Serial Numbers
 

I noticed today on a flight from ORD to PHL, that the United planes have a four numbers along their lower body below the tail. These numbers don't match the registration number. Does anyoone know what these numbers represent?

They are basically an internal inventory number used by United. The first two numbers denote the configuration of the aircraft, e.g., there are at least three configurations of 777s.

a/k/a the nose number, you can derive an N number from it, e.g. 8193 = N193UA (for example). http://www.flyertalk.com/forum/smile.gif

Internally we don't use the registration number; everything is done using nose number for maintenance/flight operations.

The nose number is the most important number on your plane (apart from your seat number, unless it's 44E http://www.flyertalk.com/forum/smile.gif ). It shows you the configuration of your bird before you get on board....

For example, wanna know if that ratty 737 sitting at the gate is an ex-sh*ttle plane? (thank god, this will soon be history!), look for:

737-300's: 10xx, 13xx
737-500's: 97xx

And yes, the 777's have multiple configurations:

23xx - 777A, 3 class
25xx - 777A, 2 class
26xx - 777B, 3 class, C+, Y+ (10F)
27xx - 777B, 3 class, C+ (12F)
28xx - 777B, 3 class, C+, (10F)
29xx - 777B, 3 class, C+, Y+ (12F)

etc etc

http://www.flyertalk.com/forum/smile.gif

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RichardMEL, UA 1K
A Star Alliance Member.

So does United change the nose number of a plane if it gets reconfigured? What happens if 28xx goes into the shop and they reconfigure it for E+ (let's just say they wanted to add E+ to more of the fleet)... will it be renumbered 26xx? Or do the nose numbers lose their meaning over time?

Yep. The nose number changes when the configuration of the aircraft changes.

Is there anyway to figure out the nose number before you even get to the airport?

Make a friend who works at UA. http://www.flyertalk.com/forum/biggrin.gif

So, is this 8193 the callsign that would be used on the domestic segment of a flight that uses the same flight number but different equipment on an international segment?

No - the nose number will have no relation to the radio callsign. The radio callsign is usually a variation of the original flight number (but certainly not always), depending on the range of numbers available.

apollo shows planned routings for aircraft so yes, a UA person could tell you. Of course it's subject to changes on day of departure, mechanicals and the like, and I'd only trust what apollo said a few days out. UA angels are the best http://www.flyertalk.com/forum/biggrin.gif

Of course, I tried asking a gate agent at LAX once the nose/fleet number of our aircraft (it was too dark to see out the window!). They had no idea what I was talking about. Asked a colleague who tapped away and said "777" - thanks, for that! LOL.

OK, who has a special nose number/aircraft that they like to be on for one reason or another? for me, it's 2066 (now 2366)....


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RichardMEL, UA 1K
A Star Alliance Member.