airport. 1. Why would they use VOR radials for this on a VFR chart, when a VOR isn't even required for VFR flight? 2. The C airspace set up for Jacksonville international doesn't even have a VOR. Is there a source where I can get more information on the legend that the sectionals have? |
#3
|
|||
|
|||
The radial from the VOR merely defines the airspace for that frequency. It
does not require that you use the VOR in flight to determine whether you are in that space or not. The same is true for defining TSAs and many restricted or prohibited airspace. Relate the information to your sectional and then determine your position relative to that airspace via normal pilotage. -- ------------------------------- Travis "Magnus" wrote in message ... In the legend on sectional charts there are a number of frequencies listed for the various class B and C airspaces and airports. For example, the northern florida chart has jacksonville listed as "120.75 (091-180)". Now, during my commercial checkride a month ago my examiner asked me what the numbers in parenthesis were and I said they were courses from that C-airspace primary airport. So if you would draw lines from Jacksonville international and out on a magnetic course of 091 and 180 degrees, you would have as a result a pie-shaped sector on the chart. If you're approaching the C-airspace and your location is withing that pie-sector you should use 120.75 Mhz to get your clearance to enter the airspace. There is also a small COMMs box on the chart itself located southeast of the airspace so that makes sense to me. However, my examiner said that 091-180 in the legend are in fact RADIALS. The airspace in question on my checkride was the B airspace around orlando, and she said these numbers are radials from (in that case) ORL VOR and not courses from the airport. 1. Why would they use VOR radials for this on a VFR chart, when a VOR isn't even required for VFR flight? 2. The C airspace set up for Jacksonville international doesn't even have a VOR. Is there a source where I can get more information on the legend that the sectionals have? |
#4
|
|||
|
|||
That doesn't make any sense to me. So which VOR am I supposed to use
for Jacksonvill Intl. then? It doesn't havve a VOR anywhere in the C airspace. The only VOR in that entire region is Craig, but that's not even close to jacksonville. It doesn't make sense to me to have a chart that defines COMM areas based on VORs when the chart is for VFR flights only. If I'm flying to Jacksonville VFR I won't have a VOR to use as my point of reference because there's none there. Why would the makers of the chart even consider using radiostations, all that matters is to have a point of reference from which the courses should be drawn so you can identify which fq you should contact approach on, and from that viewpoint using the actual airport makes more sense than some VOR that might or might not be there. More importantly, I have NOT found any information that actually states how the legend on the sectional was meant to be used. Surely there must be some source of information for these charts detailing how they should be used? How do examiners and instructors determine that these numbers next to the frequencies are from VORs? There's nothing on the chart legend that suggest it. On 2004-04-24 08:48:20 -0400, "Travis Marlatte" said: The radial from the VOR merely defines the airspace for that frequency. It does not require that you use the VOR in flight to determine whether you are in that space or not. The same is true for defining TSAs and many restricted or prohibited airspace. Relate the information to your sectional and then determine your position relative to that airspace via normal pilotage. |
#5
|
|||
|
|||
"Magnus" wrote in message ... In the legend on sectional charts there are a number of frequencies listed for the various class B and C airspaces and airports. For example, the northern florida chart has jacksonville listed as "120.75 (091-180)". Now, during my commercial checkride a month ago my examiner asked me what the numbers in parenthesis were and I said they were courses from that C-airspace primary airport. So if you would draw lines from Jacksonville international and out on a magnetic course of 091 and 180 degrees, you would have as a result a pie-shaped sector on the chart. If you're approaching the C-airspace and your location is withing that pie-sector you should use 120.75 Mhz to get your clearance to enter the airspace. There is also a small COMMs box on the chart itself located southeast of the airspace so that makes sense to me. However, my examiner said that 091-180 in the legend are in fact RADIALS. The airspace in question on my checkride was the B airspace around orlando, and she said these numbers are radials from (in that case) ORL VOR and not courses from the airport. 1. Why would they use VOR radials for this on a VFR chart, when a VOR isn't even required for VFR flight? 2. The C airspace set up for Jacksonville international doesn't even have a VOR. Is there a source where I can get more information on the legend that the sectionals have? The A/FD doesn't have any additional information. I don't recall seeing anything that actually stated these were bearings from the field, but, like you, I always assumed they were. Obviously, they can't be radials in airspace without VORs, so to be consistent they'd have to be bearings from the field. In the case of ORL, it wouldn't make a difference as the VOR is on the field. I would've asked the examiner for her source on that. |
#6
|
|||
|
|||
"Travis Marlatte" wrote in message news The radial from the VOR merely defines the airspace for that frequency. It does not require that you use the VOR in flight to determine whether you are in that space or not. The same is true for defining TSAs and many restricted or prohibited airspace. What's a TSA? |
#7
|
|||
|
|||
