A350 Flap indicator question

The Airbus A350 flap and slat position indicator, displayed on the ECAM systems pages and referenced during approach and departure procedures, uses a series of positional markers and indexes to convey both commanded and actual surface positions simultaneously. The indexes appearing at the top of the indicator are target position markers — small symbols that move to reflect the position selected via the flap lever, distinct from the actual surface position indication shown by the moving tape or pointer below. This dual-indication architecture is consistent across the Airbus fly-by-wire family, designed so crews can immediately detect a disagree condition in which the surfaces have not reached their commanded configuration.

On the A350 specifically, the flap/slat indicator separates slat travel (left side) from flap travel (right side), with labeled gate positions corresponding to the aircraft's certified configurations: 0, 1, 1+F, 2, 3, and FULL for flaps, and corresponding slat deployments. The indexes at the top of the scale function as a "fly-to" reference — once a new flap selection is made, the index moves immediately to the target gate, and the crew monitors the actual position indication traveling toward it. A mismatch between index and actual position, particularly one that persists beyond the normal transit time, is an actionable cue that a surface has jammed, disconnected, or asymmetried, and triggers abnormal checklist procedures.

For type-rated A350 pilots, understanding the distinction between commanded and actual indications on this display is foundational to managing flap and slat abnormals — scenarios in which ECAM alerts may not always fire in advance of a visual disagree on the indicator. The design reflects Airbus philosophy of providing redundant cueing: both the alert system and the position indicator independently communicate surface state. Pilots transitioning from older Airbus variants should note that the A350's ECAM presentation has evolved in resolution and labeling clarity compared to the A320 family's SD pages, though the underlying logic remains similar.

This type of systems-level question surfaces frequently among pilots in recurrent training and type rating preparation, particularly around the flap/slat system's protection logic and the interaction between the FWC (Flight Warning Computer), SFCC (Slat Flap Control Computer), and ECAM display. A thorough understanding of what each element on the indicator represents is directly applicable during line operations when time pressure and workload in approach phases require rapid interpretation of surface state without reference to checklists or supporting documentation.