ADS-B and Mod-C in aircraft cert’d with no elec.

[CerroTorre]

Question is specific to 91.215(b)3(ii) and 91.225(e)2 - 2 questions really.

It’s a reg that is fairly limited in scope and unlikely to affect most operations. As I read it with respect to Class B operations for aircraft originally certified with no electrical (and therefore no ADS-B) it says you have to stay below the ceiling of a Bravo while within 30nm or below 10,000msl, whichever is lower. This is moot at most B’s since most go to 10k (edit: not moot - non-elec certified, no-ads-b aircraft can fly above 10k and below 18k - there just aren’t many of these in the NAS), but does it mean that in a location like PHX where the Bravo tops at 9k I am required to stay below 9k while within the Mode-C veil? That’s how I’m reading it anyway.

Where it gets a little more confusing is the inclusion of Class C airports in the reg. There is no Mode C 30nm veil, so how does this apply in those cases? Is the reg written for the potential future cases where there may be a veil put in place around C’s? So you’d be required to stay below (for example) 4,000 within 30nm of a C airport?

Am I reading things incorrectly? Thanks.

 

[skyking3286]

Stay out of class B and you can fly in the veil and under the shelves. Don’t overthink it and read the advisory stuff from FAA and AOPA and the type clubs. A few CFIs are up on the non-electrical exemptions but I wouldn’t count on it. I consider over the top as off limits.

 

[Lindberg]

Where it gets a little more confusing is the inclusion of Class C airports in the reg. There is no Mode C 30nm veil, so how does this apply in those cases?

What specifically is confusing? Neither reg mentions "Mode C veil."

 

[Capt. Geoffrey Thorpe]

You can't fly in or over B or C.
You can fly inside or over the 30nm ring of death (except directly over the B or C), under the B or C shelves, or over 10,000 feet in class E where you would have been otherwise excluded.

 

[brcase]

14 CFR 91.225(b) (Requirement and exception to operate above 10,000ft)

After January 1, 2020, except as prohibited in paragraph (i)(2) of this section or unless otherwise authorized by ATC, no person may operate an aircraft below 18,000 feet MSL and in airspace described in paragraph (d) of this section unless the aircraft has equipment installed that—


14 CFR 91.225(d) (Requirement stay out of Class B and C Airspace, and above up to 10,000 feet, and Mode C Veil)

After January 1, 2020, except as prohibited in paragraph (i)(2) of this section or unless otherwise authorized by ATC, no person may operate an aircraft in the following airspace unless the aircraft has equipment installed that meets the requirements in paragraph (b) of this section:

(1) Class B and Class C airspace areas;

(2) Except as provided for in paragraph (e) of this section, within 30 nautical miles of an airport listed in appendix D, section 1 to this part from the surface upward to 10,000 feet MSL;

(3) Above the ceiling and within the lateral boundaries of a Class B or Class C airspace area designated for an airport upward to 10,000 feet MSL;

(4) Except as provided in paragraph (e) of this section, Class E airspace within the 48 contiguous states and the District of Columbia at and above 10,000 feet MSL, excluding the airspace at and below 2,500 feet above the surface; and

(5) Class E airspace at and above 3,000 feet MSL over the Gulf of Mexico from the coastline of the United States out to 12 nautical miles.

14 CFR 91.225(e) (Exception for Operating in the Mode C Veil and above 10,000 feet)

The requirements of paragraph (b) of this section do not apply to any aircraft that was not originally certificated with an electrical system, or that has not subsequently been certified with such a system installed, including balloons and gliders. These aircraft may conduct operations without ADS–B Out in the airspace specified in paragraphs (d)(2) and (d)(4) of this section. Operations authorized by this section must be conducted—

(1) Outside any Class B or Class C airspace area; and

(2) Below the altitude of the ceiling of a Class B or Class C airspace area designated for an airport, or 10,000 feet MSL, whichever is lower.

Brian
CFIIG/ASEL
Glider LS6b N1720 "GG"

 

[CerroTorre]

What specifically is confusing? Neither reg mentions "Mode C veil."

It does actually. Just by way of referring to the 30nm limitation.

Specifically this section has always been tough to interpret: (2) Below the altitude of the ceiling of a Class B or Class C airspace area designated for an airport, or 10,000 feet MSL, whichever is lower.

the reg already states that you cannot be inside the B or C. So what is the pertinence of “below the ceiling”. Unless it applies to outside of the airspace and inside the 30nm ring…

 

[midlifeflyer]

It does actually. Just by way of referring to the 30nm limitation.

