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Question - Class B (and C) airliners


Dan Kent

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I was flying under the Houston Class B airspace a couple of weeks ago and spotted a commercial aircraft entering the Class B at the very bottom of the outer ring (4000' to 10,000').   I first spotted him on ADS - B but was eventually able to see him as well, and this got me thinking.

 

Here's my inexperienced question - are airliners obligated to enter Class B (or C) as soon as they can, or could an airliner fly under the outer shelves and then get their clearance to enter.

 

It would seem to be quite dangerous for us little guys if they end up flying in the Class E space under the shelf as we do.

 

Thanks in advance.

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Part 121 (airlines) and most part 135 (charter) and many part 91 (company owned) larger aircraft are required by reg or insurance to be on an IFR flight plan.

 

That being said, when we were flying little jets like Citations out of untowered rural airports on the non-revenue leg (no passengers) in VFR weather we often flew just like a Cessna 172.

 

In answer to your question, the airliner is almost 99.999% certain to be on an IFR flight plan. Even an empty airliner on a maintenance reposition flight would be on a flight plan.

 

The floor doesn't mean an airliner can't be under it (though it is unlikely) it only means you can't be above it and not be talking to ATC.

 

If the airport is busy and is using multiple runways, it may well be bringing planes in at different altitudes. We used to complain that they'd keep the airliners high and force us to get down low 50 or 100 miles out of Chicago, making us burn a lot of fuel at maybe 7,000 or even 5,000 feet.

 

Figure that if O'Hare is using two runways, or three, and Midway is using 2 and a couple of the local reliever airports are busy, they will be having airplanes stacked from bottom to top.

 

Bottom line, as Roger said, is they are almost 100% certain to be talking to ATC when coming into Houston. Now, landing at Cedar Rapids KCID on their 8000 foot runway at 0130 when the tower is closed, at some stage Chicago Center will turn them over to CTAF and they could be flying just like you in your CTSW.

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Whenever you fly near class charlie airspace, you should contact ATC just to simply listen to advisories and let them know you are listening in. It's not a requirement to contact them when flying under, over, or around the class charlie rings, but if you are going to be flying in the approach or departure path of the active runways, you definitely should give them the courtesy. If you have a working transponder, ATC will see you and route around you if they are not in contact with you. If there are other operating airfields under the Charlie outer shelf, then you don't even need to worry about contacting ATC, because airport plans will account for other airfield traffic and route around them (ever see "objectionable" on a chart? It's because that airport's traffic patterns interfere with another airfield). Flying over class C, up to 10k feet MSL, you must have a mode C transponder.

 

Class bravo airspace generally has a "Mode C" veil, which is a 30 mile radius from the airport in which all aircraft must have a mode C transponder. You must have a mode C transponder if flying under or over any of the shelves, or within the veil. if you are overflying, you must have a mode C transponder at ALL altitudes. You are still not required to contact them unless you are about to enter their airspace.

 

Note 1: Class charlie simply requires establishment of two way communication, class bravo airspace requires clearance, do not enter class bravo until you hear "cleared into class bravo airspace".

 

Note 2: There is an exception to the mode C veil, and operations within the bravo airspace shelving: you may call air traffic control one hour before your scheduled departure, and they will tell you the flight path you must follow to leave the veil. The same is true for flying into an airfield that is within the veil.

 

Note 3: The various classes of airspace already have a significant safety factor built in. The point of the shelves are so that ATC can keep the approach and departure paths clear enough so that the aircraft can safely use their own navigation before they hit the edge of the airspace.

 

Note 4: there are other numerous little nuances and exceptions to the airspace system. An example is KVPS (eglin air force base). Eglin AFB is given a special designation around their airspace, which falls under FAR 93, and is marked by prohibited airspace hashes. You can enter that airspace AFTER you have received permission from Eglin AFB approach (people do all the time, they just need control of that airspace because it's the Gulf Coast defense AFB). if in doubt, read the charts carefully, read the terminal procedures carefully, read the AF/D carefully, and ASK FLIGHT SERVICE!

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I am also told not to even attempt a fly over of Charlie without contacting apporach control and stating intent. And that a fly over of Bravo is restricted entirely.

 

At least that's my understanding and how I am flying right now. If that's wrong, please advise.

No need to contact anyone when overflying Class C. Sometimes I will if close to their ceiling. If well above and not on flight following there's not much point.

 

I have overflown several Bravos - Miami with regularity in the past and Atlanta at least a couple of times. So if it's restricted now in any way it's something new.

