J

jtrusso

Well Known Member
Mel,

I read in your post in the thread about the Space Shuttle lanuch date that the Shuttle is not required to have an "Experimental" placard due to FAR 45.22 (if the Shuttle were controlled by the FARs of course).

I have a question about that, part of FAR 45.22 is copied below (emphasis mine):

A small U.S.-registered aircraft built at least 30 years ago or a U.S.-registered aircraft for which an experimental certificate has been issued under ?21.191(d) or 21.191(g) for operation as an exhibition aircraft or as an amateur-built aircraft and which has the same external configuration as an aircraft built at least 30 years ago may be operated without displaying marks in accordance with ??45.21 and 45.23 through 45.33 if:

(1) It displays in accordance with ?45.21(c) marks at least 2 inches high on each side of the fuselage or vertical tail surface consisting of the Roman capital letter ?N? followed by:

(i) The U.S. registration number of the aircraft; or

(ii) The symbol appropriate to the airworthiness certificate of the aircraft (?C?, standard; ?R?, restricted; ?L?, limited; or ?X?, experimental) followed by the U.S. registration number of the aircraft;

Does this mean if you build an RV3 or RV4, and it has the same "external configuration" as the first RV3 or RV4 that received it's airworthiness cert (when we reach the 30 year mark) that you don't need to the "EXPERIMENTAL" markings on the plane? By including "X" in your N number you satisfy the "EXPERIMENTAL" placard requirement?

That is pretty cool, I had no idea.

I learn something new everyday on these forums, good work Doug!
 
You are correct. There are actually quite a few amateur-built aircraft designs that meet this requirement nowadays. Pietenpols, Wittman Tailwinds, Cassutt Racers and a bunch more are designs that go back at least 30 years. Any of these aircraft can use the small (2 inch) N numbers, and may display the number as "NX****" instead of just "N****". When the "NX" prefix is used, you are not required to have the "EXPERIMENTAL" two-inch lettering near the entrance(s).

Remember that the "X" doesn't show up on any of the paperwork for the aircraft. The registration certificate and airworthiness certificate will only show the "N", and when you search the aircraft's records on the FAA web site it will not accept or recognize the "X". The only place the "X" shows up is on the aircraft itself.

Note too that there is no speed restriction under the 45.22 special rules. It doesn't matter what the maximum cruising speed is. Any aircraft that fits the special rule can use minimum 2 inch registration marks (aka "N numbers").

Cheers!

Joe
 
N Number Question

So if you go with the NX nomenclature, when contacting ATC do you have to then use November Xray .... or can you omit the Xray portion? Does the X become part of the official N number? Do you have to reapply for a new N number with the Xray included?

N144SH (or is that NX144SH...)
 
No more NX

I just read on the registry site that they are not issuing NX numbers any more. The X was part of your call, just like NC (National Commercial). So, if they're not issuing NX numbers, I don't see how we can delete the EXPERIMENTAL placard anymore.
 
I'm not a lawyer...

n144sh said:
So if you go with the NX nomenclature, when contacting ATC do you have to then use November Xray .... or can you omit the Xray portion? Does the X become part of the official N number? Do you have to reapply for a new N number with the Xray included?

N144SH (or is that NX144SH...)
Click to expand...

...and slept at home last night... but...

(ii) The symbol appropriate to the airworthiness certificate of the aircraft (“C”, standard; “R”, restricted; “L”, limited; or “X”, experimental) followed by the U.S. registration number of the aircraft;

A careful reading will say the "X" is a "Symbol" and is then followed by the US registration number.

That is, the "X" is not part of the registration number - it is just a marking on the plane.

This bit -

A small U.S.-registered aircraft built at least 30 years ago or a U.S.-registered aircraft for which an experimental certificate has been issued under §21.191(d) or 21.191(g) for operation as an exhibition aircraft or as an amateur-built aircraft and which has the same external configuration as an aircraft built at least 30 years ago may be operated without displaying marks in accordance with §§45.21 and 45.23 through 45.33 if:

- also specifically exempts you from FAR 45.23 which requires the word "EXPERIMENTAL"

http://www.flightsimaviation.com/data/FARS/part_45-23.html
 
Last edited:
not 30 years

My interpretation is that you don't need to fulfill the 30 year rule to use the X. The 30 year rule gets you out of using 12 inch high letters. The X can be used on any experimental to avoid the placard saying "EXPERIMENTAL".

So if your number for your RV-7A is N777SL then you would paint NX777SL on the side in 12 inch letters.

