RUNWAY DISTANCE IS A STARTING ASSUMPTION
Begin with the runway and actual takeoff starting point. Declared distances and runway geometry are operational data; an airport name alone does not establish them. An intersection, displaced threshold or changed line-up can alter the distance relevant to a calculation. Confirm what the performance application used and compare it with the intended entry. A takeoff clearance from an unfamiliar intersection is a new preparation question. The crew must establish that the revised departure fits before accepting the instruction as a continuation of the old plan. [21, PDF pp. 215–216] [74, PDF pp. 8–9]
Keep TO SHIFT separate from remaining takeoff run available. In the supplied Thales guide, shift is the distance from runway threshold to the start-of-takeoff point, in the selected units. It is not an instruction to type the remaining runway length into that field. The source also describes its role in climb-profile computation and position updating without GPS. The professional crosscheck is dimensional as well as numerical: establish what the field measures, where its zero is and which unit is selected before comparing its value with a chart. [66, PDF pp. 125–128]
A field-length-compatible takeoff also needs the applicable climb and obstacle assessment. A departure route that looks clear on the navigation display does not itself establish engine-out obstacle clearance. Identify whether the briefed failure continuation is an engine-out procedure, the published SID or another cleared path, and what decision points distinguish them. The all-engine noise-abatement acceleration plan and the engine-out acceleration plan serve different objectives. Preserve their references and keep the required climb configuration available until the applicable procedure allows the next change. [21, PDF pp. 121–124] [21, PDF pp. 221–224]
Airbus describes takeoff surveillance as an additional safety net whose functions depend on installed standard. Its examples include gross input checks and comparison of expected lift-off distance with available distance. This guide has not established that every such manufacturer function or software standard is implemented in every Fenix configuration. Therefore, a successful T.O CONFIG test is not taken as proof that the takeoff calculation, runway identity and obstacle plan have all been independently validated by the simulation. [125, Takeoff-surveillance functions, input checks and runway-distance comparison]
Before runway entry, be able to identify the runway, entry point, accepted calculation and initial/failure flight paths without searching through several unrelated pages. If line-up geometry changes, revisit the assumption before movement commits the aircraft to it. A useful simulator variation is to prepare a full-length departure, receive an intersection change while stopped, and work through the consequences aloud. The criterion for completion is an explained revised plan, not merely another set of numbers accepted by the MCDU. [21, PDF pp. 215–216] [74, PDF pp. 8–9]