In the beginning, the standard registration suffix SWA desired was "SW", but lo, there came a day when the "SW" suffix was not available for a particular number. The back-up plan was "WN", using Southwest's two-letter airline code. Though rare, sometimes both "SW" and "WN" were not available for a particular number, and "SA" (Southwest Airlines) was used.
There are some exceptions to the above general rule(s):
" These -300s were formerly operated by AA
(AA inherited them from the AirCal merger), and the aircraft lessor didn't want the registration numbers on our several "AA" aircraft changed. Some lessors will, some, won't. As another example, we picked-up 3 737-200s from Midway Airlines (v1.0), and they were N702ML, N721ML, and N722ML. The lessor for N702ML said "nyet" to the change, while the a different lessor for N721ML and N722ML said OK
, and those two aircraft became N721WN and N722WN.
We have several single-use suffixes that are named after company officiers, such as "HK" for Herb, "CB
" for Colleen, "JW
" for Jim Wimberly, "GB
" for Gary Barron, and "RR" for Ron Ricks. For maintenance, we also have "QC" for quality control, and "WR" and "JC" to honor a couple of PHX
mechanics who died in a light airplane crash.
0-130, 702, 721, 722: Used to be used by the -200s, all retired. The 702, 721, and 722 numbers won't be re-used for the -700s.
The -300s started with (naturally) N300SW, and when we ran out of those, we used 600-series numbers.
The -500s run from 500-528, although there are only 25 in the fleet, i.e. a couple of numbers were skipped.
The -700s started (and filled-up) the 700-series, as did the 400-series, and we're up to N224WN (the just-delivered "Slam Dunk One) in the 200-series.
We also have numbers reserved in the 800-series and 900-series. After that, my guess is that we'd go to the 100-series, and then the 300-series and 500-series once those aircraft started retiring. N300SW is 21 years old now, so my guess is we'll start seeing those retire in 2006 or 2007.
[Edited 2005-11-04 22:33:32]
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.