|Quoting Simairlinenet (Thread starter):|
One field I don't understand is labeled "var tab no." Any idea what this is? It only has values for Boeing aircraft. Some examples from our 747-400s:
It's a Boeing internal number that's unique to the aircraft. Much like a serial number, except with more information on configuration. Serial numbers are assigned sequentially by orders across all models, so (as far as I know) the serial number doesn't tell you anything about the aircraft it's attached to.
Variable numbers are assigned by configuration blocks. The first letter is always model specific...747's start with "R", 737NG's with "Y", 787's with "Z", etc. The rest of the number is a group of like-configured airplanes, with the numbers going up by build sequence. So, for example, RT401-404 are all going to be virtually the same configuration (usually operator specific) and RT401 was built first, RT402 second, etc. (although almost certainly not back-to-back on the production line).
The variable number is the primary identifier used inside Boeing for aircraft.