"Magnus" wrote in message ... That doesn't make any sense to me. So which VOR am I supposed to use for Jacksonvill Intl. then? It doesn't havve a VOR anywhere in the C airspace. The only VOR in that entire region is Craig, but that's not even close to jacksonville. It doesn't make sense to me to have a chart that defines COMM areas based on VORs when the chart is for VFR flights only. If I'm flying to Jacksonville VFR I won't have a VOR to use as my point of reference because there's none there. Why would the makers of the chart even consider using radiostations, all that matters is to have a point of reference from which the courses should be drawn so you can identify which fq you should contact approach on, and from that viewpoint using the actual airport makes more sense than some VOR that might or might not be there. More importantly, I have NOT found any information that actually states how the legend on the sectional was meant to be used. Surely there must be some source of information for these charts detailing how they should be used? How do examiners and instructors determine that these numbers next to the frequencies are from VORs? There's nothing on the chart legend that suggest it. Some facilities don't use bearings at all. Madison approach splits East and West, and that's how it's indicated in the frequency tab on the sectional. The Letter of Agreement with Chicago Center designates the division as the extended centerlines of runway 18/36. They could have used VOR radials, I suppose, as Madison VOR is on the field. But they didn't. More anecdotal evidence that these are not radials. |
#8
|
|||
|
|||
A little more info:
This is all from the Chicago Sectional. There are three VOR's located inside the Chicago Class B. The frequency split (in degrees) is: 360 - 179, and 180 - 359. The split for the Madison Class C is East and West. The split for the Milwaukee Class C is Southeast and Northwest. The split for the Moline Class C is S/SE of active runway and N/NE of active runway. And finally, the split for the Muskegon TRSA is N of V2 (low altitude airway) and S of V2. Given all of this, I think it would be a safe bet that these splits are NOT based on VOR radials, and the level of precision required is very low. "Magnus" wrote in message ... That doesn't make any sense to me. So which VOR am I supposed to use for Jacksonvill Intl. then? It doesn't havve a VOR anywhere in the C airspace. The only VOR in that entire region is Craig, but that's not even close to jacksonville. It doesn't make sense to me to have a chart that defines COMM areas based on VORs when the chart is for VFR flights only. If I'm flying to Jacksonville VFR I won't have a VOR to use as my point of reference because there's none there. Why would the makers of the chart even consider using radiostations, all that matters is to have a point of reference from which the courses should be drawn so you can identify which fq you should contact approach on, and from that viewpoint using the actual airport makes more sense than some VOR that might or might not be there. More importantly, I have NOT found any information that actually states how the legend on the sectional was meant to be used. Surely there must be some source of information for these charts detailing how they should be used? How do examiners and instructors determine that these numbers next to the frequencies are from VORs? There's nothing on the chart legend that suggest it. On 2004-04-24 08:48:20 -0400, "Travis Marlatte" said: The radial from the VOR merely defines the airspace for that frequency. It does not require that you use the VOR in flight to determine whether you are in that space or not. The same is true for defining TSAs and many restricted or prohibited airspace. Relate the information to your sectional and then determine your position relative to that airspace via normal pilotage. |
#9
|
|||
|
|||
"Bill Denton" wrote in message ... The split for the Madison Class C is East and West. The split for the Milwaukee Class C is Southeast and Northwest. Milwaukee's split, like Madison's, is along the extended runway centerline. Madison's is fixed along runway 18/36, but Milwaukee's varies with runway usage. Sometimes it's along runway 7/25, sometimes it's along runway 1/19. |
#10
|
|||
|
|||
"Magnus" wrote in message
... [...] 1. Why would they use VOR radials for this on a VFR chart, when a VOR isn't even required for VFR flight? Someone else answered that. You don't need a VOR receiver to be able to know where a VOR radial is, when flying VFR. 2. The C airspace set up for Jacksonville international doesn't even have a VOR. Is there a source where I can get more information on the legend that the sectionals have? I'm still trying to figure out why it matters. At an airport without a VOR, obviously they cannot be radials from the VOR. At an airport with a VOR, the difference between a radial and a bearing from the airport is, for the purposes of determining which frequency to use for ATC, inconsequential. If you are so close to the radial/bearing that it makes a difference, the right frequency to use is the one for the sector you're about the fly into, regardless of which side of which boundary you happen to be on. The only boundary case I can see even coming close to mattering is if you happen to be flying inbound or outbound right smack on the boundary itself. My guess is that in that case, ATC doesn't care which sector you contact. If they do, it is easy enough for them to send you over to the correct one, if you happen to choose the wrong one. If I had to guess, I'd guess it's bearing from the airport, for the reasons pointed out already (that defining it as VOR radials would be meaningless at an airport without a VOR). But in reality, the sectors can be chopped up differently from what's on the chart anyway, due to those pesky letters of agreement. Use the chart as a guideline as best you can, and if you get it wrong, no big deal. ATC will straighten things out. Pete |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Florida Mil and NASA Comms Log - Tues, 18 May 2004 | AllanStern | Military Aviation | 4 | July 10th 04 02:00 AM |
Florida Military Comms Log - Thurs 15 Apr 2004 | AllanStern | Military Aviation | 1 | April 17th 04 08:38 PM |
Lost comms after radar vector | Mike Ciholas | Instrument Flight Rules | 119 | January 31st 04 11:39 PM |
"I Want To FLY!"-(Youth) My store to raise funds for flying lessons | Curtl33 | General Aviation | 7 | January 9th 04 11:35 PM |
USAF = US Amphetamine Fools | RT | Military Aviation | 104 | September 25th 03 03:17 PM |