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N-Number size to fly in the ADIZ?

Gregmarlow

Well Known Member
Hello,

Wondering about the size of my N number on my RV if I'm planning on flying in the ADIZ, IFR or VFR?

I hate to have to use the 12 inch numbers, but that's what I hear is required.

Thanks,
 
FAR part 45.29(h)

states that "After March 7, 1988, each operator of an aircraft penetrating an ADIZ or DEWIZ shall display on that aircraft temporary or permanent nationality and registration marks at least 12 inches high."
 
When is an ADIZ not an ADIZ?

I don't want to mislead anyone, but I don't think the Washington DC zone is treated the same way. I seem to recall that it only applied to ADIZ's that actually protected a/the border. I supposed it could have changed, but I checked it before flying into the previously defined (original) DC area ADIZ to go to Baltimore. You may want to ask AOPA.

My numbers are the small ones.
 
Here's the Scoop Directly From the FAA

First of all, the DC ADIZ no longer exists. It is now a SFRA as of 2/17.

From three sources, the FAR pertaining to 12" high N numbers only refers to the off shore ADIZ's that encompass international boundaries. This was from the FSDO, a rep from the FAA FAST team, and AOPA. There is nothing in the Notam or SFRA rules that talk about N number size.

About two months ago we had a FAA FAST team rep come to my airport and have a meeting with a few of us that are involved in groups or management from our airport which is inside of the SFRA (former DC ADIZ) about issues with the then ADIZ. I specifically asked about this because there were so many questions about it and the FARs are not clear. She confirmed what I said above.

For our purposes, 3" is fine.

If anyone want to challenge this again, call the FAA directly and you will get the answer that 3" is fine.
 
and i'm permanently moving back to MD in november, and would love to commute to College Park (KCGS), from St. Mary's Regional (K2W6).
 
My experience with smaller numbers in the DC ADIZ

Within the last 18 mos I was flying IFR and routed myself around the then DC ADIZ because I do not have 12 inch numbers. I was rerouted through the ADIZ and, upon getting the new clearance, told the controller I was unable because of my number size. He told me there was no such restriction except for flight into the FRZ. I have no idea where he got that information but apparently that is the procedure they followed then and may still do.
 
Kirk Groves flew his -8 down to visit me, even though he was skirting the DC SFRA, he was getting GS in excess of 230.. :cool:

with 3" letters still legal in the SFRA.
 
3" Is Fine

There is no N number size rules for an SFRA.

The FAR states:
(iii) Marks at least 3 inches high may be displayed on an aircraft for which an experimental certificate has been issued under Sec. 21.191(d) or 21.191(g) for operating as an exhibition aircraft or as an amateur-built aircraft when the maximum cruising speed of the aircraft does not exceed 180 knots CAS

Calibrated Airspeed:
Calibrated airspeed (CAS) is indicated airspeed corrected for instrument errors, position error (due to incorrect pressure at the static port) and installation errors.

Van's RV8 Performance Numbers Solo in TAS MPH/Kts
Cruise [75% @ 8000 ft] 197/171 204/177 212/184

I would find it hard to swallow that anything over 75% power would be considered cruise and TAS is higher than IAS/CAS at 8000'.

Conclusion: For an -8 you should be fine. For a Rocket....you legally would probably need 12".

Reality: Potomac Approach controllers don't care what size your N number is.

P.S. We are now pronouncing the SFRA as the "Suffer".
 
FAR part 45.29(h)

states that "After March 7, 1988, each operator of an aircraft penetrating an ADIZ or DEWIZ shall display on that aircraft temporary or permanent nationality and registration marks at least 12 inches high."
Was hoping to use temporary 12 inch N- numbers just to return from Bahamas to Florida since the Bahamians don’t care when you land coming from Florida. The way it reads, 12 inch numbers are required both ways even if no one is going to see the out bound numbers.
 
Returning from the Bahamas, I always use blue painters tape to size up my N# to 12”
Yup, blue painters tape works just fine for operating within the ADIZ as you can see in the attached photo. You can even use green, yellow or any color that looks good on your airplane, as long as it contrasts from the background.
 

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With this rule enacted before ADS-B, I think this rule is now antiquated. I just no longer see the need to have 12 inch letters with ADS-B providing all the information needed to positively identify the aircraft. Yes one could falsify the ID but one could also falsify the 12 inch letters taped on.
 
