Transport Category Aircraft Series Numbers

[Squawk7777]

Something I never really got the hang out of it:

Let's take a transport category airplane, e.g. a 737. There are different series of the 737: 737-200, -300 up to the -900 series.

If you look closer at the model number however, you will never find that G-XXXX or NXXXX is a 737-300, instead it will display something like: 737-3H4. What does 3H4 represent (equipment, engines, year?) and does 3H4 mean that it is a 300 series aircraft?

In simple words: Can you decode 3H4?

[DONT THINK]

The 3 refers to the series and the H4 is usually a customer number from the manufacturer .

[PaperTiger]

Boeing assigns a code to every customer.. .<a href="http://www.house747.freeserve.co.uk/boeing.htm" target="_blank">http://www.house747.freeserve.co.uk/boeing.htm</a>. .This becomes part of the official aircraft model designation, and doesn't change when the airplane is sold. So you can always tell who the first owner of a Boeing was (737-3H4 indicates a -300 series 737 built for Southwest).. .Airbus doesn't do this, although they do have different sub-numbers (eg A320-211) although I have no idea what they mean. Ditto Lockheed.. .Douglas did not distinguish beyond the basic model DC-9-50 etc.. .Vickers (aaah !) used to do the same thing with customer codes, but I got confused when the (BA) 111s came along. Never figured out that scehme either.