Registrations and construction numbers are the ultimate means to identify an aircraft, or in other words, to make it individual, set it apart from something else.
When you start having an interest in aircraft, you begin to make the first separation already: you set them apart from cars, trains, people, and anything else. Some people (like my wife
) stay in this stage. Many people go to the next stage: they see that some aircraft are carrying Continental Airlines titles, and others American Airlines. And then suddenly they see a Skymaster Airlines aircraft, wow, that is interesting. Why? Because it is different.
And they also see that some aircraft have two engines under the wing and others two on the aft fuselage. On inquiring they find out one is a Boeing 737, the other a MD-80. They try now to keep them apart and find it quite a sport. They start making a photo of an aircraft now and then, but after a while they have enough shots of Continental Airlines Boeing 737s and American Airlines MD-80s, when you got one, you got them all.
Then they see somebody pointing a telescope at aircraft and jotting down something in a spiral notebook. They are curious and start talking to the guy. He happens to be British and explains to them that he notes down the registrations, or "numberplates" of the aircraft. When asked why, he continues to explain that you can find information about the aircraft with that, like the aircraft type, owner, build date, etc. He gives them some internet URLs and some book titles which they can use for that.
They now note down a few registrations themselves to look them up at home on one of the URLs. They find out that they saw two different types of Continental B737s, a 737-524, and a 737-3T0. Next time when they go to the airport they try to spot the difference, and indeed, one is longer than the other. They pick up on photography again, because, with the help of the registration, they can add details to their photos like the exact aircraft type, and the registration is a good means to classify their photos. They now also have a means to find out the type of an aircraft they didn't recognize (ah, is that a Cessna 172).
In one of their references they see that one of the Continental 737s, N17356, previously had a different registration, N320AW. How do they know that, they ask themselves. After some study they find out that the registration of an aircraft can change, but that all aircraft have a unique identity, the construction number, also called manufacturers serial number. With this number it is now possible to follow the whole history of the aircraft, from roll-out to broken-up (or worse). And they also find out that this number forms the basis of all aircraft history research. Now they can find everything about an aircraft what there is to know.
Basically, I have followed this path as well, and I have never been looking back. It is the most fascinating hobby I can imagine!
Now to Airliners.net: how interesting would the site be, when we wouldn't include aircraft types at all? Quite boring I suppose. So we decide to include aircraft types. How do you know the aircraft type? By looking-up the registration somewhere. But sometimes the same registration is used on different aircraft of the same type. How do you know which is which? By looking-up the construction number, and with the help of that the history.
Look at these examples:
You see a Cargolux B747-200 with the registration LX-DCV. After looking it up in the references you find that there are two different LX-DCVs, cn 20887 and cn 21650. With the help of the cns you can verify the histories of both, and you find that 21650 carried LX-DCV from 1979 to 1987, and cn 20887 from 1991. The first is a 747-2R7F/SCD, and the second a 747-228F/SCD. You can now identify these two pictures:
Left is cn 21650, right is cn 20887.
Or these two, both are HS-125 variants, and both are YL-VIP:
Left is HS-125-700B cn 257103, right is BAe-125-800B cn 258078.
And there were eight BAe-125-800s which carried the reg N800BA. Only by finding the histories via the cns you could correctly identify this one as cn 258003:
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Photo © AirNikon
How far you go into your hobby is your own decision, as long as you have fun. I respect you all, even when you are staring the whole day at the top of your fishing-rod.
Chief Database Editor