Specifically, on the form there's Item 10 Equipment and Item 18 Other Information. Item 10 has two parts: avionics and surveillance capability. What makes the codes confusing is that unlike the older domestic flight plan form that used installed equipment, the ICAO flight plan goes a step further. The codes not only could refer to installed equipment (e.g., "D" for DME), but also capability ("B" for LPV) and approvals ("W" for RVSM Approved-reduced vertical separation minima, above FL290) and at times, combinations such as "Y" for VHF with 8.33 kHz channel spacing capability. Got that?