In the old days when I went to Baja quite often in my 6A. Used shoe polish and it came off with Windex when I got home. Nobody on either side said anything. The Mexico guys always brought water out for my dog..
 
I have been to the Bahamas a half dozen times and I have about 4.5" numbers. Never an issue.
I have also never had the need to be intercepted by an F-16.
Some have been told on the US side that tape is not sufficient.

Go figure.
 
I have been to the Bahamas a half dozen times and I have about 4.5" numbers. Never an issue.
I have also never had the need to be intercepted by an F-16.
Some have been told on the US side that tape is not sufficient.

Go figure.
I sure wouldn’t risk it and I’ll tell you why. Friend had on his bucket list to take his 6A one time to the Bahamas. He asked me about it and I advised he wasn’t legal. So we decide to fly up to fort pierce for lunch and stop in at customs and ask if it would be ok for a one time trip with small n numbers. Customs guy was super nice, and agreed to a one time trip he wouldn’t violate.
next day off he goes, and returns at 5:30 before customs closes at 6pm. He calls me on the phone and tells me he is being violated and has been told to secure the plane and come back in to do the paper work. He told me that the officer the day before was there, and advised the violating officer he had approved a one time trip, but the supervising officer that was doing the violation admonished the officer that said it was ok and told him he was not to get involved.
Friend came in and the paper work process was started for the violation. At 5:50 10 minutes before closing, two large aircraft arrived with about 20 people to process. officer looked at my friend and said, it’s your lucky day, I don’t have time for you to deal with this as I’ve got 20 plus pax to process before closing and took all the paper work that had been started, voided it, and told my friend to get the heck out of there
 
The way to get around this is go to Home Depot and get blue painter’s tape, make 12 inch N numbers. I don’t even try to make them look nice. When I get to customs I remove them. One would think that intercepting aircraft could get your tail number thru ADS-B. Just saying.
 
Sporties sells N number decals that work great and probably are not much more expensive than rolls of blue tape.
 

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If you can read Tommy's 12" N#'s against those black stripes, Captcha says you are "not a robot." :LOL:

Are we seriously expecting common sense re: ADS-B to prevail with bureaucrats? I'm not immediately aware of examples where that has happened.
 
One would think that intercepting aircraft could get your tail number thru ADS-B. Just saying.
Yea, like you can't just enter any registration in an ADS-B OUT signal.

The interceptor still has to see the numbers when you get intercepted to confirm you are who you pretend to be. It's a bigger sky out there than your little portion of it. :unsure:
 
Yea, like you can't just enter any registration in an ADS-B OUT signal.

The interceptor still has to see the numbers when you get intercepted to confirm you are who you pretend to be. It's a bigger sky out there than your little portion of it. :unsure:
Yeah what what keeps someone from taping a different N number on the plane. Either case is the same
 
Some have been told on the US side that tape is not sufficient.
Not surprised but also something I wouldn't worry too much about, unless someone can point to a reg that specifies a specific degree of stickyness. Which there would have to be otherwise all the planes with self-adhesive vinyl N numbers are illegal for border crossings :rolleyes:

Oh, plus this:
FAR part 45.29(h)

states that "After March 7, 1988, each operator of an aircraft penetrating an ADIZ or DEWIZ shall display on that aircraft temporary or permanent nationality and registration marks at least 12 inches high."
 
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Yeah what what keeps someone from taping a different N number on the plane. Either case is the same
You can visually see the tape, you can't visually see the ADS-B signal. HUGE difference to the interceptor aircraft, confirming which aircraft was actually intercepted so appropriate action is taken. Been there, done that!
 
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You can visually see the tape, you can't visually see the ADS-B signal. HUGE difference to the interceptor aircraft, confirming which aircraft was actually intercepted so appropriate action is taken. Been there, done that!
Sure you can, just look at the target on the screen 😉
 
Sure you can, just look at the target on the screen 😉
Unless you are in the fantasy world of Hollywood, and not in the real air defense world, NOBODY can confirm the tail number a suspect aircraft using ADS-B. You have to physically intercept it and get close enough to read the tail number. Hence the 12" size requirement.
You can visually see the tape, you can't visually see the ADS-B signal. HUGE difference to the interceptor aircraft, confirming which aircraft was actually intercepted so appropriate action is taken. Been there, done that!
 