This is my interpretation of the rule.
 
sglynn said:
My interpretation is that you don't need to fulfill the 30 year rule to use the X.
Click to expand...

This is not correct. The only regulation that allows you to use the "X" (or whatever letter is appropriate to the certification of your aircraft) is 45.22(b) which specifically requires that the aircraft either be 30 years old or have the same external configuration as one at least 30 years old. Aircraft that do not meet the requirements of 45.22 are not allowed to use the "X" designator.

In turn, section 45.23 allows the deletion of the "EXPERIMENTAL" placard only for those aircraft that are able to display the "X" in accordance with 45.22. So an aircraft that cannot display N numbers per 45.22 cannot use the "X" designator when displaying their registration mark.

Cheers!

Joe
 
A strange interpretation...

sglynn said:
My interpretation is that you don't need to fulfill the 30 year rule to use the X. The 30 year rule gets you out of using 12 inch high letters. The X can be used on any experimental to avoid the placard saying "EXPERIMENTAL".

So if your number for your RV-7A is N777SL then you would paint NX777SL on the side in 12 inch letters.

This is my interpretation of the rule.
Click to expand...

...especially when the rule is called "Exhibition, antique, and other aircraft: Special rules"

The (b) section is quite specific as to when it applies.

Read in full...

Exhibition, antique, and other aircraft: Special rules.

(a) When display of aircraft nationality and registration marks in accordance with Secs. 45.21 and 45.23 through 45.33 would be inconsistent with exhibition of that aircraft, a U.S.-registered aircraft may be operated without displaying those marks anywhere on the aircraft if:
(1) It is operated for the purpose of exhibition, including a motion picture or television production, or an airshow;
(2) Except for practice and test fights necessary for exhibition purposes, it is operated only at the location of the exhibition, between the exhibition locations, and between those locations and the base of operations of the aircraft; and
(3) For each flight in the United States:
(i) It is operated with the prior approval of the Flight Standards District Office, in the case of a flight within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for the takeoff airport, or within 4.4 nautical miles of that airport if it is within
Class G airspace; or
(ii) It is operated under a flight plan filed under either Sec. 91.153 or Sec. 91.169 of this chapter describing the marks it displays, in the case of any other flight.
(b) A small U.S.-registered aircraft built at least 30 years ago or a U.S.-registered aircraft for which an experimental certificate has been issued under Sec. 21.191(d) or 21.191(g) for operation as an exhibition aircraft or as an amateur-built aircraft and which has the same external configuration as an aircraft built at least 30 years ago may be operated without displaying marks in accordance with Secs. 45.21 and 45.23 through 45.33 if:
(1) It displays in accordance with Sec. 45.21(c) marks at least 2 inches high on each side of the fuselage or vertical tail surface consisting of the Roman capital letter "N" followed by:
(i) The U.S. registration number of the aircraft; or
(ii) The symbol appropriate to the airworthiness certificate of the aircraft ("C", standard; "R", restricted; "L", limited; or "X", experimental) followed by the U.S. registration number of the aircraft; and
(2) It displays no other mark that begins with the letter "N" anywhere on the aircraft, unless it is the same mark that is displayed under paragraph (b)(1) of this section.
(c) No person may operate an aircraft under paragraph (a) or (b) of this section--
(1) In an ADIZ or DEWIZ described in Part 99 of this chapter unless it temporarily bears marks in accordance with Secs. 45.21 and 45.23 through 45.33;
(2) In a foreign country unless that country consents to that operation; or
[(3) In any operation conducted under Part 121, 133, 135, or 137 of this chapter.]
(d) If, due to the configuration of an aircraft, it is impossible for a person to mark it in accordance with Secs. 45.21 and 45.23 through 45.33, he may apply to the Administrator for a different marking procedure.

It exempts you from FAR 45.23 in special cases (the 30 year bit)

Normally you need this...

Display of marks; general.

(a) Each operator of an aircraft shall display on that aircraft marks consisting of the Roman capital letter "N" (denoting United States registration) followed by the registration number of the aircraft. Each suffix letter used in the marks displayed must also be a Roman capital letter.
[(b) When marks include only the Roman capital letter "N" and the registration number is displayed on limited, restricted or light-sport category aircraft or experimental or provisionally certificated aircraft, the operator must also display on that aircraft near each entrance to the cabin, cockpit, or pilot station, in letters not less than 2 inches nor more than 6 inches high, the words "limited," "restricted," "light-sport," "experimental," or "provisional," as applicable.]

Your reading is creative...:)
 
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