 

Edited to add: this was all before being restricted to 10,000' as a Sport Pilot. ATL goes up to 12,500', so that's obviously a no-go for a Sport Pilot. My Cirrus had oxygen installed, so flight above 12,500' to clear Atlanta's Bravo was a realistic option. However, MIA and JFK just go up to 7,000', so overflying them VFR as a Sport Pilot should not be an issue.

 

As an aside, overflying MIA at night above 7,000' was quite a gorgeous spectacle. I assume JFK would be at least as impressive!

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Whenever you fly near class charlie airspace, you should contact ATC just to simply listen to advisories and let them know you are listening in. It's not a requirement to contact them when flying under, over, or around the class charlie rings, but if you are going to be flying in the approach or departure path of the active runways, you definitely should give them the courtesy. If you have a working transponder, ATC will see you and route around you if they are not in contact with you.

This seems to me to be a matter of personal preference. I almost always monitor the Class C frequency and almost never announce myself to them if I am not required to. What is the point in it? Their airspace is designed so that arrival and departure routes will not be affected by airplanes flying according to the airspace rules. My most frequent experience is flying both IFR and VFR in and around Cedar Rapids, a Class C airport, but of course like most of you I've flown into and around many Class C airports.

There have been rare occasions when I heard myself being pointed out to other traffic but not all that often and never in a situation where there was any remote danger.

One reason I seldom talk to Class C is that as a VFR pilot, there is very little benefit to me for doing so. If I am in contact, ATC may reroute me for their or other traffic's convenience, but not because of a regulatory requirement. In other words, by talking to ATC unnecessarily, I am putting myself in the position of having to comply with instructions that will cause me to change my route or altitude, but again, not because of a regulatory requirement. The most frequent occasion has been when I'm skirting the 10 nm outer circle at, let's say, 5500 or 4500 feet. CID Departure could instruct departing IFR traffic to remain at or below an altitude until they are clear of me but instead they may choose to divert me further to the west so the departing traffic does not have to adhere to an altitude restriction or they may put an altitude restriction on me.

If I were a crop duster or flying my non-electric Champ, this question would never come up - ATC would route traffic around my legal activities. So, why should I put myself in a situation where the only things that can happen from my voluntary contact with ATC are negative to me? Again, I'm likely monitoring ATC and ATIS if I have a radio so I can hear what they're telling other traffic, including when they are talking about me.

I'm not saying don't talk to ATC in this situation. I'm saying I don't.

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Hi Jim!

 

It really depends on the airport too, to be honest. Some class charlies shouldn't be class charlies anymore. When I say flying around C space, I mean flying over, under, or along the edges.

 

If you flew near port columbus (KCMH), you would see that there is a LOT of traffic in and out, and it's easy to get caught in the approach paths if you are high enough. There's also a tremendous amount of GA traffic around coming out of the Ohio State University Airport (KOSU) to the northwest, and some out of Bolton Field (KTZR) to the southeast, along with some military and cargo traffic out of Rickenbacker (KLCK) to the south. It's a very busy area and a very good idea to talk to approach if you don't have a TIS system.

 

Also, unless you are within their airspace, you can tell them no. They cannot force you to change your routing. That's why it's called "traffic advisories" outside of their airspace.

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From the FAA Air Traffic Policy, Order JO 7110.65T:

 

7-9-3. METHODS
a. To the extent practical, clear large turbine engine‐powered airplanes to/from the primary airport using altitudes and routes that avoid VFR corridors and airspace below the Class B airspace floor where VFR aircraft are operating.
NOTE: Pilots operating in accordance with VFR are expected toadvise ATC if compliance with assigned altitudes,headings, or routes will cause violation of any part of the CFR.

 

b. Vector aircraft to remain in Class B airspace after entry. Inform the aircraft when leaving and reentering Class B airspace if it becomes necessary to extend the flight path outside Class B airspace for spacing.

 

NOTE-14 CFR Section 91.131 states that “Unless otherwise authorized by ATC, each person operating a large turbine
engine‐powered airplane to or from a primary airport for which a Class B airspace area is designated must operate at or above the designated floors of the Class B airspace area while within the lateral limits of that area.” Suchauthorization should be the exception rather than the rule. REFERENCEFAAO JO 7110.65, Para 5-1-10, Deviation Advisories.

 

Possibly not the latest: This version is dated Feb 11, 2010...and I haven't checked on this in a while.