I worked the SE ADIZ for most of my career as an ATC. Having worked Customs and DOD intercepts, I've had: guys call themselves N123 while the Customs Kingair was scoping N456 on the fuselage, piggyback flights on legitimate flight plans (6'oclock formation flying), and trying to fly "under the RADAR", etc. The 12" numbers are for the interceptor drivers to more easily verify the "actual vs reported" callsign of the A/C. 9/11 boosted the level of "interest" on inbound A/C even more (200lbs of coke or weed was less destructive than 200lbs of HE). ADSB can be swapped (or hacked) or "it was working when we took off". The bad guys are quite creative, and there is no perfect system, but we do the best we can :)
 
I worked the SE ADIZ for most of my career as an ATC. Having worked Customs and DOD intercepts, I've had: guys call themselves N123 while the Customs Kingair was scoping N456 on the fuselage, piggyback flights on legitimate flight plans (6'oclock formation flying), and trying to fly "under the RADAR", etc. The 12" numbers are for the interceptor drivers to more easily verify the "actual vs reported" callsign of the A/C. 9/11 boosted the level of "interest" on inbound A/C even more (200lbs of coke or weed was less destructive than 200lbs of HE). ADSB can be swapped (or hacked) or "it was working when we took off". The bad guys are quite creative, and there is no perfect system, but we do the best we can :)
Very well said. Who knows, maybe you controlled me on one of the intercepts I did while flying for US Customs. You are another who can say: "been there, done that!". ;)
 
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I live on the US/Mexico border and we have many US registered aircraft clear customs with 2" N Numbers. I am talking multiple times a day. With no violations.
 
I live on the US/Mexico border and we have many US registered aircraft clear customs with 2" N Numbers. I am talking multiple times a day. With no violations.
🎲 🎲 you gotta' ask yourself, do you feel lucky today?
Let's be real, regs say 12" numbers, it's not that complicated, play by the rules.
Dont play by the rules we might all have to have 12" permanent numbers. You really want that?
 
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I live on the US/Mexico border and we have many US registered aircraft clear customs with 2" N Numbers. I am talking multiple times a day. With no violations.
There is no ADIZ between the US and Mexico, just like there is no ADIZ between the US and Canada. No ADIZ, no 12" requirement.
 
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There is no ADIZ between the US and Mexico, just like there is no ADIZ between the US and Canada. No ADIZ, no 12" requirement.
Is that right? My sectional shows ‘contiguous ADIZ’ at the TX - Mexico border. (Not at Canadian border, though).
 
There is no ADIZ between the US and Mexico, just like there is no ADIZ between the US and Canada. No ADIZ, no 12" requirement.
Is that right? My sectional shows ‘contiguous ADIZ’ at the TX - Mexico border. (Not at Canadian border, though).
It looks like the contiguous US ADIZ is across the entire southern border with Mexico, at least as shown on the ForeFlight Sectionals.
 
It looks like the contiguous US ADIZ is across the entire southern border with Mexico, at least as shown on the ForeFlight Sectionals.
Look closer. What you reference is in MEXICO (Mexico FIR) not the US. The US has no authority in Mexican airspace nor can we intercept aircraft in Mexican airspace to check their tail number. In U.S. airspace, where we have jurisdiction, it is specifically designated as "Defense Area" not ADIZ.

But interestingly enough charts now say "Report to FAA radio prior to entering ADIZ" which is something it didn't say when I was working the border centuries ago. But there are no inner and outer ADIZ boundaries to designate where the ZONE starts and ends for mandatory compliance with the requirements. Again, we can't enforce our requirements in Mexican airspace and in the adjoining U.S. airspace it is designated "Defense Area" not ADIZ.

Off both coasts of the U.S. the ADIZ has a very specific inner and outer boundaries where requirements are enforced. It seems a bit confusing and might be why they don't enforcing the requirement there, an actual and designated "ZONE" does not exist. But that is just me speculating.
 
