Nose Numbers

Nose Numbers are something of a mystery. I thought I had this figured out, but it turns out that I don't understand this as much as I thought. My hope was to figure out the purpose of these numbers in order to help identify aircraft in photos. Before I dive into the nose numbers, allow me a moment to deliver a primer on the different types of aircraft numbers.

One number is the Construction Number (CN, C/N). This number represents the number of aircraft that was constructed by the company. The Construction Number spans all makes, models, and production facilities. It's a universal company number to keep track of what they've made and works as a type of inventory control number. For Invaders, this number begins with 6,813.

Another number is the Serial Number. This is a number assigned by the Air Force. The First Invader had a serial number of 41-39100. The first two digits represent the Fiscal Year the plane was ordered. In this case, 1941. This is an important distinction because this plane wasn't built until 1944. The rest of the serial number represents that plane in the Air Force inventory across all manufacturers and types of planes. For example, the plane right before the first Invader was 41-39099, an experimental plane manufactured by Erco called the XPQ-13.

The third number is the Tail Number. The tail number is an abbreviated form of the Serial Number. For example, the first Invader with serial number 41-39100 would have a tail number of 139100. The first digit is omitted from the number and it is displayed without the dash. A small point of note; after the plane has been operational for more than 10 years the tail code changes, otherwise it would hypothetically be possible to mix it up with a newer plane (like 51-39100 (there really isn't one, this is just an example)). I've seen this done two ways. 0-139100 is the most common way. A zero precedes the tail number with a dash. On a couple of planes I have seen it done differently: 0-1100. In this case the first digit is the last digit of the Fiscal Year, and then the last 3 digits of the serial number. But I have only seen this rarely and in cases where there was no possibility for confusion. For example, it would be a bad idea to use this approach with 44-34257 because it might be confused with 44-35257.

The last number that's common only appears on planes during the Korean War and after. It's called a "buzz code" and is written on the Fuselage. 41-39100 would have a Buzz Code of BC-100. Although there are repeats of the buzz codes, the logic is that two planes with the same buzz code won't be in the same place at the same time. It's a short-hand code used for easy reference.

Now that we've got this all out of the way, that brings us to the Nose Numbers. I don't even know if that's the actual term for these, it's just what I'm calling them. Let's take a look at this plane: