Why does the B777-200 freighter not use the letters I, N, O and Q for deck positions? The B777-200 Freighter has positions on the main deck to describe how the cargo will be loaded in a left to right sequence. They are identified as A, B, C, D, E, F, G, H, J, K, L, M, P and R.

What is the reason that the letters I, N, O, and Q are omitted?
Those letters are commonly unused in aviation in markings, registrations etc. They might be easily confused with similar letters (I with J, N with M) and are therefore left out.