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c/n???

Pro Member Chief Captain
pilotwannabe Chief Captain

Hey,

I've noticed one airliner census' and delivery tables etc that each aircraft has an assigned unique c/n. Some manufacturers seem to call it msn as well. I though maybe that it stood for consruction number but i've just seen an Air France A318 with c/n 2750?? There's no way 2750 A318's have been built.

Any ideas what c/n is all about??? Thanks 😉

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

C/N does in fact mean Construction Number.

Some information on serial numbers etc:

The United States Army purchased its first heavier-than-air aircraft, a Wright Model A, in 1908. It was allocated the serial number 1. Further Army aircraft were assigned serial numbers in sequence of their purchase. Unfortunately, early records from these days are rather incomplete, and there are numerous gaps and conflicts. To add to the confusion, it often happened that at the time an aircraft was rebuilt, it was assigned a brand new serial number. Some aircraft from this period (for example the DH-4 "Liberty Plane") are known to have carried at least four serial numbers during their careers.

This serial number scheme continued until the end of US Fiscal Year (FY) 1921 (which was June 30, 1921). At that time, the numbers had reached 69592, plus a special block of 1919-1921 experimental procurements in the 94022/94112 range.

Starting in July of 1921 (the beginning of FY 1922) a new system was adopted based on procurement within each Fiscal Year. Each serial number now consisted of a base number corresponding to the last two digits of the FY in which money was used to manufacture the aircraft, and a sequence number indicating the sequential order in which the particular aircraft was ordered within that particular FY. For example, airplane 22-1 was the first aircraft ordered in FY 1922, 23-1 was the first example ordered in FY 1923, etc. This system is still in use today.

It is important to recognize that the serial number reflects the Fiscal Year in which the order for the aircraft is placed, NOT the year in which it is delivered. Nowadays, the difference between the time the order is placed and the time the aircraft is actually delivered can be as much as several years.

In September of 1947, the United States Army Air Force became the United States Air Force, but the earlier fiscal-year serial number system remained unchanged. However, according to USAF regulation 5304.9003 promulgated in that year, the sequence number was now required to have at least 3 digits. This means that fiscal year serials with individual sequence numbers less than 1000 are filled up with zeroes to bring them up to 3 digits in length. So 48-1 is written as 48-001 in official documentation. Sequence numbers greater than 9999 are written with 5 digits. In 1958, the minimum was raised to four digits, so that the 1958 aircraft series started at 58-0001.

From here (theres a lot more information you might be interested in):

😉

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

...and I just came across this in my search; a short informative article on construction numbers including C/N, L/N and MSN:

http://www.airliners.net/addphotos/cnhelp.inc

😉

Pro Member Chief Captain
pilotwannabe Chief Captain

Thanks Jon, that explains the c/n's of USAF crafts....I think. Does it mean for example that a C-5 with the c/n of 69-002 was ordered in 1969 and was the second to be ordered in that year....I think so??

But what about civil aircraft from Boeing and Airbus.

For example BA own a 747-400 with the reg. G-BNLC.

It has c/n of 23190 and a line number of 734. I'm guessing the line number indicates it was the 734th 744 of the production line but what about c/n, is it just a unique code for that aircraft that never changes regardless of operator??

To add to the confusion, Airbus' don't seem to have line numbers just c/n's.

Pro Member Chief Captain
pilotwannabe Chief Captain

OK, I think I understand....the c/n is purely a unique code that is assigned to each aircraft whereas line number...only seen on Boeing's, was the position of that craft on the production line.

Thanks 😉

Pro Member Chief Captain
pilotwannabe Chief Captain

Just one more question.....

I've noticed in some cockpit shots that there's a plate near the instruments. On top is the registration, below it is a code called the SELCAL??

For example a B767 of BA has reg. G-BNWA and SELCAL of HP-BC??

Any ideas what this means??

Thanks 😉

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

pilotwannabe wrote:

Thanks Jon, that explains the c/n's of USAF crafts....I think. Does it mean for example that a C-5 with the c/n of 69-002 was ordered in 1969 and was the second to be ordered in that year....I think so??

Yes, aircraft orders start in each new FY, which means that the first numbers i.e. 69 are the last 2 digits of the FY, and the rest is the sequential order number.

pilotwannabe wrote:

But what about civil aircraft from Boeing and Airbus.