Specifically this section has always been tough to interpret: (2) Below the altitude of the ceiling of a Class B or Class C airspace area designated for an airport, or 10,000 feet MSL, whichever is lower.

the reg already states that you cannot be inside the B or C. So what is the pertinence of “below the ceiling”. Unless it applies to outside of the airspace and inside the 30nm ring…

Below the ceiling means below the lateral boundaries of the widest largest layer of the Class B airspace. That is not coextensive with the 30 nm veil Remember tha Bs are designed for traffic, so they can be larger, smaller, off-center and odd-shaped, while "within 30 nm of" a Class B airport" (the definition of the veil) is, well, always "within 30 nm of" a Class B airport".

Here's an example with a difference. Blue Class B, magenta veil. You can be in the veil but not within the lateral boundaries. And, yes, in the opposite end, you can be within the lateral boundaries and not be in the veil. You'll see it at many, especially odd-shaped Bs.

 

[Lindberg]

Specifically this section has always been tough to interpret: (2) Below the altitude of the ceiling of a Class B or Class C airspace area designated for an airport, or 10,000 feet MSL, whichever is lower.

the reg already states that you cannot be inside the B or C. So what is the pertinence of “below the ceiling”. Unless it applies to outside of the airspace and inside the 30nm ring…

 

[CerroTorre]

Below the ceiling means below the lateral boundaries of the widest largest layer of the Class B airspace. That is not coextensive with the 30 nm veil Remember tha Bs are designed for traffic, so they can be larger, smaller, off-center and odd-shaped, while "within 30 nm of" a Class B airport" (the definition of the veil) is, well, always "within 30 nm of" a Class B airport".

Here's an example with a difference. Blue Class B, magenta veil. You can be in the veil but not within the lateral boundaries. And, yes, in the opposite end, you can be within the lateral boundaries and not be in the veil. You'll see it at many, especially odd-shaped Bs.

View attachment 117311

There is a difference between “below the ceiling” and “below the altitude of the ceiling”. Your way reads it as not being allowed under the shelf. And I agree that makes intuitive sense. But that’s not what “below the altitude of the ceiling” means. THAT would mean that (for example) anything above 9k around PHX was prohibited.

It’s written in a specifically different way than the regs governing above or below the shelf. My confusion is in figuring out why.

edit: it’s written as if it is describing a horizontal (altitude) barrier and not a lateral barrier.

 

[CerroTorre]

Yeah, so this reg effectively adds an altitude barrier for non-electrical aircraft out beyond the lateral limits of the B or C airspace - out to 30nm. That’s the belief I’ve been operating under.


But…


This gets a little weirder in the case you’re showing - Class Charlie airspace. Since the regulation includes C airspace (which does not normally include a 30nm veil) then what lateral limits are placed on the ADS-B & Mode C requirement for non-electrical aircraft airspace around that (Class C) case when it’s inside of a veil? It seems slightly different than what you describe. Since, in your example, a small sliver of C goes under the veil, you could infer that that means the 4,100 ft limitation then extends throughout the rest of the Mode C area surrounding KPHL. Which seems non-sensical. Or in the case of SJC under SFO is there a 4k ceiling throughout the rest of the mode C area (for non-elec, non-equipped aircraft only)? And is it based on the lowest ceiling in that C? Or highest? Edit: or below the altitude of the ceiling of OAK - which gets even MORE weird…


I realize I could be getting confused by something that’s actually straight-forward for most everyone else. Wouldn’t be the first time my brain wasn’t catching a detail. But the issues inherent here seem to be fairly specific but rarely discussed and with at least some ambiguity. Enough to result in an altitude bust in a few limited cases.


Still don’t see the ambiguity?


My general rule is to give a Bravo a wide berth in any plane like this. Whenever possible. But that just isn’t always the case.

 

[CerroTorre]

Sort of. (and thanks for being willing to engage on this even though it’s likely headache inducing for some). Your re-write gets to part of the issue but doesn’t really fix the ambiguity (and might also imply no flight allowed under the shelf). The reg already reads that Mode C and ADS-B are required within those airspaces - (b)3(i). So your re-write only restates that requirement.

My point is that the existence of the (b)3(ii) text “Below the altitude of the ceiling of a Class B or Class C airspace area designated for an airport or 10,000 feet MSL, whichever is lower" indicates that this is a requirement in addition to what is stated elsewhere. Therefore it indicates a ceiling outside of the lateral boundaries of the airspace where the only pertinent lateral limit is the 30nm veil. Thus the 9k limit outside of PHX noted above.

So this all raises the question of, if the above is correct, how to interpret the impact of Class C on this rule - since it does get included in the reg.