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Look closer. What you reference is in MEXICO (Mexico FIR) not the US. The US has no authority in Mexican airspace nor can we intercept aircraft in Mexican airspace to check their tail number. In US airspace, where we have jurisdiction, it is designated "Defense Area" not ADIZ.
I'm certainly not an expert, but it does say "Contiguous US ADIZ" in addition to "Mexico FIR MMFR"

Screenshot 2024-04-18 at 7.50.10 PM.jpg

Also this item from the FAA website specifically says there is no ADIZ between the US and Canada, but fails to mention the same for Mexico. It also mentions additional requirements for Defense VFR flight before penetrating the ADIZ.


"Air Defense Identification Zone (ADIZ)
All aircraft entering U.S. domestic airspace from points outside must provide for identification prior to entry or exit. ADIZs have been established to assist in early identification of aircraft in the vicinity of international U.S. airspace boundaries (AIM Section 6, 5-6-1).
Many aircraft inbound to the U.S. will cross an ADIZ. There is no ADIZ between the U.S. and Canada. According to FAR Part 99, if penetrating an ADIZ, all aircraft of U.S. or foreign registry must file, activate, and close a flight plan with the appropriate aeronautical facility. In addition to normal ADIZ position reports, and any other reports Air Traffic Control may require, a foreign civil aircraft must give a position report at least one hour before ADIZ penetration, if it is not more than two hours average cruising speed from the U.S.
For Defense VFR (DVFR) flights, the estimated time of ADIZ penetration must be filed with the appropriate aeronautical facility at least 15 minutes before penetration, except for flights in the Alaskan ADIZ, in which case, report prior to penetration. Additionally, VFR pilots must receive and transmit a discrete transponder code."

And the capper, from this recent AOPA article about flying into Mexico:


" • 12-inch registration marks are required for crossing the ADIZ into Mexico."
 
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I'm certainly not an expert, but it does say "Contiguous US ADIZ" in addition to "Mexico FIR MMFR"

Also this item from the FAA website specifically says there is no ADIZ between the US and Canada, but fails to mention the same for Mexico. It also mentions additional requirements for Defense VFR flight before penetrating the ADIZ.


"Air Defense Identification Zone (ADIZ)
All aircraft entering U.S. domestic airspace from points outside must provide for identification prior to entry or exit. ADIZs have been established to assist in early identification of aircraft in the vicinity of international U.S. airspace boundaries (AIM Section 6, 5-6-1).
Many aircraft inbound to the U.S. will cross an ADIZ. There is no ADIZ between the U.S. and Canada. According to FAR Part 99, if penetrating an ADIZ, all aircraft of U.S. or foreign registry must file, activate, and close a flight plan with the appropriate aeronautical facility. In addition to normal ADIZ position reports, and any other reports Air Traffic Control may require, a foreign civil aircraft must give a position report at least one hour before ADIZ penetration, if it is not more than two hours average cruising speed from the U.S.
For Defense VFR (DVFR) flights, the estimated time of ADIZ penetration must be filed with the appropriate aeronautical facility at least 15 minutes before penetration, except for flights in the Alaskan ADIZ, in which case, report prior to penetration. Additionally, VFR pilots must receive and transmit a discrete transponder code."

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Also from this recent AOPA article about flying into Mexico:


" • 12-inch registration marks are required for crossing the ADIZ into Mexico."
But where is the "ZONE"? Where does it begin and end that you have to comply with the regs while flying? :unsure:
 
I live on the US/Mexico border and we have many US registered aircraft clear customs with 2" N Numbers. I am talking multiple times a day. With no violations.
No "Zone" is why this post makes perfect sense. One every few months or so, Law Enforcement Officer discretion. Multiple times a day, that is policy. ;)
 
Was told by CBP in Ft Pierce several years ago my painter's tape numbers were unacceptable and that I narrowly scraped by without a violation. He said if I did it again it wouldn't end as well.
 
Was told by CBP in Ft Pierce several years ago my painter's tape numbers were unacceptable and that I narrowly scraped by without a violation. He said if I did it again it wouldn't end as well.
I believe you. That erroneous information was clarified years ago to all CBP airports of entry. FAR part 45.29(h) clearly state temporary numbers are acceptable and does not specify how to make temporary numbers. You can see an example in the attached photo taken in Puerto Rico during one of our many trips to and from the Caribbean.
 

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