For example BA own a 747-400 with the reg. G-BNLC.

It has c/n of 23190 and a line number of 734. I'm guessing the line number indicates it was the 734th 744 of the production line but what about c/n, is it just a unique code for that aircraft that never changes regardless of operator??

To add to the confusion, Airbus' don't seem to have line numbers just c/n's.

I'm not sure about the C/N; it is the permanent identity of an aircraft assigned by the manufacturer, but as for how they choose it, I'm not too sure. Serial numbers / construction numbers are usually very long, so I guess they make up and then just go up in increments from there, but thats only a guess - I did a search but couldn't find anything in much more detail, sorry.

Hope that helps a bit 😉

Pro Member Chief Captain
pilotwannabe Chief Captain

Thanks Jon, you've been a great help 👍

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

pilotwannabe wrote:

Just one more question.....

I've noticed in some cockpit shots that there's a plate near the instruments. On top is the registration, below it is a code called the SELCAL??

For example a B767 of BA has reg. G-BNWA and SELCAL of HP-BC??

Any ideas what this means??

Thanks 😉

SELCAL is Selective Calling where ATC can contact an individual aircraft although they aren't specifically monitoring a specific frequency. A ground encoder sends a VHF or HF frequency consisting of two paired tones out over the radio frequency to a specific aircraft, to alert them that they ar being contacted. Once the aircraft has been contacted, they can communicate with the ground station via COMM2.

The letters represent specific frequencies that are picked up.

H =645.7
P =1083.9
B =346.7
C =348.6

(Measured in Hertz)
The letters can be changed by the FO to pick up different frequencies.

Pro Member Chief Captain
pilotwannabe Chief Captain

Oh right, so it gets rid of the need for pilots to constantly monitor a frequency but know when they are being contacted.

Great, thanks Jon 😉

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

I think its more for emergency use. Its not an excuse for sloppyness or lazyness, because most of the time, they should be tuned to the correct COM frequency. It is also used across the Atlantic where you can change your frequency because you are less likely to need instructions from ATC at FL370 mid-Atlantic. Once you reach the other side of the Atlantic, you'll be contacted via SELCAL 😉

Pro Member First Officer
oreo005 First Officer

99jolegg wrote:

C/N does in fact mean Construction Number.

Some information on serial numbers etc:

The United States Army purchased its first heavier-than-air aircraft, a Wright Model A, in 1908. It was allocated the serial number 1. Further Army aircraft were assigned serial numbers in sequence of their purchase. Unfortunately, early records from these days are rather incomplete, and there are numerous gaps and conflicts. To add to the confusion, it often happened that at the time an aircraft was rebuilt, it was assigned a brand new serial number. Some aircraft from this period (for example the DH-4 "Liberty Plane") are known to have carried at least four serial numbers during their careers.

This serial number scheme continued until the end of US Fiscal Year (FY) 1921 (which was June 30, 1921). At that time, the numbers had reached 69592, plus a special block of 1919-1921 experimental procurements in the 94022/94112 range.

Starting in July of 1921 (the beginning of FY 1922) a new system was adopted based on procurement within each Fiscal Year. Each serial number now consisted of a base number corresponding to the last two digits of the FY in which money was used to manufacture the aircraft, and a sequence number indicating the sequential order in which the particular aircraft was ordered within that particular FY. For example, airplane 22-1 was the first aircraft ordered in FY 1922, 23-1 was the first example ordered in FY 1923, etc. This system is still in use today.

It is important to recognize that the serial number reflects the Fiscal Year in which the order for the aircraft is placed, NOT the year in which it is delivered. Nowadays, the difference between the time the order is placed and the time the aircraft is actually delivered can be as much as several years.

In September of 1947, the United States Army Air Force became the United States Air Force, but the earlier fiscal-year serial number system remained unchanged. However, according to USAF regulation 5304.9003 promulgated in that year, the sequence number was now required to have at least 3 digits. This means that fiscal year serials with individual sequence numbers less than 1000 are filled up with zeroes to bring them up to 3 digits in length. So 48-1 is written as 48-001 in official documentation. Sequence numbers greater than 9999 are written with 5 digits. In 1958, the minimum was raised to four digits, so that the 1958 aircraft series started at 58-0001.

From here (theres a lot more information you might be interested in)

😉

some information? LOL

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