Fwiw, I will potentially need to transition the SFO Bravo area (Mode C zone only - not inside the B itself) in an old Cub at some time soon. So this isn’t all just entirely academic if there is some part of the reg regarding the local C airspace that might impact my route and altitude choices.

Thanks.

 

[Mongoose Aviator]

Fwiw, I will potentially need to transition the SFO Bravo area (Mode C zone only - not inside the B itself) in an old Cub at some time soon. So this isn’t all just entirely academic if there is some part of the reg regarding the local C airspace that might impact my route and altitude choices.

A couple times, I had questions regarding the DC SFRA airspace. From the ground, I called (on the telephone) the Potomac Approach controllers and had a very nice discussion with them. Perhaps you can do the same with the controllers for the SFO airspace?

 

[CerroTorre]

A couple times, I had questions regarding the DC SFRA airspace. From the ground, I called (on the telephone) the Potomac Approach controllers and had a very nice discussion with them. Perhaps you can do the same with the controllers for the SFO airspace?

Yeah that’s good advice. I do plan to call them prior to passing through or close to the area. Might also put in a call to the OAK FSDO on this one. Can’t hurt and maybe they’ll shed light or point out anything I’m misinterpreting.

 

[Lindberg]

There is a difference between “below the ceiling” and “below the altitude of the ceiling”. Your way reads it as not being allowed under the shelf.

I don't understand how you could read it that way. The reg is telling you where you are allowed to go. Is under the shelf not below the altitude of the ceiling?

 

[Checkout_my_Six]

what part of mode C veil are we not understanding?......you need mode C to pass that line it doesn't matter what altitude you're floating into.

 

[CerroTorre]

I don't understand how you could read it that way. The reg is telling you where you are allowed to go. Is under the shelf not below the altitude of the ceiling?

Fair question. I’d argue that there is a distinct difference between the two wordings. But Tomayto / Tomahto …

The FAA uses two different wordings with respect to airspace restrictions in this context:
- “All aircraft in all airspace above the ceiling and within the lateral boundaries”
- “Below the altitude of the ceiling of a Class B or Class C airspace”

The lack of “within the lateral boundaries” in the second is notably different from the former. A straight reading of the two describes different limits.

 

[CerroTorre]

what part of mode C veil are we not understanding?......you need mode C to pass that line it doesn't matter what altitude you're floating into.

I understand the Mode C veil. This is specific to exceptions when flying old aircraft certified with no electrical and therefore some allowances to fly inside the veil with no Mode C or ADS-B.

 

[Lindberg]

Fair question. I’d argue that there is a distinct difference between the two wordings. But Tomayto / Tomahto …

The FAA uses two different wordings with respect to airspace restrictions in this context:
- “All aircraft in all airspace above the ceiling and within the lateral boundaries”
- “Below the altitude of the ceiling of a Class B or Class C airspace”

The lack of “within the lateral boundaries” in the second is notably different from the former. A straight reading of the two describes different limits.

Yes, these describe two completely different airspaces. I'm still not sure where the confusion is coming from, but it seems like you might be trying to fit the words to what you think they mean, rather than just reading them as written.

 

[CerroTorre]

Yes, these describe two completely different airspaces. I'm still not sure where the confusion is coming from, but it seems like you might be trying to fit the words to what you think they mean, rather than just reading them as written.

You’re saying that we are not allowed to fly below the shelf with no ADS-B or Mode C (in aircraft certified with no electrical). I disagree.

Very much not trying to get into an argument. But I do think there are some important distinctions. Just pilots spitballing around the campfire. And I could always be wrong. All good.

Edit: I need to reword this. I don’t actually think you are saying this. I think we’re approaching the topic from two different angles that makes it hard to delineate. If we are allowed below the shelf (we are) but not allowed into the B or C then there’s no need for the additional requirement to stay below the ceiling unless it extends beyond the lateral limits of the airspace.

It’s a problem of how it’s written in a very specific way. I think it means it must extend beyond those lateral limits. But I’m guessing this is testing people’s limits for rabbit holing. Cheers to all. I’ll post additional clarification if I get any.

 

[Mongoose Aviator]

@CerroTorre - Have you read the Knickerbocker 2006 Legal Interpretation?
https://www.faa.gov/about/office_or...6/Knickerbocker_2006_Legal_Interpretation.pdf

In terms of ADSB, the Ferrara 2019 Legal Interpretation is perhaps also relevant.
https://www.faa.gov/sites/faa.gov/f...ps/2019/Ferrara_2019_Legal_Interpretation.pdf

 

[Lindberg]

If we are allowed below the shelf (we are) but not allowed into the B or C then there’s no need for the additional requirement to stay below the ceiling unless it extends beyond the lateral limits of the airspace.

