Tango-Bravo From United States of America, joined Jun 2001, 3813 posts, RR: 26
Reply 3, posted (14 years 3 months 1 week 22 hours ago) and read 2211 times:
While most of American's 727-100s were designated 727-23, two of the later examples they received (N1964 and N1965) were listed as 727-123s. Likewise, most of Northwest's 727-100s were 727-51s although their fleet also included two 727-151Cs (N488US and N489US). Why both designators were used remains, to me, an unanswered question.
It is of interest to note that the Boeing 720 had a unique system of airline customer designators. A 720 ordered by American was a 720-023 while a fanjet 720 ordered by Northwest was a 720-051B. The 720 was only aircraft type to have a "0" preceding the Boeing customer code in the model number.
FlagshipAZ From United States of America, joined Jan 2001, 3419 posts, RR: 13
Reply 5, posted (14 years 3 months 1 week 22 hours ago) and read 2204 times:
It's basically a matter of record-keeping on Boeing's part. The older 727s will have the -0XX designation, while you can tell the newer ones by the full subtype code, such as -123. If you can find this link...
...it may explain it better than I can, alto it won't give a definite answer. Hope that helps. Regards.
"Beer is living proof that God loves us and wants us to be happy." --Ben Franklin