ADS-B required under Class C outer layer?

A

alanbreck

Pre-Flight
Joined
May 15, 2015
Messages
78
Display Name
Display name:
AlanB
I've read the ADS-B regs, and I think I know the answer, but want to get input from others to see if I have it right ....

For a pilot-controlled airport which lies underneath the outer layer of a Class C airport/airspace (3I7 for example), is ADS-B required to operate in/out of that airport?
 
I believe after 2020 you will require ADSB if you wish to fly in any controlled airspace. Don't know about above, though.
 
steingar said:
I believe after 2020 you will require ADSB if you wish to fly in any controlled airspace. Don't know about above, though.
Click to expand...

That's incorrect. The easy way to think about this is anywhere you need a mode C now will require ADS-B.
 
You asked, so here is the reg. I fly out of 3I7. The key requirement for class C is

91.225 paragraph d, sub paragraph 3.

Above Class C and within the lateral boundaries up to 10k.

So, yes you need ADSB Out. No more flying over or under Class C without ADSB Out. Yes, this was a subtle airspace grab. AOPA asleep at the switch.
 
Sky dog... I was just getting ready to post the same graphic. You are correct, but you WILL need to fly over Class C.
 
Rcmutz said:
You asked, so here is the reg. I fly out of 3I7. The key requirement for class C is

91.225 paragraph d, sub paragraph 3.

Above Class C and within the lateral boundaries up to 10k.

So, yes you need ADSB Out. No more flying over or under Class C without ADSB Out. Yes, this was a subtle airspace grab. AOPA asleep at the switch.
Click to expand...

It’s no bigger airspace grab. If you need Mode C now, then in 2020 it’s ADSB and Mode C, nothing changes to the airspace.
 
BillTIZ said:
It’s no bigger airspace grab. If you need Mode C now, then in 2020 it’s ADSB and Mode C, nothing changes to the airspace.
Click to expand...
Actually, I believe it does. If I'm not mistaken right now you don't need mode C to overfly a Charlie or a Delta. You'll need ADSB to overfly them after 2020.
 
Wow, it's been awhile since I've seen this many wrong answers in one thread. How about not posting if you all you're going to do is guess?

91.215(b)(4) requires Mode C right now
"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"

91.225(d)(3) requires ADS-B after January 1, 2020
"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"

The above wording is, in fact, identical.
 
Last edited:
I fly a homebuilt that was certified without an engine driven electrical system. Right now I can fly over and under controlled airspace without Mode C. So, I'll NOT need ADS-B to do the same on 2020.
 
tinerj said:
I fly a homebuilt that was certified without an engine driven electrical system. Right now I can fly over and under controlled airspace without Mode C. So, I'll NOT need ADS-B to do the same on 2020.
Click to expand...

Are you required to phone ahead, similar to regs for other aircraft not equipped with a Mode C transponder currently in other places? Seriously curious. A similar conversation has been being had down at our local flight school.
 
Don't need to phone ahead. If flying into, usual rules abt radio contact applies.
 
Maybe I'm thinking about aircraft without a radio. Sorry. We have been having a conversation about aircraft that aren't ADS-B equipped when 2020 rolls around though and whether or not there will be a change forthcoming.
 
Screenshot_2018-06-05-14-02-08-1.png Creve Coeur 1H0 is enbedded in STL airspace, and has Spirit nearly touching. I can, carefully, fly there without a transponder, and only need the radio to self address intentions on Creve Coeur CTAF. (Come to think of it, a radio is not required at uncontrolled fields.)
 
Last edited:
Rcmutz said:
You asked, so here is the reg. I fly out of 3I7. The key requirement for class C is

91.225 paragraph d, sub paragraph 3.

Above Class C and within the lateral boundaries up to 10k.

So, yes you need ADSB Out. No more flying over or under Class C without ADSB Out. Yes, this was a subtle airspace grab. AOPA asleep at the switch.
Click to expand...

