ENTRY GRAMMAR, FIELD SEMANTICS AND DISPLAY CONVENTIONS
The scratchpad is an editing buffer and a message display, not a second copy of the receiving field. The decisive readback is the value accepted beside the page label. Check format, units, sign, reference and combined-field order separately. These checks become particularly important when a valid number can describe the wrong quantity: a mass, a percentage, a flight level and a pressure may all be syntactically acceptable somewhere on the MCDU. [66, PDF pp. 73-83,665-674]
1. Prepare the complete intended entry. Type it, inspect the scratchpad, then select the receiving label. Use the displayed page and field rather than a remembered LSK. Combined entries use their documented separators. For a trailing item entered alone, the guide generally requires its leading slash. That does not make slash a universal separator: the documented PERF DES combined Mach/speed format uses a dash. [66, PDF pp. 73-83,665-674]
2. Distinguish data from defaults. In the cited standard, pilot entries and supplied/default values can use different font sizes; colour and prompts add further context. Read the label and value together. Small-font data is not automatically unavailable, nor does a large-font entry prove an operationally correct choice. Inspect the accepted state and the calculation it produces rather than deriving meaning from font size alone. [66, PDF pp. 73-83,665-674]
3. Use CLR for the intended job. With scratchpad text present, a short CLR removes a character; the guide describes a sustained press for clearing that text. With an empty scratchpad, CLR becomes a deletion command that can be transferred to a field. Those are substantially different operations. Before selecting a line, confirm whether you are removing a typed character, dismissing a message or deleting stored flight data. [66, PDF pp. 73-83,665-674]
4. Handle partial combined entries deliberately. A format-table example such as a leading slash for the second member is a grammar example, not a value recommendation. Inspect what remains in the untouched member after insertion. For modern Fenix ZFW/ZFWCG, 60.0/27.0 means mass then percentage; the old guide's reversed illustration is not an alternative way to enter that modern field. [66, PDF pp. 73-83,665-674]
5. Read after rejection. FORMAT ERROR points towards type, width or grammar; ENTRY OUT OF RANGE points towards an allowed range or state. Neither is resolved by clearing its text alone. Return to the receiving field, establish whether anything changed, and correct the specific cause. If another message then appears, read it independently: clearing one message can reveal the next queued item. [66, PDF pp. 73-83,665-674]