 

Many moons ago when the San Diego TCA was being formed, I was the EAA rep on a user group for the airspace and remember it being a requirement for ATC to keep the airliners inside the TCA airspace.  Looks like it has softened a bit but the intent is there for them to be inside it..otherwise, it defeats the purpose of the "segregation".

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Interesting discussion. Over here the major airports have been introducing "listening squawks" which we are encouraged to use when flying close to, but not cleared into controlled airspace. So when in the vicinity of a large chunk of busy controlled airspace we just select the appropriate frequency, set the squawk and know that if the controller wishes to speak to us he/she can. Saves a lot of time on the radio - picture here

flyontrack.co.uk/wp-content/uploads/2013/04/Squawk4Q2013.pdf

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Something to think about.  When flying under the floor of a B airspace or just around it you are flying into a limited airspace all the other "avoiding class B" airplanes are flying into.  Just under the floor, it can quite often get very conjested in a narrow band.  I would suggest flight following anytime you are near a class B.

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I generally do not talk to approach when flying under the floor of the Atlanta Class B.

 

It certainly is an option to do so, but those controllers often have their hands pretty full to devote attention to little guys under their airspace.

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On my way past Jacksonville today, I had two airliners pass under me while cruising at 3700ft. I was on flight following and maintaining altitude as requested by ATC, it was just strange to see airliners under my little puddle jumper.

Just curious but how were you @ 3700 feet? I am under the impression that if you are above 3000 feet AGL you either need to be @ 3500, 5500 .. or 4500, 6500... Of course this is VFR.

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Just curious but how were you @ 3700 feet? I am under the impression that if you are above 3000 feet AGL you either need to be @ 3500, 5500 .. or 4500, 6500... Of course this is VFR.

I was inside the Jacksonville class C, and was maintaining that altitude at the request of ATC for traffic separation. I had been cruising at 4500, but there were clouds ahead so I told them I'd like to descend to 3000 to maintain VFR, which would drop me inside the class C. They approved the change, but a minute later said the would like me to maintain 3500 or better for separation. I had descended by then to 3700, and was a bit below any nearby clouds, so I told then I would hold there.

 

When I got to the edge of the class C I told them I'd like to finish my descent to 3000, which they approved.

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The introduction to FAR 91.159 explains it. Quote: "Except while holding in a holding pattern of 2 minutes or less, or while turning, each person operating an aircraft under VFR in level cruising flight more than 3,000 feet above the surface shall maintain the appropriate altitude or flight level prescribed below, unless otherwise authorized by ATC:"

 

Going to Denton from Pearland or back, Regional Approach (DFW) has so far taken me through the west side of the DFW Class B to/from Ft Worth Alliance at 3500, no matter whether I'm going north or south.  The Houston Class B controllers tend to give me an "operate at or below" clearance, which depending on the clouds, might put me anywhere.

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Andy's,

Thanks for clarifying.

 

My pleasure!  I always like to tell people how I've done things I've never done before so that if I'm doing it wrong it can get pointed out so I get it right the next time.  :)

 

BTW, I was not sure I would like it, but on longer trips I *really* like being on flight following.  It keeps things less boring because you have to pay attention to the radio, and you get to feel like you are "part of the club" talking to ATC and being in the system.  As a nice side benefit you are already talking to someone if something goes wrong, so you don't have to fiddle the with the radio in the middle of being saturated with all the other tasks you have to manage in an emergency.

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Communications with an ATC facility is just another resource we have available to us.  No different than GPS or another able body pilot sitting next to us.

And personally . . . . I need all the help I can get.     :D

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My pleasure!  I always like to tell people how I've done things I've never done before so that if I'm doing it wrong it can get pointed out so I get it right the next time.  :)

 

BTW, I was not sure I would like it, but on longer trips I *really* like being on flight following.  It keeps things less boring because you have to pay attention to the radio, and you get to feel like you are "part of the club" talking to ATC and being in the system.  As a nice side benefit you are already talking to someone if something goes wrong, so you don't have to fiddle the with the radio in the middle of being saturated with all the other tasks you have to manage in an emergency.

Andy,

I have had a totally different experience with flight following and now don't use it.

 

The distributor of my airplane is in N. Little Rock, and I took several flights between my local airport (KCXO) and KORK (N. Little Rock) using flight following (I made the trip twice with my CFI, and always had issues). There are 6 handoffs for the 3+ hr flight. Since I got my license I have made 2-3 more trips with FF and came to the conclusion that it was too much work for the value. The controllers in the bigger airports were good but in between it took a lot of work on my part.