Correct. And as Midlifeflyer explained, that is frequently the case. Class B airspaces are not perfect 30nm radius circles.

 

[CerroTorre]

@CerroTorre - Have you read the Knickerbocker 2006 Legal Interpretation?
https://www.faa.gov/about/office_or...6/Knickerbocker_2006_Legal_Interpretation.pdf

In terms of ADSB, the Ferrara 2019 Legal Interpretation is perhaps also relevant.
https://www.faa.gov/sites/faa.gov/f...ps/2019/Ferrara_2019_Legal_Interpretation.pdf

Thanks for those @Mongoose Aviator - those are interesting. The second interpretation doesn’t directly apply to the sliver of airspace I’m looking at but does provide some context to help understand the thinking. Helpful links

 

[Dana]

Where do turbine aircraft typically enter and exit class B or C? Does their climb or descent profile usually take them in and out of the ceiling of the B or C or do they normally exit through the outer wall of the upper rings?

 

[CerroTorre]

Fwiw, got a call back from the FSDO and while the really helpful gentleman I spoke to agreed the above oddities in the regulation weren’t all that clear and might warrant some additional exploration, we both also agreed the best solution is to just give the whole mess of airspace in the Bay Area a wide berth. So … anybody flying around under the Bravo over the next little while, at least I can tell you that you won’t have to worry about smashing into my particular little yellow Cub over the next few days. So there’s that. =)

 

[Lindberg]

Fwiw, got a call back from the FSDO and while the really helpful gentleman I spoke to agreed the above oddities in the regulation weren’t all that clear and might warrant some additional exploration, we both also agreed the best solution is to just give the whole mess of airspace in the Bay Area a wide berth. So … anybody flying around under the Bravo over the next little while, at least I can tell you that you won’t have to worry about smashing into my particular little yellow Cub over the next few days. So there’s that. =)

Is there a specific spot on the map where you and he couldn't figure out if it was legal to fly the Cub?

 

[Doug Reid]

Seems fairly simple to me..

 

[champ driver]

View attachment 117412 Seems fairly simple to me..

That drawing only addresses "normal" planes, and says nothing about planes without electrical systems.

Where do turbine aircraft typically enter and exit class B or C? Does their climb or descent profile usually take them in and out of the ceiling of the B or C or do they normally exit through the outer wall of the upper rings?

I can tell you that at the MSP Class B we normally fly under at least one of the shelves going into STP, and we sure aren't doing 180kts either.

 

[Doug Reid]

The pic I posted explains ADS-B airspace pretty well..it is from an FAA site. The only discrepancy I can see is whether or not it is legal to fly within the 30 mile Mode C ring at a Class B airport and stay below Class B airspace. According to the diagram, it is not allowed, but I know it happens a lot at small outlying airports.

Attached is another FAA document.

https://medium.com/faa/ads-b-on-non...t remain (1) Outside,MSL), whichever is lower.

 

[champ driver]

The pic I posted explains ADS-B airspace pretty well..it is from an FAA site. The only discrepancy I can see is whether or not it is legal to fly within the 30 mile Mode C ring at a Class B airport and stay below Class B airspace. According to the diagram, it is not allowed, but I know it happens a lot at small outlying airports.

Attached is another FAA document.

https://medium.com/faa/ads-b-on-non-electric-aircraft-we-answer-your-top-questions-ddb4f7ed4f91#:~:text=You must remain (1) Outside,MSL), whichever is lower.

Your first drawing is a good simple explaination of Class B and the veil for normal planes. But it doesn't address the many planes that fly without an electrical system.
Your second attachment goes more in depth into the entire reg (which most pilots don't even read) including the part that addresses planes without electrical systems.

Yes, it's perfecly legal to fly a Cub like plane into the Mode C veil all day long, as long as you stay out of the Class B itself.

 

[Doug Reid]

Why would you want to fly an airplane without an electrical system into a busy Class B environment ? I suppose you can call atc and request a special clearance, but it is like riding a bicycle on the freeway, IMO. I love old planes..I own two myself, but it seems best to avoid busy airspace if you are not equipped to fly in that environment without jumping thru hoops.

We were all told how ads-b was for safety....really ? If you fly in New Zealand or Australia, you can purchase a portable ads-b out system...why not here in the USA ? I have a friend who purchased a Tailbeacon X and AV20 for his Breezy...he has a handheld mounted on the yoke...so that is an option.

 

[skyking3286]

Wow, this brings to mind the expression: Philadelphia Lawyers. It's so simple. Just stay out of the B and C airspace and the veil doesn't apply by reg for planes certified without an electrical system. Fly with your eyes out and remember your little video screen doesn't give the whole picture.