So, for data input purposes, I've been thinking about how well seat letters can be mapped to the seat position (window, middle, aisle) on the aircraft. A few random actual seating samples:

AB-CD
ABC-DE
ABC-DEF
ABC-HJK
AB-CDE-FG
AB-DEF-HJ
AC-DFG-HK
AB-CDEFG-HJ
ABC-DEG-HJK
ABC-DEFG-HJK

With 601 plane types registered on 5770 airlines, it's obviously impossible to achieve 100% accuracy, but there do seem to be some rules that are virtually always followed. Here's what I've got so far:

A -- Always a window, period.
B -- Can be middle, aisle or even a window (eg. at the back of some Lufthansa 747s).
C -- Always an aisle?
D, E, F, G -- Can be anything, although E almost always seems to mean a middle and G an aisle...?
H -- Always an aisle?
J -- Can be middle or window.
K -- Always a window?

Any counterexamples on major carriers, or something else that I'm missing?