They have been asleep for quite some time
 
tinerj said:
Don't need to phone ahead. If flying into, usual rules abt radio contact applies.
Click to expand...

I think I found the answer to my question, even though this isn't what I was looking for when I found it, lol:

Can I get a one-time deviation from the requirement?
14 CFR § 91.225 subparagraph (g) states:

Requests for air traffic control (ATC) authorized deviations from the requirements of this section must be made to the ATCfacility having jurisdiction over the concerned airspace within the time periods specified as follows:

  1. For operation of an aircraft with an inoperative ADS-B Out, to the airport of ultimate destination, including any intermediate stops, or to proceed to a place where suitable repairs can be made, or both. The request may be made at any time.
  2. For operation of an aircraft that is not equipped with ADS-B Out, the request must be made at least one hour before the proposed operation.
Under the above conditions, an aircraft operator may request to deviate from the ADS-B Rule on a case-by-case basis. The ATC facility with jurisdiction of the applicable airspace has discretionary authority to determine whether accommodations for non--ADS-B equipped aircraft can be made. ATC has the authority to deny such requests when deemed appropriate.

SO...it is entirely possible that you could be denied permission to enter the airspace by ATC. I assume it's similar now, but don't know.
 
BGF_Yankee said:
I think I found the answer to my question, even though this isn't what I was looking for when I found it, lol:

Can I get a one-time deviation from the requirement?
14 CFR § 91.225 subparagraph (g) states:

Requests for air traffic control (ATC) authorized deviations from the requirements of this section must be made to the ATCfacility having jurisdiction over the concerned airspace within the time periods specified as follows:
Click to expand...

That only applies if you need a deviation from the requirements...

If you are flying an aircraft that was not built with an engine driven electrical system, you are already exempt from much of the 91.215 / 225 requirements for a transponder inside the 30nm ring of death so you don't need a deviation which means you don't need to call for permission.

"(e) 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."
 
If you fly in this airspace you must be equipped with ADS-B
Airspace Altitude
A All
B Generally, from surface to 10,000ft mean sea level (MSL) including the airspace from portions of Class Bravo that extend beyond the Mode C veil up to 10,000 feet MSL (i.e.- SEA, CLE, PHX)
C Generally, from surface up to 4,000ft MSL including the airspace above the lateral boundary up to 10,000ft MSL
E Above 10,000ft MSL over the 48 states and DC, excluding airspace at and below 2,500ft AGL
Over the Gulf of Mexico at and above 3,000 feet MSL within 12 nm of the coastline of the United States
Airspace within 30 nautical miles (Mode C veil) at all Class B locations from the surface up to 10,000 feet MSL

https://www.faa.gov/nextgen/equipadsb/research/airspace/
 
Morgan3820 said:
If you fly in this airspace you must be equipped with ADS-B
Airspace Altitude
A All
B Generally, from surface to 10,000ft mean sea level (MSL) including the airspace from portions of Class Bravo that extend beyond the Mode C veil up to 10,000 feet MSL (i.e.- SEA, CLE, PHX)
C Generally, from surface up to 4,000ft MSL including the airspace above the lateral boundary up to 10,000ft MSL
E Above 10,000ft MSL over the 48 states and DC, excluding airspace at and below 2,500ft AGL
Over the Gulf of Mexico at and above 3,000 feet MSL within 12 nm of the coastline of the United States
Airspace within 30 nautical miles (Mode C veil) at all Class B locations from the surface up to 10,000 feet MSL
https://www.faa.gov/nextgen/equipadsb/research/airspace/
Click to expand...
Quite right. Airspace below the floor of Class C is Class E (or D in some places). Not Class C, so the language you highlighted does not apply. The graphic on that web page confirms it.

FAR 91.225 expressly states that airspace above the Class C, to 10,000' MSL, is included; but airspace below Class C is not similarly described.