 

Many times the new station just would not answer. I eventually either returned to the previous station explaining the problem, or started asking for a radio check on the frequency that would not respond. I spent 5-10 minutes at times with a new station trying to get them to respond, all the time knowing that I was basically stuck on the xponder code at my heading and elevation. Also, I didn't like asking for permission to break radio contact to check weather at the upcoming airport, as I found I do that a lot as well as listen th CTAF's.

 

I concluded that if something went wrong I was really on my own anyhow, so why get frustrated with trying to get someone to respond.

 

I also have ADS-B which I think is solid for identifying traffic, so that support of FF is of no benefit. Transition class C and B would be nice, but didn't really encounter much and can generally fly over class C.

 

Maybe I like the solitude of solo flight, and if something really went wrong I might miss a friendly voice.

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Dan:

 

Flight following is not regulatory, they can ask you to fly an altitude, but you are not required to follow while VFR. That's why they say "advise of altitude changes". It's flight following, which is an advisory service. The exception is while you are in class D, C, or B airspace, since it's not flight following anymore :P

 

There's another purpose of flight following, Dan. If your transponder stops transmitting, they have the last known position and will send help if they can't contact you. It's not as precise as modern ELTs, but I would definitely make use of it in mountainous or watery (swamp) areas. Radio signals travel farther and better than radar, and they will advise you when "Radar Contact Lost" and will ask you to report positions. ELTs are useful as long as the device or antenna are not damaged. Considering that CTs mount the ELT antenna on the BELLY (WHY?!), it's good for us CT owners to consider it.

 

There's yet another purpose of flight following too. If you are approaching a special use airspace, such as MOAs, TFRs, or Restricted Airspace, they WILL advise you of a course of action. In particular, MOAs are coordinated with ARTCC, and if there are military operations occurring, they will advise a recommended course, and can inform the military ops of your presence.

 

Also, if you are having transmittal problems, then you might want to review the IFR charts for your area. You may be flying too low for proper communication. There's not really a communication altitude (IFR minimum altitudes are for navaids and obstacle clearances), but you can bet that if you see minimum altitudes and you are flying well below the lowest listed, especially MOCAs, then that will be a very strong reason why you don't seem to get very good radio range.

 

If you are flying in areas that's pretty much flat terrain and no major activity, then don't worry about flight following since you have good equipment on board.

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Hey Dan,

 

I'd advise using flight following especially if you're on the west side of Houston below the Class B and near the east-west I-10 VFR corridor.  It gets really busy over there especially under the Class B, and I wouldn't trust that you're going to see everyone even with  ADS-B. 

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Dan:

 

Flight following is not regulatory, they can ask you to fly an altitude, but you are not required to follow while VFR. That's why they say "advise of altitude changes". It's flight following, which is an advisory service. The exception is while you are in class D, C, or B airspace, since it's not flight following anymore :P

 

There's another purpose of flight following, Dan. If your transponder stops transmitting, they have the last known position and will send help if they can't contact you. It's not as precise as modern ELTs, but I would definitely make use of it in mountainous or watery (swamp) areas. Radio signals travel farther and better than radar, and they will advise you when "Radar Contact Lost" and will ask you to report positions. ELTs are useful as long as the device or antenna are not damaged. Considering that CTs mount the ELT antenna on the BELLY (WHY?!), it's good for us CT owners to consider it.

 

There's yet another purpose of flight following too. If you are approaching a special use airspace, such as MOAs, TFRs, or Restricted Airspace, they WILL advise you of a course of action. In particular, MOAs are coordinated with ARTCC, and if there are military operations occurring, they will advise a recommended course, and can inform the military ops of your presence.

 

Also, if you are having transmittal problems, then you might want to review the IFR charts for your area. You may be flying too low for proper communication. There's not really a communication altitude (IFR minimum altitudes are for navaids and obstacle clearances), but you can bet that if you see minimum altitudes and you are flying well below the lowest listed, especially MOCAs, then that will be a very strong reason why you don't seem to get very good radio range.

 

If you are flying in areas that's pretty much flat terrain and no major activity, then don't worry about flight following since you have good equipment on board.

 

Thanks for the thorough explanation.  My flying is pretty much over flat terrain and no major activities, although on my trips up to N. Little Rock, I fly right through a MOA and never got a peep out of the controller on activity the 5-6 times I went through.  Maybe this trip is just a bad stretch at the edge of communications.

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