That table is inartfully written, anyway. "Up to 4,000' MSL"? What about higher-elevation Class C areas? Refer to the regulation itself.
 
Last edited:
Morgan3820 said:
If you fly in this airspace you must be equipped with ADS-B
Airspace Altitude
A All
B Generally, from surface to 10,000ft mean sea level (MSL) including the airspace from portions of Class Bravo that extend beyond the Mode C veil up to 10,000 feet MSL (i.e.- SEA, CLE, PHX)
C Generally, from surface up to 4,000ft MSL including the airspace above the lateral boundary up to 10,000ft MSL
E Above 10,000ft MSL over the 48 states and DC, excluding airspace at and below 2,500ft AGL
Over the Gulf of Mexico at and above 3,000 feet MSL within 12 nm of the coastline of the United States
Airspace within 30 nautical miles (Mode C veil) at all Class B locations from the surface up to 10,000 feet MSL

https://www.faa.gov/nextgen/equipadsb/research/airspace/
Click to expand...

So where is the "below" part?
 
Capt. Geoffrey Thorpe said:
That only applies if you need a deviation from the requirements...

If you are flying an aircraft that was not built with an engine driven electrical system, you are already exempt from much of the 91.215 / 225 requirements for a transponder inside the 30nm ring of death so you don't need a deviation which means you don't need to call for permission.

"(e) 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."
Click to expand...

Yeah, but that answered my particular part of the question. Local flight school brought up the question as it relates to on-demand exemptions...
 
Refresh my memory.

As of right now, can I not fly under the outer ring of a Class C shelf with my xponder turned off? Perhaps unsafe, but is it illegal? It's not controlled under the shelf and it's not a bravo with a Mode C ring on the sectional.

If that's true, stands to reason I can still do it 1/1/2020.

I'm assuming I'm wrong, so what's the verdict?
 
jimmyjack said:
Refresh my memory.

As of right now, can I not fly under the outer ring of a Class C shelf with my xponder turned off? Perhaps unsafe, but is it illegal? It's not controlled under the shelf and it's not a bravo with a Mode C ring on the sectional.

If that's true, stands to reason I can still do it 1/1/2020.

I'm assuming I'm wrong, so what's the verdict?
Click to expand...

"(c) Transponder-on operation. While in the airspace as specified in paragraph (b) of this section or in all controlled airspace, each person operating an aircraft equipped with an operable ATC transponder maintained in accordance with §91.413 of this part shall operate the transponder, including Mode C equipment if installed, and shall reply on the appropriate code or as assigned by ATC."

You got it, you flaunt it.
 
Capt. Geoffrey Thorpe said:
or as assigned by ATC."
Click to expand...
But if I'm not talking to them they don't know what I have. Can I not, right now, depart from my uncontrolled, go on a 200 nm XC to another uncontrolled, stay away from B, C and D's and land at another uncontrolled, all without turning my xponder on?
 
jimmyjack said:
But if I'm not talking to them they don't know what I have. Can I not, right now, depart from my uncontrolled, go on a 200 nm XC to another uncontrolled, stay away from B, C and D's and land at another uncontrolled, all without turning my xponder on?
Click to expand...
Are you asking if it's legal, or are you asking if you can get away with it?
 
Pilawt said:
Are you asking if it's legal, or are you asking if you can get away with it?
Click to expand...

I'm asking if it's legal. I have always assumed that if you were outside a B, C or D veil, outside a specified Mode C ring and outside the DC SFRA an xponder was not required.
 
jimmyjack said:
I'm asking if it's legal. I have always assumed that if you were outside a B, C or D veil, outside a specified Mode C ring and outside the DC SFRA an xponder was not required.
Click to expand...

You are asking two different questions.

A transponder is not required.

As Capt. Thorpe pointed out, if you have one and it's operable, it must be on when in anything other than Class G.
 
You must log in or register to reply here.
Back
Top